text: /* Amalgamated source file */
  #include "upb.h"
  /*
  * This is where we define macros used across upb.
  *
  * All of these macros are undef'd in port_undef.inc to avoid leaking them to
  * users.
  *
  * The correct usage is:
  *
  *   #include "upb/foobar.h"
  *   #include "upb/baz.h"
  *
  *   // MUST be last included header.
  *   #include "upb/port_def.inc"
  *
  *   // Code for this file.
  *   // <...>
  *
  *   // Can be omitted for .c files, required for .h.
  *   #include "upb/port_undef.inc"
  *
  * This file is private and must not be included by users!
  */
  #ifndef UINTPTR_MAX
  #error must include stdint.h first
  #endif
  
  #if UINTPTR_MAX == 0xffffffff
  #define UPB_SIZE(size32, size64) size32
  #else
  #define UPB_SIZE(size32, size64) size64
  #endif
  
  #define UPB_FIELD_AT(msg, fieldtype, offset) \
    *(fieldtype*)((const char*)(msg) + offset)
  
  #define UPB_READ_ONEOF(msg, fieldtype, offset, case_offset, case_val, default) \
    UPB_FIELD_AT(msg, int, case_offset) == case_val                              \
        ? UPB_FIELD_AT(msg, fieldtype, offset)                                   \
        : default
  
  #define UPB_WRITE_ONEOF(msg, fieldtype, offset, value, case_offset, case_val) \
    UPB_FIELD_AT(msg, int, case_offset) = case_val;                             \
    UPB_FIELD_AT(msg, fieldtype, offset) = value;
  
  /* UPB_INLINE: inline if possible, emit standalone code if required. */
  #ifdef __cplusplus
  #define UPB_INLINE inline
  #elif defined (__GNUC__) || defined(__clang__)
  #define UPB_INLINE static __inline__
  #else
  #define UPB_INLINE static
  #endif
  
  /* Hints to the compiler about likely/unlikely branches. */
  #if defined (__GNUC__) || defined(__clang__)
  #define UPB_LIKELY(x) __builtin_expect((x),1)
  #define UPB_UNLIKELY(x) __builtin_expect((x),0)
  #else
  #define UPB_LIKELY(x) (x)
  #define UPB_UNLIKELY(x) (x)
  #endif
  
  /* Define UPB_BIG_ENDIAN manually if you're on big endian and your compiler
   * doesn't provide these preprocessor symbols. */
  #if defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
  #define UPB_BIG_ENDIAN
  #endif
  
  /* Macros for function attributes on compilers that support them. */
  #ifdef __GNUC__
  #define UPB_FORCEINLINE __inline__ __attribute__((always_inline))
  #define UPB_NOINLINE __attribute__((noinline))
  #define UPB_NORETURN __attribute__((__noreturn__))
  #else  /* !defined(__GNUC__) */
  #define UPB_FORCEINLINE
  #define UPB_NOINLINE
  #define UPB_NORETURN
  #endif
  
  #if __STDC_VERSION__ >= 199901L || __cplusplus >= 201103L
  /* C99/C++11 versions. */
  #include <stdio.h>
  #define _upb_snprintf snprintf
  #define _upb_vsnprintf vsnprintf
  #define _upb_va_copy(a, b) va_copy(a, b)
  #elif defined(_MSC_VER)
  /* Microsoft C/C++ versions. */
  #include <stdarg.h>
  #include <stdio.h>
  #if _MSC_VER < 1900
  int msvc_snprintf(char* s, size_t n, const char* format, ...);
  int msvc_vsnprintf(char* s, size_t n, const char* format, va_list arg);
  #define UPB_MSVC_VSNPRINTF
  #define _upb_snprintf msvc_snprintf
  #define _upb_vsnprintf msvc_vsnprintf
  #else
  #define _upb_snprintf snprintf
  #define _upb_vsnprintf vsnprintf
  #endif
  #define _upb_va_copy(a, b) va_copy(a, b)
  #elif defined __GNUC__
  /* A few hacky workarounds for functions not in C89.
   * For internal use only!
   * TODO(haberman): fix these by including our own implementations, or finding
   * another workaround.
   */
  #define _upb_snprintf __builtin_snprintf
  #define _upb_vsnprintf __builtin_vsnprintf
  #define _upb_va_copy(a, b) __va_copy(a, b)
  #else
  #error Need implementations of [v]snprintf and va_copy
  #endif
  
  #ifdef __cplusplus
  #if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__) || \
      (defined(_MSC_VER) && _MSC_VER >= 1900)
  // C++11 is present
  #else
  #error upb requires C++11 for C++ support
  #endif
  #endif
  
  #define UPB_MAX(x, y) ((x) > (y) ? (x) : (y))
  #define UPB_MIN(x, y) ((x) < (y) ? (x) : (y))
  
  #define UPB_UNUSED(var) (void)var
  
  /* UPB_ASSERT(): in release mode, we use the expression without letting it be
   * evaluated.  This prevents "unused variable" warnings. */
  #ifdef NDEBUG
  #define UPB_ASSERT(expr) do {} while (false && (expr))
  #else
  #define UPB_ASSERT(expr) assert(expr)
  #endif
  
  /* UPB_ASSERT_DEBUGVAR(): assert that uses functions or variables that only
   * exist in debug mode.  This turns into regular assert. */
  #define UPB_ASSERT_DEBUGVAR(expr) assert(expr)
  
  #if defined(__GNUC__) || defined(__clang__)
  #define UPB_UNREACHABLE() do { assert(0); __builtin_unreachable(); } while(0)
  #else
  #define UPB_UNREACHABLE() do { assert(0); } while(0)
  #endif
  
  /* UPB_INFINITY representing floating-point positive infinity. */
  #include <math.h>
  #ifdef INFINITY
  #define UPB_INFINITY INFINITY
  #else
  #define UPB_INFINITY (1.0 / 0.0)
  #endif
  
  #include <string.h>
  
  
  /* Maps descriptor type -> upb field type.  */
  const uint8_t upb_desctype_to_fieldtype[] = {
    UPB_WIRE_TYPE_END_GROUP,  /* ENDGROUP */
    UPB_TYPE_DOUBLE,          /* DOUBLE */
    UPB_TYPE_FLOAT,           /* FLOAT */
    UPB_TYPE_INT64,           /* INT64 */
    UPB_TYPE_UINT64,          /* UINT64 */
    UPB_TYPE_INT32,           /* INT32 */
    UPB_TYPE_UINT64,          /* FIXED64 */
    UPB_TYPE_UINT32,          /* FIXED32 */
    UPB_TYPE_BOOL,            /* BOOL */
    UPB_TYPE_STRING,          /* STRING */
    UPB_TYPE_MESSAGE,         /* GROUP */
    UPB_TYPE_MESSAGE,         /* MESSAGE */
    UPB_TYPE_BYTES,           /* BYTES */
    UPB_TYPE_UINT32,          /* UINT32 */
    UPB_TYPE_ENUM,            /* ENUM */
    UPB_TYPE_INT32,           /* SFIXED32 */
    UPB_TYPE_INT64,           /* SFIXED64 */
    UPB_TYPE_INT32,           /* SINT32 */
    UPB_TYPE_INT64,           /* SINT64 */
  };
  
  /* Data pertaining to the parse. */
  typedef struct {
    const char *ptr;           /* Current parsing position. */
    const char *field_start;   /* Start of this field. */
    const char *limit;         /* End of delimited region or end of buffer. */
    upb_arena *arena;
    int depth;
    uint32_t end_group;  /* Set to field number of END_GROUP tag, if any. */
  } upb_decstate;
  
  /* Data passed by value to each parsing function. */
  typedef struct {
    char *msg;
    const upb_msglayout *layout;
    upb_decstate *state;
  } upb_decframe;
  
  #define CHK(x) if (!(x)) { return 0; }
  
  static bool upb_skip_unknowngroup(upb_decstate *d, int field_number);
  static bool upb_decode_message(upb_decstate *d, char *msg,
                                 const upb_msglayout *l);
  
  static bool upb_decode_varint(const char **ptr, const char *limit,
                                uint64_t *val) {
    uint8_t byte;
    int bitpos = 0;
    const char *p = *ptr;
    *val = 0;
  
    do {
      CHK(bitpos < 70 && p < limit);
      byte = *p;
      *val |= (uint64_t)(byte & 0x7F) << bitpos;
      p++;
      bitpos += 7;
    } while (byte & 0x80);
  
    *ptr = p;
    return true;
  }
  
  static bool upb_decode_varint32(const char **ptr, const char *limit,
                                  uint32_t *val) {
    uint64_t u64;
    CHK(upb_decode_varint(ptr, limit, &u64) && u64 <= UINT32_MAX);
    *val = (uint32_t)u64;
    return true;
  }
  
  static bool upb_decode_64bit(const char **ptr, const char *limit,
                               uint64_t *val) {
    CHK(limit - *ptr >= 8);
    memcpy(val, *ptr, 8);
    *ptr += 8;
    return true;
  }
  
  static bool upb_decode_32bit(const char **ptr, const char *limit,
                               uint32_t *val) {
    CHK(limit - *ptr >= 4);
    memcpy(val, *ptr, 4);
    *ptr += 4;
    return true;
  }
  
  static int32_t upb_zzdecode_32(uint32_t n) {
    return (n >> 1) ^ -(int32_t)(n & 1);
  }
  
  static int64_t upb_zzdecode_64(uint64_t n) {
    return (n >> 1) ^ -(int64_t)(n & 1);
  }
  
  static bool upb_decode_string(const char **ptr, const char *limit,
                                int *outlen) {
    uint32_t len;
  
    CHK(upb_decode_varint32(ptr, limit, &len) &&
        len < INT32_MAX &&
        limit - *ptr >= (int32_t)len);
  
    *outlen = len;
    return true;
  }
  
  static void upb_set32(void *msg, size_t ofs, uint32_t val) {
    memcpy((char*)msg + ofs, &val, sizeof(val));
  }
  
  static bool upb_append_unknown(upb_decstate *d, upb_decframe *frame) {
    upb_msg_addunknown(frame->msg, d->field_start, d->ptr - d->field_start,
                       d->arena);
    return true;
  }
  
  
  static bool upb_skip_unknownfielddata(upb_decstate *d, uint32_t tag,
                                        uint32_t group_fieldnum) {
    switch (tag & 7) {
      case UPB_WIRE_TYPE_VARINT: {
        uint64_t val;
        return upb_decode_varint(&d->ptr, d->limit, &val);
      }
      case UPB_WIRE_TYPE_32BIT: {
        uint32_t val;
        return upb_decode_32bit(&d->ptr, d->limit, &val);
      }
      case UPB_WIRE_TYPE_64BIT: {
        uint64_t val;
        return upb_decode_64bit(&d->ptr, d->limit, &val);
      }
      case UPB_WIRE_TYPE_DELIMITED: {
        int len;
        CHK(upb_decode_string(&d->ptr, d->limit, &len));
        d->ptr += len;
        return true;
      }
      case UPB_WIRE_TYPE_START_GROUP:
        return upb_skip_unknowngroup(d, tag >> 3);
      case UPB_WIRE_TYPE_END_GROUP:
        return (tag >> 3) == group_fieldnum;
    }
    return false;
  }
  
  static bool upb_skip_unknowngroup(upb_decstate *d, int field_number) {
    while (d->ptr < d->limit && d->end_group == 0) {
      uint32_t tag = 0;
      CHK(upb_decode_varint32(&d->ptr, d->limit, &tag));
      CHK(upb_skip_unknownfielddata(d, tag, field_number));
    }
  
    CHK(d->end_group == field_number);
    d->end_group = 0;
    return true;
  }
  
  static bool upb_array_grow(upb_array *arr, size_t elements, size_t elem_size,
                             upb_arena *arena) {
    size_t needed = arr->len + elements;
    size_t new_size = UPB_MAX(arr->size, 8);
    size_t new_bytes;
    size_t old_bytes;
    void *new_data;
    upb_alloc *alloc = upb_arena_alloc(arena);
  
    while (new_size < needed) {
      new_size *= 2;
    }
  
    old_bytes = arr->len * elem_size;
    new_bytes = new_size * elem_size;
    new_data = upb_realloc(alloc, arr->data, old_bytes, new_bytes);
    CHK(new_data);
  
    arr->data = new_data;
    arr->size = new_size;
    return true;
  }
  
  static void *upb_array_reserve(upb_array *arr, size_t elements,
                                 size_t elem_size, upb_arena *arena) {
    if (arr->size - arr->len < elements) {
      CHK(upb_array_grow(arr, elements, elem_size, arena));
    }
    return (char*)arr->data + (arr->len * elem_size);
  }
  
  bool upb_array_add(upb_array *arr, size_t elements, size_t elem_size,
                     const void *data, upb_arena *arena) {
    void *dest = upb_array_reserve(arr, elements, elem_size, arena);
  
    CHK(dest);
    arr->len += elements;
    memcpy(dest, data, elements * elem_size);
  
    return true;
  }
  
  static upb_array *upb_getarr(upb_decframe *frame,
                               const upb_msglayout_field *field) {
    UPB_ASSERT(field->label == UPB_LABEL_REPEATED);
    return *(upb_array**)&frame->msg[field->offset];
  }
  
  static upb_array *upb_getorcreatearr(upb_decframe *frame,
                                       const upb_msglayout_field *field) {
    upb_array *arr = upb_getarr(frame, field);
  
    if (!arr) {
      arr = upb_array_new(frame->state->arena);
      CHK(arr);
      *(upb_array**)&frame->msg[field->offset] = arr;
    }
  
    return arr;
  }
  
  static upb_msg *upb_getorcreatemsg(upb_decframe *frame,
                                     const upb_msglayout_field *field,
                                     const upb_msglayout **subm) {
    upb_msg **submsg = (void*)(frame->msg + field->offset);
    *subm = frame->layout->submsgs[field->submsg_index];
  
    UPB_ASSERT(field->label != UPB_LABEL_REPEATED);
  
    if (!*submsg) {
      *submsg = upb_msg_new(*subm, frame->state->arena);
      CHK(*submsg);
    }
  
    return *submsg;
  }
  
  static upb_msg *upb_addmsg(upb_decframe *frame,
                             const upb_msglayout_field *field,
                             const upb_msglayout **subm) {
    upb_msg *submsg;
    upb_array *arr = upb_getorcreatearr(frame, field);
  
    *subm = frame->layout->submsgs[field->submsg_index];
    submsg = upb_msg_new(*subm, frame->state->arena);
    CHK(submsg);
    upb_array_add(arr, 1, sizeof(submsg), &submsg, frame->state->arena);
  
    return submsg;
  }
  
  static void upb_sethasbit(upb_decframe *frame,
                            const upb_msglayout_field *field) {
    int32_t hasbit = field->presence;
    UPB_ASSERT(field->presence > 0);
    frame->msg[hasbit / 8] |= (1 << (hasbit % 8));
  }
  
  static void upb_setoneofcase(upb_decframe *frame,
                               const upb_msglayout_field *field) {
    UPB_ASSERT(field->presence < 0);
    upb_set32(frame->msg, ~field->presence, field->number);
  }
  
  static bool upb_decode_addval(upb_decframe *frame,
                                 const upb_msglayout_field *field, void *val,
                                 size_t size) {
    char *field_mem = frame->msg + field->offset;
    upb_array *arr;
  
    if (field->label == UPB_LABEL_REPEATED) {
      arr = upb_getorcreatearr(frame, field);
      CHK(arr);
      field_mem = upb_array_reserve(arr, 1, size, frame->state->arena);
      CHK(field_mem);
    }
  
    memcpy(field_mem, val, size);
    return true;
  }
  
  static void upb_decode_setpresent(upb_decframe *frame,
                                    const upb_msglayout_field *field) {
    if (field->label == UPB_LABEL_REPEATED) {
     upb_array *arr = upb_getarr(frame, field);
     UPB_ASSERT(arr->len < arr->size);
     arr->len++;
    } else if (field->presence < 0) {
      upb_setoneofcase(frame, field);
    } else if (field->presence > 0) {
      upb_sethasbit(frame, field);
    }
  }
  
  static bool upb_decode_msgfield(upb_decstate *d, upb_msg *msg,
                                  const upb_msglayout *layout, int limit) {
    const char* saved_limit = d->limit;
    d->limit = d->ptr + limit;
    CHK(--d->depth >= 0);
    upb_decode_message(d, msg, layout);
    d->depth++;
    d->limit = saved_limit;
    CHK(d->end_group == 0);
    return true;
  }
  
  static bool upb_decode_groupfield(upb_decstate *d, upb_msg *msg,
                                    const upb_msglayout *layout,
                                    int field_number) {
    CHK(--d->depth >= 0);
    upb_decode_message(d, msg, layout);
    d->depth++;
    CHK(d->end_group == field_number);
    d->end_group = 0;
    return true;
  }
  
  static bool upb_decode_varintfield(upb_decstate *d, upb_decframe *frame,
                                     const upb_msglayout_field *field) {
    uint64_t val;
    CHK(upb_decode_varint(&d->ptr, d->limit, &val));
  
    switch (field->descriptortype) {
      case UPB_DESCRIPTOR_TYPE_INT64:
      case UPB_DESCRIPTOR_TYPE_UINT64:
        CHK(upb_decode_addval(frame, field, &val, sizeof(val)));
        break;
      case UPB_DESCRIPTOR_TYPE_INT32:
      case UPB_DESCRIPTOR_TYPE_UINT32:
      case UPB_DESCRIPTOR_TYPE_ENUM: {
        uint32_t val32 = (uint32_t)val;
        CHK(upb_decode_addval(frame, field, &val32, sizeof(val32)));
        break;
      }
      case UPB_DESCRIPTOR_TYPE_BOOL: {
        bool valbool = val != 0;
        CHK(upb_decode_addval(frame, field, &valbool, sizeof(valbool)));
        break;
      }
      case UPB_DESCRIPTOR_TYPE_SINT32: {
        int32_t decoded = upb_zzdecode_32((uint32_t)val);
        CHK(upb_decode_addval(frame, field, &decoded, sizeof(decoded)));
        break;
      }
      case UPB_DESCRIPTOR_TYPE_SINT64: {
        int64_t decoded = upb_zzdecode_64(val);
        CHK(upb_decode_addval(frame, field, &decoded, sizeof(decoded)));
        break;
      }
      default:
        return upb_append_unknown(d, frame);
    }
  
    upb_decode_setpresent(frame, field);
    return true;
  }
  
  static bool upb_decode_64bitfield(upb_decstate *d, upb_decframe *frame,
                                    const upb_msglayout_field *field) {
    uint64_t val;
    CHK(upb_decode_64bit(&d->ptr, d->limit, &val));
  
    switch (field->descriptortype) {
      case UPB_DESCRIPTOR_TYPE_DOUBLE:
      case UPB_DESCRIPTOR_TYPE_FIXED64:
      case UPB_DESCRIPTOR_TYPE_SFIXED64:
        CHK(upb_decode_addval(frame, field, &val, sizeof(val)));
        break;
      default:
        return upb_append_unknown(d, frame);
    }
  
    upb_decode_setpresent(frame, field);
    return true;
  }
  
  static bool upb_decode_32bitfield(upb_decstate *d, upb_decframe *frame,
                                    const upb_msglayout_field *field) {
    uint32_t val;
    CHK(upb_decode_32bit(&d->ptr, d->limit, &val));
  
    switch (field->descriptortype) {
      case UPB_DESCRIPTOR_TYPE_FLOAT:
      case UPB_DESCRIPTOR_TYPE_FIXED32:
      case UPB_DESCRIPTOR_TYPE_SFIXED32:
        CHK(upb_decode_addval(frame, field, &val, sizeof(val)));
        break;
      default:
        return upb_append_unknown(d, frame);
    }
  
    upb_decode_setpresent(frame, field);
    return true;
  }
  
  static bool upb_decode_fixedpacked(upb_decstate *d, upb_array *arr,
                                     uint32_t len, int elem_size) {
    size_t elements = len / elem_size;
  
    CHK((size_t)(elements * elem_size) == len);
    CHK(upb_array_add(arr, elements, elem_size, d->ptr, d->arena));
    d->ptr += len;
  
    return true;
  }
  
  static upb_strview upb_decode_strfield(upb_decstate *d, uint32_t len) {
    upb_strview ret;
    ret.data = d->ptr;
    ret.size = len;
    d->ptr += len;
    return ret;
  }
  
  static bool upb_decode_toarray(upb_decstate *d, upb_decframe *frame,
                                 const upb_msglayout_field *field, int len) {
    upb_array *arr = upb_getorcreatearr(frame, field);
    CHK(arr);
  
  #define VARINT_CASE(ctype, decode) \
    VARINT_CASE_EX(ctype, decode, decode)
  
  #define VARINT_CASE_EX(ctype, decode, dtype)                           \
    {                                                                    \
      const char *ptr = d->ptr;                                          \
      const char *limit = ptr + len;                                     \
      while (ptr < limit) {                                              \
        uint64_t val;                                                    \
        ctype decoded;                                                   \
        CHK(upb_decode_varint(&ptr, limit, &val));                       \
        decoded = (decode)((dtype)val);                                  \
        CHK(upb_array_add(arr, 1, sizeof(decoded), &decoded, d->arena)); \
      }                                                                  \
      d->ptr = ptr;                                                      \
      return true;                                                       \
    }
  
    switch (field->descriptortype) {
      case UPB_DESCRIPTOR_TYPE_STRING:
      case UPB_DESCRIPTOR_TYPE_BYTES: {
        upb_strview str = upb_decode_strfield(d, len);
        return upb_array_add(arr, 1, sizeof(str), &str, d->arena);
      }
      case UPB_DESCRIPTOR_TYPE_FLOAT:
      case UPB_DESCRIPTOR_TYPE_FIXED32:
      case UPB_DESCRIPTOR_TYPE_SFIXED32:
        return upb_decode_fixedpacked(d, arr, len, sizeof(int32_t));
      case UPB_DESCRIPTOR_TYPE_DOUBLE:
      case UPB_DESCRIPTOR_TYPE_FIXED64:
      case UPB_DESCRIPTOR_TYPE_SFIXED64:
        return upb_decode_fixedpacked(d, arr, len, sizeof(int64_t));
      case UPB_DESCRIPTOR_TYPE_INT32:
      case UPB_DESCRIPTOR_TYPE_UINT32:
      case UPB_DESCRIPTOR_TYPE_ENUM:
        VARINT_CASE(uint32_t, uint32_t);
      case UPB_DESCRIPTOR_TYPE_INT64:
      case UPB_DESCRIPTOR_TYPE_UINT64:
        VARINT_CASE(uint64_t, uint64_t);
      case UPB_DESCRIPTOR_TYPE_BOOL:
        VARINT_CASE(bool, bool);
      case UPB_DESCRIPTOR_TYPE_SINT32:
        VARINT_CASE_EX(int32_t, upb_zzdecode_32, uint32_t);
      case UPB_DESCRIPTOR_TYPE_SINT64:
        VARINT_CASE_EX(int64_t, upb_zzdecode_64, uint64_t);
      case UPB_DESCRIPTOR_TYPE_MESSAGE: {
        const upb_msglayout *subm;
        upb_msg *submsg = upb_addmsg(frame, field, &subm);
        CHK(submsg);
        return upb_decode_msgfield(d, submsg, subm, len);
      }
      case UPB_DESCRIPTOR_TYPE_GROUP:
        return upb_append_unknown(d, frame);
    }
  #undef VARINT_CASE
    UPB_UNREACHABLE();
  }
  
  static bool upb_decode_delimitedfield(upb_decstate *d, upb_decframe *frame,
                                        const upb_msglayout_field *field) {
    int len;
  
    CHK(upb_decode_string(&d->ptr, d->limit, &len));
  
    if (field->label == UPB_LABEL_REPEATED) {
      return upb_decode_toarray(d, frame, field, len);
    } else {
      switch (field->descriptortype) {
        case UPB_DESCRIPTOR_TYPE_STRING:
        case UPB_DESCRIPTOR_TYPE_BYTES: {
          upb_strview str = upb_decode_strfield(d, len);
          CHK(upb_decode_addval(frame, field, &str, sizeof(str)));
          break;
        }
        case UPB_DESCRIPTOR_TYPE_MESSAGE: {
          const upb_msglayout *subm;
          upb_msg *submsg = upb_getorcreatemsg(frame, field, &subm);
          CHK(submsg);
          CHK(upb_decode_msgfield(d, submsg, subm, len));
          break;
        }
        default:
          /* TODO(haberman): should we accept the last element of a packed? */
          d->ptr += len;
          return upb_append_unknown(d, frame);
      }
      upb_decode_setpresent(frame, field);
      return true;
    }
  }
  
  static const upb_msglayout_field *upb_find_field(const upb_msglayout *l,
                                                   uint32_t field_number) {
    /* Lots of optimization opportunities here. */
    int i;
    for (i = 0; i < l->field_count; i++) {
      if (l->fields[i].number == field_number) {
        return &l->fields[i];
      }
    }
  
    return NULL;  /* Unknown field. */
  }
  
  static bool upb_decode_field(upb_decstate *d, upb_decframe *frame) {
    uint32_t tag;
    const upb_msglayout_field *field;
    int field_number;
  
    d->field_start = d->ptr;
    CHK(upb_decode_varint32(&d->ptr, d->limit, &tag));
    field_number = tag >> 3;
    field = upb_find_field(frame->layout, field_number);
  
    if (field) {
      switch (tag & 7) {
        case UPB_WIRE_TYPE_VARINT:
          return upb_decode_varintfield(d, frame, field);
        case UPB_WIRE_TYPE_32BIT:
          return upb_decode_32bitfield(d, frame, field);
        case UPB_WIRE_TYPE_64BIT:
          return upb_decode_64bitfield(d, frame, field);
        case UPB_WIRE_TYPE_DELIMITED:
          return upb_decode_delimitedfield(d, frame, field);
        case UPB_WIRE_TYPE_START_GROUP: {
          const upb_msglayout *layout;
          upb_msg *group;
  
          if (field->label == UPB_LABEL_REPEATED) {
            group = upb_addmsg(frame, field, &layout);
          } else {
            group = upb_getorcreatemsg(frame, field, &layout);
          }
  
          return upb_decode_groupfield(d, group, layout, field_number);
        }
        case UPB_WIRE_TYPE_END_GROUP:
          d->end_group = field_number;
          return true;
        default:
          CHK(false);
      }
    } else {
      CHK(field_number != 0);
      CHK(upb_skip_unknownfielddata(d, tag, -1));
      CHK(upb_append_unknown(d, frame));
      return true;
    }
  }
  
  static bool upb_decode_message(upb_decstate *d, char *msg, const upb_msglayout *l) {
    upb_decframe frame;
    frame.msg = msg;
    frame.layout = l;
    frame.state = d;
  
    while (d->ptr < d->limit) {
      CHK(upb_decode_field(d, &frame));
    }
  
    return true;
  }
  
  bool upb_decode(const char *buf, size_t size, void *msg, const upb_msglayout *l,
                  upb_arena *arena) {
    upb_decstate state;
    state.ptr = buf;
    state.limit = buf + size;
    state.arena = arena;
    state.depth = 64;
    state.end_group = 0;
  
    CHK(upb_decode_message(&state, msg, l));
    return state.end_group == 0;
  }
  
  #undef CHK
  /* We encode backwards, to avoid pre-computing lengths (one-pass encode). */
  
  
  #include <string.h>
  
  
  
  #define UPB_PB_VARINT_MAX_LEN 10
  #define CHK(x) do { if (!(x)) { return false; } } while(0)
  
  static size_t upb_encode_varint(uint64_t val, char *buf) {
    size_t i;
    if (val < 128) { buf[0] = val; return 1; }
    i = 0;
    while (val) {
      uint8_t byte = val & 0x7fU;
      val >>= 7;
      if (val) byte |= 0x80U;
      buf[i++] = byte;
    }
    return i;
  }
  
  static uint32_t upb_zzencode_32(int32_t n) { return ((uint32_t)n << 1) ^ (n >> 31); }
  static uint64_t upb_zzencode_64(int64_t n) { return ((uint64_t)n << 1) ^ (n >> 63); }
  
  typedef struct {
    upb_alloc *alloc;
    char *buf, *ptr, *limit;
  } upb_encstate;
  
  static size_t upb_roundup_pow2(size_t bytes) {
    size_t ret = 128;
    while (ret < bytes) {
      ret *= 2;
    }
    return ret;
  }
  
  static bool upb_encode_growbuffer(upb_encstate *e, size_t bytes) {
    size_t old_size = e->limit - e->buf;
    size_t new_size = upb_roundup_pow2(bytes + (e->limit - e->ptr));
    char *new_buf = upb_realloc(e->alloc, e->buf, old_size, new_size);
    CHK(new_buf);
  
    /* We want previous data at the end, realloc() put it at the beginning. */
    if (old_size > 0) {
      memmove(new_buf + new_size - old_size, e->buf, old_size);
    }
  
    e->ptr = new_buf + new_size - (e->limit - e->ptr);
    e->limit = new_buf + new_size;
    e->buf = new_buf;
    return true;
  }
  
  /* Call to ensure that at least "bytes" bytes are available for writing at
   * e->ptr.  Returns false if the bytes could not be allocated. */
  static bool upb_encode_reserve(upb_encstate *e, size_t bytes) {
    CHK(UPB_LIKELY((size_t)(e->ptr - e->buf) >= bytes) ||
        upb_encode_growbuffer(e, bytes));
  
    e->ptr -= bytes;
    return true;
  }
  
  /* Writes the given bytes to the buffer, handling reserve/advance. */
  static bool upb_put_bytes(upb_encstate *e, const void *data, size_t len) {
    CHK(upb_encode_reserve(e, len));
    memcpy(e->ptr, data, len);
    return true;
  }
  
  static bool upb_put_fixed64(upb_encstate *e, uint64_t val) {
    /* TODO(haberman): byte-swap for big endian. */
    return upb_put_bytes(e, &val, sizeof(uint64_t));
  }
  
  static bool upb_put_fixed32(upb_encstate *e, uint32_t val) {
    /* TODO(haberman): byte-swap for big endian. */
    return upb_put_bytes(e, &val, sizeof(uint32_t));
  }
  
  static bool upb_put_varint(upb_encstate *e, uint64_t val) {
    size_t len;
    char *start;
    CHK(upb_encode_reserve(e, UPB_PB_VARINT_MAX_LEN));
    len = upb_encode_varint(val, e->ptr);
    start = e->ptr + UPB_PB_VARINT_MAX_LEN - len;
    memmove(start, e->ptr, len);
    e->ptr = start;
    return true;
  }
  
  static bool upb_put_double(upb_encstate *e, double d) {
    uint64_t u64;
    UPB_ASSERT(sizeof(double) == sizeof(uint64_t));
    memcpy(&u64, &d, sizeof(uint64_t));
    return upb_put_fixed64(e, u64);
  }
  
  static bool upb_put_float(upb_encstate *e, float d) {
    uint32_t u32;
    UPB_ASSERT(sizeof(float) == sizeof(uint32_t));
    memcpy(&u32, &d, sizeof(uint32_t));
    return upb_put_fixed32(e, u32);
  }
  
  static uint32_t upb_readcase(const char *msg, const upb_msglayout_field *f) {
    uint32_t ret;
    uint32_t offset = ~f->presence;
    memcpy(&ret, msg + offset, sizeof(ret));
    return ret;
  }
  
  static bool upb_readhasbit(const char *msg, const upb_msglayout_field *f) {
    uint32_t hasbit = f->presence;
    UPB_ASSERT(f->presence > 0);
    return msg[hasbit / 8] & (1 << (hasbit % 8));
  }
  
  static bool upb_put_tag(upb_encstate *e, int field_number, int wire_type) {
    return upb_put_varint(e, (field_number << 3) | wire_type);
  }
  
  static bool upb_put_fixedarray(upb_encstate *e, const upb_array *arr,
                                 size_t size) {
    size_t bytes = arr->len * size;
    return upb_put_bytes(e, arr->data, bytes) && upb_put_varint(e, bytes);
  }
  
  bool upb_encode_message(upb_encstate *e, const char *msg,
                          const upb_msglayout *m, size_t *size);
  
  static bool upb_encode_array(upb_encstate *e, const char *field_mem,
                               const upb_msglayout *m,
                               const upb_msglayout_field *f) {
    const upb_array *arr = *(const upb_array**)field_mem;
  
    if (arr == NULL || arr->len == 0) {
      return true;
    }
  
  #define VARINT_CASE(ctype, encode) { \
    ctype *start = arr->data; \
    ctype *ptr = start + arr->len; \
    size_t pre_len = e->limit - e->ptr; \
    do { \
      ptr--; \
      CHK(upb_put_varint(e, encode)); \
    } while (ptr != start); \
    CHK(upb_put_varint(e, e->limit - e->ptr - pre_len)); \
  } \
  break; \
  do { ; } while(0)
  
    switch (f->descriptortype) {
      case UPB_DESCRIPTOR_TYPE_DOUBLE:
        CHK(upb_put_fixedarray(e, arr, sizeof(double)));
        break;
      case UPB_DESCRIPTOR_TYPE_FLOAT:
        CHK(upb_put_fixedarray(e, arr, sizeof(float)));
        break;
      case UPB_DESCRIPTOR_TYPE_SFIXED64:
      case UPB_DESCRIPTOR_TYPE_FIXED64:
        CHK(upb_put_fixedarray(e, arr, sizeof(uint64_t)));
        break;
      case UPB_DESCRIPTOR_TYPE_FIXED32:
      case UPB_DESCRIPTOR_TYPE_SFIXED32:
        CHK(upb_put_fixedarray(e, arr, sizeof(uint32_t)));
        break;
      case UPB_DESCRIPTOR_TYPE_INT64:
      case UPB_DESCRIPTOR_TYPE_UINT64:
        VARINT_CASE(uint64_t, *ptr);
      case UPB_DESCRIPTOR_TYPE_UINT32:
        VARINT_CASE(uint32_t, *ptr);
      case UPB_DESCRIPTOR_TYPE_INT32:
      case UPB_DESCRIPTOR_TYPE_ENUM:
        VARINT_CASE(int32_t, (int64_t)*ptr);
      case UPB_DESCRIPTOR_TYPE_BOOL:
        VARINT_CASE(bool, *ptr);
      case UPB_DESCRIPTOR_TYPE_SINT32:
        VARINT_CASE(int32_t, upb_zzencode_32(*ptr));
      case UPB_DESCRIPTOR_TYPE_SINT64:
        VARINT_CASE(int64_t, upb_zzencode_64(*ptr));
      case UPB_DESCRIPTOR_TYPE_STRING:
      case UPB_DESCRIPTOR_TYPE_BYTES: {
        upb_strview *start = arr->data;
        upb_strview *ptr = start + arr->len;
        do {
          ptr--;
          CHK(upb_put_bytes(e, ptr->data, ptr->size) &&
              upb_put_varint(e, ptr->size) &&
              upb_put_tag(e, f->number, UPB_WIRE_TYPE_DELIMITED));
        } while (ptr != start);
        return true;
      }
      case UPB_DESCRIPTOR_TYPE_GROUP: {
        void **start = arr->data;
        void **ptr = start + arr->len;
        const upb_msglayout *subm = m->submsgs[f->submsg_index];
        do {
          size_t size;
          ptr--;
          CHK(upb_put_tag(e, f->number, UPB_WIRE_TYPE_END_GROUP) &&
              upb_encode_message(e, *ptr, subm, &size) &&
              upb_put_tag(e, f->number, UPB_WIRE_TYPE_START_GROUP));
        } while (ptr != start);
        return true;
      }
      case UPB_DESCRIPTOR_TYPE_MESSAGE: {
        void **start = arr->data;
        void **ptr = start + arr->len;
        const upb_msglayout *subm = m->submsgs[f->submsg_index];
        do {
          size_t size;
          ptr--;
          CHK(upb_encode_message(e, *ptr, subm, &size) &&
              upb_put_varint(e, size) &&
              upb_put_tag(e, f->number, UPB_WIRE_TYPE_DELIMITED));
        } while (ptr != start);
        return true;
      }
    }
  #undef VARINT_CASE
  
    /* We encode all primitive arrays as packed, regardless of what was specified
     * in the .proto file.  Could special case 1-sized arrays. */
    CHK(upb_put_tag(e, f->number, UPB_WIRE_TYPE_DELIMITED));
    return true;
  }
  
  static bool upb_encode_scalarfield(upb_encstate *e, const char *field_mem,
                                     const upb_msglayout *m,
                                     const upb_msglayout_field *f,
                                     bool skip_zero_value) {
  #define CASE(ctype, type, wire_type, encodeval) do { \
    ctype val = *(ctype*)field_mem; \
    if (skip_zero_value && val == 0) { \
      return true; \
    } \
    return upb_put_ ## type(e, encodeval) && \
        upb_put_tag(e, f->number, wire_type); \
  } while(0)
  
    switch (f->descriptortype) {
      case UPB_DESCRIPTOR_TYPE_DOUBLE:
        CASE(double, double, UPB_WIRE_TYPE_64BIT, val);
      case UPB_DESCRIPTOR_TYPE_FLOAT:
        CASE(float, float, UPB_WIRE_TYPE_32BIT, val);
      case UPB_DESCRIPTOR_TYPE_INT64:
      case UPB_DESCRIPTOR_TYPE_UINT64:
        CASE(uint64_t, varint, UPB_WIRE_TYPE_VARINT, val);
      case UPB_DESCRIPTOR_TYPE_UINT32:
        CASE(uint32_t, varint, UPB_WIRE_TYPE_VARINT, val);
      case UPB_DESCRIPTOR_TYPE_INT32:
      case UPB_DESCRIPTOR_TYPE_ENUM:
        CASE(int32_t, varint, UPB_WIRE_TYPE_VARINT, (int64_t)val);
      case UPB_DESCRIPTOR_TYPE_SFIXED64:
      case UPB_DESCRIPTOR_TYPE_FIXED64:
        CASE(uint64_t, fixed64, UPB_WIRE_TYPE_64BIT, val);
      case UPB_DESCRIPTOR_TYPE_FIXED32:
      case UPB_DESCRIPTOR_TYPE_SFIXED32:
        CASE(uint32_t, fixed32, UPB_WIRE_TYPE_32BIT, val);
      case UPB_DESCRIPTOR_TYPE_BOOL:
        CASE(bool, varint, UPB_WIRE_TYPE_VARINT, val);
      case UPB_DESCRIPTOR_TYPE_SINT32:
        CASE(int32_t, varint, UPB_WIRE_TYPE_VARINT, upb_zzencode_32(val));
      case UPB_DESCRIPTOR_TYPE_SINT64:
        CASE(int64_t, varint, UPB_WIRE_TYPE_VARINT, upb_zzencode_64(val));
      case UPB_DESCRIPTOR_TYPE_STRING:
      case UPB_DESCRIPTOR_TYPE_BYTES: {
        upb_strview view = *(upb_strview*)field_mem;
        if (skip_zero_value && view.size == 0) {
          return true;
        }
        return upb_put_bytes(e, view.data, view.size) &&
            upb_put_varint(e, view.size) &&
            upb_put_tag(e, f->number, UPB_WIRE_TYPE_DELIMITED);
      }
      case UPB_DESCRIPTOR_TYPE_GROUP: {
        size_t size;
        void *submsg = *(void **)field_mem;
        const upb_msglayout *subm = m->submsgs[f->submsg_index];
        if (submsg == NULL) {
          return true;
        }
        return upb_put_tag(e, f->number, UPB_WIRE_TYPE_END_GROUP) &&
            upb_encode_message(e, submsg, subm, &size) &&
            upb_put_tag(e, f->number, UPB_WIRE_TYPE_START_GROUP);
      }
      case UPB_DESCRIPTOR_TYPE_MESSAGE: {
        size_t size;
        void *submsg = *(void **)field_mem;
        const upb_msglayout *subm = m->submsgs[f->submsg_index];
        if (submsg == NULL) {
          return true;
        }
        return upb_encode_message(e, submsg, subm, &size) &&
            upb_put_varint(e, size) &&
            upb_put_tag(e, f->number, UPB_WIRE_TYPE_DELIMITED);
      }
    }
  #undef CASE
    UPB_UNREACHABLE();
  }
  
  bool upb_encode_message(upb_encstate *e, const char *msg,
                          const upb_msglayout *m, size_t *size) {
    int i;
    size_t pre_len = e->limit - e->ptr;
    const char *unknown;
    size_t unknown_size;
  
    for (i = m->field_count - 1; i >= 0; i--) {
      const upb_msglayout_field *f = &m->fields[i];
  
      if (f->label == UPB_LABEL_REPEATED) {
        CHK(upb_encode_array(e, msg + f->offset, m, f));
      } else {
        bool skip_empty = false;
        if (f->presence == 0) {
          /* Proto3 presence. */
          skip_empty = true;
        } else if (f->presence > 0) {
          /* Proto2 presence: hasbit. */
          if (!upb_readhasbit(msg, f)) {
            continue;
          }
        } else {
          /* Field is in a oneof. */
          if (upb_readcase(msg, f) != f->number) {
            continue;
          }
        }
        CHK(upb_encode_scalarfield(e, msg + f->offset, m, f, skip_empty));
      }
    }
  
    unknown = upb_msg_getunknown(msg, &unknown_size);
  
    if (unknown) {
      upb_put_bytes(e, unknown, unknown_size);
    }
  
    *size = (e->limit - e->ptr) - pre_len;
    return true;
  }
  
  char *upb_encode(const void *msg, const upb_msglayout *m, upb_arena *arena,
                   size_t *size) {
    upb_encstate e;
    e.alloc = upb_arena_alloc(arena);
    e.buf = NULL;
    e.limit = NULL;
    e.ptr = NULL;
  
    if (!upb_encode_message(&e, msg, m, size)) {
      *size = 0;
      return NULL;
    }
  
    *size = e.limit - e.ptr;
  
    if (*size == 0) {
      static char ch;
      return &ch;
    } else {
      UPB_ASSERT(e.ptr);
      return e.ptr;
    }
  }
  
  #undef CHK
  
  
  
  
  #define VOIDPTR_AT(msg, ofs) (void*)((char*)msg + (int)ofs)
  
  /* Internal members of a upb_msg.  We can change this without breaking binary
   * compatibility.  We put these before the user's data.  The user's upb_msg*
   * points after the upb_msg_internal. */
  
  /* Used when a message is not extendable. */
  typedef struct {
    char *unknown;
    size_t unknown_len;
    size_t unknown_size;
  } upb_msg_internal;
  
  /* Used when a message is extendable. */
  typedef struct {
    upb_inttable *extdict;
    upb_msg_internal base;
  } upb_msg_internal_withext;
  
  static int upb_msg_internalsize(const upb_msglayout *l) {
    return sizeof(upb_msg_internal) - l->extendable * sizeof(void *);
  }
  
  static size_t upb_msg_sizeof(const upb_msglayout *l) {
    return l->size + upb_msg_internalsize(l);
  }
  
  static upb_msg_internal *upb_msg_getinternal(upb_msg *msg) {
    return VOIDPTR_AT(msg, -sizeof(upb_msg_internal));
  }
  
  static const upb_msg_internal *upb_msg_getinternal_const(const upb_msg *msg) {
    return VOIDPTR_AT(msg, -sizeof(upb_msg_internal));
  }
  
  static upb_msg_internal_withext *upb_msg_getinternalwithext(
      upb_msg *msg, const upb_msglayout *l) {
    UPB_ASSERT(l->extendable);
    return VOIDPTR_AT(msg, -sizeof(upb_msg_internal_withext));
  }
  
  upb_msg *upb_msg_new(const upb_msglayout *l, upb_arena *a) {
    upb_alloc *alloc = upb_arena_alloc(a);
    void *mem = upb_malloc(alloc, upb_msg_sizeof(l));
    upb_msg_internal *in;
    upb_msg *msg;
  
    if (!mem) {
      return NULL;
    }
  
    msg = VOIDPTR_AT(mem, upb_msg_internalsize(l));
  
    /* Initialize normal members. */
    memset(msg, 0, l->size);
  
    /* Initialize internal members. */
    in = upb_msg_getinternal(msg);
    in->unknown = NULL;
    in->unknown_len = 0;
    in->unknown_size = 0;
  
    if (l->extendable) {
      upb_msg_getinternalwithext(msg, l)->extdict = NULL;
    }
  
    return msg;
  }
  
  upb_array *upb_array_new(upb_arena *a) {
    upb_array *ret = upb_arena_malloc(a, sizeof(upb_array));
  
    if (!ret) {
      return NULL;
    }
  
    ret->data = NULL;
    ret->len = 0;
    ret->size = 0;
  
    return ret;
  }
  
  void upb_msg_addunknown(upb_msg *msg, const char *data, size_t len,
                          upb_arena *arena) {
    upb_msg_internal *in = upb_msg_getinternal(msg);
    if (len > in->unknown_size - in->unknown_len) {
      upb_alloc *alloc = upb_arena_alloc(arena);
      size_t need = in->unknown_size + len;
      size_t newsize = UPB_MAX(in->unknown_size * 2, need);
      in->unknown = upb_realloc(alloc, in->unknown, in->unknown_size, newsize);
      in->unknown_size = newsize;
    }
    memcpy(in->unknown + in->unknown_len, data, len);
    in->unknown_len += len;
  }
  
  const char *upb_msg_getunknown(const upb_msg *msg, size_t *len) {
    const upb_msg_internal* in = upb_msg_getinternal_const(msg);
    *len = in->unknown_len;
    return in->unknown;
  }
  
  #undef VOIDPTR_AT
  
  
  #ifdef UPB_MSVC_VSNPRINTF
  /* Visual C++ earlier than 2015 doesn't have standard C99 snprintf and
   * vsnprintf. To support them, missing functions are manually implemented
   * using the existing secure functions. */
  int msvc_vsnprintf(char* s, size_t n, const char* format, va_list arg) {
    if (!s) {
      return _vscprintf(format, arg);
    }
    int ret = _vsnprintf_s(s, n, _TRUNCATE, format, arg);
    if (ret < 0) {
  	ret = _vscprintf(format, arg);
    }
    return ret;
  }
  
  int msvc_snprintf(char* s, size_t n, const char* format, ...) {
    va_list arg;
    va_start(arg, format);
    int ret = msvc_vsnprintf(s, n, format, arg);
    va_end(arg);
    return ret;
  }
  #endif
  /*
  ** upb_table Implementation
  **
  ** Implementation is heavily inspired by Lua's ltable.c.
  */
  
  
  #include <string.h>
  
  
  #define UPB_MAXARRSIZE 16  /* 64k. */
  
  /* From Chromium. */
  #define ARRAY_SIZE(x) \
      ((sizeof(x)/sizeof(0[x])) / ((size_t)(!(sizeof(x) % sizeof(0[x])))))
  
  static void upb_check_alloc(upb_table *t, upb_alloc *a) {
    UPB_UNUSED(t);
    UPB_UNUSED(a);
    UPB_ASSERT_DEBUGVAR(t->alloc == a);
  }
  
  static const double MAX_LOAD = 0.85;
  
  /* The minimum utilization of the array part of a mixed hash/array table.  This
   * is a speed/memory-usage tradeoff (though it's not straightforward because of
   * cache effects).  The lower this is, the more memory we'll use. */
  static const double MIN_DENSITY = 0.1;
  
  bool is_pow2(uint64_t v) { return v == 0 || (v & (v - 1)) == 0; }
  
  int log2ceil(uint64_t v) {
    int ret = 0;
    bool pow2 = is_pow2(v);
    while (v >>= 1) ret++;
    ret = pow2 ? ret : ret + 1;  /* Ceiling. */
    return UPB_MIN(UPB_MAXARRSIZE, ret);
  }
  
  char *upb_strdup(const char *s, upb_alloc *a) {
    return upb_strdup2(s, strlen(s), a);
  }
  
  char *upb_strdup2(const char *s, size_t len, upb_alloc *a) {
    size_t n;
    char *p;
  
    /* Prevent overflow errors. */
    if (len == SIZE_MAX) return NULL;
    /* Always null-terminate, even if binary data; but don't rely on the input to
     * have a null-terminating byte since it may be a raw binary buffer. */
    n = len + 1;
    p = upb_malloc(a, n);
    if (p) {
      memcpy(p, s, len);
      p[len] = 0;
    }
    return p;
  }
  
  /* A type to represent the lookup key of either a strtable or an inttable. */
  typedef union {
    uintptr_t num;
    struct {
      const char *str;
      size_t len;
    } str;
  } lookupkey_t;
  
  static lookupkey_t strkey2(const char *str, size_t len) {
    lookupkey_t k;
    k.str.str = str;
    k.str.len = len;
    return k;
  }
  
  static lookupkey_t intkey(uintptr_t key) {
    lookupkey_t k;
    k.num = key;
    return k;
  }
  
  typedef uint32_t hashfunc_t(upb_tabkey key);
  typedef bool eqlfunc_t(upb_tabkey k1, lookupkey_t k2);
  
  /* Base table (shared code) ***************************************************/
  
  /* For when we need to cast away const. */
  static upb_tabent *mutable_entries(upb_table *t) {
    return (upb_tabent*)t->entries;
  }
  
  static bool isfull(upb_table *t) {
    if (upb_table_size(t) == 0) {
      return true;
    } else {
      return ((double)(t->count + 1) / upb_table_size(t)) > MAX_LOAD;
    }
  }
  
  static bool init(upb_table *t, upb_ctype_t ctype, uint8_t size_lg2,
                   upb_alloc *a) {
    size_t bytes;
  
    t->count = 0;
    t->ctype = ctype;
    t->size_lg2 = size_lg2;
    t->mask = upb_table_size(t) ? upb_table_size(t) - 1 : 0;
  #ifndef NDEBUG
    t->alloc = a;
  #endif
    bytes = upb_table_size(t) * sizeof(upb_tabent);
    if (bytes > 0) {
      t->entries = upb_malloc(a, bytes);
      if (!t->entries) return false;
      memset(mutable_entries(t), 0, bytes);
    } else {
      t->entries = NULL;
    }
    return true;
  }
  
  static void uninit(upb_table *t, upb_alloc *a) {
    upb_check_alloc(t, a);
    upb_free(a, mutable_entries(t));
  }
  
  static upb_tabent *emptyent(upb_table *t) {
    upb_tabent *e = mutable_entries(t) + upb_table_size(t);
    while (1) { if (upb_tabent_isempty(--e)) return e; UPB_ASSERT(e > t->entries); }
  }
  
  static upb_tabent *getentry_mutable(upb_table *t, uint32_t hash) {
    return (upb_tabent*)upb_getentry(t, hash);
  }
  
  static const upb_tabent *findentry(const upb_table *t, lookupkey_t key,
                                     uint32_t hash, eqlfunc_t *eql) {
    const upb_tabent *e;
  
    if (t->size_lg2 == 0) return NULL;
    e = upb_getentry(t, hash);
    if (upb_tabent_isempty(e)) return NULL;
    while (1) {
      if (eql(e->key, key)) return e;
      if ((e = e->next) == NULL) return NULL;
    }
  }
  
  static upb_tabent *findentry_mutable(upb_table *t, lookupkey_t key,
                                       uint32_t hash, eqlfunc_t *eql) {
    return (upb_tabent*)findentry(t, key, hash, eql);
  }
  
  static bool lookup(const upb_table *t, lookupkey_t key, upb_value *v,
                     uint32_t hash, eqlfunc_t *eql) {
    const upb_tabent *e = findentry(t, key, hash, eql);
    if (e) {
      if (v) {
        _upb_value_setval(v, e->val.val, t->ctype);
      }
      return true;
    } else {
      return false;
    }
  }
  
  /* The given key must not already exist in the table. */
  static void insert(upb_table *t, lookupkey_t key, upb_tabkey tabkey,
                     upb_value val, uint32_t hash,
                     hashfunc_t *hashfunc, eqlfunc_t *eql) {
    upb_tabent *mainpos_e;
    upb_tabent *our_e;
  
    UPB_ASSERT(findentry(t, key, hash, eql) == NULL);
    UPB_ASSERT_DEBUGVAR(val.ctype == t->ctype);
  
    t->count++;
    mainpos_e = getentry_mutable(t, hash);
    our_e = mainpos_e;
  
    if (upb_tabent_isempty(mainpos_e)) {
      /* Our main position is empty; use it. */
      our_e->next = NULL;
    } else {
      /* Collision. */
      upb_tabent *new_e = emptyent(t);
      /* Head of collider's chain. */
      upb_tabent *chain = getentry_mutable(t, hashfunc(mainpos_e->key));
      if (chain == mainpos_e) {
        /* Existing ent is in its main posisiton (it has the same hash as us, and
         * is the head of our chain).  Insert to new ent and append to this chain. */
        new_e->next = mainpos_e->next;
        mainpos_e->next = new_e;
        our_e = new_e;
      } else {
        /* Existing ent is not in its main position (it is a node in some other
         * chain).  This implies that no existing ent in the table has our hash.
         * Evict it (updating its chain) and use its ent for head of our chain. */
        *new_e = *mainpos_e;  /* copies next. */
        while (chain->next != mainpos_e) {
          chain = (upb_tabent*)chain->next;
          UPB_ASSERT(chain);
        }
        chain->next = new_e;
        our_e = mainpos_e;
        our_e->next = NULL;
      }
    }
    our_e->key = tabkey;
    our_e->val.val = val.val;
    UPB_ASSERT(findentry(t, key, hash, eql) == our_e);
  }
  
  static bool rm(upb_table *t, lookupkey_t key, upb_value *val,
                 upb_tabkey *removed, uint32_t hash, eqlfunc_t *eql) {
    upb_tabent *chain = getentry_mutable(t, hash);
    if (upb_tabent_isempty(chain)) return false;
    if (eql(chain->key, key)) {
      /* Element to remove is at the head of its chain. */
      t->count--;
      if (val) _upb_value_setval(val, chain->val.val, t->ctype);
      if (removed) *removed = chain->key;
      if (chain->next) {
        upb_tabent *move = (upb_tabent*)chain->next;
        *chain = *move;
        move->key = 0;  /* Make the slot empty. */
      } else {
        chain->key = 0;  /* Make the slot empty. */
      }
      return true;
    } else {
      /* Element to remove is either in a non-head position or not in the
       * table. */
      while (chain->next && !eql(chain->next->key, key)) {
        chain = (upb_tabent*)chain->next;
      }
      if (chain->next) {
        /* Found element to remove. */
        upb_tabent *rm = (upb_tabent*)chain->next;
        t->count--;
        if (val) _upb_value_setval(val, chain->next->val.val, t->ctype);
        if (removed) *removed = rm->key;
        rm->key = 0;  /* Make the slot empty. */
        chain->next = rm->next;
        return true;
      } else {
        /* Element to remove is not in the table. */
        return false;
      }
    }
  }
  
  static size_t next(const upb_table *t, size_t i) {
    do {
      if (++i >= upb_table_size(t))
        return SIZE_MAX;
    } while(upb_tabent_isempty(&t->entries[i]));
  
    return i;
  }
  
  static size_t begin(const upb_table *t) {
    return next(t, -1);
  }
  
  
  /* upb_strtable ***************************************************************/
  
  /* A simple "subclass" of upb_table that only adds a hash function for strings. */
  
  static upb_tabkey strcopy(lookupkey_t k2, upb_alloc *a) {
    uint32_t len = (uint32_t) k2.str.len;
    char *str = upb_malloc(a, k2.str.len + sizeof(uint32_t) + 1);
    if (str == NULL) return 0;
    memcpy(str, &len, sizeof(uint32_t));
    memcpy(str + sizeof(uint32_t), k2.str.str, k2.str.len);
    str[sizeof(uint32_t) + k2.str.len] = '\0';
    return (uintptr_t)str;
  }
  
  static uint32_t strhash(upb_tabkey key) {
    uint32_t len;
    char *str = upb_tabstr(key, &len);
    return upb_murmur_hash2(str, len, 0);
  }
  
  static bool streql(upb_tabkey k1, lookupkey_t k2) {
    uint32_t len;
    char *str = upb_tabstr(k1, &len);
    return len == k2.str.len && memcmp(str, k2.str.str, len) == 0;
  }
  
  bool upb_strtable_init2(upb_strtable *t, upb_ctype_t ctype, upb_alloc *a) {
    return init(&t->t, ctype, 2, a);
  }
  
  void upb_strtable_uninit2(upb_strtable *t, upb_alloc *a) {
    size_t i;
    for (i = 0; i < upb_table_size(&t->t); i++)
      upb_free(a, (void*)t->t.entries[i].key);
    uninit(&t->t, a);
  }
  
  bool upb_strtable_resize(upb_strtable *t, size_t size_lg2, upb_alloc *a) {
    upb_strtable new_table;
    upb_strtable_iter i;
  
    upb_check_alloc(&t->t, a);
  
    if (!init(&new_table.t, t->t.ctype, size_lg2, a))
      return false;
    upb_strtable_begin(&i, t);
    for ( ; !upb_strtable_done(&i); upb_strtable_next(&i)) {
      upb_strtable_insert3(
          &new_table,
          upb_strtable_iter_key(&i),
          upb_strtable_iter_keylength(&i),
          upb_strtable_iter_value(&i),
          a);
    }
    upb_strtable_uninit2(t, a);
    *t = new_table;
    return true;
  }
  
  bool upb_strtable_insert3(upb_strtable *t, const char *k, size_t len,
                            upb_value v, upb_alloc *a) {
    lookupkey_t key;
    upb_tabkey tabkey;
    uint32_t hash;
  
    upb_check_alloc(&t->t, a);
  
    if (isfull(&t->t)) {
      /* Need to resize.  New table of double the size, add old elements to it. */
      if (!upb_strtable_resize(t, t->t.size_lg2 + 1, a)) {
        return false;
      }
    }
  
    key = strkey2(k, len);
    tabkey = strcopy(key, a);
    if (tabkey == 0) return false;
  
    hash = upb_murmur_hash2(key.str.str, key.str.len, 0);
    insert(&t->t, key, tabkey, v, hash, &strhash, &streql);
    return true;
  }
  
  bool upb_strtable_lookup2(const upb_strtable *t, const char *key, size_t len,
                            upb_value *v) {
    uint32_t hash = upb_murmur_hash2(key, len, 0);
    return lookup(&t->t, strkey2(key, len), v, hash, &streql);
  }
  
  bool upb_strtable_remove3(upb_strtable *t, const char *key, size_t len,
                           upb_value *val, upb_alloc *alloc) {
    uint32_t hash = upb_murmur_hash2(key, len, 0);
    upb_tabkey tabkey;
    if (rm(&t->t, strkey2(key, len), val, &tabkey, hash, &streql)) {
      upb_free(alloc, (void*)tabkey);
      return true;
    } else {
      return false;
    }
  }
  
  /* Iteration */
  
  static const upb_tabent *str_tabent(const upb_strtable_iter *i) {
    return &i->t->t.entries[i->index];
  }
  
  void upb_strtable_begin(upb_strtable_iter *i, const upb_strtable *t) {
    i->t = t;
    i->index = begin(&t->t);
  }
  
  void upb_strtable_next(upb_strtable_iter *i) {
    i->index = next(&i->t->t, i->index);
  }
  
  bool upb_strtable_done(const upb_strtable_iter *i) {
    if (!i->t) return true;
    return i->index >= upb_table_size(&i->t->t) ||
           upb_tabent_isempty(str_tabent(i));
  }
  
  const char *upb_strtable_iter_key(const upb_strtable_iter *i) {
    UPB_ASSERT(!upb_strtable_done(i));
    return upb_tabstr(str_tabent(i)->key, NULL);
  }
  
  size_t upb_strtable_iter_keylength(const upb_strtable_iter *i) {
    uint32_t len;
    UPB_ASSERT(!upb_strtable_done(i));
    upb_tabstr(str_tabent(i)->key, &len);
    return len;
  }
  
  upb_value upb_strtable_iter_value(const upb_strtable_iter *i) {
    UPB_ASSERT(!upb_strtable_done(i));
    return _upb_value_val(str_tabent(i)->val.val, i->t->t.ctype);
  }
  
  void upb_strtable_iter_setdone(upb_strtable_iter *i) {
    i->t = NULL;
    i->index = SIZE_MAX;
  }
  
  bool upb_strtable_iter_isequal(const upb_strtable_iter *i1,
                                 const upb_strtable_iter *i2) {
    if (upb_strtable_done(i1) && upb_strtable_done(i2))
      return true;
    return i1->t == i2->t && i1->index == i2->index;
  }
  
  
  /* upb_inttable ***************************************************************/
  
  /* For inttables we use a hybrid structure where small keys are kept in an
   * array and large keys are put in the hash table. */
  
  static uint32_t inthash(upb_tabkey key) { return upb_inthash(key); }
  
  static bool inteql(upb_tabkey k1, lookupkey_t k2) {
    return k1 == k2.num;
  }
  
  static upb_tabval *mutable_array(upb_inttable *t) {
    return (upb_tabval*)t->array;
  }
  
  static upb_tabval *inttable_val(upb_inttable *t, uintptr_t key) {
    if (key < t->array_size) {
      return upb_arrhas(t->array[key]) ? &(mutable_array(t)[key]) : NULL;
    } else {
      upb_tabent *e =
          findentry_mutable(&t->t, intkey(key), upb_inthash(key), &inteql);
      return e ? &e->val : NULL;
    }
  }
  
  static const upb_tabval *inttable_val_const(const upb_inttable *t,
                                              uintptr_t key) {
    return inttable_val((upb_inttable*)t, key);
  }
  
  size_t upb_inttable_count(const upb_inttable *t) {
    return t->t.count + t->array_count;
  }
  
  static void check(upb_inttable *t) {
    UPB_UNUSED(t);
  #if defined(UPB_DEBUG_TABLE) && !defined(NDEBUG)
    {
      /* This check is very expensive (makes inserts/deletes O(N)). */
      size_t count = 0;
      upb_inttable_iter i;
      upb_inttable_begin(&i, t);
      for(; !upb_inttable_done(&i); upb_inttable_next(&i), count++) {
        UPB_ASSERT(upb_inttable_lookup(t, upb_inttable_iter_key(&i), NULL));
      }
      UPB_ASSERT(count == upb_inttable_count(t));
    }
  #endif
  }
  
  bool upb_inttable_sizedinit(upb_inttable *t, upb_ctype_t ctype,
                              size_t asize, int hsize_lg2, upb_alloc *a) {
    size_t array_bytes;
  
    if (!init(&t->t, ctype, hsize_lg2, a)) return false;
    /* Always make the array part at least 1 long, so that we know key 0
     * won't be in the hash part, which simplifies things. */
    t->array_size = UPB_MAX(1, asize);
    t->array_count = 0;
    array_bytes = t->array_size * sizeof(upb_value);
    t->array = upb_malloc(a, array_bytes);
    if (!t->array) {
      uninit(&t->t, a);
      return false;
    }
    memset(mutable_array(t), 0xff, array_bytes);
    check(t);
    return true;
  }
  
  bool upb_inttable_init2(upb_inttable *t, upb_ctype_t ctype, upb_alloc *a) {
    return upb_inttable_sizedinit(t, ctype, 0, 4, a);
  }
  
  void upb_inttable_uninit2(upb_inttable *t, upb_alloc *a) {
    uninit(&t->t, a);
    upb_free(a, mutable_array(t));
  }
  
  bool upb_inttable_insert2(upb_inttable *t, uintptr_t key, upb_value val,
                            upb_alloc *a) {
    upb_tabval tabval;
    tabval.val = val.val;
    UPB_ASSERT(upb_arrhas(tabval));  /* This will reject (uint64_t)-1.  Fix this. */
  
    upb_check_alloc(&t->t, a);
  
    if (key < t->array_size) {
      UPB_ASSERT(!upb_arrhas(t->array[key]));
      t->array_count++;
      mutable_array(t)[key].val = val.val;
    } else {
      if (isfull(&t->t)) {
        /* Need to resize the hash part, but we re-use the array part. */
        size_t i;
        upb_table new_table;
  
        if (!init(&new_table, t->t.ctype, t->t.size_lg2 + 1, a)) {
          return false;
        }
  
        for (i = begin(&t->t); i < upb_table_size(&t->t); i = next(&t->t, i)) {
          const upb_tabent *e = &t->t.entries[i];
          uint32_t hash;
          upb_value v;
  
          _upb_value_setval(&v, e->val.val, t->t.ctype);
          hash = upb_inthash(e->key);
          insert(&new_table, intkey(e->key), e->key, v, hash, &inthash, &inteql);
        }
  
        UPB_ASSERT(t->t.count == new_table.count);
  
        uninit(&t->t, a);
        t->t = new_table;
      }
      insert(&t->t, intkey(key), key, val, upb_inthash(key), &inthash, &inteql);
    }
    check(t);
    return true;
  }
  
  bool upb_inttable_lookup(const upb_inttable *t, uintptr_t key, upb_value *v) {
    const upb_tabval *table_v = inttable_val_const(t, key);
    if (!table_v) return false;
    if (v) _upb_value_setval(v, table_v->val, t->t.ctype);
    return true;
  }
  
  bool upb_inttable_replace(upb_inttable *t, uintptr_t key, upb_value val) {
    upb_tabval *table_v = inttable_val(t, key);
    if (!table_v) return false;
    table_v->val = val.val;
    return true;
  }
  
  bool upb_inttable_remove(upb_inttable *t, uintptr_t key, upb_value *val) {
    bool success;
    if (key < t->array_size) {
      if (upb_arrhas(t->array[key])) {
        upb_tabval empty = UPB_TABVALUE_EMPTY_INIT;
        t->array_count--;
        if (val) {
          _upb_value_setval(val, t->array[key].val, t->t.ctype);
        }
        mutable_array(t)[key] = empty;
        success = true;
      } else {
        success = false;
      }
    } else {
      success = rm(&t->t, intkey(key), val, NULL, upb_inthash(key), &inteql);
    }
    check(t);
    return success;
  }
  
  bool upb_inttable_push2(upb_inttable *t, upb_value val, upb_alloc *a) {
    upb_check_alloc(&t->t, a);
    return upb_inttable_insert2(t, upb_inttable_count(t), val, a);
  }
  
  upb_value upb_inttable_pop(upb_inttable *t) {
    upb_value val;
    bool ok = upb_inttable_remove(t, upb_inttable_count(t) - 1, &val);
    UPB_ASSERT(ok);
    return val;
  }
  
  bool upb_inttable_insertptr2(upb_inttable *t, const void *key, upb_value val,
                               upb_alloc *a) {
    upb_check_alloc(&t->t, a);
    return upb_inttable_insert2(t, (uintptr_t)key, val, a);
  }
  
  bool upb_inttable_lookupptr(const upb_inttable *t, const void *key,
                              upb_value *v) {
    return upb_inttable_lookup(t, (uintptr_t)key, v);
  }
  
  bool upb_inttable_removeptr(upb_inttable *t, const void *key, upb_value *val) {
    return upb_inttable_remove(t, (uintptr_t)key, val);
  }
  
  void upb_inttable_compact2(upb_inttable *t, upb_alloc *a) {
    /* A power-of-two histogram of the table keys. */
    size_t counts[UPB_MAXARRSIZE + 1] = {0};
  
    /* The max key in each bucket. */
    uintptr_t max[UPB_MAXARRSIZE + 1] = {0};
  
    upb_inttable_iter i;
    size_t arr_count;
    int size_lg2;
    upb_inttable new_t;
  
    upb_check_alloc(&t->t, a);
  
    upb_inttable_begin(&i, t);
    for (; !upb_inttable_done(&i); upb_inttable_next(&i)) {
      uintptr_t key = upb_inttable_iter_key(&i);
      int bucket = log2ceil(key);
      max[bucket] = UPB_MAX(max[bucket], key);
      counts[bucket]++;
    }
  
    /* Find the largest power of two that satisfies the MIN_DENSITY
     * definition (while actually having some keys). */
    arr_count = upb_inttable_count(t);
  
    for (size_lg2 = ARRAY_SIZE(counts) - 1; size_lg2 > 0; size_lg2--) {
      if (counts[size_lg2] == 0) {
        /* We can halve again without losing any entries. */
        continue;
      } else if (arr_count >= (1 << size_lg2) * MIN_DENSITY) {
        break;
      }
  
      arr_count -= counts[size_lg2];
    }
  
    UPB_ASSERT(arr_count <= upb_inttable_count(t));
  
    {
      /* Insert all elements into new, perfectly-sized table. */
      size_t arr_size = max[size_lg2] + 1;  /* +1 so arr[max] will fit. */
      size_t hash_count = upb_inttable_count(t) - arr_count;
      size_t hash_size = hash_count ? (hash_count / MAX_LOAD) + 1 : 0;
      int hashsize_lg2 = log2ceil(hash_size);
  
      upb_inttable_sizedinit(&new_t, t->t.ctype, arr_size, hashsize_lg2, a);
      upb_inttable_begin(&i, t);
      for (; !upb_inttable_done(&i); upb_inttable_next(&i)) {
        uintptr_t k = upb_inttable_iter_key(&i);
        upb_inttable_insert2(&new_t, k, upb_inttable_iter_value(&i), a);
      }
      UPB_ASSERT(new_t.array_size == arr_size);
      UPB_ASSERT(new_t.t.size_lg2 == hashsize_lg2);
    }
    upb_inttable_uninit2(t, a);
    *t = new_t;
  }
  
  /* Iteration. */
  
  static const upb_tabent *int_tabent(const upb_inttable_iter *i) {
    UPB_ASSERT(!i->array_part);
    return &i->t->t.entries[i->index];
  }
  
  static upb_tabval int_arrent(const upb_inttable_iter *i) {
    UPB_ASSERT(i->array_part);
    return i->t->array[i->index];
  }
  
  void upb_inttable_begin(upb_inttable_iter *i, const upb_inttable *t) {
    i->t = t;
    i->index = -1;
    i->array_part = true;
    upb_inttable_next(i);
  }
  
  void upb_inttable_next(upb_inttable_iter *iter) {
    const upb_inttable *t = iter->t;
    if (iter->array_part) {
      while (++iter->index < t->array_size) {
        if (upb_arrhas(int_arrent(iter))) {
          return;
        }
      }
      iter->array_part = false;
      iter->index = begin(&t->t);
    } else {
      iter->index = next(&t->t, iter->index);
    }
  }
  
  bool upb_inttable_done(const upb_inttable_iter *i) {
    if (!i->t) return true;
    if (i->array_part) {
      return i->index >= i->t->array_size ||
             !upb_arrhas(int_arrent(i));
    } else {
      return i->index >= upb_table_size(&i->t->t) ||
             upb_tabent_isempty(int_tabent(i));
    }
  }
  
  uintptr_t upb_inttable_iter_key(const upb_inttable_iter *i) {
    UPB_ASSERT(!upb_inttable_done(i));
    return i->array_part ? i->index : int_tabent(i)->key;
  }
  
  upb_value upb_inttable_iter_value(const upb_inttable_iter *i) {
    UPB_ASSERT(!upb_inttable_done(i));
    return _upb_value_val(
        i->array_part ? i->t->array[i->index].val : int_tabent(i)->val.val,
        i->t->t.ctype);
  }
  
  void upb_inttable_iter_setdone(upb_inttable_iter *i) {
    i->t = NULL;
    i->index = SIZE_MAX;
    i->array_part = false;
  }
  
  bool upb_inttable_iter_isequal(const upb_inttable_iter *i1,
                                            const upb_inttable_iter *i2) {
    if (upb_inttable_done(i1) && upb_inttable_done(i2))
      return true;
    return i1->t == i2->t && i1->index == i2->index &&
           i1->array_part == i2->array_part;
  }
  
  #if defined(UPB_UNALIGNED_READS_OK) || defined(__s390x__)
  /* -----------------------------------------------------------------------------
   * MurmurHash2, by Austin Appleby (released as public domain).
   * Reformatted and C99-ified by Joshua Haberman.
   * Note - This code makes a few assumptions about how your machine behaves -
   *   1. We can read a 4-byte value from any address without crashing
   *   2. sizeof(int) == 4 (in upb this limitation is removed by using uint32_t
   * And it has a few limitations -
   *   1. It will not work incrementally.
   *   2. It will not produce the same results on little-endian and big-endian
   *      machines. */
  uint32_t upb_murmur_hash2(const void *key, size_t len, uint32_t seed) {
    /* 'm' and 'r' are mixing constants generated offline.
     * They're not really 'magic', they just happen to work well. */
    const uint32_t m = 0x5bd1e995;
    const int32_t r = 24;
  
    /* Initialize the hash to a 'random' value */
    uint32_t h = seed ^ len;
  
    /* Mix 4 bytes at a time into the hash */
    const uint8_t * data = (const uint8_t *)key;
    while(len >= 4) {
      uint32_t k = *(uint32_t *)data;
  
      k *= m;
      k ^= k >> r;
      k *= m;
  
      h *= m;
      h ^= k;
  
      data += 4;
      len -= 4;
    }
  
    /* Handle the last few bytes of the input array */
    switch(len) {
      case 3: h ^= data[2] << 16;
      case 2: h ^= data[1] << 8;
      case 1: h ^= data[0]; h *= m;
    };
  
    /* Do a few final mixes of the hash to ensure the last few
     * bytes are well-incorporated. */
    h ^= h >> 13;
    h *= m;
    h ^= h >> 15;
  
    return h;
  }
  
  #else /* !UPB_UNALIGNED_READS_OK */
  
  /* -----------------------------------------------------------------------------
   * MurmurHashAligned2, by Austin Appleby
   * Same algorithm as MurmurHash2, but only does aligned reads - should be safer
   * on certain platforms.
   * Performance will be lower than MurmurHash2 */
  
  #define MIX(h,k,m) { k *= m; k ^= k >> r; k *= m; h *= m; h ^= k; }
  
  uint32_t upb_murmur_hash2(const void * key, size_t len, uint32_t seed) {
    const uint32_t m = 0x5bd1e995;
    const int32_t r = 24;
    const uint8_t * data = (const uint8_t *)key;
    uint32_t h = (uint32_t)(seed ^ len);
    uint8_t align = (uintptr_t)data & 3;
  
    if(align && (len >= 4)) {
      /* Pre-load the temp registers */
      uint32_t t = 0, d = 0;
      int32_t sl;
      int32_t sr;
  
      switch(align) {
        case 1: t |= data[2] << 16;
        case 2: t |= data[1] << 8;
        case 3: t |= data[0];
      }
  
      t <<= (8 * align);
  
      data += 4-align;
      len -= 4-align;
  
      sl = 8 * (4-align);
      sr = 8 * align;
  
      /* Mix */
  
      while(len >= 4) {
        uint32_t k;
  
        d = *(uint32_t *)data;
        t = (t >> sr) | (d << sl);
  
        k = t;
  
        MIX(h,k,m);
  
        t = d;
  
        data += 4;
        len -= 4;
      }
  
      /* Handle leftover data in temp registers */
  
      d = 0;
  
      if(len >= align) {
        uint32_t k;
  
        switch(align) {
          case 3: d |= data[2] << 16;
          case 2: d |= data[1] << 8;
          case 1: d |= data[0];
        }
  
        k = (t >> sr) | (d << sl);
        MIX(h,k,m);
  
        data += align;
        len -= align;
  
        /* ----------
         * Handle tail bytes */
  
        switch(len) {
          case 3: h ^= data[2] << 16;
          case 2: h ^= data[1] << 8;
          case 1: h ^= data[0]; h *= m;
        };
      } else {
        switch(len) {
          case 3: d |= data[2] << 16;
          case 2: d |= data[1] << 8;
          case 1: d |= data[0];
          case 0: h ^= (t >> sr) | (d << sl); h *= m;
        }
      }
  
      h ^= h >> 13;
      h *= m;
      h ^= h >> 15;
  
      return h;
    } else {
      while(len >= 4) {
        uint32_t k = *(uint32_t *)data;
  
        MIX(h,k,m);
  
        data += 4;
        len -= 4;
      }
  
      /* ----------
       * Handle tail bytes */
  
      switch(len) {
        case 3: h ^= data[2] << 16;
        case 2: h ^= data[1] << 8;
        case 1: h ^= data[0]; h *= m;
      };
  
      h ^= h >> 13;
      h *= m;
      h ^= h >> 15;
  
      return h;
    }
  }
  #undef MIX
  
  #endif /* UPB_UNALIGNED_READS_OK */
  
  
  #include <errno.h>
  #include <stdarg.h>
  #include <stddef.h>
  #include <stdint.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  
  /* Guarantee null-termination and provide ellipsis truncation.
   * It may be tempting to "optimize" this by initializing these final
   * four bytes up-front and then being careful never to overwrite them,
   * this is safer and simpler. */
  static void nullz(upb_status *status) {
    const char *ellipsis = "...";
    size_t len = strlen(ellipsis);
    UPB_ASSERT(sizeof(status->msg) > len);
    memcpy(status->msg + sizeof(status->msg) - len, ellipsis, len);
  }
  
  /* upb_status *****************************************************************/
  
  void upb_status_clear(upb_status *status) {
    if (!status) return;
    status->ok = true;
    status->msg[0] = '\0';
  }
  
  bool upb_ok(const upb_status *status) { return status->ok; }
  
  const char *upb_status_errmsg(const upb_status *status) { return status->msg; }
  
  void upb_status_seterrmsg(upb_status *status, const char *msg) {
    if (!status) return;
    status->ok = false;
    strncpy(status->msg, msg, sizeof(status->msg));
    nullz(status);
  }
  
  void upb_status_seterrf(upb_status *status, const char *fmt, ...) {
    va_list args;
    va_start(args, fmt);
    upb_status_vseterrf(status, fmt, args);
    va_end(args);
  }
  
  void upb_status_vseterrf(upb_status *status, const char *fmt, va_list args) {
    if (!status) return;
    status->ok = false;
    _upb_vsnprintf(status->msg, sizeof(status->msg), fmt, args);
    nullz(status);
  }
  
  /* upb_alloc ******************************************************************/
  
  static void *upb_global_allocfunc(upb_alloc *alloc, void *ptr, size_t oldsize,
                                    size_t size) {
    UPB_UNUSED(alloc);
    UPB_UNUSED(oldsize);
    if (size == 0) {
      free(ptr);
      return NULL;
    } else {
      return realloc(ptr, size);
    }
  }
  
  upb_alloc upb_alloc_global = {&upb_global_allocfunc};
  
  /* upb_arena ******************************************************************/
  
  /* Be conservative and choose 16 in case anyone is using SSE. */
  static const size_t maxalign = 16;
  
  static size_t align_up_max(size_t size) {
    return ((size + maxalign - 1) / maxalign) * maxalign;
  }
  
  struct upb_arena {
    /* We implement the allocator interface.
     * This must be the first member of upb_arena! */
    upb_alloc alloc;
  
    /* Allocator to allocate arena blocks.  We are responsible for freeing these
     * when we are destroyed. */
    upb_alloc *block_alloc;
  
    size_t bytes_allocated;
    size_t next_block_size;
    size_t max_block_size;
  
    /* Linked list of blocks.  Points to an arena_block, defined in env.c */
    void *block_head;
  
    /* Cleanup entries.  Pointer to a cleanup_ent, defined in env.c */
    void *cleanup_head;
  };
  
  typedef struct mem_block {
    struct mem_block *next;
    size_t size;
    size_t used;
    bool owned;
    /* Data follows. */
  } mem_block;
  
  typedef struct cleanup_ent {
    struct cleanup_ent *next;
    upb_cleanup_func *cleanup;
    void *ud;
  } cleanup_ent;
  
  static void upb_arena_addblock(upb_arena *a, void *ptr, size_t size,
                                 bool owned) {
    mem_block *block = ptr;
  
    block->next = a->block_head;
    block->size = size;
    block->used = align_up_max(sizeof(mem_block));
    block->owned = owned;
  
    a->block_head = block;
  
    /* TODO(haberman): ASAN poison. */
  }
  
  static mem_block *upb_arena_allocblock(upb_arena *a, size_t size) {
    size_t block_size = UPB_MAX(size, a->next_block_size) + sizeof(mem_block);
    mem_block *block = upb_malloc(a->block_alloc, block_size);
  
    if (!block) {
      return NULL;
    }
  
    upb_arena_addblock(a, block, block_size, true);
    a->next_block_size = UPB_MIN(block_size * 2, a->max_block_size);
  
    return block;
  }
  
  static void *upb_arena_doalloc(upb_alloc *alloc, void *ptr, size_t oldsize,
                                 size_t size) {
    upb_arena *a = (upb_arena*)alloc;  /* upb_alloc is initial member. */
    mem_block *block = a->block_head;
    void *ret;
  
    if (size == 0) {
      return NULL;  /* We are an arena, don't need individual frees. */
    }
  
    size = align_up_max(size);
  
    /* TODO(haberman): special-case if this is a realloc of the last alloc? */
  
    if (!block || block->size - block->used < size) {
      /* Slow path: have to allocate a new block. */
      block = upb_arena_allocblock(a, size);
  
      if (!block) {
        return NULL;  /* Out of memory. */
      }
    }
  
    ret = (char*)block + block->used;
    block->used += size;
  
    if (oldsize > 0) {
      memcpy(ret, ptr, oldsize);  /* Preserve existing data. */
    }
  
    /* TODO(haberman): ASAN unpoison. */
  
    a->bytes_allocated += size;
    return ret;
  }
  
  /* Public Arena API ***********************************************************/
  
  #define upb_alignof(type) offsetof (struct { char c; type member; }, member)
  
  upb_arena *upb_arena_init(void *mem, size_t n, upb_alloc *alloc) {
    const size_t first_block_overhead = sizeof(upb_arena) + sizeof(mem_block);
    upb_arena *a;
    bool owned = false;
  
    /* Round block size down to alignof(*a) since we will allocate the arena
     * itself at the end. */
    n &= ~(upb_alignof(upb_arena) - 1);
  
    if (n < first_block_overhead) {
      /* We need to malloc the initial block. */
      n = first_block_overhead + 256;
      owned = true;
      if (!alloc || !(mem = upb_malloc(alloc, n))) {
        return NULL;
      }
    }
  
    a = (void*)((char*)mem + n - sizeof(*a));
    n -= sizeof(*a);
  
    a->alloc.func = &upb_arena_doalloc;
    a->block_alloc = &upb_alloc_global;
    a->bytes_allocated = 0;
    a->next_block_size = 256;
    a->max_block_size = 16384;
    a->cleanup_head = NULL;
    a->block_head = NULL;
    a->block_alloc = alloc;
  
    upb_arena_addblock(a, mem, n, owned);
  
    return a;
  }
  
  #undef upb_alignof
  
  void upb_arena_free(upb_arena *a) {
    cleanup_ent *ent = a->cleanup_head;
    mem_block *block = a->block_head;
  
    while (ent) {
      ent->cleanup(ent->ud);
      ent = ent->next;
    }
  
    /* Must do this after running cleanup functions, because this will delete
     * the memory we store our cleanup entries in! */
    while (block) {
      /* Load first since we are deleting block. */
      mem_block *next = block->next;
  
      if (block->owned) {
        upb_free(a->block_alloc, block);
      }
  
      block = next;
    }
  }
  
  bool upb_arena_addcleanup(upb_arena *a, void *ud, upb_cleanup_func *func) {
    cleanup_ent *ent = upb_malloc(&a->alloc, sizeof(cleanup_ent));
    if (!ent) {
      return false;  /* Out of memory. */
    }
  
    ent->cleanup = func;
    ent->ud = ud;
    ent->next = a->cleanup_head;
    a->cleanup_head = ent;
  
    return true;
  }
  
  size_t upb_arena_bytesallocated(const upb_arena *a) {
    return a->bytes_allocated;
  }
  /* This file was generated by upbc (the upb compiler) from the input
   * file:
   *
   *     google/protobuf/descriptor.proto
   *
   * Do not edit -- your changes will be discarded when the file is
   * regenerated. */
  
  #include <stddef.h>
  
  
  static const upb_msglayout *const google_protobuf_FileDescriptorSet_submsgs[1] = {
    &google_protobuf_FileDescriptorProto_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_FileDescriptorSet__fields[1] = {
    {1, UPB_SIZE(0, 0), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_FileDescriptorSet_msginit = {
    &google_protobuf_FileDescriptorSet_submsgs[0],
    &google_protobuf_FileDescriptorSet__fields[0],
    UPB_SIZE(4, 8), 1, false,
  };
  
  static const upb_msglayout *const google_protobuf_FileDescriptorProto_submsgs[6] = {
    &google_protobuf_DescriptorProto_msginit,
    &google_protobuf_EnumDescriptorProto_msginit,
    &google_protobuf_FieldDescriptorProto_msginit,
    &google_protobuf_FileOptions_msginit,
    &google_protobuf_ServiceDescriptorProto_msginit,
    &google_protobuf_SourceCodeInfo_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_FileDescriptorProto__fields[12] = {
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    {4, UPB_SIZE(40, 80), 0, 0, 11, 3},
    {5, UPB_SIZE(44, 88), 0, 1, 11, 3},
    {6, UPB_SIZE(48, 96), 0, 4, 11, 3},
    {7, UPB_SIZE(52, 104), 0, 2, 11, 3},
    {8, UPB_SIZE(28, 56), 4, 3, 11, 1},
    {9, UPB_SIZE(32, 64), 5, 5, 11, 1},
    {10, UPB_SIZE(56, 112), 0, 0, 5, 3},
    {11, UPB_SIZE(60, 120), 0, 0, 5, 3},
    {12, UPB_SIZE(20, 40), 3, 0, 9, 1},
  };
  
  const upb_msglayout google_protobuf_FileDescriptorProto_msginit = {
    &google_protobuf_FileDescriptorProto_submsgs[0],
    &google_protobuf_FileDescriptorProto__fields[0],
    UPB_SIZE(64, 128), 12, false,
  };
  
  static const upb_msglayout *const google_protobuf_DescriptorProto_submsgs[8] = {
    &google_protobuf_DescriptorProto_msginit,
    &google_protobuf_DescriptorProto_ExtensionRange_msginit,
    &google_protobuf_DescriptorProto_ReservedRange_msginit,
    &google_protobuf_EnumDescriptorProto_msginit,
    &google_protobuf_FieldDescriptorProto_msginit,
    &google_protobuf_MessageOptions_msginit,
    &google_protobuf_OneofDescriptorProto_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_DescriptorProto__fields[10] = {
    {1, UPB_SIZE(4, 8), 1, 0, 9, 1},
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    {3, UPB_SIZE(20, 40), 0, 0, 11, 3},
    {4, UPB_SIZE(24, 48), 0, 3, 11, 3},
    {5, UPB_SIZE(28, 56), 0, 1, 11, 3},
    {6, UPB_SIZE(32, 64), 0, 4, 11, 3},
    {7, UPB_SIZE(12, 24), 2, 5, 11, 1},
    {8, UPB_SIZE(36, 72), 0, 6, 11, 3},
    {9, UPB_SIZE(40, 80), 0, 2, 11, 3},
    {10, UPB_SIZE(44, 88), 0, 0, 9, 3},
  };
  
  const upb_msglayout google_protobuf_DescriptorProto_msginit = {
    &google_protobuf_DescriptorProto_submsgs[0],
    &google_protobuf_DescriptorProto__fields[0],
    UPB_SIZE(48, 96), 10, false,
  };
  
  static const upb_msglayout *const google_protobuf_DescriptorProto_ExtensionRange_submsgs[1] = {
    &google_protobuf_ExtensionRangeOptions_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_DescriptorProto_ExtensionRange__fields[3] = {
    {1, UPB_SIZE(4, 4), 1, 0, 5, 1},
    {2, UPB_SIZE(8, 8), 2, 0, 5, 1},
    {3, UPB_SIZE(12, 16), 3, 0, 11, 1},
  };
  
  const upb_msglayout google_protobuf_DescriptorProto_ExtensionRange_msginit = {
    &google_protobuf_DescriptorProto_ExtensionRange_submsgs[0],
    &google_protobuf_DescriptorProto_ExtensionRange__fields[0],
    UPB_SIZE(16, 24), 3, false,
  };
  
  static const upb_msglayout_field google_protobuf_DescriptorProto_ReservedRange__fields[2] = {
    {1, UPB_SIZE(4, 4), 1, 0, 5, 1},
    {2, UPB_SIZE(8, 8), 2, 0, 5, 1},
  };
  
  const upb_msglayout google_protobuf_DescriptorProto_ReservedRange_msginit = {
    NULL,
    &google_protobuf_DescriptorProto_ReservedRange__fields[0],
    UPB_SIZE(12, 12), 2, false,
  };
  
  static const upb_msglayout *const google_protobuf_ExtensionRangeOptions_submsgs[1] = {
    &google_protobuf_UninterpretedOption_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_ExtensionRangeOptions__fields[1] = {
    {999, UPB_SIZE(0, 0), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_ExtensionRangeOptions_msginit = {
    &google_protobuf_ExtensionRangeOptions_submsgs[0],
    &google_protobuf_ExtensionRangeOptions__fields[0],
    UPB_SIZE(4, 8), 1, false,
  };
  
  static const upb_msglayout *const google_protobuf_FieldDescriptorProto_submsgs[1] = {
    &google_protobuf_FieldOptions_msginit,
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  static const upb_msglayout_field google_protobuf_FieldDescriptorProto__fields[10] = {
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    {3, UPB_SIZE(24, 24), 3, 0, 5, 1},
    {4, UPB_SIZE(8, 8), 1, 0, 14, 1},
    {5, UPB_SIZE(16, 16), 2, 0, 14, 1},
    {6, UPB_SIZE(48, 64), 7, 0, 9, 1},
    {7, UPB_SIZE(56, 80), 8, 0, 9, 1},
    {8, UPB_SIZE(72, 112), 10, 0, 11, 1},
    {9, UPB_SIZE(28, 28), 4, 0, 5, 1},
    {10, UPB_SIZE(64, 96), 9, 0, 9, 1},
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  const upb_msglayout google_protobuf_FieldDescriptorProto_msginit = {
    &google_protobuf_FieldDescriptorProto_submsgs[0],
    &google_protobuf_FieldDescriptorProto__fields[0],
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  static const upb_msglayout *const google_protobuf_OneofDescriptorProto_submsgs[1] = {
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  static const upb_msglayout_field google_protobuf_OneofDescriptorProto__fields[2] = {
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  const upb_msglayout google_protobuf_OneofDescriptorProto_msginit = {
    &google_protobuf_OneofDescriptorProto_submsgs[0],
    &google_protobuf_OneofDescriptorProto__fields[0],
    UPB_SIZE(16, 32), 2, false,
  };
  
  static const upb_msglayout *const google_protobuf_EnumDescriptorProto_submsgs[3] = {
    &google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit,
    &google_protobuf_EnumOptions_msginit,
    &google_protobuf_EnumValueDescriptorProto_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_EnumDescriptorProto__fields[5] = {
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    {4, UPB_SIZE(20, 40), 0, 0, 11, 3},
    {5, UPB_SIZE(24, 48), 0, 0, 9, 3},
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  const upb_msglayout google_protobuf_EnumDescriptorProto_msginit = {
    &google_protobuf_EnumDescriptorProto_submsgs[0],
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  static const upb_msglayout_field google_protobuf_EnumDescriptorProto_EnumReservedRange__fields[2] = {
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  const upb_msglayout google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit = {
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  static const upb_msglayout *const google_protobuf_EnumValueDescriptorProto_submsgs[1] = {
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  static const upb_msglayout_field google_protobuf_EnumValueDescriptorProto__fields[3] = {
    {1, UPB_SIZE(8, 8), 2, 0, 9, 1},
    {2, UPB_SIZE(4, 4), 1, 0, 5, 1},
    {3, UPB_SIZE(16, 24), 3, 0, 11, 1},
  };
  
  const upb_msglayout google_protobuf_EnumValueDescriptorProto_msginit = {
    &google_protobuf_EnumValueDescriptorProto_submsgs[0],
    &google_protobuf_EnumValueDescriptorProto__fields[0],
    UPB_SIZE(24, 32), 3, false,
  };
  
  static const upb_msglayout *const google_protobuf_ServiceDescriptorProto_submsgs[2] = {
    &google_protobuf_MethodDescriptorProto_msginit,
    &google_protobuf_ServiceOptions_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_ServiceDescriptorProto__fields[3] = {
    {1, UPB_SIZE(4, 8), 1, 0, 9, 1},
    {2, UPB_SIZE(16, 32), 0, 0, 11, 3},
    {3, UPB_SIZE(12, 24), 2, 1, 11, 1},
  };
  
  const upb_msglayout google_protobuf_ServiceDescriptorProto_msginit = {
    &google_protobuf_ServiceDescriptorProto_submsgs[0],
    &google_protobuf_ServiceDescriptorProto__fields[0],
    UPB_SIZE(24, 48), 3, false,
  };
  
  static const upb_msglayout *const google_protobuf_MethodDescriptorProto_submsgs[1] = {
    &google_protobuf_MethodOptions_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_MethodDescriptorProto__fields[6] = {
    {1, UPB_SIZE(4, 8), 3, 0, 9, 1},
    {2, UPB_SIZE(12, 24), 4, 0, 9, 1},
    {3, UPB_SIZE(20, 40), 5, 0, 9, 1},
    {4, UPB_SIZE(28, 56), 6, 0, 11, 1},
    {5, UPB_SIZE(1, 1), 1, 0, 8, 1},
    {6, UPB_SIZE(2, 2), 2, 0, 8, 1},
  };
  
  const upb_msglayout google_protobuf_MethodDescriptorProto_msginit = {
    &google_protobuf_MethodDescriptorProto_submsgs[0],
    &google_protobuf_MethodDescriptorProto__fields[0],
    UPB_SIZE(32, 64), 6, false,
  };
  
  static const upb_msglayout *const google_protobuf_FileOptions_submsgs[1] = {
    &google_protobuf_UninterpretedOption_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_FileOptions__fields[21] = {
    {1, UPB_SIZE(28, 32), 11, 0, 9, 1},
    {8, UPB_SIZE(36, 48), 12, 0, 9, 1},
    {9, UPB_SIZE(8, 8), 1, 0, 14, 1},
    {10, UPB_SIZE(16, 16), 2, 0, 8, 1},
    {11, UPB_SIZE(44, 64), 13, 0, 9, 1},
    {16, UPB_SIZE(17, 17), 3, 0, 8, 1},
    {17, UPB_SIZE(18, 18), 4, 0, 8, 1},
    {18, UPB_SIZE(19, 19), 5, 0, 8, 1},
    {20, UPB_SIZE(20, 20), 6, 0, 8, 1},
    {23, UPB_SIZE(21, 21), 7, 0, 8, 1},
    {27, UPB_SIZE(22, 22), 8, 0, 8, 1},
    {31, UPB_SIZE(23, 23), 9, 0, 8, 1},
    {36, UPB_SIZE(52, 80), 14, 0, 9, 1},
    {37, UPB_SIZE(60, 96), 15, 0, 9, 1},
    {39, UPB_SIZE(68, 112), 16, 0, 9, 1},
    {40, UPB_SIZE(76, 128), 17, 0, 9, 1},
    {41, UPB_SIZE(84, 144), 18, 0, 9, 1},
    {42, UPB_SIZE(24, 24), 10, 0, 8, 1},
    {44, UPB_SIZE(92, 160), 19, 0, 9, 1},
    {45, UPB_SIZE(100, 176), 20, 0, 9, 1},
    {999, UPB_SIZE(108, 192), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_FileOptions_msginit = {
    &google_protobuf_FileOptions_submsgs[0],
    &google_protobuf_FileOptions__fields[0],
    UPB_SIZE(112, 208), 21, false,
  };
  
  static const upb_msglayout *const google_protobuf_MessageOptions_submsgs[1] = {
    &google_protobuf_UninterpretedOption_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_MessageOptions__fields[5] = {
    {1, UPB_SIZE(1, 1), 1, 0, 8, 1},
    {2, UPB_SIZE(2, 2), 2, 0, 8, 1},
    {3, UPB_SIZE(3, 3), 3, 0, 8, 1},
    {7, UPB_SIZE(4, 4), 4, 0, 8, 1},
    {999, UPB_SIZE(8, 8), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_MessageOptions_msginit = {
    &google_protobuf_MessageOptions_submsgs[0],
    &google_protobuf_MessageOptions__fields[0],
    UPB_SIZE(12, 16), 5, false,
  };
  
  static const upb_msglayout *const google_protobuf_FieldOptions_submsgs[1] = {
    &google_protobuf_UninterpretedOption_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_FieldOptions__fields[7] = {
    {1, UPB_SIZE(8, 8), 1, 0, 14, 1},
    {2, UPB_SIZE(24, 24), 3, 0, 8, 1},
    {3, UPB_SIZE(25, 25), 4, 0, 8, 1},
    {5, UPB_SIZE(26, 26), 5, 0, 8, 1},
    {6, UPB_SIZE(16, 16), 2, 0, 14, 1},
    {10, UPB_SIZE(27, 27), 6, 0, 8, 1},
    {999, UPB_SIZE(28, 32), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_FieldOptions_msginit = {
    &google_protobuf_FieldOptions_submsgs[0],
    &google_protobuf_FieldOptions__fields[0],
    UPB_SIZE(32, 40), 7, false,
  };
  
  static const upb_msglayout *const google_protobuf_OneofOptions_submsgs[1] = {
    &google_protobuf_UninterpretedOption_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_OneofOptions__fields[1] = {
    {999, UPB_SIZE(0, 0), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_OneofOptions_msginit = {
    &google_protobuf_OneofOptions_submsgs[0],
    &google_protobuf_OneofOptions__fields[0],
    UPB_SIZE(4, 8), 1, false,
  };
  
  static const upb_msglayout *const google_protobuf_EnumOptions_submsgs[1] = {
    &google_protobuf_UninterpretedOption_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_EnumOptions__fields[3] = {
    {2, UPB_SIZE(1, 1), 1, 0, 8, 1},
    {3, UPB_SIZE(2, 2), 2, 0, 8, 1},
    {999, UPB_SIZE(4, 8), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_EnumOptions_msginit = {
    &google_protobuf_EnumOptions_submsgs[0],
    &google_protobuf_EnumOptions__fields[0],
    UPB_SIZE(8, 16), 3, false,
  };
  
  static const upb_msglayout *const google_protobuf_EnumValueOptions_submsgs[1] = {
    &google_protobuf_UninterpretedOption_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_EnumValueOptions__fields[2] = {
    {1, UPB_SIZE(1, 1), 1, 0, 8, 1},
    {999, UPB_SIZE(4, 8), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_EnumValueOptions_msginit = {
    &google_protobuf_EnumValueOptions_submsgs[0],
    &google_protobuf_EnumValueOptions__fields[0],
    UPB_SIZE(8, 16), 2, false,
  };
  
  static const upb_msglayout *const google_protobuf_ServiceOptions_submsgs[1] = {
    &google_protobuf_UninterpretedOption_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_ServiceOptions__fields[2] = {
    {33, UPB_SIZE(1, 1), 1, 0, 8, 1},
    {999, UPB_SIZE(4, 8), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_ServiceOptions_msginit = {
    &google_protobuf_ServiceOptions_submsgs[0],
    &google_protobuf_ServiceOptions__fields[0],
    UPB_SIZE(8, 16), 2, false,
  };
  
  static const upb_msglayout *const google_protobuf_MethodOptions_submsgs[1] = {
    &google_protobuf_UninterpretedOption_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_MethodOptions__fields[3] = {
    {33, UPB_SIZE(16, 16), 2, 0, 8, 1},
    {34, UPB_SIZE(8, 8), 1, 0, 14, 1},
    {999, UPB_SIZE(20, 24), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_MethodOptions_msginit = {
    &google_protobuf_MethodOptions_submsgs[0],
    &google_protobuf_MethodOptions__fields[0],
    UPB_SIZE(24, 32), 3, false,
  };
  
  static const upb_msglayout *const google_protobuf_UninterpretedOption_submsgs[1] = {
    &google_protobuf_UninterpretedOption_NamePart_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_UninterpretedOption__fields[7] = {
    {2, UPB_SIZE(56, 80), 0, 0, 11, 3},
    {3, UPB_SIZE(32, 32), 4, 0, 9, 1},
    {4, UPB_SIZE(8, 8), 1, 0, 4, 1},
    {5, UPB_SIZE(16, 16), 2, 0, 3, 1},
    {6, UPB_SIZE(24, 24), 3, 0, 1, 1},
    {7, UPB_SIZE(40, 48), 5, 0, 12, 1},
    {8, UPB_SIZE(48, 64), 6, 0, 9, 1},
  };
  
  const upb_msglayout google_protobuf_UninterpretedOption_msginit = {
    &google_protobuf_UninterpretedOption_submsgs[0],
    &google_protobuf_UninterpretedOption__fields[0],
    UPB_SIZE(64, 96), 7, false,
  };
  
  static const upb_msglayout_field google_protobuf_UninterpretedOption_NamePart__fields[2] = {
    {1, UPB_SIZE(4, 8), 2, 0, 9, 2},
    {2, UPB_SIZE(1, 1), 1, 0, 8, 2},
  };
  
  const upb_msglayout google_protobuf_UninterpretedOption_NamePart_msginit = {
    NULL,
    &google_protobuf_UninterpretedOption_NamePart__fields[0],
    UPB_SIZE(16, 32), 2, false,
  };
  
  static const upb_msglayout *const google_protobuf_SourceCodeInfo_submsgs[1] = {
    &google_protobuf_SourceCodeInfo_Location_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_SourceCodeInfo__fields[1] = {
    {1, UPB_SIZE(0, 0), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_SourceCodeInfo_msginit = {
    &google_protobuf_SourceCodeInfo_submsgs[0],
    &google_protobuf_SourceCodeInfo__fields[0],
    UPB_SIZE(4, 8), 1, false,
  };
  
  static const upb_msglayout_field google_protobuf_SourceCodeInfo_Location__fields[5] = {
    {1, UPB_SIZE(20, 40), 0, 0, 5, 3},
    {2, UPB_SIZE(24, 48), 0, 0, 5, 3},
    {3, UPB_SIZE(4, 8), 1, 0, 9, 1},
    {4, UPB_SIZE(12, 24), 2, 0, 9, 1},
    {6, UPB_SIZE(28, 56), 0, 0, 9, 3},
  };
  
  const upb_msglayout google_protobuf_SourceCodeInfo_Location_msginit = {
    NULL,
    &google_protobuf_SourceCodeInfo_Location__fields[0],
    UPB_SIZE(32, 64), 5, false,
  };
  
  static const upb_msglayout *const google_protobuf_GeneratedCodeInfo_submsgs[1] = {
    &google_protobuf_GeneratedCodeInfo_Annotation_msginit,
  };
  
  static const upb_msglayout_field google_protobuf_GeneratedCodeInfo__fields[1] = {
    {1, UPB_SIZE(0, 0), 0, 0, 11, 3},
  };
  
  const upb_msglayout google_protobuf_GeneratedCodeInfo_msginit = {
    &google_protobuf_GeneratedCodeInfo_submsgs[0],
    &google_protobuf_GeneratedCodeInfo__fields[0],
    UPB_SIZE(4, 8), 1, false,
  };
  
  static const upb_msglayout_field google_protobuf_GeneratedCodeInfo_Annotation__fields[4] = {
    {1, UPB_SIZE(20, 32), 0, 0, 5, 3},
    {2, UPB_SIZE(12, 16), 3, 0, 9, 1},
    {3, UPB_SIZE(4, 4), 1, 0, 5, 1},
    {4, UPB_SIZE(8, 8), 2, 0, 5, 1},
  };
  
  const upb_msglayout google_protobuf_GeneratedCodeInfo_Annotation_msginit = {
    NULL,
    &google_protobuf_GeneratedCodeInfo_Annotation__fields[0],
    UPB_SIZE(24, 48), 4, false,
  };
  
  
  
  
  #include <ctype.h>
  #include <errno.h>
  #include <stdlib.h>
  #include <string.h>
  
  
  typedef struct {
    size_t len;
    char str[1];  /* Null-terminated string data follows. */
  } str_t;
  
  static str_t *newstr(upb_alloc *alloc, const char *data, size_t len) {
    str_t *ret = upb_malloc(alloc, sizeof(*ret) + len);
    if (!ret) return NULL;
    ret->len = len;
    memcpy(ret->str, data, len);
    ret->str[len] = '\0';
    return ret;
  }
  
  struct upb_fielddef {
    const upb_filedef *file;
    const upb_msgdef *msgdef;
    const char *full_name;
    union {
      int64_t sint;
      uint64_t uint;
      double dbl;
      float flt;
      bool boolean;
      str_t *str;
    } defaultval;
    const upb_oneofdef *oneof;
    union {
      const upb_msgdef *msgdef;
      const upb_enumdef *enumdef;
      const google_protobuf_FieldDescriptorProto *unresolved;
    } sub;
    uint32_t number_;
    uint32_t index_;
    uint32_t selector_base;  /* Used to index into a upb::Handlers table. */
    bool is_extension_;
    bool lazy_;
    bool packed_;
    upb_descriptortype_t type_;
    upb_label_t label_;
  };
  
  struct upb_msgdef {
    const upb_filedef *file;
    const char *full_name;
    uint32_t selector_count;
    uint32_t submsg_field_count;
  
    /* Tables for looking up fields by number and name. */
    upb_inttable itof;
    upb_strtable ntof;
  
    const upb_fielddef *fields;
    const upb_oneofdef *oneofs;
    int field_count;
    int oneof_count;
  
    /* Is this a map-entry message? */
    bool map_entry;
    upb_wellknowntype_t well_known_type;
  
    /* TODO(haberman): proper extension ranges (there can be multiple). */
  };
  
  struct upb_enumdef {
    const upb_filedef *file;
    const char *full_name;
    upb_strtable ntoi;
    upb_inttable iton;
    int32_t defaultval;
  };
  
  struct upb_oneofdef {
    const upb_msgdef *parent;
    const char *full_name;
    uint32_t index;
    upb_strtable ntof;
    upb_inttable itof;
  };
  
  struct upb_filedef {
    const char *name;
    const char *package;
    const char *phpprefix;
    const char *phpnamespace;
    upb_syntax_t syntax;
  
    const upb_filedef **deps;
    const upb_msgdef *msgs;
    const upb_enumdef *enums;
    const upb_fielddef *exts;
  
    int dep_count;
    int msg_count;
    int enum_count;
    int ext_count;
  };
  
  struct upb_symtab {
    upb_arena *arena;
    upb_strtable syms;  /* full_name -> packed def ptr */
    upb_strtable files;  /* file_name -> upb_filedef* */
  };
  
  /* Inside a symtab we store tagged pointers to specific def types. */
  typedef enum {
    UPB_DEFTYPE_MSG = 0,
    UPB_DEFTYPE_ENUM = 1,
    UPB_DEFTYPE_FIELD = 2,
    UPB_DEFTYPE_ONEOF = 3
  } upb_deftype_t;
  
  static const void *unpack_def(upb_value v, upb_deftype_t type) {
    uintptr_t num = (uintptr_t)upb_value_getconstptr(v);
    return (num & 3) == type ? (const void*)(num & ~3) : NULL;
  }
  
  static upb_value pack_def(const void *ptr, upb_deftype_t type) {
    uintptr_t num = (uintptr_t)ptr | type;
    return upb_value_constptr((const void*)num);
  }
  
  /* isalpha() etc. from <ctype.h> are locale-dependent, which we don't want. */
  static bool upb_isbetween(char c, char low, char high) {
    return c >= low && c <= high;
  }
  
  static bool upb_isletter(char c) {
    return upb_isbetween(c, 'A', 'Z') || upb_isbetween(c, 'a', 'z') || c == '_';
  }
  
  static bool upb_isalphanum(char c) {
    return upb_isletter(c) || upb_isbetween(c, '0', '9');
  }
  
  static bool upb_isident(upb_strview name, bool full, upb_status *s) {
    const char *str = name.data;
    size_t len = name.size;
    bool start = true;
    size_t i;
    for (i = 0; i < len; i++) {
      char c = str[i];
      if (c == '.') {
        if (start || !full) {
          upb_status_seterrf(s, "invalid name: unexpected '.' (%s)", str);
          return false;
        }
        start = true;
      } else if (start) {
        if (!upb_isletter(c)) {
          upb_status_seterrf(
              s, "invalid name: path components must start with a letter (%s)",
              str);
          return false;
        }
        start = false;
      } else {
        if (!upb_isalphanum(c)) {
          upb_status_seterrf(s, "invalid name: non-alphanumeric character (%s)",
                             str);
          return false;
        }
      }
    }
    return !start;
  }
  
  static const char *shortdefname(const char *fullname) {
    const char *p;
  
    if (fullname == NULL) {
      return NULL;
    } else if ((p = strrchr(fullname, '.')) == NULL) {
      /* No '.' in the name, return the full string. */
      return fullname;
    } else {
      /* Return one past the last '.'. */
      return p + 1;
    }
  }
  
  /* All submessage fields are lower than all other fields.
   * Secondly, fields are increasing in order. */
  uint32_t field_rank(const upb_fielddef *f) {
    uint32_t ret = upb_fielddef_number(f);
    const uint32_t high_bit = 1 << 30;
    UPB_ASSERT(ret < high_bit);
    if (!upb_fielddef_issubmsg(f))
      ret |= high_bit;
    return ret;
  }
  
  int cmp_fields(const void *p1, const void *p2) {
    const upb_fielddef *f1 = *(upb_fielddef*const*)p1;
    const upb_fielddef *f2 = *(upb_fielddef*const*)p2;
    return field_rank(f1) - field_rank(f2);
  }
  
  /* A few implementation details of handlers.  We put these here to avoid
   * a def -> handlers dependency. */
  
  #define UPB_STATIC_SELECTOR_COUNT 3  /* Warning: also in upb/handlers.h. */
  
  static uint32_t upb_handlers_selectorbaseoffset(const upb_fielddef *f) {
    return upb_fielddef_isseq(f) ? 2 : 0;
  }
  
  static uint32_t upb_handlers_selectorcount(const upb_fielddef *f) {
    uint32_t ret = 1;
    if (upb_fielddef_isseq(f)) ret += 2;    /* STARTSEQ/ENDSEQ */
    if (upb_fielddef_isstring(f)) ret += 2; /* [STRING]/STARTSTR/ENDSTR */
    if (upb_fielddef_issubmsg(f)) {
      /* ENDSUBMSG (STARTSUBMSG is at table beginning) */
      ret += 0;
      if (upb_fielddef_lazy(f)) {
        /* STARTSTR/ENDSTR/STRING (for lazy) */
        ret += 3;
      }
    }
    return ret;
  }
  
  static bool assign_msg_indices(upb_msgdef *m, upb_status *s) {
    /* Sort fields.  upb internally relies on UPB_TYPE_MESSAGE fields having the
     * lowest indexes, but we do not publicly guarantee this. */
    upb_msg_field_iter j;
    upb_msg_oneof_iter k;
    int i;
    uint32_t selector;
    int n = upb_msgdef_numfields(m);
    upb_fielddef **fields;
  
    if (n == 0) {
      m->selector_count = UPB_STATIC_SELECTOR_COUNT;
      m->submsg_field_count = 0;
      return true;
    }
  
    fields = upb_gmalloc(n * sizeof(*fields));
    if (!fields) {
      upb_status_setoom(s);
      return false;
    }
  
    m->submsg_field_count = 0;
    for(i = 0, upb_msg_field_begin(&j, m);
        !upb_msg_field_done(&j);
        upb_msg_field_next(&j), i++) {
      upb_fielddef *f = upb_msg_iter_field(&j);
      UPB_ASSERT(f->msgdef == m);
      if (upb_fielddef_issubmsg(f)) {
        m->submsg_field_count++;
      }
      fields[i] = f;
    }
  
    qsort(fields, n, sizeof(*fields), cmp_fields);
  
    selector = UPB_STATIC_SELECTOR_COUNT + m->submsg_field_count;
    for (i = 0; i < n; i++) {
      upb_fielddef *f = fields[i];
      f->index_ = i;
      f->selector_base = selector + upb_handlers_selectorbaseoffset(f);
      selector += upb_handlers_selectorcount(f);
    }
    m->selector_count = selector;
  
    for(upb_msg_oneof_begin(&k, m), i = 0;
        !upb_msg_oneof_done(&k);
        upb_msg_oneof_next(&k), i++) {
      upb_oneofdef *o = (upb_oneofdef*)upb_msg_iter_oneof(&k);
      o->index = i;
    }
  
    upb_gfree(fields);
    return true;
  }
  
  static void assign_msg_wellknowntype(upb_msgdef *m) {
    const char *name = upb_msgdef_fullname(m);
    if (name == NULL) {
      m->well_known_type = UPB_WELLKNOWN_UNSPECIFIED;
      return;
    }
    if (!strcmp(name, "google.protobuf.Any")) {
      m->well_known_type = UPB_WELLKNOWN_ANY;
    } else if (!strcmp(name, "google.protobuf.FieldMask")) {
      m->well_known_type = UPB_WELLKNOWN_FIELDMASK;
    } else if (!strcmp(name, "google.protobuf.Duration")) {
      m->well_known_type = UPB_WELLKNOWN_DURATION;
    } else if (!strcmp(name, "google.protobuf.Timestamp")) {
      m->well_known_type = UPB_WELLKNOWN_TIMESTAMP;
    } else if (!strcmp(name, "google.protobuf.DoubleValue")) {
      m->well_known_type = UPB_WELLKNOWN_DOUBLEVALUE;
    } else if (!strcmp(name, "google.protobuf.FloatValue")) {
      m->well_known_type = UPB_WELLKNOWN_FLOATVALUE;
    } else if (!strcmp(name, "google.protobuf.Int64Value")) {
      m->well_known_type = UPB_WELLKNOWN_INT64VALUE;
    } else if (!strcmp(name, "google.protobuf.UInt64Value")) {
      m->well_known_type = UPB_WELLKNOWN_UINT64VALUE;
    } else if (!strcmp(name, "google.protobuf.Int32Value")) {
      m->well_known_type = UPB_WELLKNOWN_INT32VALUE;
    } else if (!strcmp(name, "google.protobuf.UInt32Value")) {
      m->well_known_type = UPB_WELLKNOWN_UINT32VALUE;
    } else if (!strcmp(name, "google.protobuf.BoolValue")) {
      m->well_known_type = UPB_WELLKNOWN_BOOLVALUE;
    } else if (!strcmp(name, "google.protobuf.StringValue")) {
      m->well_known_type = UPB_WELLKNOWN_STRINGVALUE;
    } else if (!strcmp(name, "google.protobuf.BytesValue")) {
      m->well_known_type = UPB_WELLKNOWN_BYTESVALUE;
    } else if (!strcmp(name, "google.protobuf.Value")) {
      m->well_known_type = UPB_WELLKNOWN_VALUE;
    } else if (!strcmp(name, "google.protobuf.ListValue")) {
      m->well_known_type = UPB_WELLKNOWN_LISTVALUE;
    } else if (!strcmp(name, "google.protobuf.Struct")) {
      m->well_known_type = UPB_WELLKNOWN_STRUCT;
    } else {
      m->well_known_type = UPB_WELLKNOWN_UNSPECIFIED;
    }
  }
  
  
  /* upb_enumdef ****************************************************************/
  
  const char *upb_enumdef_fullname(const upb_enumdef *e) {
    return e->full_name;
  }
  
  const char *upb_enumdef_name(const upb_enumdef *e) {
    return shortdefname(e->full_name);
  }
  
  const upb_filedef *upb_enumdef_file(const upb_enumdef *e) {
    return e->file;
  }
  
  int32_t upb_enumdef_default(const upb_enumdef *e) {
    UPB_ASSERT(upb_enumdef_iton(e, e->defaultval));
    return e->defaultval;
  }
  
  int upb_enumdef_numvals(const upb_enumdef *e) {
    return upb_strtable_count(&e->ntoi);
  }
  
  void upb_enum_begin(upb_enum_iter *i, const upb_enumdef *e) {
    /* We iterate over the ntoi table, to account for duplicate numbers. */
    upb_strtable_begin(i, &e->ntoi);
  }
  
  void upb_enum_next(upb_enum_iter *iter) { upb_strtable_next(iter); }
  bool upb_enum_done(upb_enum_iter *iter) { return upb_strtable_done(iter); }
  
  bool upb_enumdef_ntoi(const upb_enumdef *def, const char *name,
                        size_t len, int32_t *num) {
    upb_value v;
    if (!upb_strtable_lookup2(&def->ntoi, name, len, &v)) {
      return false;
    }
    if (num) *num = upb_value_getint32(v);
    return true;
  }
  
  const char *upb_enumdef_iton(const upb_enumdef *def, int32_t num) {
    upb_value v;
    return upb_inttable_lookup32(&def->iton, num, &v) ?
        upb_value_getcstr(v) : NULL;
  }
  
  const char *upb_enum_iter_name(upb_enum_iter *iter) {
    return upb_strtable_iter_key(iter);
  }
  
  int32_t upb_enum_iter_number(upb_enum_iter *iter) {
    return upb_value_getint32(upb_strtable_iter_value(iter));
  }
  
  
  /* upb_fielddef ***************************************************************/
  
  const char *upb_fielddef_fullname(const upb_fielddef *f) {
    return f->full_name;
  }
  
  upb_fieldtype_t upb_fielddef_type(const upb_fielddef *f) {
    switch (f->type_) {
      case UPB_DESCRIPTOR_TYPE_DOUBLE:
        return UPB_TYPE_DOUBLE;
      case UPB_DESCRIPTOR_TYPE_FLOAT:
        return UPB_TYPE_FLOAT;
      case UPB_DESCRIPTOR_TYPE_INT64:
      case UPB_DESCRIPTOR_TYPE_SINT64:
      case UPB_DESCRIPTOR_TYPE_SFIXED64:
        return UPB_TYPE_INT64;
      case UPB_DESCRIPTOR_TYPE_INT32:
      case UPB_DESCRIPTOR_TYPE_SFIXED32:
      case UPB_DESCRIPTOR_TYPE_SINT32:
        return UPB_TYPE_INT32;
      case UPB_DESCRIPTOR_TYPE_UINT64:
      case UPB_DESCRIPTOR_TYPE_FIXED64:
        return UPB_TYPE_UINT64;
      case UPB_DESCRIPTOR_TYPE_UINT32:
      case UPB_DESCRIPTOR_TYPE_FIXED32:
        return UPB_TYPE_UINT32;
      case UPB_DESCRIPTOR_TYPE_ENUM:
        return UPB_TYPE_ENUM;
      case UPB_DESCRIPTOR_TYPE_BOOL:
        return UPB_TYPE_BOOL;
      case UPB_DESCRIPTOR_TYPE_STRING:
        return UPB_TYPE_STRING;
      case UPB_DESCRIPTOR_TYPE_BYTES:
        return UPB_TYPE_BYTES;
      case UPB_DESCRIPTOR_TYPE_GROUP:
      case UPB_DESCRIPTOR_TYPE_MESSAGE:
        return UPB_TYPE_MESSAGE;
    }
    UPB_UNREACHABLE();
  }
  
  upb_descriptortype_t upb_fielddef_descriptortype(const upb_fielddef *f) {
    return f->type_;
  }
  
  uint32_t upb_fielddef_index(const upb_fielddef *f) {
    return f->index_;
  }
  
  upb_label_t upb_fielddef_label(const upb_fielddef *f) {
    return f->label_;
  }
  
  uint32_t upb_fielddef_number(const upb_fielddef *f) {
    return f->number_;
  }
  
  bool upb_fielddef_isextension(const upb_fielddef *f) {
    return f->is_extension_;
  }
  
  bool upb_fielddef_lazy(const upb_fielddef *f) {
    return f->lazy_;
  }
  
  bool upb_fielddef_packed(const upb_fielddef *f) {
    return f->packed_;
  }
  
  const char *upb_fielddef_name(const upb_fielddef *f) {
    return shortdefname(f->full_name);
  }
  
  uint32_t upb_fielddef_selectorbase(const upb_fielddef *f) {
    return f->selector_base;
  }
  
  size_t upb_fielddef_getjsonname(const upb_fielddef *f, char *buf, size_t len) {
    const char *name = upb_fielddef_name(f);
    size_t src, dst = 0;
    bool ucase_next = false;
  
  #define WRITE(byte) \
    ++dst; \
    if (dst < len) buf[dst - 1] = byte; \
    else if (dst == len) buf[dst - 1] = '\0'
  
    if (!name) {
      WRITE('\0');
      return 0;
    }
  
    /* Implement the transformation as described in the spec:
     *   1. upper case all letters after an underscore.
     *   2. remove all underscores.
     */
    for (src = 0; name[src]; src++) {
      if (name[src] == '_') {
        ucase_next = true;
        continue;
      }
  
      if (ucase_next) {
        WRITE(toupper(name[src]));
        ucase_next = false;
      } else {
        WRITE(name[src]);
      }
    }
  
    WRITE('\0');
    return dst;
  
  #undef WRITE
  }
  
  const upb_msgdef *upb_fielddef_containingtype(const upb_fielddef *f) {
    return f->msgdef;
  }
  
  const upb_oneofdef *upb_fielddef_containingoneof(const upb_fielddef *f) {
    return f->oneof;
  }
  
  static void chkdefaulttype(const upb_fielddef *f, int ctype) {
    UPB_UNUSED(f);
    UPB_UNUSED(ctype);
  }
  
  int64_t upb_fielddef_defaultint64(const upb_fielddef *f) {
    chkdefaulttype(f, UPB_TYPE_INT64);
    return f->defaultval.sint;
  }
  
  int32_t upb_fielddef_defaultint32(const upb_fielddef *f) {
    chkdefaulttype(f, UPB_TYPE_INT32);
    return f->defaultval.sint;
  }
  
  uint64_t upb_fielddef_defaultuint64(const upb_fielddef *f) {
    chkdefaulttype(f, UPB_TYPE_UINT64);
    return f->defaultval.uint;
  }
  
  uint32_t upb_fielddef_defaultuint32(const upb_fielddef *f) {
    chkdefaulttype(f, UPB_TYPE_UINT32);
    return f->defaultval.uint;
  }
  
  bool upb_fielddef_defaultbool(const upb_fielddef *f) {
    chkdefaulttype(f, UPB_TYPE_BOOL);
    return f->defaultval.boolean;
  }
  
  float upb_fielddef_defaultfloat(const upb_fielddef *f) {
    chkdefaulttype(f, UPB_TYPE_FLOAT);
    return f->defaultval.flt;
  }
  
  double upb_fielddef_defaultdouble(const upb_fielddef *f) {
    chkdefaulttype(f, UPB_TYPE_DOUBLE);
    return f->defaultval.dbl;
  }
  
  const char *upb_fielddef_defaultstr(const upb_fielddef *f, size_t *len) {
    str_t *str = f->defaultval.str;
    UPB_ASSERT(upb_fielddef_type(f) == UPB_TYPE_STRING ||
           upb_fielddef_type(f) == UPB_TYPE_BYTES ||
           upb_fielddef_type(f) == UPB_TYPE_ENUM);
    if (str) {
      if (len) *len = str->len;
      return str->str;
    } else {
      if (len) *len = 0;
      return NULL;
    }
  }
  
  const upb_msgdef *upb_fielddef_msgsubdef(const upb_fielddef *f) {
    UPB_ASSERT(upb_fielddef_type(f) == UPB_TYPE_MESSAGE);
    return f->sub.msgdef;
  }
  
  const upb_enumdef *upb_fielddef_enumsubdef(const upb_fielddef *f) {
    UPB_ASSERT(upb_fielddef_type(f) == UPB_TYPE_ENUM);
    return f->sub.enumdef;
  }
  
  bool upb_fielddef_issubmsg(const upb_fielddef *f) {
    return upb_fielddef_type(f) == UPB_TYPE_MESSAGE;
  }
  
  bool upb_fielddef_isstring(const upb_fielddef *f) {
    return upb_fielddef_type(f) == UPB_TYPE_STRING ||
           upb_fielddef_type(f) == UPB_TYPE_BYTES;
  }
  
  bool upb_fielddef_isseq(const upb_fielddef *f) {
    return upb_fielddef_label(f) == UPB_LABEL_REPEATED;
  }
  
  bool upb_fielddef_isprimitive(const upb_fielddef *f) {
    return !upb_fielddef_isstring(f) && !upb_fielddef_issubmsg(f);
  }
  
  bool upb_fielddef_ismap(const upb_fielddef *f) {
    return upb_fielddef_isseq(f) && upb_fielddef_issubmsg(f) &&
           upb_msgdef_mapentry(upb_fielddef_msgsubdef(f));
  }
  
  bool upb_fielddef_hassubdef(const upb_fielddef *f) {
    return upb_fielddef_issubmsg(f) || upb_fielddef_type(f) == UPB_TYPE_ENUM;
  }
  
  bool upb_fielddef_haspresence(const upb_fielddef *f) {
    if (upb_fielddef_isseq(f)) return false;
    if (upb_fielddef_issubmsg(f)) return true;
    return f->file->syntax == UPB_SYNTAX_PROTO2;
  }
  
  static bool between(int32_t x, int32_t low, int32_t high) {
    return x >= low && x <= high;
  }
  
  bool upb_fielddef_checklabel(int32_t label) { return between(label, 1, 3); }
  bool upb_fielddef_checktype(int32_t type) { return between(type, 1, 11); }
  bool upb_fielddef_checkintfmt(int32_t fmt) { return between(fmt, 1, 3); }
  
  bool upb_fielddef_checkdescriptortype(int32_t type) {
    return between(type, 1, 18);
  }
  
  /* upb_msgdef *****************************************************************/
  
  const char *upb_msgdef_fullname(const upb_msgdef *m) {
    return m->full_name;
  }
  
  const upb_filedef *upb_msgdef_file(const upb_msgdef *m) {
    return m->file;
  }
  
  const char *upb_msgdef_name(const upb_msgdef *m) {
    return shortdefname(m->full_name);
  }
  
  upb_syntax_t upb_msgdef_syntax(const upb_msgdef *m) {
    return m->file->syntax;
  }
  
  size_t upb_msgdef_selectorcount(const upb_msgdef *m) {
    return m->selector_count;
  }
  
  uint32_t upb_msgdef_submsgfieldcount(const upb_msgdef *m) {
    return m->submsg_field_count;
  }
  
  const upb_fielddef *upb_msgdef_itof(const upb_msgdef *m, uint32_t i) {
    upb_value val;
    return upb_inttable_lookup32(&m->itof, i, &val) ?
        upb_value_getconstptr(val) : NULL;
  }
  
  const upb_fielddef *upb_msgdef_ntof(const upb_msgdef *m, const char *name,
                                      size_t len) {
    upb_value val;
  
    if (!upb_strtable_lookup2(&m->ntof, name, len, &val)) {
      return NULL;
    }
  
    return unpack_def(val, UPB_DEFTYPE_FIELD);
  }
  
  const upb_oneofdef *upb_msgdef_ntoo(const upb_msgdef *m, const char *name,
                                      size_t len) {
    upb_value val;
  
    if (!upb_strtable_lookup2(&m->ntof, name, len, &val)) {
      return NULL;
    }
  
    return unpack_def(val, UPB_DEFTYPE_ONEOF);
  }
  
  bool upb_msgdef_lookupname(const upb_msgdef *m, const char *name, size_t len,
                             const upb_fielddef **f, const upb_oneofdef **o) {
    upb_value val;
  
    if (!upb_strtable_lookup2(&m->ntof, name, len, &val)) {
      return false;
    }
  
    *o = unpack_def(val, UPB_DEFTYPE_ONEOF);
    *f = unpack_def(val, UPB_DEFTYPE_FIELD);
    UPB_ASSERT((*o != NULL) ^ (*f != NULL));  /* Exactly one of the two should be set. */
    return true;
  }
  
  int upb_msgdef_numfields(const upb_msgdef *m) {
    /* The number table contains only fields. */
    return upb_inttable_count(&m->itof);
  }
  
  int upb_msgdef_numoneofs(const upb_msgdef *m) {
    /* The name table includes oneofs, and the number table does not. */
    return upb_strtable_count(&m->ntof) - upb_inttable_count(&m->itof);
  }
  
  bool upb_msgdef_mapentry(const upb_msgdef *m) {
    return m->map_entry;
  }
  
  upb_wellknowntype_t upb_msgdef_wellknowntype(const upb_msgdef *m) {
    return m->well_known_type;
  }
  
  bool upb_msgdef_isnumberwrapper(const upb_msgdef *m) {
    upb_wellknowntype_t type = upb_msgdef_wellknowntype(m);
    return type >= UPB_WELLKNOWN_DOUBLEVALUE &&
           type <= UPB_WELLKNOWN_UINT32VALUE;
  }
  
  void upb_msg_field_begin(upb_msg_field_iter *iter, const upb_msgdef *m) {
    upb_inttable_begin(iter, &m->itof);
  }
  
  void upb_msg_field_next(upb_msg_field_iter *iter) { upb_inttable_next(iter); }
  
  bool upb_msg_field_done(const upb_msg_field_iter *iter) {
    return upb_inttable_done(iter);
  }
  
  upb_fielddef *upb_msg_iter_field(const upb_msg_field_iter *iter) {
    return (upb_fielddef *)upb_value_getconstptr(upb_inttable_iter_value(iter));
  }
  
  void upb_msg_field_iter_setdone(upb_msg_field_iter *iter) {
    upb_inttable_iter_setdone(iter);
  }
  
  bool upb_msg_field_iter_isequal(const upb_msg_field_iter * iter1,
                                  const upb_msg_field_iter * iter2) {
    return upb_inttable_iter_isequal(iter1, iter2);
  }
  
  void upb_msg_oneof_begin(upb_msg_oneof_iter *iter, const upb_msgdef *m) {
    upb_strtable_begin(iter, &m->ntof);
    /* We need to skip past any initial fields. */
    while (!upb_strtable_done(iter) &&
           !unpack_def(upb_strtable_iter_value(iter), UPB_DEFTYPE_ONEOF)) {
      upb_strtable_next(iter);
    }
  }
  
  void upb_msg_oneof_next(upb_msg_oneof_iter *iter) {
    /* We need to skip past fields to return only oneofs. */
    do {
      upb_strtable_next(iter);
    } while (!upb_strtable_done(iter) &&
             !unpack_def(upb_strtable_iter_value(iter), UPB_DEFTYPE_ONEOF));
  }
  
  bool upb_msg_oneof_done(const upb_msg_oneof_iter *iter) {
    return upb_strtable_done(iter);
  }
  
  const upb_oneofdef *upb_msg_iter_oneof(const upb_msg_oneof_iter *iter) {
    return unpack_def(upb_strtable_iter_value(iter), UPB_DEFTYPE_ONEOF);
  }
  
  void upb_msg_oneof_iter_setdone(upb_msg_oneof_iter *iter) {
    upb_strtable_iter_setdone(iter);
  }
  
  bool upb_msg_oneof_iter_isequal(const upb_msg_oneof_iter *iter1,
                                  const upb_msg_oneof_iter *iter2) {
    return upb_strtable_iter_isequal(iter1, iter2);
  }
  
  /* upb_oneofdef ***************************************************************/
  
  const char *upb_oneofdef_name(const upb_oneofdef *o) {
    return shortdefname(o->full_name);
  }
  
  const upb_msgdef *upb_oneofdef_containingtype(const upb_oneofdef *o) {
    return o->parent;
  }
  
  int upb_oneofdef_numfields(const upb_oneofdef *o) {
    return upb_strtable_count(&o->ntof);
  }
  
  uint32_t upb_oneofdef_index(const upb_oneofdef *o) {
    return o->index;
  }
  
  const upb_fielddef *upb_oneofdef_ntof(const upb_oneofdef *o,
                                        const char *name, size_t length) {
    upb_value val;
    return upb_strtable_lookup2(&o->ntof, name, length, &val) ?
        upb_value_getptr(val) : NULL;
  }
  
  const upb_fielddef *upb_oneofdef_itof(const upb_oneofdef *o, uint32_t num) {
    upb_value val;
    return upb_inttable_lookup32(&o->itof, num, &val) ?
        upb_value_getptr(val) : NULL;
  }
  
  void upb_oneof_begin(upb_oneof_iter *iter, const upb_oneofdef *o) {
    upb_inttable_begin(iter, &o->itof);
  }
  
  void upb_oneof_next(upb_oneof_iter *iter) {
    upb_inttable_next(iter);
  }
  
  bool upb_oneof_done(upb_oneof_iter *iter) {
    return upb_inttable_done(iter);
  }
  
  upb_fielddef *upb_oneof_iter_field(const upb_oneof_iter *iter) {
    return (upb_fielddef *)upb_value_getconstptr(upb_inttable_iter_value(iter));
  }
  
  void upb_oneof_iter_setdone(upb_oneof_iter *iter) {
    upb_inttable_iter_setdone(iter);
  }
  
  /* Code to build defs from descriptor protos. *********************************/
  
  /* There is a question of how much validation to do here.  It will be difficult
   * to perfectly match the amount of validation performed by proto2.  But since
   * this code is used to directly build defs from Ruby (for example) we do need
   * to validate important constraints like uniqueness of names and numbers. */
  
  #define CHK(x) if (!(x)) { return false; }
  #define CHK_OOM(x) if (!(x)) { upb_status_setoom(ctx->status); return false; }
  
  typedef struct {
    const upb_symtab *symtab;
    upb_filedef *file;  /* File we are building. */
    upb_alloc *alloc;    /* Allocate defs here. */
    upb_alloc *tmp;      /* Alloc for addtab and any other tmp data. */
    upb_strtable *addtab;  /* full_name -> packed def ptr for new defs. */
    upb_status *status;  /* Record errors here. */
  } symtab_addctx;
  
  static char* strviewdup(const symtab_addctx *ctx, upb_strview view) {
    return upb_strdup2(view.data, view.size, ctx->alloc);
  }
  
  static bool streql2(const char *a, size_t n, const char *b) {
    return n == strlen(b) && memcmp(a, b, n) == 0;
  }
  
  static bool streql_view(upb_strview view, const char *b) {
    return streql2(view.data, view.size, b);
  }
  
  static const char *makefullname(const symtab_addctx *ctx, const char *prefix,
                                  upb_strview name) {
    if (prefix) {
      /* ret = prefix + '.' + name; */
      size_t n = strlen(prefix);
      char *ret = upb_malloc(ctx->alloc, n + name.size + 2);
      CHK_OOM(ret);
      strcpy(ret, prefix);
      ret[n] = '.';
      memcpy(&ret[n + 1], name.data, name.size);
      ret[n + 1 + name.size] = '\0';
      return ret;
    } else {
      return strviewdup(ctx, name);
    }
  }
  
  static bool symtab_add(const symtab_addctx *ctx, const char *name,
                         upb_value v) {
    upb_value tmp;
    if (upb_strtable_lookup(ctx->addtab, name, &tmp) ||
        upb_strtable_lookup(&ctx->symtab->syms, name, &tmp)) {
      upb_status_seterrf(ctx->status, "duplicate symbol '%s'", name);
      return false;
    }
  
    CHK_OOM(upb_strtable_insert3(ctx->addtab, name, strlen(name), v, ctx->tmp));
    return true;
  }
  
  /* Given a symbol and the base symbol inside which it is defined, find the
   * symbol's definition in t. */
  static bool resolvename(const upb_strtable *t, const upb_fielddef *f,
                          const char *base, upb_strview sym,
                          upb_deftype_t type, upb_status *status,
                          const void **def) {
    if(sym.size == 0) return NULL;
    if(sym.data[0] == '.') {
      /* Symbols starting with '.' are absolute, so we do a single lookup.
       * Slice to omit the leading '.' */
      upb_value v;
      if (!upb_strtable_lookup2(t, sym.data + 1, sym.size - 1, &v)) {
        return false;
      }
  
      *def = unpack_def(v, type);
  
      if (!*def) {
        upb_status_seterrf(status,
                           "type mismatch when resolving field %s, name %s",
                           f->full_name, sym.data);
        return false;
      }
  
      return true;
    } else {
      /* Remove components from base until we find an entry or run out.
       * TODO: This branch is totally broken, but currently not used. */
      (void)base;
      UPB_ASSERT(false);
      return false;
    }
  }
  
  const void *symtab_resolve(const symtab_addctx *ctx, const upb_fielddef *f,
                             const char *base, upb_strview sym,
                             upb_deftype_t type) {
    const void *ret;
    if (!resolvename(ctx->addtab, f, base, sym, type, ctx->status, &ret) &&
        !resolvename(&ctx->symtab->syms, f, base, sym, type, ctx->status, &ret)) {
      if (upb_ok(ctx->status)) {
        upb_status_seterrf(ctx->status, "couldn't resolve name '%s'", sym.data);
      }
      return false;
    }
    return ret;
  }
  
  static bool create_oneofdef(
      const symtab_addctx *ctx, upb_msgdef *m,
      const google_protobuf_OneofDescriptorProto *oneof_proto) {
    upb_oneofdef *o;
    upb_strview name = google_protobuf_OneofDescriptorProto_name(oneof_proto);
    upb_value v;
  
    o = (upb_oneofdef*)&m->oneofs[m->oneof_count++];
    o->parent = m;
    o->full_name = makefullname(ctx, m->full_name, name);
  
    v = pack_def(o, UPB_DEFTYPE_ONEOF);
    CHK_OOM(symtab_add(ctx, o->full_name, v));
    CHK_OOM(upb_strtable_insert3(&m->ntof, name.data, name.size, v, ctx->alloc));
  
    CHK_OOM(upb_inttable_init2(&o->itof, UPB_CTYPE_CONSTPTR, ctx->alloc));
    CHK_OOM(upb_strtable_init2(&o->ntof, UPB_CTYPE_CONSTPTR, ctx->alloc));
  
    return true;
  }
  
  static bool parse_default(const symtab_addctx *ctx, const char *str, size_t len,
                            upb_fielddef *f) {
    char *end;
    char nullz[64];
    errno = 0;
  
    switch (upb_fielddef_type(f)) {
      case UPB_TYPE_INT32:
      case UPB_TYPE_INT64:
      case UPB_TYPE_UINT32:
      case UPB_TYPE_UINT64:
      case UPB_TYPE_DOUBLE:
      case UPB_TYPE_FLOAT:
        /* Standard C number parsing functions expect null-terminated strings. */
        if (len >= sizeof(nullz) - 1) {
          return false;
        }
        memcpy(nullz, str, len);
        nullz[len] = '\0';
        str = nullz;
        break;
      default:
        break;
    }
  
    switch (upb_fielddef_type(f)) {
      case UPB_TYPE_INT32: {
        long val = strtol(str, &end, 0);
        CHK(val <= INT32_MAX && val >= INT32_MIN && errno != ERANGE && !*end);
        f->defaultval.sint = val;
        break;
      }
      case UPB_TYPE_ENUM: {
        const upb_enumdef *e = f->sub.enumdef;
        int32_t val;
        CHK(upb_enumdef_ntoi(e, str, len, &val));
        f->defaultval.sint = val;
        break;
      }
      case UPB_TYPE_INT64: {
        /* XXX: Need to write our own strtoll, since it's not available in c89. */
        long long val = strtol(str, &end, 0);
        CHK(val <= INT64_MAX && val >= INT64_MIN && errno != ERANGE && !*end);
        f->defaultval.sint = val;
        break;
      }
      case UPB_TYPE_UINT32: {
        unsigned long val = strtoul(str, &end, 0);
        CHK(val <= UINT32_MAX && errno != ERANGE && !*end);
        f->defaultval.uint = val;
        break;
      }
      case UPB_TYPE_UINT64: {
        /* XXX: Need to write our own strtoull, since it's not available in c89. */
        unsigned long long val = strtoul(str, &end, 0);
        CHK(val <= UINT64_MAX && errno != ERANGE && !*end);
        f->defaultval.uint = val;
        break;
      }
      case UPB_TYPE_DOUBLE: {
        double val = strtod(str, &end);
        CHK(errno != ERANGE && !*end);
        f->defaultval.dbl = val;
        break;
      }
      case UPB_TYPE_FLOAT: {
        /* XXX: Need to write our own strtof, since it's not available in c89. */
        float val = strtod(str, &end);
        CHK(errno != ERANGE && !*end);
        f->defaultval.flt = val;
        break;
      }
      case UPB_TYPE_BOOL: {
        if (streql2(str, len, "false")) {
          f->defaultval.boolean = false;
        } else if (streql2(str, len, "true")) {
          f->defaultval.boolean = true;
        } else {
          return false;
        }
        break;
      }
      case UPB_TYPE_STRING:
        f->defaultval.str = newstr(ctx->alloc, str, len);
        break;
      case UPB_TYPE_BYTES:
        /* XXX: need to interpret the C-escaped value. */
        f->defaultval.str = newstr(ctx->alloc, str, len);
        break;
      case UPB_TYPE_MESSAGE:
        /* Should not have a default value. */
        return false;
    }
    return true;
  }
  
  static void set_default_default(const symtab_addctx *ctx, upb_fielddef *f) {
    switch (upb_fielddef_type(f)) {
      case UPB_TYPE_INT32:
      case UPB_TYPE_INT64:
      case UPB_TYPE_ENUM:
        f->defaultval.sint = 0;
        break;
      case UPB_TYPE_UINT64:
      case UPB_TYPE_UINT32:
        f->defaultval.uint = 0;
        break;
      case UPB_TYPE_DOUBLE:
      case UPB_TYPE_FLOAT:
        f->defaultval.dbl = 0;
        break;
      case UPB_TYPE_STRING:
      case UPB_TYPE_BYTES:
        f->defaultval.str = newstr(ctx->alloc, NULL, 0);
        break;
      case UPB_TYPE_BOOL:
        f->defaultval.boolean = false;
        break;
      case UPB_TYPE_MESSAGE:
        break;
    }
  }
  
  static bool create_fielddef(
      const symtab_addctx *ctx, const char *prefix, upb_msgdef *m,
      const google_protobuf_FieldDescriptorProto *field_proto) {
    upb_alloc *alloc = ctx->alloc;
    upb_fielddef *f;
    const google_protobuf_FieldOptions *options;
    upb_strview name;
    const char *full_name;
    const char *shortname;
    uint32_t field_number;
  
    if (!google_protobuf_FieldDescriptorProto_has_name(field_proto)) {
      upb_status_seterrmsg(ctx->status, "field has no name");
      return false;
    }
  
    name = google_protobuf_FieldDescriptorProto_name(field_proto);
    CHK(upb_isident(name, false, ctx->status));
    full_name = makefullname(ctx, prefix, name);
    shortname = shortdefname(full_name);
  
    field_number = google_protobuf_FieldDescriptorProto_number(field_proto);
  
    if (field_number == 0 || field_number > UPB_MAX_FIELDNUMBER) {
      upb_status_seterrf(ctx->status, "invalid field number (%u)", field_number);
      return false;
    }
  
    if (m) {
      /* direct message field. */
      upb_value v, packed_v;
  
      f = (upb_fielddef*)&m->fields[m->field_count++];
      f->msgdef = m;
      f->is_extension_ = false;
  
      packed_v = pack_def(f, UPB_DEFTYPE_FIELD);
      v = upb_value_constptr(f);
  
      if (!upb_strtable_insert3(&m->ntof, name.data, name.size, packed_v, alloc)) {
        upb_status_seterrf(ctx->status, "duplicate field name (%s)", shortname);
        return false;
      }
  
      if (!upb_inttable_insert2(&m->itof, field_number, v, alloc)) {
        upb_status_seterrf(ctx->status, "duplicate field number (%u)",
                           field_number);
        return false;
      }
    } else {
      /* extension field. */
      f = (upb_fielddef*)&ctx->file->exts[ctx->file->ext_count];
      f->is_extension_ = true;
      CHK_OOM(symtab_add(ctx, full_name, pack_def(f, UPB_DEFTYPE_FIELD)));
    }
  
    f->full_name = full_name;
    f->file = ctx->file;
    f->type_ = (int)google_protobuf_FieldDescriptorProto_type(field_proto);
    f->label_ = (int)google_protobuf_FieldDescriptorProto_label(field_proto);
    f->number_ = field_number;
    f->oneof = NULL;
  
    /* We can't resolve the subdef or (in the case of extensions) the containing
     * message yet, because it may not have been defined yet.  We stash a pointer
     * to the field_proto until later when we can properly resolve it. */
    f->sub.unresolved = field_proto;
  
    if (f->label_ == UPB_LABEL_REQUIRED && f->file->syntax == UPB_SYNTAX_PROTO3) {
      upb_status_seterrf(ctx->status, "proto3 fields cannot be required (%s)",
                         f->full_name);
      return false;
    }
  
    if (google_protobuf_FieldDescriptorProto_has_oneof_index(field_proto)) {
      int oneof_index =
          google_protobuf_FieldDescriptorProto_oneof_index(field_proto);
      upb_oneofdef *oneof;
      upb_value v = upb_value_constptr(f);
  
      if (upb_fielddef_label(f) != UPB_LABEL_OPTIONAL) {
        upb_status_seterrf(ctx->status,
                           "fields in oneof must have OPTIONAL label (%s)",
                           f->full_name);
        return false;
      }
  
      if (!m) {
        upb_status_seterrf(ctx->status,
                           "oneof_index provided for extension field (%s)",
                           f->full_name);
        return false;
      }
  
      if (oneof_index >= m->oneof_count) {
        upb_status_seterrf(ctx->status, "oneof_index out of range (%s)",
                           f->full_name);
        return false;
      }
  
      oneof = (upb_oneofdef*)&m->oneofs[oneof_index];
      f->oneof = oneof;
  
      CHK(upb_inttable_insert2(&oneof->itof, f->number_, v, alloc));
      CHK(upb_strtable_insert3(&oneof->ntof, name.data, name.size, v, alloc));
    } else {
      f->oneof = NULL;
    }
  
    if (google_protobuf_FieldDescriptorProto_has_options(field_proto)) {
      options = google_protobuf_FieldDescriptorProto_options(field_proto);
      f->lazy_ = google_protobuf_FieldOptions_lazy(options);
      f->packed_ = google_protobuf_FieldOptions_packed(options);
    } else {
      f->lazy_ = false;
      f->packed_ = false;
    }
  
    return true;
  }
  
  static bool create_enumdef(
      const symtab_addctx *ctx, const char *prefix,
      const google_protobuf_EnumDescriptorProto *enum_proto) {
    upb_enumdef *e;
    const google_protobuf_EnumValueDescriptorProto *const *values;
    upb_strview name;
    size_t i, n;
  
    name = google_protobuf_EnumDescriptorProto_name(enum_proto);
    CHK(upb_isident(name, false, ctx->status));
  
    e = (upb_enumdef*)&ctx->file->enums[ctx->file->enum_count++];
    e->full_name = makefullname(ctx, prefix, name);
    CHK_OOM(symtab_add(ctx, e->full_name, pack_def(e, UPB_DEFTYPE_ENUM)));
  
    CHK_OOM(upb_strtable_init2(&e->ntoi, UPB_CTYPE_INT32, ctx->alloc));
    CHK_OOM(upb_inttable_init2(&e->iton, UPB_CTYPE_CSTR, ctx->alloc));
  
    e->file = ctx->file;
    e->defaultval = 0;
  
    values = google_protobuf_EnumDescriptorProto_value(enum_proto, &n);
  
    if (n == 0) {
      upb_status_seterrf(ctx->status,
                         "enums must contain at least one value (%s)",
                         e->full_name);
      return false;
    }
  
    for (i = 0; i < n; i++) {
      const google_protobuf_EnumValueDescriptorProto *value = values[i];
      upb_strview name = google_protobuf_EnumValueDescriptorProto_name(value);
      char *name2 = strviewdup(ctx, name);
      int32_t num = google_protobuf_EnumValueDescriptorProto_number(value);
      upb_value v = upb_value_int32(num);
  
      if (i == 0 && e->file->syntax == UPB_SYNTAX_PROTO3 && num != 0) {
        upb_status_seterrf(ctx->status,
                           "for proto3, the first enum value must be zero (%s)",
                           e->full_name);
        return false;
      }
  
      if (upb_strtable_lookup(&e->ntoi, name2, NULL)) {
        upb_status_seterrf(ctx->status, "duplicate enum label '%s'", name2);
        return false;
      }
  
      CHK_OOM(name2)
      CHK_OOM(
          upb_strtable_insert3(&e->ntoi, name2, strlen(name2), v, ctx->alloc));
  
      if (!upb_inttable_lookup(&e->iton, num, NULL)) {
        upb_value v = upb_value_cstr(name2);
        CHK_OOM(upb_inttable_insert2(&e->iton, num, v, ctx->alloc));
      }
    }
  
    upb_inttable_compact2(&e->iton, ctx->alloc);
  
    return true;
  }
  
  static bool create_msgdef(const symtab_addctx *ctx, const char *prefix,
                            const google_protobuf_DescriptorProto *msg_proto) {
    upb_msgdef *m;
    const google_protobuf_MessageOptions *options;
    const google_protobuf_OneofDescriptorProto *const *oneofs;
    const google_protobuf_FieldDescriptorProto *const *fields;
    const google_protobuf_EnumDescriptorProto *const *enums;
    const google_protobuf_DescriptorProto *const *msgs;
    size_t i, n;
    upb_strview name;
  
    name = google_protobuf_DescriptorProto_name(msg_proto);
    CHK(upb_isident(name, false, ctx->status));
  
    m = (upb_msgdef*)&ctx->file->msgs[ctx->file->msg_count++];
    m->full_name = makefullname(ctx, prefix, name);
    CHK_OOM(symtab_add(ctx, m->full_name, pack_def(m, UPB_DEFTYPE_MSG)));
  
    CHK_OOM(upb_inttable_init2(&m->itof, UPB_CTYPE_CONSTPTR, ctx->alloc));
    CHK_OOM(upb_strtable_init2(&m->ntof, UPB_CTYPE_CONSTPTR, ctx->alloc));
  
    m->file = ctx->file;
    m->map_entry = false;
  
    options = google_protobuf_DescriptorProto_options(msg_proto);
  
    if (options) {
      m->map_entry = google_protobuf_MessageOptions_map_entry(options);
    }
  
    oneofs = google_protobuf_DescriptorProto_oneof_decl(msg_proto, &n);
    m->oneof_count = 0;
    m->oneofs = upb_malloc(ctx->alloc, sizeof(*m->oneofs) * n);
    for (i = 0; i < n; i++) {
      CHK(create_oneofdef(ctx, m, oneofs[i]));
    }
  
    fields = google_protobuf_DescriptorProto_field(msg_proto, &n);
    m->field_count = 0;
    m->fields = upb_malloc(ctx->alloc, sizeof(*m->fields) * n);
    for (i = 0; i < n; i++) {
      CHK(create_fielddef(ctx, m->full_name, m, fields[i]));
    }
  
    CHK(assign_msg_indices(m, ctx->status));
    assign_msg_wellknowntype(m);
    upb_inttable_compact2(&m->itof, ctx->alloc);
  
    /* This message is built.  Now build nested messages and enums. */
  
    enums = google_protobuf_DescriptorProto_enum_type(msg_proto, &n);
    for (i = 0; i < n; i++) {
      CHK(create_enumdef(ctx, m->full_name, enums[i]));
    }
  
    msgs = google_protobuf_DescriptorProto_nested_type(msg_proto, &n);
    for (i = 0; i < n; i++) {
      CHK(create_msgdef(ctx, m->full_name, msgs[i]));
    }
  
    return true;
  }
  
  typedef struct {
    int msg_count;
    int enum_count;
    int ext_count;
  } decl_counts;
  
  static void count_types_in_msg(const google_protobuf_DescriptorProto *msg_proto,
                                 decl_counts *counts) {
    const google_protobuf_DescriptorProto *const *msgs;
    size_t i, n;
  
    counts->msg_count++;
  
    msgs = google_protobuf_DescriptorProto_nested_type(msg_proto, &n);
    for (i = 0; i < n; i++) {
      count_types_in_msg(msgs[i], counts);
    }
  
    google_protobuf_DescriptorProto_enum_type(msg_proto, &n);
    counts->enum_count += n;
  
    google_protobuf_DescriptorProto_extension(msg_proto, &n);
    counts->ext_count += n;
  }
  
  static void count_types_in_file(
      const google_protobuf_FileDescriptorProto *file_proto,
      decl_counts *counts) {
    const google_protobuf_DescriptorProto *const *msgs;
    size_t i, n;
  
    msgs = google_protobuf_FileDescriptorProto_message_type(file_proto, &n);
    for (i = 0; i < n; i++) {
      count_types_in_msg(msgs[i], counts);
    }
  
    google_protobuf_FileDescriptorProto_enum_type(file_proto, &n);
    counts->enum_count += n;
  
    google_protobuf_FileDescriptorProto_extension(file_proto, &n);
    counts->ext_count += n;
  }
  
  static bool resolve_fielddef(const symtab_addctx *ctx, const char *prefix,
                               upb_fielddef *f) {
    upb_strview name;
    const google_protobuf_FieldDescriptorProto *field_proto = f->sub.unresolved;
  
    if (f->is_extension_) {
      if (!google_protobuf_FieldDescriptorProto_has_extendee(field_proto)) {
        upb_status_seterrf(ctx->status,
                           "extension for field '%s' had no extendee",
                           f->full_name);
        return false;
      }
  
      name = google_protobuf_FieldDescriptorProto_extendee(field_proto);
      f->msgdef = symtab_resolve(ctx, f, prefix, name, UPB_DEFTYPE_MSG);
      CHK(f->msgdef);
    }
  
    if ((upb_fielddef_issubmsg(f) || f->type_ == UPB_DESCRIPTOR_TYPE_ENUM) &&
        !google_protobuf_FieldDescriptorProto_has_type_name(field_proto)) {
      upb_status_seterrf(ctx->status, "field '%s' is missing type name",
                         f->full_name);
      return false;
    }
  
    name = google_protobuf_FieldDescriptorProto_type_name(field_proto);
  
    if (upb_fielddef_issubmsg(f)) {
      f->sub.msgdef = symtab_resolve(ctx, f, prefix, name, UPB_DEFTYPE_MSG);
      CHK(f->sub.msgdef);
    } else if (f->type_ == UPB_DESCRIPTOR_TYPE_ENUM) {
      f->sub.enumdef = symtab_resolve(ctx, f, prefix, name, UPB_DEFTYPE_ENUM);
      CHK(f->sub.enumdef);
    }
  
    /* Have to delay resolving of the default value until now because of the enum
     * case, since enum defaults are specified with a label. */
    if (google_protobuf_FieldDescriptorProto_has_default_value(field_proto)) {
      upb_strview defaultval =
          google_protobuf_FieldDescriptorProto_default_value(field_proto);
  
      if (f->file->syntax == UPB_SYNTAX_PROTO3) {
        upb_status_seterrf(ctx->status,
                           "proto3 fields cannot have explicit defaults (%s)",
                           f->full_name);
        return false;
      }
  
      if (upb_fielddef_issubmsg(f)) {
        upb_status_seterrf(ctx->status,
                           "message fields cannot have explicit defaults (%s)",
                           f->full_name);
        return false;
      }
  
      if (!parse_default(ctx, defaultval.data, defaultval.size, f)) {
        upb_status_seterrf(ctx->status,
                           "couldn't parse default '" UPB_STRVIEW_FORMAT
                           "' for field (%s)",
                           UPB_STRVIEW_ARGS(defaultval), f->full_name);
        return false;
      }
    } else {
      set_default_default(ctx, f);
    }
  
    return true;
  }
  
  static bool build_filedef(
      const symtab_addctx *ctx, upb_filedef *file,
      const google_protobuf_FileDescriptorProto *file_proto) {
    upb_alloc *alloc = ctx->alloc;
    const google_protobuf_FileOptions *file_options_proto;
    const google_protobuf_DescriptorProto *const *msgs;
    const google_protobuf_EnumDescriptorProto *const *enums;
    const google_protobuf_FieldDescriptorProto *const *exts;
    const upb_strview* strs;
    size_t i, n;
    decl_counts counts = {0};
  
    count_types_in_file(file_proto, &counts);
  
    file->msgs = upb_malloc(alloc, sizeof(*file->msgs) * counts.msg_count);
    file->enums = upb_malloc(alloc, sizeof(*file->enums) * counts.enum_count);
    file->exts = upb_malloc(alloc, sizeof(*file->exts) * counts.ext_count);
  
    CHK_OOM(counts.msg_count == 0 || file->msgs);
    CHK_OOM(counts.enum_count == 0 || file->enums);
    CHK_OOM(counts.ext_count == 0 || file->exts);
  
    /* We increment these as defs are added. */
    file->msg_count = 0;
    file->enum_count = 0;
    file->ext_count = 0;
  
    if (!google_protobuf_FileDescriptorProto_has_name(file_proto)) {
      upb_status_seterrmsg(ctx->status, "File has no name");
      return false;
    }
  
    file->name =
        strviewdup(ctx, google_protobuf_FileDescriptorProto_name(file_proto));
    file->phpprefix = NULL;
    file->phpnamespace = NULL;
  
    if (google_protobuf_FileDescriptorProto_has_package(file_proto)) {
      upb_strview package =
          google_protobuf_FileDescriptorProto_package(file_proto);
      CHK(upb_isident(package, true, ctx->status));
      file->package = strviewdup(ctx, package);
    } else {
      file->package = NULL;
    }
  
    if (google_protobuf_FileDescriptorProto_has_syntax(file_proto)) {
      upb_strview syntax =
          google_protobuf_FileDescriptorProto_syntax(file_proto);
  
      if (streql_view(syntax, "proto2")) {
        file->syntax = UPB_SYNTAX_PROTO2;
      } else if (streql_view(syntax, "proto3")) {
        file->syntax = UPB_SYNTAX_PROTO3;
      } else {
        upb_status_seterrf(ctx->status, "Invalid syntax '%s'", syntax);
        return false;
      }
    } else {
      file->syntax = UPB_SYNTAX_PROTO2;
    }
  
    /* Read options. */
    file_options_proto = google_protobuf_FileDescriptorProto_options(file_proto);
    if (file_options_proto) {
      if (google_protobuf_FileOptions_has_php_class_prefix(file_options_proto)) {
        file->phpprefix = strviewdup(
            ctx,
            google_protobuf_FileOptions_php_class_prefix(file_options_proto));
      }
      if (google_protobuf_FileOptions_has_php_namespace(file_options_proto)) {
        file->phpnamespace = strviewdup(
            ctx, google_protobuf_FileOptions_php_namespace(file_options_proto));
      }
    }
  
    /* Verify dependencies. */
    strs = google_protobuf_FileDescriptorProto_dependency(file_proto, &n);
    file->deps = upb_malloc(alloc, sizeof(*file->deps) * n) ;
    CHK_OOM(n == 0 || file->deps);
  
    for (i = 0; i < n; i++) {
      upb_strview dep_name = strs[i];
      upb_value v;
      if (!upb_strtable_lookup2(&ctx->symtab->files, dep_name.data,
                                dep_name.size, &v)) {
        upb_status_seterrf(ctx->status,
                           "Depends on file '" UPB_STRVIEW_FORMAT
                           "', but it has not been loaded",
                           UPB_STRVIEW_ARGS(dep_name));
        return false;
      }
      file->deps[i] = upb_value_getconstptr(v);
    }
  
    /* Create messages. */
    msgs = google_protobuf_FileDescriptorProto_message_type(file_proto, &n);
    for (i = 0; i < n; i++) {
      CHK(create_msgdef(ctx, file->package, msgs[i]));
    }
  
    /* Create enums. */
    enums = google_protobuf_FileDescriptorProto_enum_type(file_proto, &n);
    for (i = 0; i < n; i++) {
      CHK(create_enumdef(ctx, file->package, enums[i]));
    }
  
    /* Create extensions. */
    exts = google_protobuf_FileDescriptorProto_extension(file_proto, &n);
    file->exts = upb_malloc(alloc, sizeof(*file->exts) * n);
    CHK_OOM(n == 0 || file->exts);
    for (i = 0; i < n; i++) {
      CHK(create_fielddef(ctx, file->package, NULL, exts[i]));
    }
  
    /* Now that all names are in the table, resolve references. */
    for (i = 0; i < file->ext_count; i++) {
      CHK(resolve_fielddef(ctx, file->package, (upb_fielddef*)&file->exts[i]));
    }
  
    for (i = 0; i < file->msg_count; i++) {
      const upb_msgdef *m = &file->msgs[i];
      int j;
      for (j = 0; j < m->field_count; j++) {
        CHK(resolve_fielddef(ctx, m->full_name, (upb_fielddef*)&m->fields[j]));
      }
    }
  
    return true;
   }
  
  static bool upb_symtab_addtotabs(upb_symtab *s, symtab_addctx *ctx,
                                   upb_status *status) {
    const upb_filedef *file = ctx->file;
    upb_alloc *alloc = upb_arena_alloc(s->arena);
    upb_strtable_iter iter;
  
    CHK_OOM(upb_strtable_insert3(&s->files, file->name, strlen(file->name),
                                 upb_value_constptr(file), alloc));
  
    upb_strtable_begin(&iter, ctx->addtab);
    for (; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
      const char *key = upb_strtable_iter_key(&iter);
      size_t keylen = upb_strtable_iter_keylength(&iter);
      upb_value value = upb_strtable_iter_value(&iter);
      CHK_OOM(upb_strtable_insert3(&s->syms, key, keylen, value, alloc));
    }
  
    return true;
  }
  
  /* upb_filedef ****************************************************************/
  
  const char *upb_filedef_name(const upb_filedef *f) {
    return f->name;
  }
  
  const char *upb_filedef_package(const upb_filedef *f) {
    return f->package;
  }
  
  const char *upb_filedef_phpprefix(const upb_filedef *f) {
    return f->phpprefix;
  }
  
  const char *upb_filedef_phpnamespace(const upb_filedef *f) {
    return f->phpnamespace;
  }
  
  upb_syntax_t upb_filedef_syntax(const upb_filedef *f) {
    return f->syntax;
  }
  
  int upb_filedef_msgcount(const upb_filedef *f) {
    return f->msg_count;
  }
  
  int upb_filedef_depcount(const upb_filedef *f) {
    return f->dep_count;
  }
  
  int upb_filedef_enumcount(const upb_filedef *f) {
    return f->enum_count;
  }
  
  const upb_filedef *upb_filedef_dep(const upb_filedef *f, int i) {
    return i < 0 || i >= f->dep_count ? NULL : f->deps[i];
  }
  
  const upb_msgdef *upb_filedef_msg(const upb_filedef *f, int i) {
    return i < 0 || i >= f->msg_count ? NULL : &f->msgs[i];
  }
  
  const upb_enumdef *upb_filedef_enum(const upb_filedef *f, int i) {
    return i < 0 || i >= f->enum_count ? NULL : &f->enums[i];
  }
  
  void upb_symtab_free(upb_symtab *s) {
    upb_arena_free(s->arena);
    upb_gfree(s);
  }
  
  upb_symtab *upb_symtab_new(void) {
    upb_symtab *s = upb_gmalloc(sizeof(*s));
    upb_alloc *alloc;
  
    if (!s) {
      return NULL;
    }
  
    s->arena = upb_arena_new();
    alloc = upb_arena_alloc(s->arena);
  
    if (!upb_strtable_init2(&s->syms, UPB_CTYPE_CONSTPTR, alloc) ||
        !upb_strtable_init2(&s->files, UPB_CTYPE_CONSTPTR, alloc)) {
      upb_arena_free(s->arena);
      upb_gfree(s);
      s = NULL;
    }
    return s;
  }
  
  const upb_msgdef *upb_symtab_lookupmsg(const upb_symtab *s, const char *sym) {
    upb_value v;
    return upb_strtable_lookup(&s->syms, sym, &v) ?
        unpack_def(v, UPB_DEFTYPE_MSG) : NULL;
  }
  
  const upb_msgdef *upb_symtab_lookupmsg2(const upb_symtab *s, const char *sym,
                                          size_t len) {
    upb_value v;
    return upb_strtable_lookup2(&s->syms, sym, len, &v) ?
        unpack_def(v, UPB_DEFTYPE_MSG) : NULL;
  }
  
  const upb_enumdef *upb_symtab_lookupenum(const upb_symtab *s, const char *sym) {
    upb_value v;
    return upb_strtable_lookup(&s->syms, sym, &v) ?
        unpack_def(v, UPB_DEFTYPE_ENUM) : NULL;
  }
  
  const upb_filedef *upb_symtab_lookupfile(const upb_symtab *s, const char *name) {
    upb_value v;
    return upb_strtable_lookup(&s->files, name, &v) ? upb_value_getconstptr(v)
                                                    : NULL;
  }
  
  const upb_filedef *upb_symtab_addfile(
      upb_symtab *s, const google_protobuf_FileDescriptorProto *file_proto,
      upb_status *status) {
    upb_arena *tmparena = upb_arena_new();
    upb_strtable addtab;
    upb_alloc *alloc = upb_arena_alloc(s->arena);
    upb_filedef *file = upb_malloc(alloc, sizeof(*file));
    bool ok;
    symtab_addctx ctx;
  
    ctx.file = file;
    ctx.symtab = s;
    ctx.alloc = alloc;
    ctx.tmp = upb_arena_alloc(tmparena);
    ctx.addtab = &addtab;
    ctx.status = status;
  
    ok = file &&
        upb_strtable_init2(&addtab, UPB_CTYPE_CONSTPTR, ctx.tmp) &&
        build_filedef(&ctx, file, file_proto) &&
        upb_symtab_addtotabs(s, &ctx, status);
  
    upb_arena_free(tmparena);
    return ok ? file : NULL;
  }
  
  /* Include here since we want most of this file to be stdio-free. */
  #include <stdio.h>
  
  bool _upb_symtab_loaddefinit(upb_symtab *s, const upb_def_init *init) {
    /* Since this function should never fail (it would indicate a bug in upb) we
     * print errors to stderr instead of returning error status to the user. */
    upb_def_init **deps = init->deps;
    google_protobuf_FileDescriptorProto *file;
    upb_arena *arena;
    upb_status status;
  
    upb_status_clear(&status);
  
    if (upb_strtable_lookup(&s->files, init->filename, NULL)) {
      return true;
    }
  
    arena = upb_arena_new();
  
    for (; *deps; deps++) {
      if (!_upb_symtab_loaddefinit(s, *deps)) goto err;
    }
  
    file = google_protobuf_FileDescriptorProto_parse(
        init->descriptor.data, init->descriptor.size, arena);
  
    if (!file) {
      upb_status_seterrf(
          &status,
          "Failed to parse compiled-in descriptor for file '%s'. This should "
          "never happen.",
          init->filename);
      goto err;
    }
  
    if (!upb_symtab_addfile(s, file, &status)) goto err;
  
    upb_arena_free(arena);
    return true;
  
  err:
    fprintf(stderr, "Error loading compiled-in descriptor: %s\n",
            upb_status_errmsg(&status));
    upb_arena_free(arena);
    return false;
  }
  
  #undef CHK
  #undef CHK_OOM
  
  
  
  static bool is_power_of_two(size_t val) {
    return (val & (val - 1)) == 0;
  }
  
  /* Align up to the given power of 2. */
  static size_t align_up(size_t val, size_t align) {
    UPB_ASSERT(is_power_of_two(align));
    return (val + align - 1) & ~(align - 1);
  }
  
  static size_t div_round_up(size_t n, size_t d) {
    return (n + d - 1) / d;
  }
  
  static size_t upb_msgval_sizeof2(upb_fieldtype_t type) {
    switch (type) {
      case UPB_TYPE_DOUBLE:
      case UPB_TYPE_INT64:
      case UPB_TYPE_UINT64:
        return 8;
      case UPB_TYPE_ENUM:
      case UPB_TYPE_INT32:
      case UPB_TYPE_UINT32:
      case UPB_TYPE_FLOAT:
        return 4;
      case UPB_TYPE_BOOL:
        return 1;
      case UPB_TYPE_MESSAGE:
        return sizeof(void*);
      case UPB_TYPE_BYTES:
      case UPB_TYPE_STRING:
        return sizeof(upb_strview);
    }
    UPB_UNREACHABLE();
  }
  
  static uint8_t upb_msg_fielddefsize(const upb_fielddef *f) {
    if (upb_fielddef_isseq(f)) {
      return sizeof(void*);
    } else {
      return upb_msgval_sizeof2(upb_fielddef_type(f));
    }
  }
  
  
  /** upb_msglayout *************************************************************/
  
  static void upb_msglayout_free(upb_msglayout *l) {
    upb_gfree(l);
  }
  
  static size_t upb_msglayout_place(upb_msglayout *l, size_t size) {
    size_t ret;
  
    l->size = align_up(l->size, size);
    ret = l->size;
    l->size += size;
    return ret;
  }
  
  static bool upb_msglayout_init(const upb_msgdef *m,
                                 upb_msglayout *l,
                                 upb_msgfactory *factory) {
    upb_msg_field_iter it;
    upb_msg_oneof_iter oit;
    size_t hasbit;
    size_t submsg_count = 0;
    const upb_msglayout **submsgs;
    upb_msglayout_field *fields;
  
    for (upb_msg_field_begin(&it, m);
         !upb_msg_field_done(&it);
         upb_msg_field_next(&it)) {
      const upb_fielddef* f = upb_msg_iter_field(&it);
      if (upb_fielddef_issubmsg(f)) {
        submsg_count++;
      }
    }
  
    memset(l, 0, sizeof(*l));
  
    fields = upb_gmalloc(upb_msgdef_numfields(m) * sizeof(*fields));
    submsgs = upb_gmalloc(submsg_count * sizeof(*submsgs));
  
    if ((!fields && upb_msgdef_numfields(m)) ||
        (!submsgs && submsg_count)) {
      /* OOM. */
      upb_gfree(fields);
      upb_gfree(submsgs);
      return false;
    }
  
    l->field_count = upb_msgdef_numfields(m);
    l->fields = fields;
    l->submsgs = submsgs;
  
    /* Allocate data offsets in three stages:
     *
     * 1. hasbits.
     * 2. regular fields.
     * 3. oneof fields.
     *
     * OPT: There is a lot of room for optimization here to minimize the size.
     */
  
    /* Allocate hasbits and set basic field attributes. */
    submsg_count = 0;
    for (upb_msg_field_begin(&it, m), hasbit = 0;
         !upb_msg_field_done(&it);
         upb_msg_field_next(&it)) {
      const upb_fielddef* f = upb_msg_iter_field(&it);
      upb_msglayout_field *field = &fields[upb_fielddef_index(f)];
  
      field->number = upb_fielddef_number(f);
      field->descriptortype = upb_fielddef_descriptortype(f);
      field->label = upb_fielddef_label(f);
  
      if (upb_fielddef_issubmsg(f)) {
        const upb_msglayout *sub_layout =
            upb_msgfactory_getlayout(factory, upb_fielddef_msgsubdef(f));
        field->submsg_index = submsg_count++;
        submsgs[field->submsg_index] = sub_layout;
      }
  
      if (upb_fielddef_haspresence(f) && !upb_fielddef_containingoneof(f)) {
        field->presence = (hasbit++);
      } else {
        field->presence = 0;
      }
    }
  
    /* Account for space used by hasbits. */
    l->size = div_round_up(hasbit, 8);
  
    /* Allocate non-oneof fields. */
    for (upb_msg_field_begin(&it, m); !upb_msg_field_done(&it);
         upb_msg_field_next(&it)) {
      const upb_fielddef* f = upb_msg_iter_field(&it);
      size_t field_size = upb_msg_fielddefsize(f);
      size_t index = upb_fielddef_index(f);
  
      if (upb_fielddef_containingoneof(f)) {
        /* Oneofs are handled separately below. */
        continue;
      }
  
      fields[index].offset = upb_msglayout_place(l, field_size);
    }
  
    /* Allocate oneof fields.  Each oneof field consists of a uint32 for the case
     * and space for the actual data. */
    for (upb_msg_oneof_begin(&oit, m); !upb_msg_oneof_done(&oit);
         upb_msg_oneof_next(&oit)) {
      const upb_oneofdef* o = upb_msg_iter_oneof(&oit);
      upb_oneof_iter fit;
  
      size_t case_size = sizeof(uint32_t);  /* Could potentially optimize this. */
      size_t field_size = 0;
      uint32_t case_offset;
      uint32_t data_offset;
  
      /* Calculate field size: the max of all field sizes. */
      for (upb_oneof_begin(&fit, o);
           !upb_oneof_done(&fit);
           upb_oneof_next(&fit)) {
        const upb_fielddef* f = upb_oneof_iter_field(&fit);
        field_size = UPB_MAX(field_size, upb_msg_fielddefsize(f));
      }
  
      /* Align and allocate case offset. */
      case_offset = upb_msglayout_place(l, case_size);
      data_offset = upb_msglayout_place(l, field_size);
  
      for (upb_oneof_begin(&fit, o);
           !upb_oneof_done(&fit);
           upb_oneof_next(&fit)) {
        const upb_fielddef* f = upb_oneof_iter_field(&fit);
        fields[upb_fielddef_index(f)].offset = data_offset;
        fields[upb_fielddef_index(f)].presence = ~case_offset;
      }
    }
  
    /* Size of the entire structure should be a multiple of its greatest
     * alignment.  TODO: track overall alignment for real? */
    l->size = align_up(l->size, 8);
  
    return true;
  }
  
  
  /** upb_msgfactory ************************************************************/
  
  struct upb_msgfactory {
    const upb_symtab *symtab;  /* We own a ref. */
    upb_inttable layouts;
  };
  
  upb_msgfactory *upb_msgfactory_new(const upb_symtab *symtab) {
    upb_msgfactory *ret = upb_gmalloc(sizeof(*ret));
  
    ret->symtab = symtab;
    upb_inttable_init(&ret->layouts, UPB_CTYPE_PTR);
  
    return ret;
  }
  
  void upb_msgfactory_free(upb_msgfactory *f) {
    upb_inttable_iter i;
    upb_inttable_begin(&i, &f->layouts);
    for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
      upb_msglayout *l = upb_value_getptr(upb_inttable_iter_value(&i));
      upb_msglayout_free(l);
    }
  
    upb_inttable_uninit(&f->layouts);
    upb_gfree(f);
  }
  
  const upb_symtab *upb_msgfactory_symtab(const upb_msgfactory *f) {
    return f->symtab;
  }
  
  const upb_msglayout *upb_msgfactory_getlayout(upb_msgfactory *f,
                                                const upb_msgdef *m) {
    upb_value v;
    UPB_ASSERT(upb_symtab_lookupmsg(f->symtab, upb_msgdef_fullname(m)) == m);
    UPB_ASSERT(!upb_msgdef_mapentry(m));
  
    if (upb_inttable_lookupptr(&f->layouts, m, &v)) {
      UPB_ASSERT(upb_value_getptr(v));
      return upb_value_getptr(v);
    } else {
      /* In case of circular dependency, layout has to be inserted first. */
      upb_msglayout *l = upb_gmalloc(sizeof(*l));
      upb_msgfactory *mutable_f = (void*)f;
      upb_inttable_insertptr(&mutable_f->layouts, m, upb_value_ptr(l));
      UPB_ASSERT(l);
      if (!upb_msglayout_init(m, l, f)) {
        upb_msglayout_free(l);
      }
      return l;
    }
  }
  /*
  ** TODO(haberman): it's unclear whether a lot of the consistency checks should
  ** UPB_ASSERT() or return false.
  */
  
  
  #include <string.h>
  
  
  
  struct upb_handlers {
    upb_handlercache *cache;
    const upb_msgdef *msg;
    const upb_handlers **sub;
    const void *top_closure_type;
    upb_handlers_tabent table[1];  /* Dynamically-sized field handler array. */
  };
  
  static void *upb_calloc(upb_arena *arena, size_t size) {
    void *mem = upb_malloc(upb_arena_alloc(arena), size);
    if (mem) {
      memset(mem, 0, size);
    }
    return mem;
  }
  
  /* Defined for the sole purpose of having a unique pointer value for
   * UPB_NO_CLOSURE. */
  char _upb_noclosure;
  
  /* Given a selector for a STARTSUBMSG handler, resolves to a pointer to the
   * subhandlers for this submessage field. */
  #define SUBH(h, selector) (h->sub[selector])
  
  /* The selector for a submessage field is the field index. */
  #define SUBH_F(h, f) SUBH(h, upb_fielddef_index(f))
  
  static int32_t trygetsel(upb_handlers *h, const upb_fielddef *f,
                           upb_handlertype_t type) {
    upb_selector_t sel;
    bool ok;
  
    ok = upb_handlers_getselector(f, type, &sel);
  
    UPB_ASSERT(upb_handlers_msgdef(h) == upb_fielddef_containingtype(f));
    UPB_ASSERT(ok);
  
    return sel;
  }
  
  static upb_selector_t handlers_getsel(upb_handlers *h, const upb_fielddef *f,
                               upb_handlertype_t type) {
    int32_t sel = trygetsel(h, f, type);
    UPB_ASSERT(sel >= 0);
    return sel;
  }
  
  static const void **returntype(upb_handlers *h, const upb_fielddef *f,
                                 upb_handlertype_t type) {
    return &h->table[handlers_getsel(h, f, type)].attr.return_closure_type;
  }
  
  static bool doset(upb_handlers *h, int32_t sel, const upb_fielddef *f,
                    upb_handlertype_t type, upb_func *func,
                    const upb_handlerattr *attr) {
    upb_handlerattr set_attr = UPB_HANDLERATTR_INIT;
    const void *closure_type;
    const void **context_closure_type;
  
    UPB_ASSERT(!h->table[sel].func);
  
    if (attr) {
      set_attr = *attr;
    }
  
    /* Check that the given closure type matches the closure type that has been
     * established for this context (if any). */
    closure_type = set_attr.closure_type;
  
    if (type == UPB_HANDLER_STRING) {
      context_closure_type = returntype(h, f, UPB_HANDLER_STARTSTR);
    } else if (f && upb_fielddef_isseq(f) &&
               type != UPB_HANDLER_STARTSEQ &&
               type != UPB_HANDLER_ENDSEQ) {
      context_closure_type = returntype(h, f, UPB_HANDLER_STARTSEQ);
    } else {
      context_closure_type = &h->top_closure_type;
    }
  
    if (closure_type && *context_closure_type &&
        closure_type != *context_closure_type) {
      return false;
    }
  
    if (closure_type)
      *context_closure_type = closure_type;
  
    /* If this is a STARTSEQ or STARTSTR handler, check that the returned pointer
     * matches any pre-existing expectations about what type is expected. */
    if (type == UPB_HANDLER_STARTSEQ || type == UPB_HANDLER_STARTSTR) {
      const void *return_type = set_attr.return_closure_type;
      const void *table_return_type = h->table[sel].attr.return_closure_type;
      if (return_type && table_return_type && return_type != table_return_type) {
        return false;
      }
  
      if (table_return_type && !return_type) {
        set_attr.return_closure_type = table_return_type;
      }
    }
  
    h->table[sel].func = (upb_func*)func;
    h->table[sel].attr = set_attr;
    return true;
  }
  
  /* Returns the effective closure type for this handler (which will propagate
   * from outer frames if this frame has no START* handler).  Not implemented for
   * UPB_HANDLER_STRING at the moment since this is not needed.  Returns NULL is
   * the effective closure type is unspecified (either no handler was registered
   * to specify it or the handler that was registered did not specify the closure
   * type). */
  const void *effective_closure_type(upb_handlers *h, const upb_fielddef *f,
                                     upb_handlertype_t type) {
    const void *ret;
    upb_selector_t sel;
  
    UPB_ASSERT(type != UPB_HANDLER_STRING);
    ret = h->top_closure_type;
  
    if (upb_fielddef_isseq(f) &&
        type != UPB_HANDLER_STARTSEQ &&
        type != UPB_HANDLER_ENDSEQ &&
        h->table[sel = handlers_getsel(h, f, UPB_HANDLER_STARTSEQ)].func) {
      ret = h->table[sel].attr.return_closure_type;
    }
  
    if (type == UPB_HANDLER_STRING &&
        h->table[sel = handlers_getsel(h, f, UPB_HANDLER_STARTSTR)].func) {
      ret = h->table[sel].attr.return_closure_type;
    }
  
    /* The effective type of the submessage; not used yet.
     * if (type == SUBMESSAGE &&
     *     h->table[sel = handlers_getsel(h, f, UPB_HANDLER_STARTSUBMSG)].func) {
     *   ret = h->table[sel].attr.return_closure_type;
     * } */
  
    return ret;
  }
  
  /* Checks whether the START* handler specified by f & type is missing even
   * though it is required to convert the established type of an outer frame
   * ("closure_type") into the established type of an inner frame (represented in
   * the return closure type of this handler's attr. */
  bool checkstart(upb_handlers *h, const upb_fielddef *f, upb_handlertype_t type,
                  upb_status *status) {
    const void *closure_type;
    const upb_handlerattr *attr;
    const void *return_closure_type;
  
    upb_selector_t sel = handlers_getsel(h, f, type);
    if (h->table[sel].func) return true;
    closure_type = effective_closure_type(h, f, type);
    attr = &h->table[sel].attr;
    return_closure_type = attr->return_closure_type;
    if (closure_type && return_closure_type &&
        closure_type != return_closure_type) {
      return false;
    }
    return true;
  }
  
  static upb_handlers *upb_handlers_new(const upb_msgdef *md,
                                        upb_handlercache *cache,
                                        upb_arena *arena) {
    int extra;
    upb_handlers *h;
  
    extra = sizeof(upb_handlers_tabent) * (upb_msgdef_selectorcount(md) - 1);
    h = upb_calloc(arena, sizeof(*h) + extra);
    if (!h) return NULL;
  
    h->cache = cache;
    h->msg = md;
  
    if (upb_msgdef_submsgfieldcount(md) > 0) {
      size_t bytes = upb_msgdef_submsgfieldcount(md) * sizeof(*h->sub);
      h->sub = upb_calloc(arena, bytes);
      if (!h->sub) return NULL;
    } else {
      h->sub = 0;
    }
  
    /* calloc() above initialized all handlers to NULL. */
    return h;
  }
  
  /* Public interface ***********************************************************/
  
  #define SETTER(name, handlerctype, handlertype)                       \
    bool upb_handlers_set##name(upb_handlers *h, const upb_fielddef *f, \
                                handlerctype func,                      \
                                const upb_handlerattr *attr) {          \
      int32_t sel = trygetsel(h, f, handlertype);                       \
      return doset(h, sel, f, handlertype, (upb_func *)func, attr);     \
    }
  
  SETTER(int32,       upb_int32_handlerfunc*,       UPB_HANDLER_INT32)
  SETTER(int64,       upb_int64_handlerfunc*,       UPB_HANDLER_INT64)
  SETTER(uint32,      upb_uint32_handlerfunc*,      UPB_HANDLER_UINT32)
  SETTER(uint64,      upb_uint64_handlerfunc*,      UPB_HANDLER_UINT64)
  SETTER(float,       upb_float_handlerfunc*,       UPB_HANDLER_FLOAT)
  SETTER(double,      upb_double_handlerfunc*,      UPB_HANDLER_DOUBLE)
  SETTER(bool,        upb_bool_handlerfunc*,        UPB_HANDLER_BOOL)
  SETTER(startstr,    upb_startstr_handlerfunc*,    UPB_HANDLER_STARTSTR)
  SETTER(string,      upb_string_handlerfunc*,      UPB_HANDLER_STRING)
  SETTER(endstr,      upb_endfield_handlerfunc*,    UPB_HANDLER_ENDSTR)
  SETTER(startseq,    upb_startfield_handlerfunc*,  UPB_HANDLER_STARTSEQ)
  SETTER(startsubmsg, upb_startfield_handlerfunc*,  UPB_HANDLER_STARTSUBMSG)
  SETTER(endsubmsg,   upb_endfield_handlerfunc*,    UPB_HANDLER_ENDSUBMSG)
  SETTER(endseq,      upb_endfield_handlerfunc*,    UPB_HANDLER_ENDSEQ)
  
  #undef SETTER
  
  bool upb_handlers_setunknown(upb_handlers *h, upb_unknown_handlerfunc *func,
                               const upb_handlerattr *attr) {
    return doset(h, UPB_UNKNOWN_SELECTOR, NULL, UPB_HANDLER_INT32,
                 (upb_func *)func, attr);
  }
  
  bool upb_handlers_setstartmsg(upb_handlers *h, upb_startmsg_handlerfunc *func,
                                const upb_handlerattr *attr) {
    return doset(h, UPB_STARTMSG_SELECTOR, NULL, UPB_HANDLER_INT32,
                 (upb_func *)func, attr);
  }
  
  bool upb_handlers_setendmsg(upb_handlers *h, upb_endmsg_handlerfunc *func,
                              const upb_handlerattr *attr) {
    return doset(h, UPB_ENDMSG_SELECTOR, NULL, UPB_HANDLER_INT32,
                 (upb_func *)func, attr);
  }
  
  bool upb_handlers_setsubhandlers(upb_handlers *h, const upb_fielddef *f,
                                   const upb_handlers *sub) {
    UPB_ASSERT(sub);
    UPB_ASSERT(upb_fielddef_issubmsg(f));
    if (SUBH_F(h, f)) return false;  /* Can't reset. */
    if (upb_handlers_msgdef(sub) != upb_fielddef_msgsubdef(f)) {
      return false;
    }
    SUBH_F(h, f) = sub;
    return true;
  }
  
  const upb_handlers *upb_handlers_getsubhandlers(const upb_handlers *h,
                                                  const upb_fielddef *f) {
    UPB_ASSERT(upb_fielddef_issubmsg(f));
    return SUBH_F(h, f);
  }
  
  upb_func *upb_handlers_gethandler(const upb_handlers *h, upb_selector_t s,
                                    const void **handler_data) {
    upb_func *ret = (upb_func *)h->table[s].func;
    if (ret && handler_data) {
      *handler_data = h->table[s].attr.handler_data;
    }
    return ret;
  }
  
  bool upb_handlers_getattr(const upb_handlers *h, upb_selector_t sel,
                            upb_handlerattr *attr) {
    if (!upb_handlers_gethandler(h, sel, NULL))
      return false;
    *attr = h->table[sel].attr;
    return true;
  }
  
  const upb_handlers *upb_handlers_getsubhandlers_sel(const upb_handlers *h,
                                                      upb_selector_t sel) {
    /* STARTSUBMSG selector in sel is the field's selector base. */
    return SUBH(h, sel - UPB_STATIC_SELECTOR_COUNT);
  }
  
  const upb_msgdef *upb_handlers_msgdef(const upb_handlers *h) { return h->msg; }
  
  bool upb_handlers_addcleanup(upb_handlers *h, void *p, upb_handlerfree *func) {
    return upb_handlercache_addcleanup(h->cache, p, func);
  }
  
  upb_handlertype_t upb_handlers_getprimitivehandlertype(const upb_fielddef *f) {
    switch (upb_fielddef_type(f)) {
      case UPB_TYPE_INT32:
      case UPB_TYPE_ENUM: return UPB_HANDLER_INT32;
      case UPB_TYPE_INT64: return UPB_HANDLER_INT64;
      case UPB_TYPE_UINT32: return UPB_HANDLER_UINT32;
      case UPB_TYPE_UINT64: return UPB_HANDLER_UINT64;
      case UPB_TYPE_FLOAT: return UPB_HANDLER_FLOAT;
      case UPB_TYPE_DOUBLE: return UPB_HANDLER_DOUBLE;
      case UPB_TYPE_BOOL: return UPB_HANDLER_BOOL;
      default: UPB_ASSERT(false); return -1;  /* Invalid input. */
    }
  }
  
  bool upb_handlers_getselector(const upb_fielddef *f, upb_handlertype_t type,
                                upb_selector_t *s) {
    uint32_t selector_base = upb_fielddef_selectorbase(f);
    switch (type) {
      case UPB_HANDLER_INT32:
      case UPB_HANDLER_INT64:
      case UPB_HANDLER_UINT32:
      case UPB_HANDLER_UINT64:
      case UPB_HANDLER_FLOAT:
      case UPB_HANDLER_DOUBLE:
      case UPB_HANDLER_BOOL:
        if (!upb_fielddef_isprimitive(f) ||
            upb_handlers_getprimitivehandlertype(f) != type)
          return false;
        *s = selector_base;
        break;
      case UPB_HANDLER_STRING:
        if (upb_fielddef_isstring(f)) {
          *s = selector_base;
        } else if (upb_fielddef_lazy(f)) {
          *s = selector_base + 3;
        } else {
          return false;
        }
        break;
      case UPB_HANDLER_STARTSTR:
        if (upb_fielddef_isstring(f) || upb_fielddef_lazy(f)) {
          *s = selector_base + 1;
        } else {
          return false;
        }
        break;
      case UPB_HANDLER_ENDSTR:
        if (upb_fielddef_isstring(f) || upb_fielddef_lazy(f)) {
          *s = selector_base + 2;
        } else {
          return false;
        }
        break;
      case UPB_HANDLER_STARTSEQ:
        if (!upb_fielddef_isseq(f)) return false;
        *s = selector_base - 2;
        break;
      case UPB_HANDLER_ENDSEQ:
        if (!upb_fielddef_isseq(f)) return false;
        *s = selector_base - 1;
        break;
      case UPB_HANDLER_STARTSUBMSG:
        if (!upb_fielddef_issubmsg(f)) return false;
        /* Selectors for STARTSUBMSG are at the beginning of the table so that the
         * selector can also be used as an index into the "sub" array of
         * subhandlers.  The indexes for the two into these two tables are the
         * same, except that in the handler table the static selectors come first. */
        *s = upb_fielddef_index(f) + UPB_STATIC_SELECTOR_COUNT;
        break;
      case UPB_HANDLER_ENDSUBMSG:
        if (!upb_fielddef_issubmsg(f)) return false;
        *s = selector_base;
        break;
    }
    UPB_ASSERT((size_t)*s < upb_msgdef_selectorcount(upb_fielddef_containingtype(f)));
    return true;
  }
  
  /* upb_handlercache ***********************************************************/
  
  struct upb_handlercache {
    upb_arena *arena;
    upb_inttable tab;  /* maps upb_msgdef* -> upb_handlers*. */
    upb_handlers_callback *callback;
    const void *closure;
  };
  
  const upb_handlers *upb_handlercache_get(upb_handlercache *c,
                                           const upb_msgdef *md) {
    upb_msg_field_iter i;
    upb_value v;
    upb_handlers *h;
  
    if (upb_inttable_lookupptr(&c->tab, md, &v)) {
      return upb_value_getptr(v);
    }
  
    h = upb_handlers_new(md, c, c->arena);
    v = upb_value_ptr(h);
  
    if (!h) return NULL;
    if (!upb_inttable_insertptr(&c->tab, md, v)) return NULL;
  
    c->callback(c->closure, h);
  
    /* For each submessage field, get or create a handlers object and set it as
     * the subhandlers. */
    for(upb_msg_field_begin(&i, md);
        !upb_msg_field_done(&i);
        upb_msg_field_next(&i)) {
      upb_fielddef *f = upb_msg_iter_field(&i);
  
      if (upb_fielddef_issubmsg(f)) {
        const upb_msgdef *subdef = upb_fielddef_msgsubdef(f);
        const upb_handlers *sub_mh = upb_handlercache_get(c, subdef);
  
        if (!sub_mh) return NULL;
  
        upb_handlers_setsubhandlers(h, f, sub_mh);
      }
    }
  
    return h;
  }
  
  
  upb_handlercache *upb_handlercache_new(upb_handlers_callback *callback,
                                         const void *closure) {
    upb_handlercache *cache = upb_gmalloc(sizeof(*cache));
  
    if (!cache) return NULL;
  
    cache->arena = upb_arena_new();
  
    cache->callback = callback;
    cache->closure = closure;
  
    if (!upb_inttable_init(&cache->tab, UPB_CTYPE_PTR)) goto oom;
  
    return cache;
  
  oom:
    upb_gfree(cache);
    return NULL;
  }
  
  void upb_handlercache_free(upb_handlercache *cache) {
    upb_inttable_uninit(&cache->tab);
    upb_arena_free(cache->arena);
    upb_gfree(cache);
  }
  
  bool upb_handlercache_addcleanup(upb_handlercache *c, void *p,
                                   upb_handlerfree *func) {
    return upb_arena_addcleanup(c->arena, p, func);
  }
  
  /* upb_byteshandler ***********************************************************/
  
  bool upb_byteshandler_setstartstr(upb_byteshandler *h,
                                    upb_startstr_handlerfunc *func, void *d) {
    h->table[UPB_STARTSTR_SELECTOR].func = (upb_func*)func;
    h->table[UPB_STARTSTR_SELECTOR].attr.handler_data = d;
    return true;
  }
  
  bool upb_byteshandler_setstring(upb_byteshandler *h,
                                  upb_string_handlerfunc *func, void *d) {
    h->table[UPB_STRING_SELECTOR].func = (upb_func*)func;
    h->table[UPB_STRING_SELECTOR].attr.handler_data = d;
    return true;
  }
  
  bool upb_byteshandler_setendstr(upb_byteshandler *h,
                                  upb_endfield_handlerfunc *func, void *d) {
    h->table[UPB_ENDSTR_SELECTOR].func = (upb_func*)func;
    h->table[UPB_ENDSTR_SELECTOR].attr.handler_data = d;
    return true;
  }
  
  /** Handlers for upb_msg ******************************************************/
  
  typedef struct {
    size_t offset;
    int32_t hasbit;
  } upb_msg_handlerdata;
  
  /* Fallback implementation if the handler is not specialized by the producer. */
  #define MSG_WRITER(type, ctype)                                               \
    bool upb_msg_set ## type (void *c, const void *hd, ctype val) {             \
      uint8_t *m = c;                                                           \
      const upb_msg_handlerdata *d = hd;                                        \
      if (d->hasbit > 0)                                                        \
        *(uint8_t*)&m[d->hasbit / 8] |= 1 << (d->hasbit % 8);                   \
      *(ctype*)&m[d->offset] = val;                                             \
      return true;                                                              \
    }                                                                           \
  
  MSG_WRITER(double, double)
  MSG_WRITER(float,  float)
  MSG_WRITER(int32,  int32_t)
  MSG_WRITER(int64,  int64_t)
  MSG_WRITER(uint32, uint32_t)
  MSG_WRITER(uint64, uint64_t)
  MSG_WRITER(bool,   bool)
  
  bool upb_msg_setscalarhandler(upb_handlers *h, const upb_fielddef *f,
                                size_t offset, int32_t hasbit) {
    upb_handlerattr attr = UPB_HANDLERATTR_INIT;
    bool ok;
  
    upb_msg_handlerdata *d = upb_gmalloc(sizeof(*d));
    if (!d) return false;
    d->offset = offset;
    d->hasbit = hasbit;
  
    attr.handler_data = d;
    attr.alwaysok = true;
    upb_handlers_addcleanup(h, d, upb_gfree);
  
  #define TYPE(u, l) \
    case UPB_TYPE_##u: \
      ok = upb_handlers_set##l(h, f, upb_msg_set##l, &attr); break;
  
    ok = false;
  
    switch (upb_fielddef_type(f)) {
      TYPE(INT64,  int64);
      TYPE(INT32,  int32);
      TYPE(ENUM,   int32);
      TYPE(UINT64, uint64);
      TYPE(UINT32, uint32);
      TYPE(DOUBLE, double);
      TYPE(FLOAT,  float);
      TYPE(BOOL,   bool);
      default: UPB_ASSERT(false); break;
    }
  #undef TYPE
  
    return ok;
  }
  
  bool upb_msg_getscalarhandlerdata(const upb_handlers *h,
                                    upb_selector_t s,
                                    upb_fieldtype_t *type,
                                    size_t *offset,
                                    int32_t *hasbit) {
    const upb_msg_handlerdata *d;
    const void *p;
    upb_func *f = upb_handlers_gethandler(h, s, &p);
  
    if ((upb_int64_handlerfunc*)f == upb_msg_setint64) {
      *type = UPB_TYPE_INT64;
    } else if ((upb_int32_handlerfunc*)f == upb_msg_setint32) {
      *type = UPB_TYPE_INT32;
    } else if ((upb_uint64_handlerfunc*)f == upb_msg_setuint64) {
      *type = UPB_TYPE_UINT64;
    } else if ((upb_uint32_handlerfunc*)f == upb_msg_setuint32) {
      *type = UPB_TYPE_UINT32;
    } else if ((upb_double_handlerfunc*)f == upb_msg_setdouble) {
      *type = UPB_TYPE_DOUBLE;
    } else if ((upb_float_handlerfunc*)f == upb_msg_setfloat) {
      *type = UPB_TYPE_FLOAT;
    } else if ((upb_bool_handlerfunc*)f == upb_msg_setbool) {
      *type = UPB_TYPE_BOOL;
    } else {
      return false;
    }
  
    d = p;
    *offset = d->offset;
    *hasbit = d->hasbit;
    return true;
  }
  
  
  bool upb_bufsrc_putbuf(const char *buf, size_t len, upb_bytessink sink) {
    void *subc;
    bool ret;
    upb_bufhandle handle = UPB_BUFHANDLE_INIT;
    handle.buf = buf;
    ret = upb_bytessink_start(sink, len, &subc);
    if (ret && len != 0) {
      ret = (upb_bytessink_putbuf(sink, subc, buf, len, &handle) >= len);
    }
    if (ret) {
      ret = upb_bytessink_end(sink);
    }
    return ret;
  }
  /*
  ** protobuf decoder bytecode compiler
  **
  ** Code to compile a upb::Handlers into bytecode for decoding a protobuf
  ** according to that specific schema and destination handlers.
  **
  ** Bytecode definition is in decoder.int.h.
  */
  
  #include <stdarg.h>
  
  #ifdef UPB_DUMP_BYTECODE
  #include <stdio.h>
  #endif
  
  
  #define MAXLABEL 5
  #define EMPTYLABEL -1
  
  /* upb_pbdecodermethod ********************************************************/
  
  static void freemethod(upb_pbdecodermethod *method) {
    upb_inttable_uninit(&method->dispatch);
    upb_gfree(method);
  }
  
  static upb_pbdecodermethod *newmethod(const upb_handlers *dest_handlers,
                                        mgroup *group) {
    upb_pbdecodermethod *ret = upb_gmalloc(sizeof(*ret));
    upb_byteshandler_init(&ret->input_handler_);
  
    ret->group = group;
    ret->dest_handlers_ = dest_handlers;
    upb_inttable_init(&ret->dispatch, UPB_CTYPE_UINT64);
  
    return ret;
  }
  
  const upb_handlers *upb_pbdecodermethod_desthandlers(
      const upb_pbdecodermethod *m) {
    return m->dest_handlers_;
  }
  
  const upb_byteshandler *upb_pbdecodermethod_inputhandler(
      const upb_pbdecodermethod *m) {
    return &m->input_handler_;
  }
  
  bool upb_pbdecodermethod_isnative(const upb_pbdecodermethod *m) {
    return m->is_native_;
  }
  
  
  /* mgroup *********************************************************************/
  
  static void freegroup(mgroup *g) {
    upb_inttable_iter i;
  
    upb_inttable_begin(&i, &g->methods);
    for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
      freemethod(upb_value_getptr(upb_inttable_iter_value(&i)));
    }
  
    upb_inttable_uninit(&g->methods);
    upb_gfree(g->bytecode);
    upb_gfree(g);
  }
  
  mgroup *newgroup(void) {
    mgroup *g = upb_gmalloc(sizeof(*g));
    upb_inttable_init(&g->methods, UPB_CTYPE_PTR);
    g->bytecode = NULL;
    g->bytecode_end = NULL;
    return g;
  }
  
  
  /* bytecode compiler **********************************************************/
  
  /* Data used only at compilation time. */
  typedef struct {
    mgroup *group;
  
    uint32_t *pc;
    int fwd_labels[MAXLABEL];
    int back_labels[MAXLABEL];
  
    /* For fields marked "lazy", parse them lazily or eagerly? */
    bool lazy;
  } compiler;
  
  static compiler *newcompiler(mgroup *group, bool lazy) {
    compiler *ret = upb_gmalloc(sizeof(*ret));
    int i;
  
    ret->group = group;
    ret->lazy = lazy;
    for (i = 0; i < MAXLABEL; i++) {
      ret->fwd_labels[i] = EMPTYLABEL;
      ret->back_labels[i] = EMPTYLABEL;
    }
    return ret;
  }
  
  static void freecompiler(compiler *c) {
    upb_gfree(c);
  }
  
  const size_t ptr_words = sizeof(void*) / sizeof(uint32_t);
  
  /* How many words an instruction is. */
  static int instruction_len(uint32_t instr) {
    switch (getop(instr)) {
      case OP_SETDISPATCH: return 1 + ptr_words;
      case OP_TAGN: return 3;
      case OP_SETBIGGROUPNUM: return 2;
      default: return 1;
    }
  }
  
  bool op_has_longofs(int32_t instruction) {
    switch (getop(instruction)) {
      case OP_CALL:
      case OP_BRANCH:
      case OP_CHECKDELIM:
        return true;
      /* The "tag" instructions only have 8 bytes available for the jump target,
       * but that is ok because these opcodes only require short jumps. */
      case OP_TAG1:
      case OP_TAG2:
      case OP_TAGN:
        return false;
      default:
        UPB_ASSERT(false);
        return false;
    }
  }
  
  static int32_t getofs(uint32_t instruction) {
    if (op_has_longofs(instruction)) {
      return (int32_t)instruction >> 8;
    } else {
      return (int8_t)(instruction >> 8);
    }
  }
  
  static void setofs(uint32_t *instruction, int32_t ofs) {
    if (op_has_longofs(*instruction)) {
      *instruction = getop(*instruction) | (uint32_t)ofs << 8;
    } else {
      *instruction = (*instruction & ~0xff00) | ((ofs & 0xff) << 8);
    }
    UPB_ASSERT(getofs(*instruction) == ofs);  /* Would fail in cases of overflow. */
  }
  
  static uint32_t pcofs(compiler *c) { return c->pc - c->group->bytecode; }
  
  /* Defines a local label at the current PC location.  All previous forward
   * references are updated to point to this location.  The location is noted
   * for any future backward references. */
  static void label(compiler *c, unsigned int label) {
    int val;
    uint32_t *codep;
  
    UPB_ASSERT(label < MAXLABEL);
    val = c->fwd_labels[label];
    codep = (val == EMPTYLABEL) ? NULL : c->group->bytecode + val;
    while (codep) {
      int ofs = getofs(*codep);
      setofs(codep, c->pc - codep - instruction_len(*codep));
      codep = ofs ? codep + ofs : NULL;
    }
    c->fwd_labels[label] = EMPTYLABEL;
    c->back_labels[label] = pcofs(c);
  }
  
  /* Creates a reference to a numbered label; either a forward reference
   * (positive arg) or backward reference (negative arg).  For forward references
   * the value returned now is actually a "next" pointer into a linked list of all
   * instructions that use this label and will be patched later when the label is
   * defined with label().
   *
   * The returned value is the offset that should be written into the instruction.
   */
  static int32_t labelref(compiler *c, int label) {
    UPB_ASSERT(label < MAXLABEL);
    if (label == LABEL_DISPATCH) {
      /* No resolving required. */
      return 0;
    } else if (label < 0) {
      /* Backward local label.  Relative to the next instruction. */
      uint32_t from = (c->pc + 1) - c->group->bytecode;
      return c->back_labels[-label] - from;
    } else {
      /* Forward local label: prepend to (possibly-empty) linked list. */
      int *lptr = &c->fwd_labels[label];
      int32_t ret = (*lptr == EMPTYLABEL) ? 0 : *lptr - pcofs(c);
      *lptr = pcofs(c);
      return ret;
    }
  }
  
  static void put32(compiler *c, uint32_t v) {
    mgroup *g = c->group;
    if (c->pc == g->bytecode_end) {
      int ofs = pcofs(c);
      size_t oldsize = g->bytecode_end - g->bytecode;
      size_t newsize = UPB_MAX(oldsize * 2, 64);
      /* TODO(haberman): handle OOM. */
      g->bytecode = upb_grealloc(g->bytecode, oldsize * sizeof(uint32_t),
                                              newsize * sizeof(uint32_t));
      g->bytecode_end = g->bytecode + newsize;
      c->pc = g->bytecode + ofs;
    }
    *c->pc++ = v;
  }
  
  static void putop(compiler *c, int op, ...) {
    va_list ap;
    va_start(ap, op);
  
    switch (op) {
      case OP_SETDISPATCH: {
        uintptr_t ptr = (uintptr_t)va_arg(ap, void*);
        put32(c, OP_SETDISPATCH);
        put32(c, ptr);
        if (sizeof(uintptr_t) > sizeof(uint32_t))
          put32(c, (uint64_t)ptr >> 32);
        break;
      }
      case OP_STARTMSG:
      case OP_ENDMSG:
      case OP_PUSHLENDELIM:
      case OP_POP:
      case OP_SETDELIM:
      case OP_HALT:
      case OP_RET:
      case OP_DISPATCH:
        put32(c, op);
        break;
      case OP_PARSE_DOUBLE:
      case OP_PARSE_FLOAT:
      case OP_PARSE_INT64:
      case OP_PARSE_UINT64:
      case OP_PARSE_INT32:
      case OP_PARSE_FIXED64:
      case OP_PARSE_FIXED32:
      case OP_PARSE_BOOL:
      case OP_PARSE_UINT32:
      case OP_PARSE_SFIXED32:
      case OP_PARSE_SFIXED64:
      case OP_PARSE_SINT32:
      case OP_PARSE_SINT64:
      case OP_STARTSEQ:
      case OP_ENDSEQ:
      case OP_STARTSUBMSG:
      case OP_ENDSUBMSG:
      case OP_STARTSTR:
      case OP_STRING:
      case OP_ENDSTR:
      case OP_PUSHTAGDELIM:
        put32(c, op | va_arg(ap, upb_selector_t) << 8);
        break;
      case OP_SETBIGGROUPNUM:
        put32(c, op);
        put32(c, va_arg(ap, int));
        break;
      case OP_CALL: {
        const upb_pbdecodermethod *method = va_arg(ap, upb_pbdecodermethod *);
        put32(c, op | (method->code_base.ofs - (pcofs(c) + 1)) << 8);
        break;
      }
      case OP_CHECKDELIM:
      case OP_BRANCH: {
        uint32_t instruction = op;
        int label = va_arg(ap, int);
        setofs(&instruction, labelref(c, label));
        put32(c, instruction);
        break;
      }
      case OP_TAG1:
      case OP_TAG2: {
        int label = va_arg(ap, int);
        uint64_t tag = va_arg(ap, uint64_t);
        uint32_t instruction = op | (tag << 16);
        UPB_ASSERT(tag <= 0xffff);
        setofs(&instruction, labelref(c, label));
        put32(c, instruction);
        break;
      }
      case OP_TAGN: {
        int label = va_arg(ap, int);
        uint64_t tag = va_arg(ap, uint64_t);
        uint32_t instruction = op | (upb_value_size(tag) << 16);
        setofs(&instruction, labelref(c, label));
        put32(c, instruction);
        put32(c, tag);
        put32(c, tag >> 32);
        break;
      }
    }
  
    va_end(ap);
  }
  
  #if defined(UPB_DUMP_BYTECODE)
  
  const char *upb_pbdecoder_getopname(unsigned int op) {
  #define QUOTE(x) #x
  #define EXPAND_AND_QUOTE(x) QUOTE(x)
  #define OPNAME(x) OP_##x
  #define OP(x) case OPNAME(x): return EXPAND_AND_QUOTE(OPNAME(x));
  #define T(x) OP(PARSE_##x)
    /* Keep in sync with list in decoder.int.h. */
    switch ((opcode)op) {
      T(DOUBLE) T(FLOAT) T(INT64) T(UINT64) T(INT32) T(FIXED64) T(FIXED32)
      T(BOOL) T(UINT32) T(SFIXED32) T(SFIXED64) T(SINT32) T(SINT64)
      OP(STARTMSG) OP(ENDMSG) OP(STARTSEQ) OP(ENDSEQ) OP(STARTSUBMSG)
      OP(ENDSUBMSG) OP(STARTSTR) OP(STRING) OP(ENDSTR) OP(CALL) OP(RET)
      OP(PUSHLENDELIM) OP(PUSHTAGDELIM) OP(SETDELIM) OP(CHECKDELIM)
      OP(BRANCH) OP(TAG1) OP(TAG2) OP(TAGN) OP(SETDISPATCH) OP(POP)
      OP(SETBIGGROUPNUM) OP(DISPATCH) OP(HALT)
    }
    return "<unknown op>";
  #undef OP
  #undef T
  }
  
  #endif
  
  #ifdef UPB_DUMP_BYTECODE
  
  static void dumpbc(uint32_t *p, uint32_t *end, FILE *f) {
  
    uint32_t *begin = p;
  
    while (p < end) {
      fprintf(f, "%p  %8tx", p, p - begin);
      uint32_t instr = *p++;
      uint8_t op = getop(instr);
      fprintf(f, " %s", upb_pbdecoder_getopname(op));
      switch ((opcode)op) {
        case OP_SETDISPATCH: {
          const upb_inttable *dispatch;
          memcpy(&dispatch, p, sizeof(void*));
          p += ptr_words;
          const upb_pbdecodermethod *method =
              (void *)((char *)dispatch -
                       offsetof(upb_pbdecodermethod, dispatch));
          fprintf(f, " %s", upb_msgdef_fullname(
                                upb_handlers_msgdef(method->dest_handlers_)));
          break;
        }
        case OP_DISPATCH:
        case OP_STARTMSG:
        case OP_ENDMSG:
        case OP_PUSHLENDELIM:
        case OP_POP:
        case OP_SETDELIM:
        case OP_HALT:
        case OP_RET:
          break;
        case OP_PARSE_DOUBLE:
        case OP_PARSE_FLOAT:
        case OP_PARSE_INT64:
        case OP_PARSE_UINT64:
        case OP_PARSE_INT32:
        case OP_PARSE_FIXED64:
        case OP_PARSE_FIXED32:
        case OP_PARSE_BOOL:
        case OP_PARSE_UINT32:
        case OP_PARSE_SFIXED32:
        case OP_PARSE_SFIXED64:
        case OP_PARSE_SINT32:
        case OP_PARSE_SINT64:
        case OP_STARTSEQ:
        case OP_ENDSEQ:
        case OP_STARTSUBMSG:
        case OP_ENDSUBMSG:
        case OP_STARTSTR:
        case OP_STRING:
        case OP_ENDSTR:
        case OP_PUSHTAGDELIM:
          fprintf(f, " %d", instr >> 8);
          break;
        case OP_SETBIGGROUPNUM:
          fprintf(f, " %d", *p++);
          break;
        case OP_CHECKDELIM:
        case OP_CALL:
        case OP_BRANCH:
          fprintf(f, " =>0x%tx", p + getofs(instr) - begin);
          break;
        case OP_TAG1:
        case OP_TAG2: {
          fprintf(f, " tag:0x%x", instr >> 16);
          if (getofs(instr)) {
            fprintf(f, " =>0x%tx", p + getofs(instr) - begin);
          }
          break;
        }
        case OP_TAGN: {
          uint64_t tag = *p++;
          tag |= (uint64_t)*p++ << 32;
          fprintf(f, " tag:0x%llx", (long long)tag);
          fprintf(f, " n:%d", instr >> 16);
          if (getofs(instr)) {
            fprintf(f, " =>0x%tx", p + getofs(instr) - begin);
          }
          break;
        }
      }
      fputs("\n", f);
    }
  }
  
  #endif
  
  static uint64_t get_encoded_tag(const upb_fielddef *f, int wire_type) {
    uint32_t tag = (upb_fielddef_number(f) << 3) | wire_type;
    uint64_t encoded_tag = upb_vencode32(tag);
    /* No tag should be greater than 5 bytes. */
    UPB_ASSERT(encoded_tag <= 0xffffffffff);
    return encoded_tag;
  }
  
  static void putchecktag(compiler *c, const upb_fielddef *f,
                          int wire_type, int dest) {
    uint64_t tag = get_encoded_tag(f, wire_type);
    switch (upb_value_size(tag)) {
      case 1:
        putop(c, OP_TAG1, dest, tag);
        break;
      case 2:
        putop(c, OP_TAG2, dest, tag);
        break;
      default:
        putop(c, OP_TAGN, dest, tag);
        break;
    }
  }
  
  static upb_selector_t getsel(const upb_fielddef *f, upb_handlertype_t type) {
    upb_selector_t selector;
    bool ok = upb_handlers_getselector(f, type, &selector);
    UPB_ASSERT(ok);
    return selector;
  }
  
  /* Takes an existing, primary dispatch table entry and repacks it with a
   * different alternate wire type.  Called when we are inserting a secondary
   * dispatch table entry for an alternate wire type. */
  static uint64_t repack(uint64_t dispatch, int new_wt2) {
    uint64_t ofs;
    uint8_t wt1;
    uint8_t old_wt2;
    upb_pbdecoder_unpackdispatch(dispatch, &ofs, &wt1, &old_wt2);
    UPB_ASSERT(old_wt2 == NO_WIRE_TYPE);  /* wt2 should not be set yet. */
    return upb_pbdecoder_packdispatch(ofs, wt1, new_wt2);
  }
  
  /* Marks the current bytecode position as the dispatch target for this message,
   * field, and wire type. */
  static void dispatchtarget(compiler *c, upb_pbdecodermethod *method,
                             const upb_fielddef *f, int wire_type) {
    /* Offset is relative to msg base. */
    uint64_t ofs = pcofs(c) - method->code_base.ofs;
    uint32_t fn = upb_fielddef_number(f);
    upb_inttable *d = &method->dispatch;
    upb_value v;
    if (upb_inttable_remove(d, fn, &v)) {
      /* TODO: prioritize based on packed setting in .proto file. */
      uint64_t repacked = repack(upb_value_getuint64(v), wire_type);
      upb_inttable_insert(d, fn, upb_value_uint64(repacked));
      upb_inttable_insert(d, fn + UPB_MAX_FIELDNUMBER, upb_value_uint64(ofs));
    } else {
      uint64_t val = upb_pbdecoder_packdispatch(ofs, wire_type, NO_WIRE_TYPE);
      upb_inttable_insert(d, fn, upb_value_uint64(val));
    }
  }
  
  static void putpush(compiler *c, const upb_fielddef *f) {
    if (upb_fielddef_descriptortype(f) == UPB_DESCRIPTOR_TYPE_MESSAGE) {
      putop(c, OP_PUSHLENDELIM);
    } else {
      uint32_t fn = upb_fielddef_number(f);
      if (fn >= 1 << 24) {
        putop(c, OP_PUSHTAGDELIM, 0);
        putop(c, OP_SETBIGGROUPNUM, fn);
      } else {
        putop(c, OP_PUSHTAGDELIM, fn);
      }
    }
  }
  
  static upb_pbdecodermethod *find_submethod(const compiler *c,
                                             const upb_pbdecodermethod *method,
                                             const upb_fielddef *f) {
    const upb_handlers *sub =
        upb_handlers_getsubhandlers(method->dest_handlers_, f);
    upb_value v;
    return upb_inttable_lookupptr(&c->group->methods, sub, &v)
               ? upb_value_getptr(v)
               : NULL;
  }
  
  static void putsel(compiler *c, opcode op, upb_selector_t sel,
                     const upb_handlers *h) {
    if (upb_handlers_gethandler(h, sel, NULL)) {
      putop(c, op, sel);
    }
  }
  
  /* Puts an opcode to call a callback, but only if a callback actually exists for
   * this field and handler type. */
  static void maybeput(compiler *c, opcode op, const upb_handlers *h,
                       const upb_fielddef *f, upb_handlertype_t type) {
    putsel(c, op, getsel(f, type), h);
  }
  
  static bool haslazyhandlers(const upb_handlers *h, const upb_fielddef *f) {
    if (!upb_fielddef_lazy(f))
      return false;
  
    return upb_handlers_gethandler(h, getsel(f, UPB_HANDLER_STARTSTR), NULL) ||
           upb_handlers_gethandler(h, getsel(f, UPB_HANDLER_STRING), NULL) ||
           upb_handlers_gethandler(h, getsel(f, UPB_HANDLER_ENDSTR), NULL);
  }
  
  
  /* bytecode compiler code generation ******************************************/
  
  /* Symbolic names for our local labels. */
  #define LABEL_LOOPSTART 1  /* Top of a repeated field loop. */
  #define LABEL_LOOPBREAK 2  /* To jump out of a repeated loop */
  #define LABEL_FIELD     3  /* Jump backward to find the most recent field. */
  #define LABEL_ENDMSG    4  /* To reach the OP_ENDMSG instr for this msg. */
  
  /* Generates bytecode to parse a single non-lazy message field. */
  static void generate_msgfield(compiler *c, const upb_fielddef *f,
                                upb_pbdecodermethod *method) {
    const upb_handlers *h = upb_pbdecodermethod_desthandlers(method);
    const upb_pbdecodermethod *sub_m = find_submethod(c, method, f);
    int wire_type;
  
    if (!sub_m) {
      /* Don't emit any code for this field at all; it will be parsed as an
       * unknown field.
       *
       * TODO(haberman): we should change this to parse it as a string field
       * instead.  It will probably be faster, but more importantly, once we
       * start vending unknown fields, a field shouldn't be treated as unknown
       * just because it doesn't have subhandlers registered. */
      return;
    }
  
    label(c, LABEL_FIELD);
  
    wire_type =
        (upb_fielddef_descriptortype(f) == UPB_DESCRIPTOR_TYPE_MESSAGE)
            ? UPB_WIRE_TYPE_DELIMITED
            : UPB_WIRE_TYPE_START_GROUP;
  
    if (upb_fielddef_isseq(f)) {
      putop(c, OP_CHECKDELIM, LABEL_ENDMSG);
      putchecktag(c, f, wire_type, LABEL_DISPATCH);
     dispatchtarget(c, method, f, wire_type);
      putop(c, OP_PUSHTAGDELIM, 0);
      putop(c, OP_STARTSEQ, getsel(f, UPB_HANDLER_STARTSEQ));
     label(c, LABEL_LOOPSTART);
      putpush(c, f);
      putop(c, OP_STARTSUBMSG, getsel(f, UPB_HANDLER_STARTSUBMSG));
      putop(c, OP_CALL, sub_m);
      putop(c, OP_POP);
      maybeput(c, OP_ENDSUBMSG, h, f, UPB_HANDLER_ENDSUBMSG);
      if (wire_type == UPB_WIRE_TYPE_DELIMITED) {
        putop(c, OP_SETDELIM);
      }
      putop(c, OP_CHECKDELIM, LABEL_LOOPBREAK);
      putchecktag(c, f, wire_type, LABEL_LOOPBREAK);
      putop(c, OP_BRANCH, -LABEL_LOOPSTART);
     label(c, LABEL_LOOPBREAK);
      putop(c, OP_POP);
      maybeput(c, OP_ENDSEQ, h, f, UPB_HANDLER_ENDSEQ);
    } else {
      putop(c, OP_CHECKDELIM, LABEL_ENDMSG);
      putchecktag(c, f, wire_type, LABEL_DISPATCH);
     dispatchtarget(c, method, f, wire_type);
      putpush(c, f);
      putop(c, OP_STARTSUBMSG, getsel(f, UPB_HANDLER_STARTSUBMSG));
      putop(c, OP_CALL, sub_m);
      putop(c, OP_POP);
      maybeput(c, OP_ENDSUBMSG, h, f, UPB_HANDLER_ENDSUBMSG);
      if (wire_type == UPB_WIRE_TYPE_DELIMITED) {
        putop(c, OP_SETDELIM);
      }
    }
  }
  
  /* Generates bytecode to parse a single string or lazy submessage field. */
  static void generate_delimfield(compiler *c, const upb_fielddef *f,
                                  upb_pbdecodermethod *method) {
    const upb_handlers *h = upb_pbdecodermethod_desthandlers(method);
  
    label(c, LABEL_FIELD);
    if (upb_fielddef_isseq(f)) {
      putop(c, OP_CHECKDELIM, LABEL_ENDMSG);
      putchecktag(c, f, UPB_WIRE_TYPE_DELIMITED, LABEL_DISPATCH);
     dispatchtarget(c, method, f, UPB_WIRE_TYPE_DELIMITED);
      putop(c, OP_PUSHTAGDELIM, 0);
      putop(c, OP_STARTSEQ, getsel(f, UPB_HANDLER_STARTSEQ));
     label(c, LABEL_LOOPSTART);
      putop(c, OP_PUSHLENDELIM);
      putop(c, OP_STARTSTR, getsel(f, UPB_HANDLER_STARTSTR));
      /* Need to emit even if no handler to skip past the string. */
      putop(c, OP_STRING, getsel(f, UPB_HANDLER_STRING));
      maybeput(c, OP_ENDSTR, h, f, UPB_HANDLER_ENDSTR);
      putop(c, OP_POP);
      putop(c, OP_SETDELIM);
      putop(c, OP_CHECKDELIM, LABEL_LOOPBREAK);
      putchecktag(c, f, UPB_WIRE_TYPE_DELIMITED, LABEL_LOOPBREAK);
      putop(c, OP_BRANCH, -LABEL_LOOPSTART);
     label(c, LABEL_LOOPBREAK);
      putop(c, OP_POP);
      maybeput(c, OP_ENDSEQ, h, f, UPB_HANDLER_ENDSEQ);
    } else {
      putop(c, OP_CHECKDELIM, LABEL_ENDMSG);
      putchecktag(c, f, UPB_WIRE_TYPE_DELIMITED, LABEL_DISPATCH);
     dispatchtarget(c, method, f, UPB_WIRE_TYPE_DELIMITED);
      putop(c, OP_PUSHLENDELIM);
      putop(c, OP_STARTSTR, getsel(f, UPB_HANDLER_STARTSTR));
      putop(c, OP_STRING, getsel(f, UPB_HANDLER_STRING));
      maybeput(c, OP_ENDSTR, h, f, UPB_HANDLER_ENDSTR);
      putop(c, OP_POP);
      putop(c, OP_SETDELIM);
    }
  }
  
  /* Generates bytecode to parse a single primitive field. */
  static void generate_primitivefield(compiler *c, const upb_fielddef *f,
                                      upb_pbdecodermethod *method) {
    const upb_handlers *h = upb_pbdecodermethod_desthandlers(method);
    upb_descriptortype_t descriptor_type = upb_fielddef_descriptortype(f);
    opcode parse_type;
    upb_selector_t sel;
    int wire_type;
  
    label(c, LABEL_FIELD);
  
    /* From a decoding perspective, ENUM is the same as INT32. */
    if (descriptor_type == UPB_DESCRIPTOR_TYPE_ENUM)
      descriptor_type = UPB_DESCRIPTOR_TYPE_INT32;
  
    parse_type = (opcode)descriptor_type;
  
    /* TODO(haberman): generate packed or non-packed first depending on "packed"
     * setting in the fielddef.  This will favor (in speed) whichever was
     * specified. */
  
    UPB_ASSERT((int)parse_type >= 0 && parse_type <= OP_MAX);
    sel = getsel(f, upb_handlers_getprimitivehandlertype(f));
    wire_type = upb_pb_native_wire_types[upb_fielddef_descriptortype(f)];
    if (upb_fielddef_isseq(f)) {
      putop(c, OP_CHECKDELIM, LABEL_ENDMSG);
      putchecktag(c, f, UPB_WIRE_TYPE_DELIMITED, LABEL_DISPATCH);
     dispatchtarget(c, method, f, UPB_WIRE_TYPE_DELIMITED);
      putop(c, OP_PUSHLENDELIM);
      putop(c, OP_STARTSEQ, getsel(f, UPB_HANDLER_STARTSEQ));  /* Packed */
     label(c, LABEL_LOOPSTART);
      putop(c, parse_type, sel);
      putop(c, OP_CHECKDELIM, LABEL_LOOPBREAK);
      putop(c, OP_BRANCH, -LABEL_LOOPSTART);
     dispatchtarget(c, method, f, wire_type);
      putop(c, OP_PUSHTAGDELIM, 0);
      putop(c, OP_STARTSEQ, getsel(f, UPB_HANDLER_STARTSEQ));  /* Non-packed */
     label(c, LABEL_LOOPSTART);
      putop(c, parse_type, sel);
      putop(c, OP_CHECKDELIM, LABEL_LOOPBREAK);
      putchecktag(c, f, wire_type, LABEL_LOOPBREAK);
      putop(c, OP_BRANCH, -LABEL_LOOPSTART);
     label(c, LABEL_LOOPBREAK);
      putop(c, OP_POP);  /* Packed and non-packed join. */
      maybeput(c, OP_ENDSEQ, h, f, UPB_HANDLER_ENDSEQ);
      putop(c, OP_SETDELIM);  /* Could remove for non-packed by dup ENDSEQ. */
    } else {
      putop(c, OP_CHECKDELIM, LABEL_ENDMSG);
      putchecktag(c, f, wire_type, LABEL_DISPATCH);
     dispatchtarget(c, method, f, wire_type);
      putop(c, parse_type, sel);
    }
  }
  
  /* Adds bytecode for parsing the given message to the given decoderplan,
   * while adding all dispatch targets to this message's dispatch table. */
  static void compile_method(compiler *c, upb_pbdecodermethod *method) {
    const upb_handlers *h;
    const upb_msgdef *md;
    uint32_t* start_pc;
    upb_msg_field_iter i;
    upb_value val;
  
    UPB_ASSERT(method);
  
    /* Clear all entries in the dispatch table. */
    upb_inttable_uninit(&method->dispatch);
    upb_inttable_init(&method->dispatch, UPB_CTYPE_UINT64);
  
    h = upb_pbdecodermethod_desthandlers(method);
    md = upb_handlers_msgdef(h);
  
   method->code_base.ofs = pcofs(c);
    putop(c, OP_SETDISPATCH, &method->dispatch);
    putsel(c, OP_STARTMSG, UPB_STARTMSG_SELECTOR, h);
   label(c, LABEL_FIELD);
    start_pc = c->pc;
    for(upb_msg_field_begin(&i, md);
        !upb_msg_field_done(&i);
        upb_msg_field_next(&i)) {
      const upb_fielddef *f = upb_msg_iter_field(&i);
      upb_fieldtype_t type = upb_fielddef_type(f);
  
      if (type == UPB_TYPE_MESSAGE && !(haslazyhandlers(h, f) && c->lazy)) {
        generate_msgfield(c, f, method);
      } else if (type == UPB_TYPE_STRING || type == UPB_TYPE_BYTES ||
                 type == UPB_TYPE_MESSAGE) {
        generate_delimfield(c, f, method);
      } else {
        generate_primitivefield(c, f, method);
      }
    }
  
    /* If there were no fields, or if no handlers were defined, we need to
     * generate a non-empty loop body so that we can at least dispatch for unknown
     * fields and check for the end of the message. */
    if (c->pc == start_pc) {
      /* Check for end-of-message. */
      putop(c, OP_CHECKDELIM, LABEL_ENDMSG);
      /* Unconditionally dispatch. */
      putop(c, OP_DISPATCH, 0);
    }
  
    /* For now we just loop back to the last field of the message (or if none,
     * the DISPATCH opcode for the message). */
    putop(c, OP_BRANCH, -LABEL_FIELD);
  
    /* Insert both a label and a dispatch table entry for this end-of-msg. */
   label(c, LABEL_ENDMSG);
    val = upb_value_uint64(pcofs(c) - method->code_base.ofs);
    upb_inttable_insert(&method->dispatch, DISPATCH_ENDMSG, val);
  
    putsel(c, OP_ENDMSG, UPB_ENDMSG_SELECTOR, h);
    putop(c, OP_RET);
  
    upb_inttable_compact(&method->dispatch);
  }
  
  /* Populate "methods" with new upb_pbdecodermethod objects reachable from "h".
   * Returns the method for these handlers.
   *
   * Generates a new method for every destination handlers reachable from "h". */
  static void find_methods(compiler *c, const upb_handlers *h) {
    upb_value v;
    upb_msg_field_iter i;
    const upb_msgdef *md;
    upb_pbdecodermethod *method;
  
    if (upb_inttable_lookupptr(&c->group->methods, h, &v))
      return;
  
    method = newmethod(h, c->group);
    upb_inttable_insertptr(&c->group->methods, h, upb_value_ptr(method));
  
    /* Find submethods. */
    md = upb_handlers_msgdef(h);
    for(upb_msg_field_begin(&i, md);
        !upb_msg_field_done(&i);
        upb_msg_field_next(&i)) {
      const upb_fielddef *f = upb_msg_iter_field(&i);
      const upb_handlers *sub_h;
      if (upb_fielddef_type(f) == UPB_TYPE_MESSAGE &&
          (sub_h = upb_handlers_getsubhandlers(h, f)) != NULL) {
        /* We only generate a decoder method for submessages with handlers.
         * Others will be parsed as unknown fields. */
        find_methods(c, sub_h);
      }
    }
  }
  
  /* (Re-)compile bytecode for all messages in "msgs."
   * Overwrites any existing bytecode in "c". */
  static void compile_methods(compiler *c) {
    upb_inttable_iter i;
  
    /* Start over at the beginning of the bytecode. */
    c->pc = c->group->bytecode;
  
    upb_inttable_begin(&i, &c->group->methods);
    for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
      upb_pbdecodermethod *method = upb_value_getptr(upb_inttable_iter_value(&i));
      compile_method(c, method);
    }
  }
  
  static void set_bytecode_handlers(mgroup *g) {
    upb_inttable_iter i;
    upb_inttable_begin(&i, &g->methods);
    for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
      upb_pbdecodermethod *m = upb_value_getptr(upb_inttable_iter_value(&i));
      upb_byteshandler *h = &m->input_handler_;
  
      m->code_base.ptr = g->bytecode + m->code_base.ofs;
  
      upb_byteshandler_setstartstr(h, upb_pbdecoder_startbc, m->code_base.ptr);
      upb_byteshandler_setstring(h, upb_pbdecoder_decode, g);
      upb_byteshandler_setendstr(h, upb_pbdecoder_end, m);
    }
  }
  
  
  /* TODO(haberman): allow this to be constructed for an arbitrary set of dest
   * handlers and other mgroups (but verify we have a transitive closure). */
  const mgroup *mgroup_new(const upb_handlers *dest, bool lazy) {
    mgroup *g;
    compiler *c;
  
    g = newgroup();
    c = newcompiler(g, lazy);
    find_methods(c, dest);
  
    /* We compile in two passes:
     * 1. all messages are assigned relative offsets from the beginning of the
     *    bytecode (saved in method->code_base).
     * 2. forwards OP_CALL instructions can be correctly linked since message
     *    offsets have been previously assigned.
     *
     * Could avoid the second pass by linking OP_CALL instructions somehow. */
    compile_methods(c);
    compile_methods(c);
    g->bytecode_end = c->pc;
    freecompiler(c);
  
  #ifdef UPB_DUMP_BYTECODE
    {
      FILE *f = fopen("/tmp/upb-bytecode", "w");
      UPB_ASSERT(f);
      dumpbc(g->bytecode, g->bytecode_end, stderr);
      dumpbc(g->bytecode, g->bytecode_end, f);
      fclose(f);
  
      f = fopen("/tmp/upb-bytecode.bin", "wb");
      UPB_ASSERT(f);
      fwrite(g->bytecode, 1, g->bytecode_end - g->bytecode, f);
      fclose(f);
    }
  #endif
  
    set_bytecode_handlers(g);
    return g;
  }
  
  
  /* upb_pbcodecache ************************************************************/
  
  upb_pbcodecache *upb_pbcodecache_new(upb_handlercache *dest) {
    upb_pbcodecache *c = upb_gmalloc(sizeof(*c));
  
    if (!c) return NULL;
  
    c->dest = dest;
    c->lazy = false;
  
    c->arena = upb_arena_new();
    if (!upb_inttable_init(&c->groups, UPB_CTYPE_CONSTPTR)) return NULL;
  
    return c;
  }
  
  void upb_pbcodecache_free(upb_pbcodecache *c) {
    upb_inttable_iter i;
  
    upb_inttable_begin(&i, &c->groups);
    for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
      upb_value val = upb_inttable_iter_value(&i);
      freegroup((void*)upb_value_getconstptr(val));
    }
  
    upb_inttable_uninit(&c->groups);
    upb_arena_free(c->arena);
    upb_gfree(c);
  }
  
  void upb_pbdecodermethodopts_setlazy(upb_pbcodecache *c, bool lazy) {
    UPB_ASSERT(upb_inttable_count(&c->groups) == 0);
    c->lazy = lazy;
  }
  
  const upb_pbdecodermethod *upb_pbcodecache_get(upb_pbcodecache *c,
                                                 const upb_msgdef *md) {
    upb_value v;
    bool ok;
    const upb_handlers *h;
    const mgroup *g;
  
    h = upb_handlercache_get(c->dest, md);
    if (upb_inttable_lookupptr(&c->groups, md, &v)) {
      g = upb_value_getconstptr(v);
    } else {
      g = mgroup_new(h, c->lazy);
      ok = upb_inttable_insertptr(&c->groups, md, upb_value_constptr(g));
      UPB_ASSERT(ok);
    }
  
    ok = upb_inttable_lookupptr(&g->methods, h, &v);
    UPB_ASSERT(ok);
    return upb_value_getptr(v);
  }
  /*
  ** upb::Decoder (Bytecode Decoder VM)
  **
  ** Bytecode must previously have been generated using the bytecode compiler in
  ** compile_decoder.c.  This decoder then walks through the bytecode op-by-op to
  ** parse the input.
  **
  ** Decoding is fully resumable; we just keep a pointer to the current bytecode
  ** instruction and resume from there.  A fair amount of the logic here is to
  ** handle the fact that values can span buffer seams and we have to be able to
  ** be capable of suspending/resuming from any byte in the stream.  This
  ** sometimes requires keeping a few trailing bytes from the last buffer around
  ** in the "residual" buffer.
  */
  
  #include <inttypes.h>
  #include <stddef.h>
  
  #ifdef UPB_DUMP_BYTECODE
  #include <stdio.h>
  #endif
  
  
  #define CHECK_SUSPEND(x) if (!(x)) return upb_pbdecoder_suspend(d);
  
  /* Error messages that are shared between the bytecode and JIT decoders. */
  const char *kPbDecoderStackOverflow = "Nesting too deep.";
  const char *kPbDecoderSubmessageTooLong =
      "Submessage end extends past enclosing submessage.";
  
  /* Error messages shared within this file. */
  static const char *kUnterminatedVarint = "Unterminated varint.";
  
  /* upb_pbdecoder **************************************************************/
  
  static opcode halt = OP_HALT;
  
  /* A dummy character we can point to when the user passes us a NULL buffer.
   * We need this because in C (NULL + 0) and (NULL - NULL) are undefined
   * behavior, which would invalidate functions like curbufleft(). */
  static const char dummy_char;
  
  /* Whether an op consumes any of the input buffer. */
  static bool consumes_input(opcode op) {
    switch (op) {
      case OP_SETDISPATCH:
      case OP_STARTMSG:
      case OP_ENDMSG:
      case OP_STARTSEQ:
      case OP_ENDSEQ:
      case OP_STARTSUBMSG:
      case OP_ENDSUBMSG:
      case OP_STARTSTR:
      case OP_ENDSTR:
      case OP_PUSHTAGDELIM:
      case OP_POP:
      case OP_SETDELIM:
      case OP_SETBIGGROUPNUM:
      case OP_CHECKDELIM:
      case OP_CALL:
      case OP_RET:
      case OP_BRANCH:
        return false;
      default:
        return true;
    }
  }
  
  static size_t stacksize(upb_pbdecoder *d, size_t entries) {
    UPB_UNUSED(d);
    return entries * sizeof(upb_pbdecoder_frame);
  }
  
  static size_t callstacksize(upb_pbdecoder *d, size_t entries) {
    UPB_UNUSED(d);
  
    return entries * sizeof(uint32_t*);
  }
  
  
  static bool in_residual_buf(const upb_pbdecoder *d, const char *p);
  
  /* It's unfortunate that we have to micro-manage the compiler with
   * UPB_FORCEINLINE and UPB_NOINLINE, especially since this tuning is necessarily
   * specific to one hardware configuration.  But empirically on a Core i7,
   * performance increases 30-50% with these annotations.  Every instance where
   * these appear, gcc 4.2.1 made the wrong decision and degraded performance in
   * benchmarks. */
  
  static void seterr(upb_pbdecoder *d, const char *msg) {
    upb_status_seterrmsg(d->status, msg);
  }
  
  void upb_pbdecoder_seterr(upb_pbdecoder *d, const char *msg) {
    seterr(d, msg);
  }
  
  
  /* Buffering ******************************************************************/
  
  /* We operate on one buffer at a time, which is either the user's buffer passed
   * to our "decode" callback or some residual bytes from the previous buffer. */
  
  /* How many bytes can be safely read from d->ptr without reading past end-of-buf
   * or past the current delimited end. */
  static size_t curbufleft(const upb_pbdecoder *d) {
    UPB_ASSERT(d->data_end >= d->ptr);
    return d->data_end - d->ptr;
  }
  
  /* How many bytes are available before end-of-buffer. */
  static size_t bufleft(const upb_pbdecoder *d) {
    return d->end - d->ptr;
  }
  
  /* Overall stream offset of d->ptr. */
  uint64_t offset(const upb_pbdecoder *d) {
    return d->bufstart_ofs + (d->ptr - d->buf);
  }
  
  /* How many bytes are available before the end of this delimited region. */
  size_t delim_remaining(const upb_pbdecoder *d) {
    return d->top->end_ofs - offset(d);
  }
  
  /* Advances d->ptr. */
  static void advance(upb_pbdecoder *d, size_t len) {
    UPB_ASSERT(curbufleft(d) >= len);
    d->ptr += len;
  }
  
  static bool in_buf(const char *p, const char *buf, const char *end) {
    return p >= buf && p <= end;
  }
  
  static bool in_residual_buf(const upb_pbdecoder *d, const char *p) {
    return in_buf(p, d->residual, d->residual_end);
  }
  
  /* Calculates the delim_end value, which is affected by both the current buffer
   * and the parsing stack, so must be called whenever either is updated. */
  static void set_delim_end(upb_pbdecoder *d) {
    size_t delim_ofs = d->top->end_ofs - d->bufstart_ofs;
    if (delim_ofs <= (size_t)(d->end - d->buf)) {
      d->delim_end = d->buf + delim_ofs;
      d->data_end = d->delim_end;
    } else {
      d->data_end = d->end;
      d->delim_end = NULL;
    }
  }
  
  static void switchtobuf(upb_pbdecoder *d, const char *buf, const char *end) {
    d->ptr = buf;
    d->buf = buf;
    d->end = end;
    set_delim_end(d);
  }
  
  static void advancetobuf(upb_pbdecoder *d, const char *buf, size_t len) {
    UPB_ASSERT(curbufleft(d) == 0);
    d->bufstart_ofs += (d->end - d->buf);
    switchtobuf(d, buf, buf + len);
  }
  
  static void checkpoint(upb_pbdecoder *d) {
    /* The assertion here is in the interests of efficiency, not correctness.
     * We are trying to ensure that we don't checkpoint() more often than
     * necessary. */
    UPB_ASSERT(d->checkpoint != d->ptr);
    d->checkpoint = d->ptr;
  }
  
  /* Skips "bytes" bytes in the stream, which may be more than available.  If we
   * skip more bytes than are available, we return a long read count to the caller
   * indicating how many bytes can be skipped over before passing actual data
   * again.  Skipped bytes can pass a NULL buffer and the decoder guarantees they
   * won't actually be read.
   */
  static int32_t skip(upb_pbdecoder *d, size_t bytes) {
    UPB_ASSERT(!in_residual_buf(d, d->ptr) || d->size_param == 0);
    UPB_ASSERT(d->skip == 0);
    if (bytes > delim_remaining(d)) {
      seterr(d, "Skipped value extended beyond enclosing submessage.");
      return upb_pbdecoder_suspend(d);
    } else if (bufleft(d) >= bytes) {
      /* Skipped data is all in current buffer, and more is still available. */
      advance(d, bytes);
      d->skip = 0;
      return DECODE_OK;
    } else {
      /* Skipped data extends beyond currently available buffers. */
      d->pc = d->last;
      d->skip = bytes - curbufleft(d);
      d->bufstart_ofs += (d->end - d->buf);
      d->residual_end = d->residual;
      switchtobuf(d, d->residual, d->residual_end);
      return d->size_param + d->skip;
    }
  }
  
  
  /* Resumes the decoder from an initial state or from a previous suspend. */
  int32_t upb_pbdecoder_resume(upb_pbdecoder *d, void *p, const char *buf,
                               size_t size, const upb_bufhandle *handle) {
    UPB_UNUSED(p);  /* Useless; just for the benefit of the JIT. */
  
    /* d->skip and d->residual_end could probably elegantly be represented
     * as a single variable, to more easily represent this invariant. */
    UPB_ASSERT(!(d->skip && d->residual_end > d->residual));
  
    /* We need to remember the original size_param, so that the value we return
     * is relative to it, even if we do some skipping first. */
    d->size_param = size;
    d->handle = handle;
  
    /* Have to handle this case specially (ie. not with skip()) because the user
     * is allowed to pass a NULL buffer here, which won't allow us to safely
     * calculate a d->end or use our normal functions like curbufleft(). */
    if (d->skip && d->skip >= size) {
      d->skip -= size;
      d->bufstart_ofs += size;
      buf = &dummy_char;
      size = 0;
  
      /* We can't just return now, because we might need to execute some ops
       * like CHECKDELIM, which could call some callbacks and pop the stack. */
    }
  
    /* We need to pretend that this was the actual buffer param, since some of the
     * calculations assume that d->ptr/d->buf is relative to this. */
    d->buf_param = buf;
  
    if (!buf) {
      /* NULL buf is ok if its entire span is covered by the "skip" above, but
       * by this point we know that "skip" doesn't cover the buffer. */
      seterr(d, "Passed NULL buffer over non-skippable region.");
      return upb_pbdecoder_suspend(d);
    }
  
    if (d->residual_end > d->residual) {
      /* We have residual bytes from the last buffer. */
      UPB_ASSERT(d->ptr == d->residual);
    } else {
      switchtobuf(d, buf, buf + size);
    }
  
    d->checkpoint = d->ptr;
  
    /* Handle skips that don't cover the whole buffer (as above). */
    if (d->skip) {
      size_t skip_bytes = d->skip;
      d->skip = 0;
      CHECK_RETURN(skip(d, skip_bytes));
      checkpoint(d);
    }
  
    /* If we're inside an unknown group, continue to parse unknown values. */
    if (d->top->groupnum < 0) {
      CHECK_RETURN(upb_pbdecoder_skipunknown(d, -1, 0));
      checkpoint(d);
    }
  
    return DECODE_OK;
  }
  
  /* Suspends the decoder at the last checkpoint, without saving any residual
   * bytes.  If there are any unconsumed bytes, returns a short byte count. */
  size_t upb_pbdecoder_suspend(upb_pbdecoder *d) {
    d->pc = d->last;
    if (d->checkpoint == d->residual) {
      /* Checkpoint was in residual buf; no user bytes were consumed. */
      d->ptr = d->residual;
      return 0;
    } else {
      size_t ret = d->size_param - (d->end - d->checkpoint);
      UPB_ASSERT(!in_residual_buf(d, d->checkpoint));
      UPB_ASSERT(d->buf == d->buf_param || d->buf == &dummy_char);
  
      d->bufstart_ofs += (d->checkpoint - d->buf);
      d->residual_end = d->residual;
      switchtobuf(d, d->residual, d->residual_end);
      return ret;
    }
  }
  
  /* Suspends the decoder at the last checkpoint, and saves any unconsumed
   * bytes in our residual buffer.  This is necessary if we need more user
   * bytes to form a complete value, which might not be contiguous in the
   * user's buffers.  Always consumes all user bytes. */
  static size_t suspend_save(upb_pbdecoder *d) {
    /* We hit end-of-buffer before we could parse a full value.
     * Save any unconsumed bytes (if any) to the residual buffer. */
    d->pc = d->last;
  
    if (d->checkpoint == d->residual) {
      /* Checkpoint was in residual buf; append user byte(s) to residual buf. */
      UPB_ASSERT((d->residual_end - d->residual) + d->size_param <=
             sizeof(d->residual));
      if (!in_residual_buf(d, d->ptr)) {
        d->bufstart_ofs -= (d->residual_end - d->residual);
      }
      memcpy(d->residual_end, d->buf_param, d->size_param);
      d->residual_end += d->size_param;
    } else {
      /* Checkpoint was in user buf; old residual bytes not needed. */
      size_t save;
      UPB_ASSERT(!in_residual_buf(d, d->checkpoint));
  
      d->ptr = d->checkpoint;
      save = curbufleft(d);
      UPB_ASSERT(save <= sizeof(d->residual));
      memcpy(d->residual, d->ptr, save);
      d->residual_end = d->residual + save;
      d->bufstart_ofs = offset(d);
    }
  
    switchtobuf(d, d->residual, d->residual_end);
    return d->size_param;
  }
  
  /* Copies the next "bytes" bytes into "buf" and advances the stream.
   * Requires that this many bytes are available in the current buffer. */
  UPB_FORCEINLINE static void consumebytes(upb_pbdecoder *d, void *buf,
                                           size_t bytes) {
    UPB_ASSERT(bytes <= curbufleft(d));
    memcpy(buf, d->ptr, bytes);
    advance(d, bytes);
  }
  
  /* Slow path for getting the next "bytes" bytes, regardless of whether they are
   * available in the current buffer or not.  Returns a status code as described
   * in decoder.int.h. */
  UPB_NOINLINE static int32_t getbytes_slow(upb_pbdecoder *d, void *buf,
                                            size_t bytes) {
    const size_t avail = curbufleft(d);
    consumebytes(d, buf, avail);
    bytes -= avail;
    UPB_ASSERT(bytes > 0);
    if (in_residual_buf(d, d->ptr)) {
      advancetobuf(d, d->buf_param, d->size_param);
    }
    if (curbufleft(d) >= bytes) {
      consumebytes(d, (char *)buf + avail, bytes);
      return DECODE_OK;
    } else if (d->data_end == d->delim_end) {
      seterr(d, "Submessage ended in the middle of a value or group");
      return upb_pbdecoder_suspend(d);
    } else {
      return suspend_save(d);
    }
  }
  
  /* Gets the next "bytes" bytes, regardless of whether they are available in the
   * current buffer or not.  Returns a status code as described in decoder.int.h.
   */
  UPB_FORCEINLINE static int32_t getbytes(upb_pbdecoder *d, void *buf,
                                          size_t bytes) {
    if (curbufleft(d) >= bytes) {
      /* Buffer has enough data to satisfy. */
      consumebytes(d, buf, bytes);
      return DECODE_OK;
    } else {
      return getbytes_slow(d, buf, bytes);
    }
  }
  
  UPB_NOINLINE static size_t peekbytes_slow(upb_pbdecoder *d, void *buf,
                                            size_t bytes) {
    size_t ret = curbufleft(d);
    memcpy(buf, d->ptr, ret);
    if (in_residual_buf(d, d->ptr)) {
      size_t copy = UPB_MIN(bytes - ret, d->size_param);
      memcpy((char *)buf + ret, d->buf_param, copy);
      ret += copy;
    }
    return ret;
  }
  
  UPB_FORCEINLINE static size_t peekbytes(upb_pbdecoder *d, void *buf,
                                          size_t bytes) {
    if (curbufleft(d) >= bytes) {
      memcpy(buf, d->ptr, bytes);
      return bytes;
    } else {
      return peekbytes_slow(d, buf, bytes);
    }
  }
  
  
  /* Decoding of wire types *****************************************************/
  
  /* Slow path for decoding a varint from the current buffer position.
   * Returns a status code as described in decoder.int.h. */
  UPB_NOINLINE int32_t upb_pbdecoder_decode_varint_slow(upb_pbdecoder *d,
                                                        uint64_t *u64) {
    uint8_t byte = 0x80;
    int bitpos;
    *u64 = 0;
    for(bitpos = 0; bitpos < 70 && (byte & 0x80); bitpos += 7) {
      CHECK_RETURN(getbytes(d, &byte, 1));
      *u64 |= (uint64_t)(byte & 0x7F) << bitpos;
    }
    if(bitpos == 70 && (byte & 0x80)) {
      seterr(d, kUnterminatedVarint);
      return upb_pbdecoder_suspend(d);
    }
    return DECODE_OK;
  }
  
  /* Decodes a varint from the current buffer position.
   * Returns a status code as described in decoder.int.h. */
  UPB_FORCEINLINE static int32_t decode_varint(upb_pbdecoder *d, uint64_t *u64) {
    if (curbufleft(d) > 0 && !(*d->ptr & 0x80)) {
      *u64 = *d->ptr;
      advance(d, 1);
      return DECODE_OK;
    } else if (curbufleft(d) >= 10) {
      /* Fast case. */
      upb_decoderet r = upb_vdecode_fast(d->ptr);
      if (r.p == NULL) {
        seterr(d, kUnterminatedVarint);
        return upb_pbdecoder_suspend(d);
      }
      advance(d, r.p - d->ptr);
      *u64 = r.val;
      return DECODE_OK;
    } else {
      /* Slow case -- varint spans buffer seam. */
      return upb_pbdecoder_decode_varint_slow(d, u64);
    }
  }
  
  /* Decodes a 32-bit varint from the current buffer position.
   * Returns a status code as described in decoder.int.h. */
  UPB_FORCEINLINE static int32_t decode_v32(upb_pbdecoder *d, uint32_t *u32) {
    uint64_t u64;
    int32_t ret = decode_varint(d, &u64);
    if (ret >= 0) return ret;
    if (u64 > UINT32_MAX) {
      seterr(d, "Unterminated 32-bit varint");
      /* TODO(haberman) guarantee that this function return is >= 0 somehow,
       * so we know this path will always be treated as error by our caller.
       * Right now the size_t -> int32_t can overflow and produce negative values.
       */
      *u32 = 0;
      return upb_pbdecoder_suspend(d);
    }
    *u32 = u64;
    return DECODE_OK;
  }
  
  /* Decodes a fixed32 from the current buffer position.
   * Returns a status code as described in decoder.int.h.
   * TODO: proper byte swapping for big-endian machines. */
  UPB_FORCEINLINE static int32_t decode_fixed32(upb_pbdecoder *d, uint32_t *u32) {
    return getbytes(d, u32, 4);
  }
  
  /* Decodes a fixed64 from the current buffer position.
   * Returns a status code as described in decoder.int.h.
   * TODO: proper byte swapping for big-endian machines. */
  UPB_FORCEINLINE static int32_t decode_fixed64(upb_pbdecoder *d, uint64_t *u64) {
    return getbytes(d, u64, 8);
  }
  
  /* Non-static versions of the above functions.
   * These are called by the JIT for fallback paths. */
  int32_t upb_pbdecoder_decode_f32(upb_pbdecoder *d, uint32_t *u32) {
    return decode_fixed32(d, u32);
  }
  
  int32_t upb_pbdecoder_decode_f64(upb_pbdecoder *d, uint64_t *u64) {
    return decode_fixed64(d, u64);
  }
  
  static double as_double(uint64_t n) { double d; memcpy(&d, &n, 8); return d; }
  static float  as_float(uint32_t n)  { float  f; memcpy(&f, &n, 4); return f; }
  
  /* Pushes a frame onto the decoder stack. */
  static bool decoder_push(upb_pbdecoder *d, uint64_t end) {
    upb_pbdecoder_frame *fr = d->top;
  
    if (end > fr->end_ofs) {
      seterr(d, kPbDecoderSubmessageTooLong);
      return false;
    } else if (fr == d->limit) {
      seterr(d, kPbDecoderStackOverflow);
      return false;
    }
  
    fr++;
    fr->end_ofs = end;
    fr->dispatch = NULL;
    fr->groupnum = 0;
    d->top = fr;
    return true;
  }
  
  static bool pushtagdelim(upb_pbdecoder *d, uint32_t arg) {
    /* While we expect to see an "end" tag (either ENDGROUP or a non-sequence
     * field number) prior to hitting any enclosing submessage end, pushing our
     * existing delim end prevents us from continuing to parse values from a
     * corrupt proto that doesn't give us an END tag in time. */
    if (!decoder_push(d, d->top->end_ofs))
      return false;
    d->top->groupnum = arg;
    return true;
  }
  
  /* Pops a frame from the decoder stack. */
  static void decoder_pop(upb_pbdecoder *d) { d->top--; }
  
  UPB_NOINLINE int32_t upb_pbdecoder_checktag_slow(upb_pbdecoder *d,
                                                   uint64_t expected) {
    uint64_t data = 0;
    size_t bytes = upb_value_size(expected);
    size_t read = peekbytes(d, &data, bytes);
    if (read == bytes && data == expected) {
      /* Advance past matched bytes. */
      int32_t ok = getbytes(d, &data, read);
      UPB_ASSERT(ok < 0);
      return DECODE_OK;
    } else if (read < bytes && memcmp(&data, &expected, read) == 0) {
      return suspend_save(d);
    } else {
      return DECODE_MISMATCH;
    }
  }
  
  int32_t upb_pbdecoder_skipunknown(upb_pbdecoder *d, int32_t fieldnum,
                                    uint8_t wire_type) {
    if (fieldnum >= 0)
      goto have_tag;
  
    while (true) {
      uint32_t tag;
      CHECK_RETURN(decode_v32(d, &tag));
      wire_type = tag & 0x7;
      fieldnum = tag >> 3;
  
  have_tag:
      if (fieldnum == 0) {
        seterr(d, "Saw invalid field number (0)");
        return upb_pbdecoder_suspend(d);
      }
  
      switch (wire_type) {
        case UPB_WIRE_TYPE_32BIT:
          CHECK_RETURN(skip(d, 4));
          break;
        case UPB_WIRE_TYPE_64BIT:
          CHECK_RETURN(skip(d, 8));
          break;
        case UPB_WIRE_TYPE_VARINT: {
          uint64_t u64;
          CHECK_RETURN(decode_varint(d, &u64));
          break;
        }
        case UPB_WIRE_TYPE_DELIMITED: {
          uint32_t len;
          CHECK_RETURN(decode_v32(d, &len));
          CHECK_RETURN(skip(d, len));
          break;
        }
        case UPB_WIRE_TYPE_START_GROUP:
          CHECK_SUSPEND(pushtagdelim(d, -fieldnum));
          break;
        case UPB_WIRE_TYPE_END_GROUP:
          if (fieldnum == -d->top->groupnum) {
            decoder_pop(d);
          } else if (fieldnum == d->top->groupnum) {
            return DECODE_ENDGROUP;
          } else {
            seterr(d, "Unmatched ENDGROUP tag.");
            return upb_pbdecoder_suspend(d);
          }
          break;
        default:
          seterr(d, "Invalid wire type");
          return upb_pbdecoder_suspend(d);
      }
  
      if (d->top->groupnum >= 0) {
        /* TODO: More code needed for handling unknown groups. */
        upb_sink_putunknown(d->top->sink, d->checkpoint, d->ptr - d->checkpoint);
        return DECODE_OK;
      }
  
      /* Unknown group -- continue looping over unknown fields. */
      checkpoint(d);
    }
  }
  
  static void goto_endmsg(upb_pbdecoder *d) {
    upb_value v;
    bool found = upb_inttable_lookup32(d->top->dispatch, DISPATCH_ENDMSG, &v);
    UPB_ASSERT(found);
    d->pc = d->top->base + upb_value_getuint64(v);
  }
  
  /* Parses a tag and jumps to the corresponding bytecode instruction for this
   * field.
   *
   * If the tag is unknown (or the wire type doesn't match), parses the field as
   * unknown.  If the tag is a valid ENDGROUP tag, jumps to the bytecode
   * instruction for the end of message. */
  static int32_t dispatch(upb_pbdecoder *d) {
    upb_inttable *dispatch = d->top->dispatch;
    uint32_t tag;
    uint8_t wire_type;
    uint32_t fieldnum;
    upb_value val;
    int32_t retval;
  
    /* Decode tag. */
    CHECK_RETURN(decode_v32(d, &tag));
    wire_type = tag & 0x7;
    fieldnum = tag >> 3;
  
    /* Lookup tag.  Because of packed/non-packed compatibility, we have to
     * check the wire type against two possibilities. */
    if (fieldnum != DISPATCH_ENDMSG &&
        upb_inttable_lookup32(dispatch, fieldnum, &val)) {
      uint64_t v = upb_value_getuint64(val);
      if (wire_type == (v & 0xff)) {
        d->pc = d->top->base + (v >> 16);
        return DECODE_OK;
      } else if (wire_type == ((v >> 8) & 0xff)) {
        bool found =
            upb_inttable_lookup(dispatch, fieldnum + UPB_MAX_FIELDNUMBER, &val);
        UPB_ASSERT(found);
        d->pc = d->top->base + upb_value_getuint64(val);
        return DECODE_OK;
      }
    }
  
    /* We have some unknown fields (or ENDGROUP) to parse.  The DISPATCH or TAG
     * bytecode that triggered this is preceded by a CHECKDELIM bytecode which
     * we need to back up to, so that when we're done skipping unknown data we
     * can re-check the delimited end. */
    d->last--;  /* Necessary if we get suspended */
    d->pc = d->last;
    UPB_ASSERT(getop(*d->last) == OP_CHECKDELIM);
  
    /* Unknown field or ENDGROUP. */
    retval = upb_pbdecoder_skipunknown(d, fieldnum, wire_type);
  
    CHECK_RETURN(retval);
  
    if (retval == DECODE_ENDGROUP) {
      goto_endmsg(d);
      return DECODE_OK;
    }
  
    return DECODE_OK;
  }
  
  /* Callers know that the stack is more than one deep because the opcodes that
   * call this only occur after PUSH operations. */
  upb_pbdecoder_frame *outer_frame(upb_pbdecoder *d) {
    UPB_ASSERT(d->top != d->stack);
    return d->top - 1;
  }
  
  
  /* The main decoding loop *****************************************************/
  
  /* The main decoder VM function.  Uses traditional bytecode dispatch loop with a
   * switch() statement. */
  size_t run_decoder_vm(upb_pbdecoder *d, const mgroup *group,
                        const upb_bufhandle* handle) {
  
  #define VMCASE(op, code) \
    case op: { code; if (consumes_input(op)) checkpoint(d); break; }
  #define PRIMITIVE_OP(type, wt, name, convfunc, ctype) \
    VMCASE(OP_PARSE_ ## type, { \
      ctype val; \
      CHECK_RETURN(decode_ ## wt(d, &val)); \
      upb_sink_put ## name(d->top->sink, arg, (convfunc)(val)); \
    })
  
    while(1) {
      int32_t instruction;
      opcode op;
      uint32_t arg;
      int32_t longofs;
  
      d->last = d->pc;
      instruction = *d->pc++;
      op = getop(instruction);
      arg = instruction >> 8;
      longofs = arg;
      UPB_ASSERT(d->ptr != d->residual_end);
      UPB_UNUSED(group);
  #ifdef UPB_DUMP_BYTECODE
      fprintf(stderr, "s_ofs=%d buf_ofs=%d data_rem=%d buf_rem=%d delim_rem=%d "
                      "%x %s (%d)\n",
              (int)offset(d),
              (int)(d->ptr - d->buf),
              (int)(d->data_end - d->ptr),
              (int)(d->end - d->ptr),
              (int)((d->top->end_ofs - d->bufstart_ofs) - (d->ptr - d->buf)),
              (int)(d->pc - 1 - group->bytecode),
              upb_pbdecoder_getopname(op),
              arg);
  #endif
      switch (op) {
        /* Technically, we are losing data if we see a 32-bit varint that is not
         * properly sign-extended.  We could detect this and error about the data
         * loss, but proto2 does not do this, so we pass. */
        PRIMITIVE_OP(INT32,    varint,  int32,  int32_t,      uint64_t)
        PRIMITIVE_OP(INT64,    varint,  int64,  int64_t,      uint64_t)
        PRIMITIVE_OP(UINT32,   varint,  uint32, uint32_t,     uint64_t)
        PRIMITIVE_OP(UINT64,   varint,  uint64, uint64_t,     uint64_t)
        PRIMITIVE_OP(FIXED32,  fixed32, uint32, uint32_t,     uint32_t)
        PRIMITIVE_OP(FIXED64,  fixed64, uint64, uint64_t,     uint64_t)
        PRIMITIVE_OP(SFIXED32, fixed32, int32,  int32_t,      uint32_t)
        PRIMITIVE_OP(SFIXED64, fixed64, int64,  int64_t,      uint64_t)
        PRIMITIVE_OP(BOOL,     varint,  bool,   bool,         uint64_t)
        PRIMITIVE_OP(DOUBLE,   fixed64, double, as_double,    uint64_t)
        PRIMITIVE_OP(FLOAT,    fixed32, float,  as_float,     uint32_t)
        PRIMITIVE_OP(SINT32,   varint,  int32,  upb_zzdec_32, uint64_t)
        PRIMITIVE_OP(SINT64,   varint,  int64,  upb_zzdec_64, uint64_t)
  
        VMCASE(OP_SETDISPATCH,
          d->top->base = d->pc - 1;
          memcpy(&d->top->dispatch, d->pc, sizeof(void*));
          d->pc += sizeof(void*) / sizeof(uint32_t);
        )
        VMCASE(OP_STARTMSG,
          CHECK_SUSPEND(upb_sink_startmsg(d->top->sink));
        )
        VMCASE(OP_ENDMSG,
          CHECK_SUSPEND(upb_sink_endmsg(d->top->sink, d->status));
        )
        VMCASE(OP_STARTSEQ,
          upb_pbdecoder_frame *outer = outer_frame(d);
          CHECK_SUSPEND(upb_sink_startseq(outer->sink, arg, &d->top->sink));
        )
        VMCASE(OP_ENDSEQ,
          CHECK_SUSPEND(upb_sink_endseq(d->top->sink, arg));
        )
        VMCASE(OP_STARTSUBMSG,
          upb_pbdecoder_frame *outer = outer_frame(d);
          CHECK_SUSPEND(upb_sink_startsubmsg(outer->sink, arg, &d->top->sink));
        )
        VMCASE(OP_ENDSUBMSG,
          CHECK_SUSPEND(upb_sink_endsubmsg(d->top->sink, arg));
        )
        VMCASE(OP_STARTSTR,
          uint32_t len = delim_remaining(d);
          upb_pbdecoder_frame *outer = outer_frame(d);
          CHECK_SUSPEND(upb_sink_startstr(outer->sink, arg, len, &d->top->sink));
          if (len == 0) {
            d->pc++;  /* Skip OP_STRING. */
          }
        )
        VMCASE(OP_STRING,
          uint32_t len = curbufleft(d);
          size_t n = upb_sink_putstring(d->top->sink, arg, d->ptr, len, handle);
          if (n > len) {
            if (n > delim_remaining(d)) {
              seterr(d, "Tried to skip past end of string.");
              return upb_pbdecoder_suspend(d);
            } else {
              int32_t ret = skip(d, n);
              /* This shouldn't return DECODE_OK, because n > len. */
              UPB_ASSERT(ret >= 0);
              return ret;
            }
          }
          advance(d, n);
          if (n < len || d->delim_end == NULL) {
            /* We aren't finished with this string yet. */
            d->pc--;  /* Repeat OP_STRING. */
            if (n > 0) checkpoint(d);
            return upb_pbdecoder_suspend(d);
          }
        )
        VMCASE(OP_ENDSTR,
          CHECK_SUSPEND(upb_sink_endstr(d->top->sink, arg));
        )
        VMCASE(OP_PUSHTAGDELIM,
          CHECK_SUSPEND(pushtagdelim(d, arg));
        )
        VMCASE(OP_SETBIGGROUPNUM,
          d->top->groupnum = *d->pc++;
        )
        VMCASE(OP_POP,
          UPB_ASSERT(d->top > d->stack);
          decoder_pop(d);
        )
        VMCASE(OP_PUSHLENDELIM,
          uint32_t len;
          CHECK_RETURN(decode_v32(d, &len));
          CHECK_SUSPEND(decoder_push(d, offset(d) + len));
          set_delim_end(d);
        )
        VMCASE(OP_SETDELIM,
          set_delim_end(d);
        )
        VMCASE(OP_CHECKDELIM,
          /* We are guaranteed of this assert because we never allow ourselves to
           * consume bytes beyond data_end, which covers delim_end when non-NULL.
           */
          UPB_ASSERT(!(d->delim_end && d->ptr > d->delim_end));
          if (d->ptr == d->delim_end)
            d->pc += longofs;
        )
        VMCASE(OP_CALL,
          d->callstack[d->call_len++] = d->pc;
          d->pc += longofs;
        )
        VMCASE(OP_RET,
          UPB_ASSERT(d->call_len > 0);
          d->pc = d->callstack[--d->call_len];
        )
        VMCASE(OP_BRANCH,
          d->pc += longofs;
        )
        VMCASE(OP_TAG1,
          uint8_t expected;
          CHECK_SUSPEND(curbufleft(d) > 0);
          expected = (arg >> 8) & 0xff;
          if (*d->ptr == expected) {
            advance(d, 1);
          } else {
            int8_t shortofs;
           badtag:
            shortofs = arg;
            if (shortofs == LABEL_DISPATCH) {
              CHECK_RETURN(dispatch(d));
            } else {
              d->pc += shortofs;
              break; /* Avoid checkpoint(). */
            }
          }
        )
        VMCASE(OP_TAG2,
          uint16_t expected;
          CHECK_SUSPEND(curbufleft(d) > 0);
          expected = (arg >> 8) & 0xffff;
          if (curbufleft(d) >= 2) {
            uint16_t actual;
            memcpy(&actual, d->ptr, 2);
            if (expected == actual) {
              advance(d, 2);
            } else {
              goto badtag;
            }
          } else {
            int32_t result = upb_pbdecoder_checktag_slow(d, expected);
            if (result == DECODE_MISMATCH) goto badtag;
            if (result >= 0) return result;
          }
        )
        VMCASE(OP_TAGN, {
          uint64_t expected;
          int32_t result;
          memcpy(&expected, d->pc, 8);
          d->pc += 2;
          result = upb_pbdecoder_checktag_slow(d, expected);
          if (result == DECODE_MISMATCH) goto badtag;
          if (result >= 0) return result;
        })
        VMCASE(OP_DISPATCH, {
          CHECK_RETURN(dispatch(d));
        })
        VMCASE(OP_HALT, {
          return d->size_param;
        })
      }
    }
  }
  
  
  /* BytesHandler handlers ******************************************************/
  
  void *upb_pbdecoder_startbc(void *closure, const void *pc, size_t size_hint) {
    upb_pbdecoder *d = closure;
    UPB_UNUSED(size_hint);
    d->top->end_ofs = UINT64_MAX;
    d->bufstart_ofs = 0;
    d->call_len = 1;
    d->callstack[0] = &halt;
    d->pc = pc;
    d->skip = 0;
    return d;
  }
  
  bool upb_pbdecoder_end(void *closure, const void *handler_data) {
    upb_pbdecoder *d = closure;
    const upb_pbdecodermethod *method = handler_data;
    uint64_t end;
    char dummy;
  
    if (d->residual_end > d->residual) {
      seterr(d, "Unexpected EOF: decoder still has buffered unparsed data");
      return false;
    }
  
    if (d->skip) {
      seterr(d, "Unexpected EOF inside skipped data");
      return false;
    }
  
    if (d->top->end_ofs != UINT64_MAX) {
      seterr(d, "Unexpected EOF inside delimited string");
      return false;
    }
  
    /* The user's end() call indicates that the message ends here. */
    end = offset(d);
    d->top->end_ofs = end;
  
    {
      const uint32_t *p = d->pc;
      d->stack->end_ofs = end;
      /* Check the previous bytecode, but guard against beginning. */
      if (p != method->code_base.ptr) p--;
      if (getop(*p) == OP_CHECKDELIM) {
        /* Rewind from OP_TAG* to OP_CHECKDELIM. */
        UPB_ASSERT(getop(*d->pc) == OP_TAG1 ||
               getop(*d->pc) == OP_TAG2 ||
               getop(*d->pc) == OP_TAGN ||
               getop(*d->pc) == OP_DISPATCH);
        d->pc = p;
      }
      upb_pbdecoder_decode(closure, handler_data, &dummy, 0, NULL);
    }
  
    if (d->call_len != 0) {
      seterr(d, "Unexpected EOF inside submessage or group");
      return false;
    }
  
    return true;
  }
  
  size_t upb_pbdecoder_decode(void *decoder, const void *group, const char *buf,
                              size_t size, const upb_bufhandle *handle) {
    int32_t result = upb_pbdecoder_resume(decoder, NULL, buf, size, handle);
  
    if (result == DECODE_ENDGROUP) goto_endmsg(decoder);
    CHECK_RETURN(result);
  
    return run_decoder_vm(decoder, group, handle);
  }
  
  
  /* Public API *****************************************************************/
  
  void upb_pbdecoder_reset(upb_pbdecoder *d) {
    d->top = d->stack;
    d->top->groupnum = 0;
    d->ptr = d->residual;
    d->buf = d->residual;
    d->end = d->residual;
    d->residual_end = d->residual;
  }
  
  upb_pbdecoder *upb_pbdecoder_create(upb_arena *a, const upb_pbdecodermethod *m,
                                      upb_sink sink, upb_status *status) {
    const size_t default_max_nesting = 64;
  #ifndef NDEBUG
    size_t size_before = upb_arena_bytesallocated(a);
  #endif
  
    upb_pbdecoder *d = upb_arena_malloc(a, sizeof(upb_pbdecoder));
    if (!d) return NULL;
  
    d->method_ = m;
    d->callstack = upb_arena_malloc(a, callstacksize(d, default_max_nesting));
    d->stack = upb_arena_malloc(a, stacksize(d, default_max_nesting));
    if (!d->stack || !d->callstack) {
      return NULL;
    }
  
    d->arena = a;
    d->limit = d->stack + default_max_nesting - 1;
    d->stack_size = default_max_nesting;
    d->status = status;
  
    upb_pbdecoder_reset(d);
    upb_bytessink_reset(&d->input_, &m->input_handler_, d);
  
    if (d->method_->dest_handlers_) {
      if (sink.handlers != d->method_->dest_handlers_)
        return NULL;
    }
    d->top->sink = sink;
  
    /* If this fails, increase the value in decoder.h. */
    UPB_ASSERT_DEBUGVAR(upb_arena_bytesallocated(a) - size_before <=
                        UPB_PB_DECODER_SIZE);
    return d;
  }
  
  uint64_t upb_pbdecoder_bytesparsed(const upb_pbdecoder *d) {
    return offset(d);
  }
  
  const upb_pbdecodermethod *upb_pbdecoder_method(const upb_pbdecoder *d) {
    return d->method_;
  }
  
  upb_bytessink upb_pbdecoder_input(upb_pbdecoder *d) {
    return d->input_;
  }
  
  size_t upb_pbdecoder_maxnesting(const upb_pbdecoder *d) {
    return d->stack_size;
  }
  
  bool upb_pbdecoder_setmaxnesting(upb_pbdecoder *d, size_t max) {
    UPB_ASSERT(d->top >= d->stack);
  
    if (max < (size_t)(d->top - d->stack)) {
      /* Can't set a limit smaller than what we are currently at. */
      return false;
    }
  
    if (max > d->stack_size) {
      /* Need to reallocate stack and callstack to accommodate. */
      size_t old_size = stacksize(d, d->stack_size);
      size_t new_size = stacksize(d, max);
      void *p = upb_arena_realloc(d->arena, d->stack, old_size, new_size);
      if (!p) {
        return false;
      }
      d->stack = p;
  
      old_size = callstacksize(d, d->stack_size);
      new_size = callstacksize(d, max);
      p = upb_arena_realloc(d->arena, d->callstack, old_size, new_size);
      if (!p) {
        return false;
      }
      d->callstack = p;
  
      d->stack_size = max;
    }
  
    d->limit = d->stack + max - 1;
    return true;
  }
  /*
  ** upb::Encoder
  **
  ** Since we are implementing pure handlers (ie. without any out-of-band access
  ** to pre-computed lengths), we have to buffer all submessages before we can
  ** emit even their first byte.
  **
  ** Not knowing the size of submessages also means we can't write a perfect
  ** zero-copy implementation, even with buffering.  Lengths are stored as
  ** varints, which means that we don't know how many bytes to reserve for the
  ** length until we know what the length is.
  **
  ** This leaves us with three main choices:
  **
  ** 1. buffer all submessage data in a temporary buffer, then copy it exactly
  **    once into the output buffer.
  **
  ** 2. attempt to buffer data directly into the output buffer, estimating how
  **    many bytes each length will take.  When our guesses are wrong, use
  **    memmove() to grow or shrink the allotted space.
  **
  ** 3. buffer directly into the output buffer, allocating a max length
  **    ahead-of-time for each submessage length.  If we overallocated, we waste
  **    space, but no memcpy() or memmove() is required.  This approach requires
  **    defining a maximum size for submessages and rejecting submessages that
  **    exceed that size.
  **
  ** (2) and (3) have the potential to have better performance, but they are more
  ** complicated and subtle to implement:
  **
  **   (3) requires making an arbitrary choice of the maximum message size; it
  **       wastes space when submessages are shorter than this and fails
  **       completely when they are longer.  This makes it more finicky and
  **       requires configuration based on the input.  It also makes it impossible
  **       to perfectly match the output of reference encoders that always use the
  **       optimal amount of space for each length.
  **
  **   (2) requires guessing the the size upfront, and if multiple lengths are
  **       guessed wrong the minimum required number of memmove() operations may
  **       be complicated to compute correctly.  Implemented properly, it may have
  **       a useful amortized or average cost, but more investigation is required
  **       to determine this and what the optimal algorithm is to achieve it.
  **
  **   (1) makes you always pay for exactly one copy, but its implementation is
  **       the simplest and its performance is predictable.
  **
  ** So for now, we implement (1) only.  If we wish to optimize later, we should
  ** be able to do it without affecting users.
  **
  ** The strategy is to buffer the segments of data that do *not* depend on
  ** unknown lengths in one buffer, and keep a separate buffer of segment pointers
  ** and lengths.  When the top-level submessage ends, we can go beginning to end,
  ** alternating the writing of lengths with memcpy() of the rest of the data.
  ** At the top level though, no buffering is required.
  */
  
  
  
  /* The output buffer is divided into segments; a segment is a string of data
   * that is "ready to go" -- it does not need any varint lengths inserted into
   * the middle.  The seams between segments are where varints will be inserted
   * once they are known.
   *
   * We also use the concept of a "run", which is a range of encoded bytes that
   * occur at a single submessage level.  Every segment contains one or more runs.
   *
   * A segment can span messages.  Consider:
   *
   *                  .--Submessage lengths---------.
   *                  |       |                     |
   *                  |       V                     V
   *                  V      | |---------------    | |-----------------
   * Submessages:    | |-----------------------------------------------
   * Top-level msg: ------------------------------------------------------------
   *
   * Segments:          -----   -------------------   -----------------
   * Runs:              *----   *--------------*---   *----------------
   * (* marks the start)
   *
   * Note that the top-level menssage is not in any segment because it does not
   * have any length preceding it.
   *
   * A segment is only interrupted when another length needs to be inserted.  So
   * observe how the second segment spans both the inner submessage and part of
   * the next enclosing message. */
  typedef struct {
    uint32_t msglen;  /* The length to varint-encode before this segment. */
    uint32_t seglen;  /* Length of the segment. */
  } upb_pb_encoder_segment;
  
  struct upb_pb_encoder {
    upb_arena *arena;
  
    /* Our input and output. */
    upb_sink input_;
    upb_bytessink output_;
  
    /* The "subclosure" -- used as the inner closure as part of the bytessink
     * protocol. */
    void *subc;
  
    /* The output buffer and limit, and our current write position.  "buf"
     * initially points to "initbuf", but is dynamically allocated if we need to
     * grow beyond the initial size. */
    char *buf, *ptr, *limit;
  
    /* The beginning of the current run, or undefined if we are at the top
     * level. */
    char *runbegin;
  
    /* The list of segments we are accumulating. */
    upb_pb_encoder_segment *segbuf, *segptr, *seglimit;
  
    /* The stack of enclosing submessages.  Each entry in the stack points to the
     * segment where this submessage's length is being accumulated. */
    int *stack, *top, *stacklimit;
  
    /* Depth of startmsg/endmsg calls. */
    int depth;
  };
  
  /* low-level buffering ********************************************************/
  
  /* Low-level functions for interacting with the output buffer. */
  
  /* TODO(haberman): handle pushback */
  static void putbuf(upb_pb_encoder *e, const char *buf, size_t len) {
    size_t n = upb_bytessink_putbuf(e->output_, e->subc, buf, len, NULL);
    UPB_ASSERT(n == len);
  }
  
  static upb_pb_encoder_segment *top(upb_pb_encoder *e) {
    return &e->segbuf[*e->top];
  }
  
  /* Call to ensure that at least "bytes" bytes are available for writing at
   * e->ptr.  Returns false if the bytes could not be allocated. */
  static bool reserve(upb_pb_encoder *e, size_t bytes) {
    if ((size_t)(e->limit - e->ptr) < bytes) {
      /* Grow buffer. */
      char *new_buf;
      size_t needed = bytes + (e->ptr - e->buf);
      size_t old_size = e->limit - e->buf;
  
      size_t new_size = old_size;
  
      while (new_size < needed) {
        new_size *= 2;
      }
  
      new_buf = upb_arena_realloc(e->arena, e->buf, old_size, new_size);
  
      if (new_buf == NULL) {
        return false;
      }
  
      e->ptr = new_buf + (e->ptr - e->buf);
      e->runbegin = new_buf + (e->runbegin - e->buf);
      e->limit = new_buf + new_size;
      e->buf = new_buf;
    }
  
    return true;
  }
  
  /* Call when "bytes" bytes have been writte at e->ptr.  The caller *must* have
   * previously called reserve() with at least this many bytes. */
  static void encoder_advance(upb_pb_encoder *e, size_t bytes) {
    UPB_ASSERT((size_t)(e->limit - e->ptr) >= bytes);
    e->ptr += bytes;
  }
  
  /* Call when all of the bytes for a handler have been written.  Flushes the
   * bytes if possible and necessary, returning false if this failed. */
  static bool commit(upb_pb_encoder *e) {
    if (!e->top) {
      /* We aren't inside a delimited region.  Flush our accumulated bytes to
       * the output.
       *
       * TODO(haberman): in the future we may want to delay flushing for
       * efficiency reasons. */
      putbuf(e, e->buf, e->ptr - e->buf);
      e->ptr = e->buf;
    }
  
    return true;
  }
  
  /* Writes the given bytes to the buffer, handling reserve/advance. */
  static bool encode_bytes(upb_pb_encoder *e, const void *data, size_t len) {
    if (!reserve(e, len)) {
      return false;
    }
  
    memcpy(e->ptr, data, len);
    encoder_advance(e, len);
    return true;
  }
  
  /* Finish the current run by adding the run totals to the segment and message
   * length. */
  static void accumulate(upb_pb_encoder *e) {
    size_t run_len;
    UPB_ASSERT(e->ptr >= e->runbegin);
    run_len = e->ptr - e->runbegin;
    e->segptr->seglen += run_len;
    top(e)->msglen += run_len;
    e->runbegin = e->ptr;
  }
  
  /* Call to indicate the start of delimited region for which the full length is
   * not yet known.  All data will be buffered until the length is known.
   * Delimited regions may be nested; their lengths will all be tracked properly. */
  static bool start_delim(upb_pb_encoder *e) {
    if (e->top) {
      /* We are already buffering, advance to the next segment and push it on the
       * stack. */
      accumulate(e);
  
      if (++e->top == e->stacklimit) {
        /* TODO(haberman): grow stack? */
        return false;
      }
  
      if (++e->segptr == e->seglimit) {
        /* Grow segment buffer. */
        size_t old_size =
            (e->seglimit - e->segbuf) * sizeof(upb_pb_encoder_segment);
        size_t new_size = old_size * 2;
        upb_pb_encoder_segment *new_buf =
            upb_arena_realloc(e->arena, e->segbuf, old_size, new_size);
  
        if (new_buf == NULL) {
          return false;
        }
  
        e->segptr = new_buf + (e->segptr - e->segbuf);
        e->seglimit = new_buf + (new_size / sizeof(upb_pb_encoder_segment));
        e->segbuf = new_buf;
      }
    } else {
      /* We were previously at the top level, start buffering. */
      e->segptr = e->segbuf;
      e->top = e->stack;
      e->runbegin = e->ptr;
    }
  
    *e->top = e->segptr - e->segbuf;
    e->segptr->seglen = 0;
    e->segptr->msglen = 0;
  
    return true;
  }
  
  /* Call to indicate the end of a delimited region.  We now know the length of
   * the delimited region.  If we are not nested inside any other delimited
   * regions, we can now emit all of the buffered data we accumulated. */
  static bool end_delim(upb_pb_encoder *e) {
    size_t msglen;
    accumulate(e);
    msglen = top(e)->msglen;
  
    if (e->top == e->stack) {
      /* All lengths are now available, emit all buffered data. */
      char buf[UPB_PB_VARINT_MAX_LEN];
      upb_pb_encoder_segment *s;
      const char *ptr = e->buf;
      for (s = e->segbuf; s <= e->segptr; s++) {
        size_t lenbytes = upb_vencode64(s->msglen, buf);
        putbuf(e, buf, lenbytes);
        putbuf(e, ptr, s->seglen);
        ptr += s->seglen;
      }
  
      e->ptr = e->buf;
      e->top = NULL;
    } else {
      /* Need to keep buffering; propagate length info into enclosing
       * submessages. */
      --e->top;
      top(e)->msglen += msglen + upb_varint_size(msglen);
    }
  
    return true;
  }
  
  
  /* tag_t **********************************************************************/
  
  /* A precomputed (pre-encoded) tag and length. */
  
  typedef struct {
    uint8_t bytes;
    char tag[7];
  } tag_t;
  
  /* Allocates a new tag for this field, and sets it in these handlerattr. */
  static void new_tag(upb_handlers *h, const upb_fielddef *f, upb_wiretype_t wt,
                      upb_handlerattr *attr) {
    uint32_t n = upb_fielddef_number(f);
  
    tag_t *tag = upb_gmalloc(sizeof(tag_t));
    tag->bytes = upb_vencode64((n << 3) | wt, tag->tag);
  
    attr->handler_data = tag;
    upb_handlers_addcleanup(h, tag, upb_gfree);
  }
  
  static bool encode_tag(upb_pb_encoder *e, const tag_t *tag) {
    return encode_bytes(e, tag->tag, tag->bytes);
  }
  
  
  /* encoding of wire types *****************************************************/
  
  static bool encode_fixed64(upb_pb_encoder *e, uint64_t val) {
    /* TODO(haberman): byte-swap for big endian. */
    return encode_bytes(e, &val, sizeof(uint64_t));
  }
  
  static bool encode_fixed32(upb_pb_encoder *e, uint32_t val) {
    /* TODO(haberman): byte-swap for big endian. */
    return encode_bytes(e, &val, sizeof(uint32_t));
  }
  
  static bool encode_varint(upb_pb_encoder *e, uint64_t val) {
    if (!reserve(e, UPB_PB_VARINT_MAX_LEN)) {
      return false;
    }
  
    encoder_advance(e, upb_vencode64(val, e->ptr));
    return true;
  }
  
  static uint64_t dbl2uint64(double d) {
    uint64_t ret;
    memcpy(&ret, &d, sizeof(uint64_t));
    return ret;
  }
  
  static uint32_t flt2uint32(float d) {
    uint32_t ret;
    memcpy(&ret, &d, sizeof(uint32_t));
    return ret;
  }
  
  
  /* encoding of proto types ****************************************************/
  
  static bool startmsg(void *c, const void *hd) {
    upb_pb_encoder *e = c;
    UPB_UNUSED(hd);
    if (e->depth++ == 0) {
      upb_bytessink_start(e->output_, 0, &e->subc);
    }
    return true;
  }
  
  static bool endmsg(void *c, const void *hd, upb_status *status) {
    upb_pb_encoder *e = c;
    UPB_UNUSED(hd);
    UPB_UNUSED(status);
    if (--e->depth == 0) {
      upb_bytessink_end(e->output_);
    }
    return true;
  }
  
  static void *encode_startdelimfield(void *c, const void *hd) {
    bool ok = encode_tag(c, hd) && commit(c) && start_delim(c);
    return ok ? c : UPB_BREAK;
  }
  
  static bool encode_unknown(void *c, const void *hd, const char *buf,
                             size_t len) {
    UPB_UNUSED(hd);
    return encode_bytes(c, buf, len) && commit(c);
  }
  
  static bool encode_enddelimfield(void *c, const void *hd) {
    UPB_UNUSED(hd);
    return end_delim(c);
  }
  
  static void *encode_startgroup(void *c, const void *hd) {
    return (encode_tag(c, hd) && commit(c)) ? c : UPB_BREAK;
  }
  
  static bool encode_endgroup(void *c, const void *hd) {
    return encode_tag(c, hd) && commit(c);
  }
  
  static void *encode_startstr(void *c, const void *hd, size_t size_hint) {
    UPB_UNUSED(size_hint);
    return encode_startdelimfield(c, hd);
  }
  
  static size_t encode_strbuf(void *c, const void *hd, const char *buf,
                              size_t len, const upb_bufhandle *h) {
    UPB_UNUSED(hd);
    UPB_UNUSED(h);
    return encode_bytes(c, buf, len) ? len : 0;
  }
  
  #define T(type, ctype, convert, encode)                                  \
    static bool encode_scalar_##type(void *e, const void *hd, ctype val) { \
      return encode_tag(e, hd) && encode(e, (convert)(val)) && commit(e);  \
    }                                                                      \
    static bool encode_packed_##type(void *e, const void *hd, ctype val) { \
      UPB_UNUSED(hd);                                                      \
      return encode(e, (convert)(val));                                    \
    }
  
  T(double,   double,   dbl2uint64,   encode_fixed64)
  T(float,    float,    flt2uint32,   encode_fixed32)
  T(int64,    int64_t,  uint64_t,     encode_varint)
  T(int32,    int32_t,  int64_t,      encode_varint)
  T(fixed64,  uint64_t, uint64_t,     encode_fixed64)
  T(fixed32,  uint32_t, uint32_t,     encode_fixed32)
  T(bool,     bool,     bool,         encode_varint)
  T(uint32,   uint32_t, uint32_t,     encode_varint)
  T(uint64,   uint64_t, uint64_t,     encode_varint)
  T(enum,     int32_t,  uint32_t,     encode_varint)
  T(sfixed32, int32_t,  uint32_t,     encode_fixed32)
  T(sfixed64, int64_t,  uint64_t,     encode_fixed64)
  T(sint32,   int32_t,  upb_zzenc_32, encode_varint)
  T(sint64,   int64_t,  upb_zzenc_64, encode_varint)
  
  #undef T
  
  
  /* code to build the handlers *************************************************/
  
  #include <stdio.h>
  static void newhandlers_callback(const void *closure, upb_handlers *h) {
    const upb_msgdef *m;
    upb_msg_field_iter i;
  
    UPB_UNUSED(closure);
  
    upb_handlers_setstartmsg(h, startmsg, NULL);
    upb_handlers_setendmsg(h, endmsg, NULL);
    upb_handlers_setunknown(h, encode_unknown, NULL);
  
    m = upb_handlers_msgdef(h);
    for(upb_msg_field_begin(&i, m);
        !upb_msg_field_done(&i);
        upb_msg_field_next(&i)) {
      const upb_fielddef *f = upb_msg_iter_field(&i);
      bool packed = upb_fielddef_isseq(f) && upb_fielddef_isprimitive(f) &&
                    upb_fielddef_packed(f);
      upb_handlerattr attr = UPB_HANDLERATTR_INIT;
      upb_wiretype_t wt =
          packed ? UPB_WIRE_TYPE_DELIMITED
                 : upb_pb_native_wire_types[upb_fielddef_descriptortype(f)];
  
      /* Pre-encode the tag for this field. */
      new_tag(h, f, wt, &attr);
  
      if (packed) {
        upb_handlers_setstartseq(h, f, encode_startdelimfield, &attr);
        upb_handlers_setendseq(h, f, encode_enddelimfield, &attr);
      }
  
  #define T(upper, lower, upbtype)                                     \
    case UPB_DESCRIPTOR_TYPE_##upper:                                  \
      if (packed) {                                                    \
        upb_handlers_set##upbtype(h, f, encode_packed_##lower, &attr); \
      } else {                                                         \
        upb_handlers_set##upbtype(h, f, encode_scalar_##lower, &attr); \
      }                                                                \
      break;
  
      switch (upb_fielddef_descriptortype(f)) {
        T(DOUBLE,   double,   double);
        T(FLOAT,    float,    float);
        T(INT64,    int64,    int64);
        T(INT32,    int32,    int32);
        T(FIXED64,  fixed64,  uint64);
        T(FIXED32,  fixed32,  uint32);
        T(BOOL,     bool,     bool);
        T(UINT32,   uint32,   uint32);
        T(UINT64,   uint64,   uint64);
        T(ENUM,     enum,     int32);
        T(SFIXED32, sfixed32, int32);
        T(SFIXED64, sfixed64, int64);
        T(SINT32,   sint32,   int32);
        T(SINT64,   sint64,   int64);
        case UPB_DESCRIPTOR_TYPE_STRING:
        case UPB_DESCRIPTOR_TYPE_BYTES:
          upb_handlers_setstartstr(h, f, encode_startstr, &attr);
          upb_handlers_setendstr(h, f, encode_enddelimfield, &attr);
          upb_handlers_setstring(h, f, encode_strbuf, &attr);
          break;
        case UPB_DESCRIPTOR_TYPE_MESSAGE:
          upb_handlers_setstartsubmsg(h, f, encode_startdelimfield, &attr);
          upb_handlers_setendsubmsg(h, f, encode_enddelimfield, &attr);
          break;
        case UPB_DESCRIPTOR_TYPE_GROUP: {
          /* Endgroup takes a different tag (wire_type = END_GROUP). */
          upb_handlerattr attr2 = UPB_HANDLERATTR_INIT;
          new_tag(h, f, UPB_WIRE_TYPE_END_GROUP, &attr2);
  
          upb_handlers_setstartsubmsg(h, f, encode_startgroup, &attr);
          upb_handlers_setendsubmsg(h, f, encode_endgroup, &attr2);
  
          break;
        }
      }
  
  #undef T
    }
  }
  
  void upb_pb_encoder_reset(upb_pb_encoder *e) {
    e->segptr = NULL;
    e->top = NULL;
    e->depth = 0;
  }
  
  
  /* public API *****************************************************************/
  
  upb_handlercache *upb_pb_encoder_newcache(void) {
    return upb_handlercache_new(newhandlers_callback, NULL);
  }
  
  upb_pb_encoder *upb_pb_encoder_create(upb_arena *arena, const upb_handlers *h,
                                        upb_bytessink output) {
    const size_t initial_bufsize = 256;
    const size_t initial_segbufsize = 16;
    /* TODO(haberman): make this configurable. */
    const size_t stack_size = 64;
  #ifndef NDEBUG
    const size_t size_before = upb_arena_bytesallocated(arena);
  #endif
  
    upb_pb_encoder *e = upb_arena_malloc(arena, sizeof(upb_pb_encoder));
    if (!e) return NULL;
  
    e->buf = upb_arena_malloc(arena, initial_bufsize);
    e->segbuf = upb_arena_malloc(arena, initial_segbufsize * sizeof(*e->segbuf));
    e->stack = upb_arena_malloc(arena, stack_size * sizeof(*e->stack));
  
    if (!e->buf || !e->segbuf || !e->stack) {
      return NULL;
    }
  
    e->limit = e->buf + initial_bufsize;
    e->seglimit = e->segbuf + initial_segbufsize;
    e->stacklimit = e->stack + stack_size;
  
    upb_pb_encoder_reset(e);
    upb_sink_reset(&e->input_, h, e);
  
    e->arena = arena;
    e->output_ = output;
    e->subc = output.closure;
    e->ptr = e->buf;
  
    /* If this fails, increase the value in encoder.h. */
    UPB_ASSERT_DEBUGVAR(upb_arena_bytesallocated(arena) - size_before <=
                        UPB_PB_ENCODER_SIZE);
    return e;
  }
  
  upb_sink upb_pb_encoder_input(upb_pb_encoder *e) { return e->input_; }
  /*
   * upb::pb::TextPrinter
   *
   * OPT: This is not optimized at all.  It uses printf() which parses the format
   * string every time, and it allocates memory for every put.
   */
  
  
  #include <ctype.h>
  #include <float.h>
  #include <inttypes.h>
  #include <stdarg.h>
  #include <stdio.h>
  #include <string.h>
  
  
  
  struct upb_textprinter {
    upb_sink input_;
    upb_bytessink output_;
    int indent_depth_;
    bool single_line_;
    void *subc;
  };
  
  #define CHECK(x) if ((x) < 0) goto err;
  
  static const char *shortname(const char *longname) {
    const char *last = strrchr(longname, '.');
    return last ? last + 1 : longname;
  }
  
  static int indent(upb_textprinter *p) {
    int i;
    if (!p->single_line_)
      for (i = 0; i < p->indent_depth_; i++)
        upb_bytessink_putbuf(p->output_, p->subc, "  ", 2, NULL);
    return 0;
  }
  
  static int endfield(upb_textprinter *p) {
    const char ch = (p->single_line_ ? ' ' : '\n');
    upb_bytessink_putbuf(p->output_, p->subc, &ch, 1, NULL);
    return 0;
  }
  
  static int putescaped(upb_textprinter *p, const char *buf, size_t len,
                        bool preserve_utf8) {
    /* Based on CEscapeInternal() from Google's protobuf release. */
    char dstbuf[4096], *dst = dstbuf, *dstend = dstbuf + sizeof(dstbuf);
    const char *end = buf + len;
  
    /* I think hex is prettier and more useful, but proto2 uses octal; should
     * investigate whether it can parse hex also. */
    const bool use_hex = false;
    bool last_hex_escape = false; /* true if last output char was \xNN */
  
    for (; buf < end; buf++) {
      bool is_hex_escape;
  
      if (dstend - dst < 4) {
        upb_bytessink_putbuf(p->output_, p->subc, dstbuf, dst - dstbuf, NULL);
        dst = dstbuf;
      }
  
      is_hex_escape = false;
      switch (*buf) {
        case '\n': *(dst++) = '\\'; *(dst++) = 'n';  break;
        case '\r': *(dst++) = '\\'; *(dst++) = 'r';  break;
        case '\t': *(dst++) = '\\'; *(dst++) = 't';  break;
        case '\"': *(dst++) = '\\'; *(dst++) = '\"'; break;
        case '\'': *(dst++) = '\\'; *(dst++) = '\''; break;
        case '\\': *(dst++) = '\\'; *(dst++) = '\\'; break;
        default:
          /* Note that if we emit \xNN and the buf character after that is a hex
           * digit then that digit must be escaped too to prevent it being
           * interpreted as part of the character code by C. */
          if ((!preserve_utf8 || (uint8_t)*buf < 0x80) &&
              (!isprint(*buf) || (last_hex_escape && isxdigit(*buf)))) {
            sprintf(dst, (use_hex ? "\\x%02x" : "\\%03o"), (uint8_t)*buf);
            is_hex_escape = use_hex;
            dst += 4;
          } else {
            *(dst++) = *buf; break;
          }
      }
      last_hex_escape = is_hex_escape;
    }
    /* Flush remaining data. */
    upb_bytessink_putbuf(p->output_, p->subc, dstbuf, dst - dstbuf, NULL);
    return 0;
  }
  
  bool putf(upb_textprinter *p, const char *fmt, ...) {
    va_list args;
    va_list args_copy;
    char *str;
    int written;
    int len;
    bool ok;
  
    va_start(args, fmt);
  
    /* Run once to get the length of the string. */
    _upb_va_copy(args_copy, args);
    len = _upb_vsnprintf(NULL, 0, fmt, args_copy);
    va_end(args_copy);
  
    /* + 1 for NULL terminator (vsprintf() requires it even if we don't). */
    str = upb_gmalloc(len + 1);
    if (!str) return false;
    written = vsprintf(str, fmt, args);
    va_end(args);
    UPB_ASSERT(written == len);
  
    ok = upb_bytessink_putbuf(p->output_, p->subc, str, len, NULL);
    upb_gfree(str);
    return ok;
  }
  
  
  /* handlers *******************************************************************/
  
  static bool textprinter_startmsg(void *c, const void *hd) {
    upb_textprinter *p = c;
    UPB_UNUSED(hd);
    if (p->indent_depth_ == 0) {
      upb_bytessink_start(p->output_, 0, &p->subc);
    }
    return true;
  }
  
  static bool textprinter_endmsg(void *c, const void *hd, upb_status *s) {
    upb_textprinter *p = c;
    UPB_UNUSED(hd);
    UPB_UNUSED(s);
    if (p->indent_depth_ == 0) {
      upb_bytessink_end(p->output_);
    }
    return true;
  }
  
  #define TYPE(name, ctype, fmt) \
    static bool textprinter_put ## name(void *closure, const void *handler_data, \
                                        ctype val) {                             \
      upb_textprinter *p = closure;                                              \
      const upb_fielddef *f = handler_data;                                      \
      CHECK(indent(p));                                                          \
      putf(p, "%s: " fmt, upb_fielddef_name(f), val);                            \
      CHECK(endfield(p));                                                        \
      return true;                                                               \
    err:                                                                         \
      return false;                                                              \
  }
  
  static bool textprinter_putbool(void *closure, const void *handler_data,
                                  bool val) {
    upb_textprinter *p = closure;
    const upb_fielddef *f = handler_data;
    CHECK(indent(p));
    putf(p, "%s: %s", upb_fielddef_name(f), val ? "true" : "false");
    CHECK(endfield(p));
    return true;
  err:
    return false;
  }
  
  #define STRINGIFY_HELPER(x) #x
  #define STRINGIFY_MACROVAL(x) STRINGIFY_HELPER(x)
  
  TYPE(int32,  int32_t,  "%" PRId32)
  TYPE(int64,  int64_t,  "%" PRId64)
  TYPE(uint32, uint32_t, "%" PRIu32)
  TYPE(uint64, uint64_t, "%" PRIu64)
  TYPE(float,  float,    "%." STRINGIFY_MACROVAL(FLT_DIG) "g")
  TYPE(double, double,   "%." STRINGIFY_MACROVAL(DBL_DIG) "g")
  
  #undef TYPE
  
  /* Output a symbolic value from the enum if found, else just print as int32. */
  static bool textprinter_putenum(void *closure, const void *handler_data,
                                  int32_t val) {
    upb_textprinter *p = closure;
    const upb_fielddef *f = handler_data;
    const upb_enumdef *enum_def = upb_fielddef_enumsubdef(f);
    const char *label = upb_enumdef_iton(enum_def, val);
    if (label) {
      indent(p);
      putf(p, "%s: %s", upb_fielddef_name(f), label);
      endfield(p);
    } else {
      if (!textprinter_putint32(closure, handler_data, val))
        return false;
    }
    return true;
  }
  
  static void *textprinter_startstr(void *closure, const void *handler_data,
                        size_t size_hint) {
    upb_textprinter *p = closure;
    const upb_fielddef *f = handler_data;
    UPB_UNUSED(size_hint);
    indent(p);
    putf(p, "%s: \"", upb_fielddef_name(f));
    return p;
  }
  
  static bool textprinter_endstr(void *closure, const void *handler_data) {
    upb_textprinter *p = closure;
    UPB_UNUSED(handler_data);
    putf(p, "\"");
    endfield(p);
    return true;
  }
  
  static size_t textprinter_putstr(void *closure, const void *hd, const char *buf,
                                   size_t len, const upb_bufhandle *handle) {
    upb_textprinter *p = closure;
    const upb_fielddef *f = hd;
    UPB_UNUSED(handle);
    CHECK(putescaped(p, buf, len, upb_fielddef_type(f) == UPB_TYPE_STRING));
    return len;
  err:
    return 0;
  }
  
  static void *textprinter_startsubmsg(void *closure, const void *handler_data) {
    upb_textprinter *p = closure;
    const char *name = handler_data;
    CHECK(indent(p));
    putf(p, "%s {%c", name, p->single_line_ ? ' ' : '\n');
    p->indent_depth_++;
    return p;
  err:
    return UPB_BREAK;
  }
  
  static bool textprinter_endsubmsg(void *closure, const void *handler_data) {
    upb_textprinter *p = closure;
    UPB_UNUSED(handler_data);
    p->indent_depth_--;
    CHECK(indent(p));
    upb_bytessink_putbuf(p->output_, p->subc, "}", 1, NULL);
    CHECK(endfield(p));
    return true;
  err:
    return false;
  }
  
  static void onmreg(const void *c, upb_handlers *h) {
    const upb_msgdef *m = upb_handlers_msgdef(h);
    upb_msg_field_iter i;
    UPB_UNUSED(c);
  
    upb_handlers_setstartmsg(h, textprinter_startmsg, NULL);
    upb_handlers_setendmsg(h, textprinter_endmsg, NULL);
  
    for(upb_msg_field_begin(&i, m);
        !upb_msg_field_done(&i);
        upb_msg_field_next(&i)) {
      upb_fielddef *f = upb_msg_iter_field(&i);
      upb_handlerattr attr = UPB_HANDLERATTR_INIT;
      attr.handler_data = f;
      switch (upb_fielddef_type(f)) {
        case UPB_TYPE_INT32:
          upb_handlers_setint32(h, f, textprinter_putint32, &attr);
          break;
        case UPB_TYPE_INT64:
          upb_handlers_setint64(h, f, textprinter_putint64, &attr);
          break;
        case UPB_TYPE_UINT32:
          upb_handlers_setuint32(h, f, textprinter_putuint32, &attr);
          break;
        case UPB_TYPE_UINT64:
          upb_handlers_setuint64(h, f, textprinter_putuint64, &attr);
          break;
        case UPB_TYPE_FLOAT:
          upb_handlers_setfloat(h, f, textprinter_putfloat, &attr);
          break;
        case UPB_TYPE_DOUBLE:
          upb_handlers_setdouble(h, f, textprinter_putdouble, &attr);
          break;
        case UPB_TYPE_BOOL:
          upb_handlers_setbool(h, f, textprinter_putbool, &attr);
          break;
        case UPB_TYPE_STRING:
        case UPB_TYPE_BYTES:
          upb_handlers_setstartstr(h, f, textprinter_startstr, &attr);
          upb_handlers_setstring(h, f, textprinter_putstr, &attr);
          upb_handlers_setendstr(h, f, textprinter_endstr, &attr);
          break;
        case UPB_TYPE_MESSAGE: {
          const char *name =
              upb_fielddef_descriptortype(f) == UPB_DESCRIPTOR_TYPE_GROUP
                  ? shortname(upb_msgdef_fullname(upb_fielddef_msgsubdef(f)))
                  : upb_fielddef_name(f);
          attr.handler_data = name;
          upb_handlers_setstartsubmsg(h, f, textprinter_startsubmsg, &attr);
          upb_handlers_setendsubmsg(h, f, textprinter_endsubmsg, &attr);
          break;
        }
        case UPB_TYPE_ENUM:
          upb_handlers_setint32(h, f, textprinter_putenum, &attr);
          break;
      }
    }
  }
  
  static void textprinter_reset(upb_textprinter *p, bool single_line) {
    p->single_line_ = single_line;
    p->indent_depth_ = 0;
  }
  
  
  /* Public API *****************************************************************/
  
  upb_textprinter *upb_textprinter_create(upb_arena *arena, const upb_handlers *h,
                                          upb_bytessink output) {
    upb_textprinter *p = upb_arena_malloc(arena, sizeof(upb_textprinter));
    if (!p) return NULL;
  
    p->output_ = output;
    upb_sink_reset(&p->input_, h, p);
    textprinter_reset(p, false);
  
    return p;
  }
  
  upb_handlercache *upb_textprinter_newcache(void) {
    return upb_handlercache_new(&onmreg, NULL);
  }
  
  upb_sink upb_textprinter_input(upb_textprinter *p) { return p->input_; }
  
  void upb_textprinter_setsingleline(upb_textprinter *p, bool single_line) {
    p->single_line_ = single_line;
  }
  
  
  /* Index is descriptor type. */
  const uint8_t upb_pb_native_wire_types[] = {
    UPB_WIRE_TYPE_END_GROUP,     /* ENDGROUP */
    UPB_WIRE_TYPE_64BIT,         /* DOUBLE */
    UPB_WIRE_TYPE_32BIT,         /* FLOAT */
    UPB_WIRE_TYPE_VARINT,        /* INT64 */
    UPB_WIRE_TYPE_VARINT,        /* UINT64 */
    UPB_WIRE_TYPE_VARINT,        /* INT32 */
    UPB_WIRE_TYPE_64BIT,         /* FIXED64 */
    UPB_WIRE_TYPE_32BIT,         /* FIXED32 */
    UPB_WIRE_TYPE_VARINT,        /* BOOL */
    UPB_WIRE_TYPE_DELIMITED,     /* STRING */
    UPB_WIRE_TYPE_START_GROUP,   /* GROUP */
    UPB_WIRE_TYPE_DELIMITED,     /* MESSAGE */
    UPB_WIRE_TYPE_DELIMITED,     /* BYTES */
    UPB_WIRE_TYPE_VARINT,        /* UINT32 */
    UPB_WIRE_TYPE_VARINT,        /* ENUM */
    UPB_WIRE_TYPE_32BIT,         /* SFIXED32 */
    UPB_WIRE_TYPE_64BIT,         /* SFIXED64 */
    UPB_WIRE_TYPE_VARINT,        /* SINT32 */
    UPB_WIRE_TYPE_VARINT,        /* SINT64 */
  };
  
  /* A basic branch-based decoder, uses 32-bit values to get good performance
   * on 32-bit architectures (but performs well on 64-bits also).
   * This scheme comes from the original Google Protobuf implementation
   * (proto2). */
  upb_decoderet upb_vdecode_max8_branch32(upb_decoderet r) {
    upb_decoderet err = {NULL, 0};
    const char *p = r.p;
    uint32_t low = (uint32_t)r.val;
    uint32_t high = 0;
    uint32_t b;
    b = *(p++); low  |= (b & 0x7fU) << 14; if (!(b & 0x80)) goto done;
    b = *(p++); low  |= (b & 0x7fU) << 21; if (!(b & 0x80)) goto done;
    b = *(p++); low  |= (b & 0x7fU) << 28;
                high  = (b & 0x7fU) >>  4; if (!(b & 0x80)) goto done;
    b = *(p++); high |= (b & 0x7fU) <<  3; if (!(b & 0x80)) goto done;
    b = *(p++); high |= (b & 0x7fU) << 10; if (!(b & 0x80)) goto done;
    b = *(p++); high |= (b & 0x7fU) << 17; if (!(b & 0x80)) goto done;
    b = *(p++); high |= (b & 0x7fU) << 24; if (!(b & 0x80)) goto done;
    b = *(p++); high |= (b & 0x7fU) << 31; if (!(b & 0x80)) goto done;
    return err;
  
  done:
    r.val = ((uint64_t)high << 32) | low;
    r.p = p;
    return r;
  }
  
  /* Like the previous, but uses 64-bit values. */
  upb_decoderet upb_vdecode_max8_branch64(upb_decoderet r) {
    const char *p = r.p;
    uint64_t val = r.val;
    uint64_t b;
    upb_decoderet err = {NULL, 0};
    b = *(p++); val |= (b & 0x7fU) << 14; if (!(b & 0x80)) goto done;
    b = *(p++); val |= (b & 0x7fU) << 21; if (!(b & 0x80)) goto done;
    b = *(p++); val |= (b & 0x7fU) << 28; if (!(b & 0x80)) goto done;
    b = *(p++); val |= (b & 0x7fU) << 35; if (!(b & 0x80)) goto done;
    b = *(p++); val |= (b & 0x7fU) << 42; if (!(b & 0x80)) goto done;
    b = *(p++); val |= (b & 0x7fU) << 49; if (!(b & 0x80)) goto done;
    b = *(p++); val |= (b & 0x7fU) << 56; if (!(b & 0x80)) goto done;
    b = *(p++); val |= (b & 0x7fU) << 63; if (!(b & 0x80)) goto done;
    return err;
  
  done:
    r.val = val;
    r.p = p;
    return r;
  }
  
  #line 1 "upb/json/parser.rl"
  /*
  ** upb::json::Parser (upb_json_parser)
  **
  ** A parser that uses the Ragel State Machine Compiler to generate
  ** the finite automata.
  **
  ** Ragel only natively handles regular languages, but we can manually
  ** program it a bit to handle context-free languages like JSON, by using
  ** the "fcall" and "fret" constructs.
  **
  ** This parser can handle the basics, but needs several things to be fleshed
  ** out:
  **
  ** - handling of unicode escape sequences (including high surrogate pairs).
  ** - properly check and report errors for unknown fields, stack overflow,
  **   improper array nesting (or lack of nesting).
  ** - handling of base64 sequences with padding characters.
  ** - handling of push-back (non-success returns from sink functions).
  ** - handling of keys/escape-sequences/etc that span input buffers.
  */
  
  #include <ctype.h>
  #include <errno.h>
  #include <float.h>
  #include <math.h>
  #include <stdint.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include <time.h>
  
  
  
  #define UPB_JSON_MAX_DEPTH 64
  
  /* Type of value message */
  enum {
    VALUE_NULLVALUE   = 0,
    VALUE_NUMBERVALUE = 1,
    VALUE_STRINGVALUE = 2,
    VALUE_BOOLVALUE   = 3,
    VALUE_STRUCTVALUE = 4,
    VALUE_LISTVALUE   = 5
  };
  
  /* Forward declare */
  static bool is_top_level(upb_json_parser *p);
  static bool is_wellknown_msg(upb_json_parser *p, upb_wellknowntype_t type);
  static bool is_wellknown_field(upb_json_parser *p, upb_wellknowntype_t type);
  
  static bool is_number_wrapper_object(upb_json_parser *p);
  static bool does_number_wrapper_start(upb_json_parser *p);
  static bool does_number_wrapper_end(upb_json_parser *p);
  
  static bool is_string_wrapper_object(upb_json_parser *p);
  static bool does_string_wrapper_start(upb_json_parser *p);
  static bool does_string_wrapper_end(upb_json_parser *p);
  
  static bool does_fieldmask_start(upb_json_parser *p);
  static bool does_fieldmask_end(upb_json_parser *p);
  static void start_fieldmask_object(upb_json_parser *p);
  static void end_fieldmask_object(upb_json_parser *p);
  
  static void start_wrapper_object(upb_json_parser *p);
  static void end_wrapper_object(upb_json_parser *p);
  
  static void start_value_object(upb_json_parser *p, int value_type);
  static void end_value_object(upb_json_parser *p);
  
  static void start_listvalue_object(upb_json_parser *p);
  static void end_listvalue_object(upb_json_parser *p);
  
  static void start_structvalue_object(upb_json_parser *p);
  static void end_structvalue_object(upb_json_parser *p);
  
  static void start_object(upb_json_parser *p);
  static void end_object(upb_json_parser *p);
  
  static void start_any_object(upb_json_parser *p, const char *ptr);
  static bool end_any_object(upb_json_parser *p, const char *ptr);
  
  static bool start_subobject(upb_json_parser *p);
  static void end_subobject(upb_json_parser *p);
  
  static void start_member(upb_json_parser *p);
  static void end_member(upb_json_parser *p);
  static bool end_membername(upb_json_parser *p);
  
  static void start_any_member(upb_json_parser *p, const char *ptr);
  static void end_any_member(upb_json_parser *p, const char *ptr);
  static bool end_any_membername(upb_json_parser *p);
  
  size_t parse(void *closure, const void *hd, const char *buf, size_t size,
               const upb_bufhandle *handle);
  static bool end(void *closure, const void *hd);
  
  static const char eof_ch = 'e';
  
  /* stringsink */
  typedef struct {
    upb_byteshandler handler;
    upb_bytessink sink;
    char *ptr;
    size_t len, size;
  } upb_stringsink;
  
  
  static void *stringsink_start(void *_sink, const void *hd, size_t size_hint) {
    upb_stringsink *sink = _sink;
    sink->len = 0;
    UPB_UNUSED(hd);
    UPB_UNUSED(size_hint);
    return sink;
  }
  
  static size_t stringsink_string(void *_sink, const void *hd, const char *ptr,
                                  size_t len, const upb_bufhandle *handle) {
    upb_stringsink *sink = _sink;
    size_t new_size = sink->size;
  
    UPB_UNUSED(hd);
    UPB_UNUSED(handle);
  
    while (sink->len + len > new_size) {
      new_size *= 2;
    }
  
    if (new_size != sink->size) {
      sink->ptr = realloc(sink->ptr, new_size);
      sink->size = new_size;
    }
  
    memcpy(sink->ptr + sink->len, ptr, len);
    sink->len += len;
  
    return len;
  }
  
  void upb_stringsink_init(upb_stringsink *sink) {
    upb_byteshandler_init(&sink->handler);
    upb_byteshandler_setstartstr(&sink->handler, stringsink_start, NULL);
    upb_byteshandler_setstring(&sink->handler, stringsink_string, NULL);
  
    upb_bytessink_reset(&sink->sink, &sink->handler, sink);
  
    sink->size = 32;
    sink->ptr = malloc(sink->size);
    sink->len = 0;
  }
  
  void upb_stringsink_uninit(upb_stringsink *sink) { free(sink->ptr); }
  
  typedef struct {
    /* For encoding Any value field in binary format. */
    upb_handlercache *encoder_handlercache;
    upb_stringsink stringsink;
  
    /* For decoding Any value field in json format. */
    upb_json_codecache *parser_codecache;
    upb_sink sink;
    upb_json_parser *parser;
  
    /* Mark the range of uninterpreted values in json input before type url. */
    const char *before_type_url_start;
    const char *before_type_url_end;
  
    /* Mark the range of uninterpreted values in json input after type url. */
    const char *after_type_url_start;
  } upb_jsonparser_any_frame;
  
  typedef struct {
    upb_sink sink;
  
    /* The current message in which we're parsing, and the field whose value we're
     * expecting next. */
    const upb_msgdef *m;
    const upb_fielddef *f;
  
    /* The table mapping json name to fielddef for this message. */
    const upb_strtable *name_table;
  
    /* We are in a repeated-field context. We need this flag to decide whether to
     * handle the array as a normal repeated field or a
     * google.protobuf.ListValue/google.protobuf.Value. */
    bool is_repeated;
  
    /* We are in a repeated-field context, ready to emit mapentries as
     * submessages. This flag alters the start-of-object (open-brace) behavior to
     * begin a sequence of mapentry messages rather than a single submessage. */
    bool is_map;
  
    /* We are in a map-entry message context. This flag is set when parsing the
     * value field of a single map entry and indicates to all value-field parsers
     * (subobjects, strings, numbers, and bools) that the map-entry submessage
     * should end as soon as the value is parsed. */
    bool is_mapentry;
  
    /* If |is_map| or |is_mapentry| is true, |mapfield| refers to the parent
     * message's map field that we're currently parsing. This differs from |f|
     * because |f| is the field in the *current* message (i.e., the map-entry
     * message itself), not the parent's field that leads to this map. */
    const upb_fielddef *mapfield;
  
    /* We are in an Any message context. This flag is set when parsing the Any
     * message and indicates to all field parsers (subobjects, strings, numbers,
     * and bools) that the parsed field should be serialized as binary data or
     * cached (type url not found yet). */
    bool is_any;
  
    /* The type of packed message in Any. */
    upb_jsonparser_any_frame *any_frame;
  
    /* True if the field to be parsed is unknown. */
    bool is_unknown_field;
  } upb_jsonparser_frame;
  
  static void init_frame(upb_jsonparser_frame* frame) {
    frame->m = NULL;
    frame->f = NULL;
    frame->name_table = NULL;
    frame->is_repeated = false;
    frame->is_map = false;
    frame->is_mapentry = false;
    frame->mapfield = NULL;
    frame->is_any = false;
    frame->any_frame = NULL;
    frame->is_unknown_field = false;
  }
  
  struct upb_json_parser {
    upb_arena *arena;
    const upb_json_parsermethod *method;
    upb_bytessink input_;
  
    /* Stack to track the JSON scopes we are in. */
    upb_jsonparser_frame stack[UPB_JSON_MAX_DEPTH];
    upb_jsonparser_frame *top;
    upb_jsonparser_frame *limit;
  
    upb_status *status;
  
    /* Ragel's internal parsing stack for the parsing state machine. */
    int current_state;
    int parser_stack[UPB_JSON_MAX_DEPTH];
    int parser_top;
  
    /* The handle for the current buffer. */
    const upb_bufhandle *handle;
  
    /* Accumulate buffer.  See details in parser.rl. */
    const char *accumulated;
    size_t accumulated_len;
    char *accumulate_buf;
    size_t accumulate_buf_size;
  
    /* Multi-part text data.  See details in parser.rl. */
    int multipart_state;
    upb_selector_t string_selector;
  
    /* Input capture.  See details in parser.rl. */
    const char *capture;
  
    /* Intermediate result of parsing a unicode escape sequence. */
    uint32_t digit;
  
    /* For resolve type url in Any. */
    const upb_symtab *symtab;
  
    /* Whether to proceed if unknown field is met. */
    bool ignore_json_unknown;
  
    /* Cache for parsing timestamp due to base and zone are handled in different
     * handlers. */
    struct tm tm;
  };
  
  static upb_jsonparser_frame* start_jsonparser_frame(upb_json_parser *p) {
    upb_jsonparser_frame *inner;
    inner = p->top + 1;
    init_frame(inner);
    return inner;
  }
  
  struct upb_json_codecache {
    upb_arena *arena;
    upb_inttable methods;   /* upb_msgdef* -> upb_json_parsermethod* */
  };
  
  struct upb_json_parsermethod {
    const upb_json_codecache *cache;
    upb_byteshandler input_handler_;
  
    /* Maps json_name -> fielddef */
    upb_strtable name_table;
  };
  
  #define PARSER_CHECK_RETURN(x) if (!(x)) return false
  
  static upb_jsonparser_any_frame *json_parser_any_frame_new(
      upb_json_parser *p) {
    upb_jsonparser_any_frame *frame;
  
    frame = upb_arena_malloc(p->arena, sizeof(upb_jsonparser_any_frame));
  
    frame->encoder_handlercache = upb_pb_encoder_newcache();
    frame->parser_codecache = upb_json_codecache_new();
    frame->parser = NULL;
    frame->before_type_url_start = NULL;
    frame->before_type_url_end = NULL;
    frame->after_type_url_start = NULL;
  
    upb_stringsink_init(&frame->stringsink);
  
    return frame;
  }
  
  static void json_parser_any_frame_set_payload_type(
      upb_json_parser *p,
      upb_jsonparser_any_frame *frame,
      const upb_msgdef *payload_type) {
    const upb_handlers *h;
    const upb_json_parsermethod *parser_method;
    upb_pb_encoder *encoder;
  
    /* Initialize encoder. */
    h = upb_handlercache_get(frame->encoder_handlercache, payload_type);
    encoder = upb_pb_encoder_create(p->arena, h, frame->stringsink.sink);
  
    /* Initialize parser. */
    parser_method = upb_json_codecache_get(frame->parser_codecache, payload_type);
    upb_sink_reset(&frame->sink, h, encoder);
    frame->parser =
        upb_json_parser_create(p->arena, parser_method, p->symtab, frame->sink,
                               p->status, p->ignore_json_unknown);
  }
  
  static void json_parser_any_frame_free(upb_jsonparser_any_frame *frame) {
    upb_handlercache_free(frame->encoder_handlercache);
    upb_json_codecache_free(frame->parser_codecache);
    upb_stringsink_uninit(&frame->stringsink);
  }
  
  static bool json_parser_any_frame_has_type_url(
    upb_jsonparser_any_frame *frame) {
    return frame->parser != NULL;
  }
  
  static bool json_parser_any_frame_has_value_before_type_url(
    upb_jsonparser_any_frame *frame) {
    return frame->before_type_url_start != frame->before_type_url_end;
  }
  
  static bool json_parser_any_frame_has_value_after_type_url(
    upb_jsonparser_any_frame *frame) {
    return frame->after_type_url_start != NULL;
  }
  
  static bool json_parser_any_frame_has_value(
    upb_jsonparser_any_frame *frame) {
    return json_parser_any_frame_has_value_before_type_url(frame) ||
           json_parser_any_frame_has_value_after_type_url(frame);
  }
  
  static void json_parser_any_frame_set_before_type_url_end(
      upb_jsonparser_any_frame *frame,
      const char *ptr) {
    if (frame->parser == NULL) {
      frame->before_type_url_end = ptr;
    }
  }
  
  static void json_parser_any_frame_set_after_type_url_start_once(
      upb_jsonparser_any_frame *frame,
      const char *ptr) {
    if (json_parser_any_frame_has_type_url(frame) &&
        frame->after_type_url_start == NULL) {
      frame->after_type_url_start = ptr;
    }
  }
  
  /* Used to signal that a capture has been suspended. */
  static char suspend_capture;
  
  static upb_selector_t getsel_for_handlertype(upb_json_parser *p,
                                               upb_handlertype_t type) {
    upb_selector_t sel;
    bool ok = upb_handlers_getselector(p->top->f, type, &sel);
    UPB_ASSERT(ok);
    return sel;
  }
  
  static upb_selector_t parser_getsel(upb_json_parser *p) {
    return getsel_for_handlertype(
        p, upb_handlers_getprimitivehandlertype(p->top->f));
  }
  
  static bool check_stack(upb_json_parser *p) {
    if ((p->top + 1) == p->limit) {
      upb_status_seterrmsg(p->status, "Nesting too deep");
      return false;
    }
  
    return true;
  }
  
  static void set_name_table(upb_json_parser *p, upb_jsonparser_frame *frame) {
    upb_value v;
    const upb_json_codecache *cache = p->method->cache;
    bool ok;
    const upb_json_parsermethod *method;
  
    ok = upb_inttable_lookupptr(&cache->methods, frame->m, &v);
    UPB_ASSERT(ok);
    method = upb_value_getconstptr(v);
  
    frame->name_table = &method->name_table;
  }
  
  /* There are GCC/Clang built-ins for overflow checking which we could start
   * using if there was any performance benefit to it. */
  
  static bool checked_add(size_t a, size_t b, size_t *c) {
    if (SIZE_MAX - a < b) return false;
    *c = a + b;
    return true;
  }
  
  static size_t saturating_multiply(size_t a, size_t b) {
    /* size_t is unsigned, so this is defined behavior even on overflow. */
    size_t ret = a * b;
    if (b != 0 && ret / b != a) {
      ret = SIZE_MAX;
    }
    return ret;
  }
  
  
  /* Base64 decoding ************************************************************/
  
  /* TODO(haberman): make this streaming. */
  
  static const signed char b64table[] = {
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      62/*+*/, -1,      -1,      -1,      63/*/ */,
    52/*0*/, 53/*1*/, 54/*2*/, 55/*3*/, 56/*4*/, 57/*5*/, 58/*6*/, 59/*7*/,
    60/*8*/, 61/*9*/, -1,      -1,      -1,      -1,      -1,      -1,
    -1,       0/*A*/,  1/*B*/,  2/*C*/,  3/*D*/,  4/*E*/,  5/*F*/,  6/*G*/,
    07/*H*/,  8/*I*/,  9/*J*/, 10/*K*/, 11/*L*/, 12/*M*/, 13/*N*/, 14/*O*/,
    15/*P*/, 16/*Q*/, 17/*R*/, 18/*S*/, 19/*T*/, 20/*U*/, 21/*V*/, 22/*W*/,
    23/*X*/, 24/*Y*/, 25/*Z*/, -1,      -1,      -1,      -1,      -1,
    -1,      26/*a*/, 27/*b*/, 28/*c*/, 29/*d*/, 30/*e*/, 31/*f*/, 32/*g*/,
    33/*h*/, 34/*i*/, 35/*j*/, 36/*k*/, 37/*l*/, 38/*m*/, 39/*n*/, 40/*o*/,
    41/*p*/, 42/*q*/, 43/*r*/, 44/*s*/, 45/*t*/, 46/*u*/, 47/*v*/, 48/*w*/,
    49/*x*/, 50/*y*/, 51/*z*/, -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1,
    -1,      -1,      -1,      -1,      -1,      -1,      -1,      -1
  };
  
  /* Returns the table value sign-extended to 32 bits.  Knowing that the upper
   * bits will be 1 for unrecognized characters makes it easier to check for
   * this error condition later (see below). */
  int32_t b64lookup(unsigned char ch) { return b64table[ch]; }
  
  /* Returns true if the given character is not a valid base64 character or
   * padding. */
  bool nonbase64(unsigned char ch) { return b64lookup(ch) == -1 && ch != '='; }
  
  static bool base64_push(upb_json_parser *p, upb_selector_t sel, const char *ptr,
                          size_t len) {
    const char *limit = ptr + len;
    for (; ptr < limit; ptr += 4) {
      uint32_t val;
      char output[3];
  
      if (limit - ptr < 4) {
        upb_status_seterrf(p->status,
                           "Base64 input for bytes field not a multiple of 4: %s",
                           upb_fielddef_name(p->top->f));
        return false;
      }
  
      val = b64lookup(ptr[0]) << 18 |
            b64lookup(ptr[1]) << 12 |
            b64lookup(ptr[2]) << 6  |
            b64lookup(ptr[3]);
  
      /* Test the upper bit; returns true if any of the characters returned -1. */
      if (val & 0x80000000) {
        goto otherchar;
      }
  
      output[0] = val >> 16;
      output[1] = (val >> 8) & 0xff;
      output[2] = val & 0xff;
      upb_sink_putstring(p->top->sink, sel, output, 3, NULL);
    }
    return true;
  
  otherchar:
    if (nonbase64(ptr[0]) || nonbase64(ptr[1]) || nonbase64(ptr[2]) ||
        nonbase64(ptr[3]) ) {
      upb_status_seterrf(p->status,
                         "Non-base64 characters in bytes field: %s",
                         upb_fielddef_name(p->top->f));
      return false;
    } if (ptr[2] == '=') {
      uint32_t val;
      char output;
  
      /* Last group contains only two input bytes, one output byte. */
      if (ptr[0] == '=' || ptr[1] == '=' || ptr[3] != '=') {
        goto badpadding;
      }
  
      val = b64lookup(ptr[0]) << 18 |
            b64lookup(ptr[1]) << 12;
  
      UPB_ASSERT(!(val & 0x80000000));
      output = val >> 16;
      upb_sink_putstring(p->top->sink, sel, &output, 1, NULL);
      return true;
    } else {
      uint32_t val;
      char output[2];
  
      /* Last group contains only three input bytes, two output bytes. */
      if (ptr[0] == '=' || ptr[1] == '=' || ptr[2] == '=') {
        goto badpadding;
      }
  
      val = b64lookup(ptr[0]) << 18 |
            b64lookup(ptr[1]) << 12 |
            b64lookup(ptr[2]) << 6;
  
      output[0] = val >> 16;
      output[1] = (val >> 8) & 0xff;
      upb_sink_putstring(p->top->sink, sel, output, 2, NULL);
      return true;
    }
  
  badpadding:
    upb_status_seterrf(p->status,
                       "Incorrect base64 padding for field: %s (%.*s)",
                       upb_fielddef_name(p->top->f),
                       4, ptr);
    return false;
  }
  
  
  /* Accumulate buffer **********************************************************/
  
  /* Functionality for accumulating a buffer.
   *
   * Some parts of the parser need an entire value as a contiguous string.  For
   * example, to look up a member name in a hash table, or to turn a string into
   * a number, the relevant library routines need the input string to be in
   * contiguous memory, even if the value spanned two or more buffers in the
   * input.  These routines handle that.
   *
   * In the common case we can just point to the input buffer to get this
   * contiguous string and avoid any actual copy.  So we optimistically begin
   * this way.  But there are a few cases where we must instead copy into a
   * separate buffer:
   *
   *   1. The string was not contiguous in the input (it spanned buffers).
   *
   *   2. The string included escape sequences that need to be interpreted to get
   *      the true value in a contiguous buffer. */
  
  static void assert_accumulate_empty(upb_json_parser *p) {
    UPB_ASSERT(p->accumulated == NULL);
    UPB_ASSERT(p->accumulated_len == 0);
  }
  
  static void accumulate_clear(upb_json_parser *p) {
    p->accumulated = NULL;
    p->accumulated_len = 0;
  }
  
  /* Used internally by accumulate_append(). */
  static bool accumulate_realloc(upb_json_parser *p, size_t need) {
    void *mem;
    size_t old_size = p->accumulate_buf_size;
    size_t new_size = UPB_MAX(old_size, 128);
    while (new_size < need) {
      new_size = saturating_multiply(new_size, 2);
    }
  
    mem = upb_arena_realloc(p->arena, p->accumulate_buf, old_size, new_size);
    if (!mem) {
      upb_status_seterrmsg(p->status, "Out of memory allocating buffer.");
      return false;
    }
  
    p->accumulate_buf = mem;
    p->accumulate_buf_size = new_size;
    return true;
  }
  
  /* Logically appends the given data to the append buffer.
   * If "can_alias" is true, we will try to avoid actually copying, but the buffer
   * must be valid until the next accumulate_append() call (if any). */
  static bool accumulate_append(upb_json_parser *p, const char *buf, size_t len,
                                bool can_alias) {
    size_t need;
  
    if (!p->accumulated && can_alias) {
      p->accumulated = buf;
      p->accumulated_len = len;
      return true;
    }
  
    if (!checked_add(p->accumulated_len, len, &need)) {
      upb_status_seterrmsg(p->status, "Integer overflow.");
      return false;
    }
  
    if (need > p->accumulate_buf_size && !accumulate_realloc(p, need)) {
      return false;
    }
  
    if (p->accumulated != p->accumulate_buf) {
      memcpy(p->accumulate_buf, p->accumulated, p->accumulated_len);
      p->accumulated = p->accumulate_buf;
    }
  
    memcpy(p->accumulate_buf + p->accumulated_len, buf, len);
    p->accumulated_len += len;
    return true;
  }
  
  /* Returns a pointer to the data accumulated since the last accumulate_clear()
   * call, and writes the length to *len.  This with point either to the input
   * buffer or a temporary accumulate buffer. */
  static const char *accumulate_getptr(upb_json_parser *p, size_t *len) {
    UPB_ASSERT(p->accumulated);
    *len = p->accumulated_len;
    return p->accumulated;
  }
  
  
  /* Mult-part text data ********************************************************/
  
  /* When we have text data in the input, it can often come in multiple segments.
   * For example, there may be some raw string data followed by an escape
   * sequence.  The two segments are processed with different logic.  Also buffer
   * seams in the input can cause multiple segments.
   *
   * As we see segments, there are two main cases for how we want to process them:
   *
   *  1. we want to push the captured input directly to string handlers.
   *
   *  2. we need to accumulate all the parts into a contiguous buffer for further
   *     processing (field name lookup, string->number conversion, etc). */
  
  /* This is the set of states for p->multipart_state. */
  enum {
    /* We are not currently processing multipart data. */
    MULTIPART_INACTIVE = 0,
  
    /* We are processing multipart data by accumulating it into a contiguous
     * buffer. */
    MULTIPART_ACCUMULATE = 1,
  
    /* We are processing multipart data by pushing each part directly to the
     * current string handlers. */
    MULTIPART_PUSHEAGERLY = 2
  };
  
  /* Start a multi-part text value where we accumulate the data for processing at
   * the end. */
  static void multipart_startaccum(upb_json_parser *p) {
    assert_accumulate_empty(p);
    UPB_ASSERT(p->multipart_state == MULTIPART_INACTIVE);
    p->multipart_state = MULTIPART_ACCUMULATE;
  }
  
  /* Start a multi-part text value where we immediately push text data to a string
   * value with the given selector. */
  static void multipart_start(upb_json_parser *p, upb_selector_t sel) {
    assert_accumulate_empty(p);
    UPB_ASSERT(p->multipart_state == MULTIPART_INACTIVE);
    p->multipart_state = MULTIPART_PUSHEAGERLY;
    p->string_selector = sel;
  }
  
  static bool multipart_text(upb_json_parser *p, const char *buf, size_t len,
                             bool can_alias) {
    switch (p->multipart_state) {
      case MULTIPART_INACTIVE:
        upb_status_seterrmsg(
            p->status, "Internal error: unexpected state MULTIPART_INACTIVE");
        return false;
  
      case MULTIPART_ACCUMULATE:
        if (!accumulate_append(p, buf, len, can_alias)) {
          return false;
        }
        break;
  
      case MULTIPART_PUSHEAGERLY: {
        const upb_bufhandle *handle = can_alias ? p->handle : NULL;
        upb_sink_putstring(p->top->sink, p->string_selector, buf, len, handle);
        break;
      }
    }
  
    return true;
  }
  
  /* Note: this invalidates the accumulate buffer!  Call only after reading its
   * contents. */
  static void multipart_end(upb_json_parser *p) {
    UPB_ASSERT(p->multipart_state != MULTIPART_INACTIVE);
    p->multipart_state = MULTIPART_INACTIVE;
    accumulate_clear(p);
  }
  
  
  /* Input capture **************************************************************/
  
  /* Functionality for capturing a region of the input as text.  Gracefully
   * handles the case where a buffer seam occurs in the middle of the captured
   * region. */
  
  static void capture_begin(upb_json_parser *p, const char *ptr) {
    UPB_ASSERT(p->multipart_state != MULTIPART_INACTIVE);
    UPB_ASSERT(p->capture == NULL);
    p->capture = ptr;
  }
  
  static bool capture_end(upb_json_parser *p, const char *ptr) {
    UPB_ASSERT(p->capture);
    if (multipart_text(p, p->capture, ptr - p->capture, true)) {
      p->capture = NULL;
      return true;
    } else {
      return false;
    }
  }
  
  /* This is called at the end of each input buffer (ie. when we have hit a
   * buffer seam).  If we are in the middle of capturing the input, this
   * processes the unprocessed capture region. */
  static void capture_suspend(upb_json_parser *p, const char **ptr) {
    if (!p->capture) return;
  
    if (multipart_text(p, p->capture, *ptr - p->capture, false)) {
      /* We use this as a signal that we were in the middle of capturing, and
       * that capturing should resume at the beginning of the next buffer.
       * 
       * We can't use *ptr here, because we have no guarantee that this pointer
       * will be valid when we resume (if the underlying memory is freed, then
       * using the pointer at all, even to compare to NULL, is likely undefined
       * behavior). */
      p->capture = &suspend_capture;
    } else {
      /* Need to back up the pointer to the beginning of the capture, since
       * we were not able to actually preserve it. */
      *ptr = p->capture;
    }
  }
  
  static void capture_resume(upb_json_parser *p, const char *ptr) {
    if (p->capture) {
      UPB_ASSERT(p->capture == &suspend_capture);
      p->capture = ptr;
    }
  }
  
  
  /* Callbacks from the parser **************************************************/
  
  /* These are the functions called directly from the parser itself.
   * We define these in the same order as their declarations in the parser. */
  
  static char escape_char(char in) {
    switch (in) {
      case 'r': return '\r';
      case 't': return '\t';
      case 'n': return '\n';
      case 'f': return '\f';
      case 'b': return '\b';
      case '/': return '/';
      case '"': return '"';
      case '\\': return '\\';
      default:
        UPB_ASSERT(0);
        return 'x';
    }
  }
  
  static bool escape(upb_json_parser *p, const char *ptr) {
    char ch = escape_char(*ptr);
    return multipart_text(p, &ch, 1, false);
  }
  
  static void start_hex(upb_json_parser *p) {
    p->digit = 0;
  }
  
  static void hexdigit(upb_json_parser *p, const char *ptr) {
    char ch = *ptr;
  
    p->digit <<= 4;
  
    if (ch >= '0' && ch <= '9') {
      p->digit += (ch - '0');
    } else if (ch >= 'a' && ch <= 'f') {
      p->digit += ((ch - 'a') + 10);
    } else {
      UPB_ASSERT(ch >= 'A' && ch <= 'F');
      p->digit += ((ch - 'A') + 10);
    }
  }
  
  static bool end_hex(upb_json_parser *p) {
    uint32_t codepoint = p->digit;
  
    /* emit the codepoint as UTF-8. */
    char utf8[3]; /* support \u0000 -- \uFFFF -- need only three bytes. */
    int length = 0;
    if (codepoint <= 0x7F) {
      utf8[0] = codepoint;
      length = 1;
    } else if (codepoint <= 0x07FF) {
      utf8[1] = (codepoint & 0x3F) | 0x80;
      codepoint >>= 6;
      utf8[0] = (codepoint & 0x1F) | 0xC0;
      length = 2;
    } else /* codepoint <= 0xFFFF */ {
      utf8[2] = (codepoint & 0x3F) | 0x80;
      codepoint >>= 6;
      utf8[1] = (codepoint & 0x3F) | 0x80;
      codepoint >>= 6;
      utf8[0] = (codepoint & 0x0F) | 0xE0;
      length = 3;
    }
    /* TODO(haberman): Handle high surrogates: if codepoint is a high surrogate
     * we have to wait for the next escape to get the full code point). */
  
    return multipart_text(p, utf8, length, false);
  }
  
  static void start_text(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_text(upb_json_parser *p, const char *ptr) {
    return capture_end(p, ptr);
  }
  
  static bool start_number(upb_json_parser *p, const char *ptr) {
    if (is_top_level(p)) {
      if (is_number_wrapper_object(p)) {
        start_wrapper_object(p);
      } else if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
        start_value_object(p, VALUE_NUMBERVALUE);
      } else {
        return false;
      }
    } else if (does_number_wrapper_start(p)) {
      if (!start_subobject(p)) {
        return false;
      }
      start_wrapper_object(p);
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_VALUE)) {
      if (!start_subobject(p)) {
        return false;
      }
      start_value_object(p, VALUE_NUMBERVALUE);
    }
  
    multipart_startaccum(p);
    capture_begin(p, ptr);
    return true;
  }
  
  static bool parse_number(upb_json_parser *p, bool is_quoted);
  
  static bool end_number_nontop(upb_json_parser *p, const char *ptr) {
    if (!capture_end(p, ptr)) {
      return false;
    }
  
    if (p->top->f == NULL) {
      multipart_end(p);
      return true;
    }
  
    return parse_number(p, false);
  }
  
  static bool end_number(upb_json_parser *p, const char *ptr) {
    if (!end_number_nontop(p, ptr)) {
      return false;
    }
  
    if (does_number_wrapper_end(p)) {
      end_wrapper_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
      return true;
    }
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
      end_value_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
      return true;
    }
  
    return true;
  }
  
  /* |buf| is NULL-terminated. |buf| itself will never include quotes;
   * |is_quoted| tells us whether this text originally appeared inside quotes. */
  static bool parse_number_from_buffer(upb_json_parser *p, const char *buf,
                                       bool is_quoted) {
    size_t len = strlen(buf);
    const char *bufend = buf + len;
    char *end;
    upb_fieldtype_t type = upb_fielddef_type(p->top->f);
    double val;
    double dummy;
    double inf = UPB_INFINITY;
  
    errno = 0;
  
    if (len == 0 || buf[0] == ' ') {
      return false;
    }
  
    /* For integer types, first try parsing with integer-specific routines.
     * If these succeed, they will be more accurate for int64/uint64 than
     * strtod().
     */
    switch (type) {
      case UPB_TYPE_ENUM:
      case UPB_TYPE_INT32: {
        long val = strtol(buf, &end, 0);
        if (errno == ERANGE || end != bufend) {
          break;
        } else if (val > INT32_MAX || val < INT32_MIN) {
          return false;
        } else {
          upb_sink_putint32(p->top->sink, parser_getsel(p), val);
          return true;
        }
      }
      case UPB_TYPE_UINT32: {
        unsigned long val = strtoul(buf, &end, 0);
        if (end != bufend) {
          break;
        } else if (val > UINT32_MAX || errno == ERANGE) {
          return false;
        } else {
          upb_sink_putuint32(p->top->sink, parser_getsel(p), val);
          return true;
        }
      }
      /* XXX: We can't handle [u]int64 properly on 32-bit machines because
       * strto[u]ll isn't in C89. */
      case UPB_TYPE_INT64: {
        long val = strtol(buf, &end, 0);
        if (errno == ERANGE || end != bufend) {
          break;
        } else {
          upb_sink_putint64(p->top->sink, parser_getsel(p), val);
          return true;
        }
      }
      case UPB_TYPE_UINT64: {
        unsigned long val = strtoul(p->accumulated, &end, 0);
        if (end != bufend) {
          break;
        } else if (errno == ERANGE) {
          return false;
        } else {
          upb_sink_putuint64(p->top->sink, parser_getsel(p), val);
          return true;
        }
      }
      default:
        break;
    }
  
    if (type != UPB_TYPE_DOUBLE && type != UPB_TYPE_FLOAT && is_quoted) {
      /* Quoted numbers for integer types are not allowed to be in double form. */
      return false;
    }
  
    if (len == strlen("Infinity") && strcmp(buf, "Infinity") == 0) {
      /* C89 does not have an INFINITY macro. */
      val = inf;
    } else if (len == strlen("-Infinity") && strcmp(buf, "-Infinity") == 0) {
      val = -inf;
    } else {
      val = strtod(buf, &end);
      if (errno == ERANGE || end != bufend) {
        return false;
      }
    }
  
    switch (type) {
  #define CASE(capitaltype, smalltype, ctype, min, max)                     \
      case UPB_TYPE_ ## capitaltype: {                                      \
        if (modf(val, &dummy) != 0 || val > max || val < min) {             \
          return false;                                                     \
        } else {                                                            \
          upb_sink_put ## smalltype(p->top->sink, parser_getsel(p),        \
                                    (ctype)val);                            \
          return true;                                                      \
        }                                                                   \
        break;                                                              \
      }
      case UPB_TYPE_ENUM:
      CASE(INT32, int32, int32_t, INT32_MIN, INT32_MAX);
      CASE(INT64, int64, int64_t, INT64_MIN, INT64_MAX);
      CASE(UINT32, uint32, uint32_t, 0, UINT32_MAX);
      CASE(UINT64, uint64, uint64_t, 0, UINT64_MAX);
  #undef CASE
  
      case UPB_TYPE_DOUBLE:
        upb_sink_putdouble(p->top->sink, parser_getsel(p), val);
        return true;
      case UPB_TYPE_FLOAT:
        if ((val > FLT_MAX || val < -FLT_MAX) && val != inf && val != -inf) {
          return false;
        } else {
          upb_sink_putfloat(p->top->sink, parser_getsel(p), val);
          return true;
        }
      default:
        return false;
    }
  }
  
  static bool parse_number(upb_json_parser *p, bool is_quoted) {
    size_t len;
    const char *buf;
  
    /* strtol() and friends unfortunately do not support specifying the length of
     * the input string, so we need to force a copy into a NULL-terminated buffer. */
    if (!multipart_text(p, "\0", 1, false)) {
      return false;
    }
  
    buf = accumulate_getptr(p, &len);
  
    if (parse_number_from_buffer(p, buf, is_quoted)) {
      multipart_end(p);
      return true;
    } else {
      upb_status_seterrf(p->status, "error parsing number: %s", buf);
      multipart_end(p);
      return false;
    }
  }
  
  static bool parser_putbool(upb_json_parser *p, bool val) {
    bool ok;
  
    if (p->top->f == NULL) {
      return true;
    }
  
    if (upb_fielddef_type(p->top->f) != UPB_TYPE_BOOL) {
      upb_status_seterrf(p->status,
                         "Boolean value specified for non-bool field: %s",
                         upb_fielddef_name(p->top->f));
      return false;
    }
  
    ok = upb_sink_putbool(p->top->sink, parser_getsel(p), val);
    UPB_ASSERT(ok);
  
    return true;
  }
  
  static bool end_bool(upb_json_parser *p, bool val) {
    if (is_top_level(p)) {
      if (is_wellknown_msg(p, UPB_WELLKNOWN_BOOLVALUE)) {
        start_wrapper_object(p);
      } else if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
        start_value_object(p, VALUE_BOOLVALUE);
      } else {
        return false;
      }
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_BOOLVALUE)) {
      if (!start_subobject(p)) {
        return false;
      }
      start_wrapper_object(p);
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_VALUE)) {
      if (!start_subobject(p)) {
        return false;
      }
      start_value_object(p, VALUE_BOOLVALUE);
    }
  
    if (p->top->is_unknown_field) {
      return true;
    }
  
    if (!parser_putbool(p, val)) {
      return false;
    }
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_BOOLVALUE)) {
      end_wrapper_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
      return true;
    }
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
      end_value_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
      return true;
    }
  
    return true;
  }
  
  static bool end_null(upb_json_parser *p) {
    const char *zero_ptr = "0";
  
    if (is_top_level(p)) {
      if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
        start_value_object(p, VALUE_NULLVALUE);
      } else {
        return true;
      }
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_VALUE)) {
      if (!start_subobject(p)) {
        return false;
      }
      start_value_object(p, VALUE_NULLVALUE);
    } else {
      return true;
    }
  
    /* Fill null_value field. */
    multipart_startaccum(p);
    capture_begin(p, zero_ptr);
    capture_end(p, zero_ptr + 1);
    parse_number(p, false);
  
    end_value_object(p);
    if (!is_top_level(p)) {
      end_subobject(p);
    }
  
    return true;
  }
  
  static bool start_any_stringval(upb_json_parser *p) {
    multipart_startaccum(p);
    return true;
  }
  
  static bool start_stringval(upb_json_parser *p) {
    if (is_top_level(p)) {
      if (is_string_wrapper_object(p) ||
          is_number_wrapper_object(p)) {
        start_wrapper_object(p);
      } else if (is_wellknown_msg(p, UPB_WELLKNOWN_FIELDMASK)) {
        start_fieldmask_object(p);
        return true;
      } else if (is_wellknown_msg(p, UPB_WELLKNOWN_TIMESTAMP) ||
                 is_wellknown_msg(p, UPB_WELLKNOWN_DURATION)) {
        start_object(p);
      } else if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
        start_value_object(p, VALUE_STRINGVALUE);
      } else {
        return false;
      }
    } else if (does_string_wrapper_start(p) ||
               does_number_wrapper_start(p)) {
      if (!start_subobject(p)) {
        return false;
      }
      start_wrapper_object(p);
    } else if (does_fieldmask_start(p)) {
      if (!start_subobject(p)) {
        return false;
      }
      start_fieldmask_object(p);
      return true;
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_TIMESTAMP) ||
               is_wellknown_field(p, UPB_WELLKNOWN_DURATION)) {
      if (!start_subobject(p)) {
        return false;
      }
      start_object(p);
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_VALUE)) {
      if (!start_subobject(p)) {
        return false;
      }
      start_value_object(p, VALUE_STRINGVALUE);
    }
  
    if (p->top->f == NULL) {
      multipart_startaccum(p);
      return true;
    }
  
    if (p->top->is_any) {
      return start_any_stringval(p);
    }
  
    if (upb_fielddef_isstring(p->top->f)) {
      upb_jsonparser_frame *inner;
      upb_selector_t sel;
  
      if (!check_stack(p)) return false;
  
      /* Start a new parser frame: parser frames correspond one-to-one with
       * handler frames, and string events occur in a sub-frame. */
      inner = start_jsonparser_frame(p);
      sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
      upb_sink_startstr(p->top->sink, sel, 0, &inner->sink);
      inner->m = p->top->m;
      inner->f = p->top->f;
      p->top = inner;
  
      if (upb_fielddef_type(p->top->f) == UPB_TYPE_STRING) {
        /* For STRING fields we push data directly to the handlers as it is
         * parsed.  We don't do this yet for BYTES fields, because our base64
         * decoder is not streaming.
         *
         * TODO(haberman): make base64 decoding streaming also. */
        multipart_start(p, getsel_for_handlertype(p, UPB_HANDLER_STRING));
        return true;
      } else {
        multipart_startaccum(p);
        return true;
      }
    } else if (upb_fielddef_type(p->top->f) != UPB_TYPE_BOOL &&
               upb_fielddef_type(p->top->f) != UPB_TYPE_MESSAGE) {
      /* No need to push a frame -- numeric values in quotes remain in the
       * current parser frame.  These values must accumulate so we can convert
       * them all at once at the end. */
      multipart_startaccum(p);
      return true;
    } else {
      upb_status_seterrf(p->status,
                         "String specified for bool or submessage field: %s",
                         upb_fielddef_name(p->top->f));
      return false;
    }
  }
  
  static bool end_any_stringval(upb_json_parser *p) {
    size_t len;
    const char *buf = accumulate_getptr(p, &len);
  
    /* Set type_url */
    upb_selector_t sel;
    upb_jsonparser_frame *inner;
    if (!check_stack(p)) return false;
    inner = p->top + 1;
  
    sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
    upb_sink_startstr(p->top->sink, sel, 0, &inner->sink);
    sel = getsel_for_handlertype(p, UPB_HANDLER_STRING);
    upb_sink_putstring(inner->sink, sel, buf, len, NULL);
    sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
    upb_sink_endstr(inner->sink, sel);
  
    multipart_end(p);
  
    /* Resolve type url */
    if (strncmp(buf, "type.googleapis.com/", 20) == 0 && len > 20) {
      const upb_msgdef *payload_type = NULL;
      buf += 20;
      len -= 20;
  
      payload_type = upb_symtab_lookupmsg2(p->symtab, buf, len);
      if (payload_type == NULL) {
        upb_status_seterrf(
            p->status, "Cannot find packed type: %.*s\n", (int)len, buf);
        return false;
      }
  
      json_parser_any_frame_set_payload_type(p, p->top->any_frame, payload_type);
  
      return true;
    } else {
      upb_status_seterrf(
          p->status, "Invalid type url: %.*s\n", (int)len, buf);
      return false;
    }
  }
  
  static bool end_stringval_nontop(upb_json_parser *p) {
    bool ok = true;
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_TIMESTAMP) ||
        is_wellknown_msg(p, UPB_WELLKNOWN_DURATION)) {
      multipart_end(p);
      return true;
    }
  
    if (p->top->f == NULL) {
      multipart_end(p);
      return true;
    }
  
    if (p->top->is_any) {
      return end_any_stringval(p);
    }
  
    switch (upb_fielddef_type(p->top->f)) {
      case UPB_TYPE_BYTES:
        if (!base64_push(p, getsel_for_handlertype(p, UPB_HANDLER_STRING),
                         p->accumulated, p->accumulated_len)) {
          return false;
        }
        /* Fall through. */
  
      case UPB_TYPE_STRING: {
        upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
        upb_sink_endstr(p->top->sink, sel);
        p->top--;
        break;
      }
  
      case UPB_TYPE_ENUM: {
        /* Resolve enum symbolic name to integer value. */
        const upb_enumdef *enumdef = upb_fielddef_enumsubdef(p->top->f);
  
        size_t len;
        const char *buf = accumulate_getptr(p, &len);
  
        int32_t int_val = 0;
        ok = upb_enumdef_ntoi(enumdef, buf, len, &int_val);
  
        if (ok) {
          upb_selector_t sel = parser_getsel(p);
          upb_sink_putint32(p->top->sink, sel, int_val);
        } else {
          upb_status_seterrf(p->status, "Enum value unknown: '%.*s'", len, buf);
        }
  
        break;
      }
  
      case UPB_TYPE_INT32:
      case UPB_TYPE_INT64:
      case UPB_TYPE_UINT32:
      case UPB_TYPE_UINT64:
      case UPB_TYPE_DOUBLE:
      case UPB_TYPE_FLOAT:
        ok = parse_number(p, true);
        break;
  
      default:
        UPB_ASSERT(false);
        upb_status_seterrmsg(p->status, "Internal error in JSON decoder");
        ok = false;
        break;
    }
  
    multipart_end(p);
  
    return ok;
  }
  
  static bool end_stringval(upb_json_parser *p) {
    /* FieldMask's stringvals have been ended when handling them. Only need to
     * close FieldMask here.*/
    if (does_fieldmask_end(p)) {
      end_fieldmask_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
      return true;
    }
  
    if (!end_stringval_nontop(p)) {
      return false;
    }
  
    if (does_string_wrapper_end(p) ||
        does_number_wrapper_end(p)) {
      end_wrapper_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
      return true;
    }
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
      end_value_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
      return true;
    }
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_TIMESTAMP) ||
        is_wellknown_msg(p, UPB_WELLKNOWN_DURATION) ||
        is_wellknown_msg(p, UPB_WELLKNOWN_FIELDMASK)) {
      end_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
      return true;
    }
  
    return true;
  }
  
  static void start_duration_base(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_duration_base(upb_json_parser *p, const char *ptr) {
    size_t len;
    const char *buf;
    char seconds_buf[14];
    char nanos_buf[12];
    char *end;
    int64_t seconds = 0;
    int32_t nanos = 0;
    double val = 0.0;
    const char *seconds_membername = "seconds";
    const char *nanos_membername = "nanos";
    size_t fraction_start;
  
    if (!capture_end(p, ptr)) {
      return false;
    }
  
    buf = accumulate_getptr(p, &len);
  
    memset(seconds_buf, 0, 14);
    memset(nanos_buf, 0, 12);
  
    /* Find out base end. The maximus duration is 315576000000, which cannot be
     * represented by double without losing precision. Thus, we need to handle
     * fraction and base separately. */
    for (fraction_start = 0; fraction_start < len && buf[fraction_start] != '.';
         fraction_start++);
  
    /* Parse base */
    memcpy(seconds_buf, buf, fraction_start);
    seconds = strtol(seconds_buf, &end, 10);
    if (errno == ERANGE || end != seconds_buf + fraction_start) {
      upb_status_seterrf(p->status, "error parsing duration: %s",
                         seconds_buf);
      return false;
    }
  
    if (seconds > 315576000000) {
      upb_status_seterrf(p->status, "error parsing duration: "
                                     "maximum acceptable value is "
                                     "315576000000");
      return false;
    }
  
    if (seconds < -315576000000) {
      upb_status_seterrf(p->status, "error parsing duration: "
                                     "minimum acceptable value is "
                                     "-315576000000");
      return false;
    }
  
    /* Parse fraction */
    nanos_buf[0] = '0';
    memcpy(nanos_buf + 1, buf + fraction_start, len - fraction_start);
    val = strtod(nanos_buf, &end);
    if (errno == ERANGE || end != nanos_buf + len - fraction_start + 1) {
      upb_status_seterrf(p->status, "error parsing duration: %s",
                         nanos_buf);
      return false;
    }
  
    nanos = val * 1000000000;
    if (seconds < 0) nanos = -nanos;
  
    /* Clean up buffer */
    multipart_end(p);
  
    /* Set seconds */
    start_member(p);
    capture_begin(p, seconds_membername);
    capture_end(p, seconds_membername + 7);
    end_membername(p);
    upb_sink_putint64(p->top->sink, parser_getsel(p), seconds);
    end_member(p);
  
    /* Set nanos */
    start_member(p);
    capture_begin(p, nanos_membername);
    capture_end(p, nanos_membername + 5);
    end_membername(p);
    upb_sink_putint32(p->top->sink, parser_getsel(p), nanos);
    end_member(p);
  
    /* Continue previous arena */
    multipart_startaccum(p);
  
    return true;
  }
  
  static int parse_timestamp_number(upb_json_parser *p) {
    size_t len;
    const char *buf;
    int val;
  
    /* atoi() and friends unfortunately do not support specifying the length of
     * the input string, so we need to force a copy into a NULL-terminated buffer. */
    multipart_text(p, "\0", 1, false);
  
    buf = accumulate_getptr(p, &len);
    val = atoi(buf);
    multipart_end(p);
    multipart_startaccum(p);
  
    return val;
  }
  
  static void start_year(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_year(upb_json_parser *p, const char *ptr) {
    if (!capture_end(p, ptr)) {
      return false;
    }
    p->tm.tm_year = parse_timestamp_number(p) - 1900;
    return true;
  }
  
  static void start_month(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_month(upb_json_parser *p, const char *ptr) {
    if (!capture_end(p, ptr)) {
      return false;
    }
    p->tm.tm_mon = parse_timestamp_number(p) - 1;
    return true;
  }
  
  static void start_day(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_day(upb_json_parser *p, const char *ptr) {
    if (!capture_end(p, ptr)) {
      return false;
    }
    p->tm.tm_mday = parse_timestamp_number(p);
    return true;
  }
  
  static void start_hour(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_hour(upb_json_parser *p, const char *ptr) {
    if (!capture_end(p, ptr)) {
      return false;
    }
    p->tm.tm_hour = parse_timestamp_number(p);
    return true;
  }
  
  static void start_minute(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_minute(upb_json_parser *p, const char *ptr) {
    if (!capture_end(p, ptr)) {
      return false;
    }
    p->tm.tm_min = parse_timestamp_number(p);
    return true;
  }
  
  static void start_second(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_second(upb_json_parser *p, const char *ptr) {
    if (!capture_end(p, ptr)) {
      return false;
    }
    p->tm.tm_sec = parse_timestamp_number(p);
    return true;
  }
  
  static void start_timestamp_base(upb_json_parser *p) {
    memset(&p->tm, 0, sizeof(struct tm));
  }
  
  static void start_timestamp_fraction(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_timestamp_fraction(upb_json_parser *p, const char *ptr) {
    size_t len;
    const char *buf;
    char nanos_buf[12];
    char *end;
    double val = 0.0;
    int32_t nanos;
    const char *nanos_membername = "nanos";
  
    memset(nanos_buf, 0, 12);
  
    if (!capture_end(p, ptr)) {
      return false;
    }
  
    buf = accumulate_getptr(p, &len);
  
    if (len > 10) {
      upb_status_seterrf(p->status,
          "error parsing timestamp: at most 9-digit fraction.");
      return false;
    }
  
    /* Parse nanos */
    nanos_buf[0] = '0';
    memcpy(nanos_buf + 1, buf, len);
    val = strtod(nanos_buf, &end);
  
    if (errno == ERANGE || end != nanos_buf + len + 1) {
      upb_status_seterrf(p->status, "error parsing timestamp nanos: %s",
                         nanos_buf);
      return false;
    }
  
    nanos = val * 1000000000;
  
    /* Clean up previous environment */
    multipart_end(p);
  
    /* Set nanos */
    start_member(p);
    capture_begin(p, nanos_membername);
    capture_end(p, nanos_membername + 5);
    end_membername(p);
    upb_sink_putint32(p->top->sink, parser_getsel(p), nanos);
    end_member(p);
  
    /* Continue previous environment */
    multipart_startaccum(p);
  
    return true;
  }
  
  static void start_timestamp_zone(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  /* epoch_days(1970, 1, 1) == 1970-01-01 == 0. */
  static int epoch_days(int year, int month, int day) {
    static const uint16_t month_yday[12] = {0,   31,  59,  90,  120, 151,
                                            181, 212, 243, 273, 304, 334};
    int febs_since_0 = month > 2 ? year + 1 : year;
    int leap_days_since_0 = div_round_up(febs_since_0, 4) -
                            div_round_up(febs_since_0, 100) +
                            div_round_up(febs_since_0, 400);
    int days_since_0 =
        365 * year + month_yday[month - 1] + (day - 1) + leap_days_since_0;
  
    /* Convert from 0-epoch (0001-01-01 BC) to Unix Epoch (1970-01-01 AD).
     * Since the "BC" system does not have a year zero, 1 BC == year zero. */
    return days_since_0 - 719528;
  }
  
  static int64_t upb_timegm(const struct tm *tp) {
    int64_t ret = epoch_days(tp->tm_year + 1900, tp->tm_mon + 1, tp->tm_mday);
    ret = (ret * 24) + tp->tm_hour;
    ret = (ret * 60) + tp->tm_min;
    ret = (ret * 60) + tp->tm_sec;
    return ret;
  }
  
  static bool end_timestamp_zone(upb_json_parser *p, const char *ptr) {
    size_t len;
    const char *buf;
    int hours;
    int64_t seconds;
    const char *seconds_membername = "seconds";
  
    if (!capture_end(p, ptr)) {
      return false;
    }
  
    buf = accumulate_getptr(p, &len);
  
    if (buf[0] != 'Z') {
      if (sscanf(buf + 1, "%2d:00", &hours) != 1) {
        upb_status_seterrf(p->status, "error parsing timestamp offset");
        return false;
      }
  
      if (buf[0] == '+') {
        hours = -hours;
      }
  
      p->tm.tm_hour += hours;
    }
  
    /* Normalize tm */
    seconds = upb_timegm(&p->tm);
  
    /* Check timestamp boundary */
    if (seconds < -62135596800) {
      upb_status_seterrf(p->status, "error parsing timestamp: "
                                     "minimum acceptable value is "
                                     "0001-01-01T00:00:00Z");
      return false;
    }
  
    /* Clean up previous environment */
    multipart_end(p);
  
    /* Set seconds */
    start_member(p);
    capture_begin(p, seconds_membername);
    capture_end(p, seconds_membername + 7);
    end_membername(p);
    upb_sink_putint64(p->top->sink, parser_getsel(p), seconds);
    end_member(p);
  
    /* Continue previous environment */
    multipart_startaccum(p);
  
    return true;
  }
  
  static void start_fieldmask_path_text(upb_json_parser *p, const char *ptr) {
    capture_begin(p, ptr);
  }
  
  static bool end_fieldmask_path_text(upb_json_parser *p, const char *ptr) {
    return capture_end(p, ptr);
  }
  
  static bool start_fieldmask_path(upb_json_parser *p) {
    upb_jsonparser_frame *inner;
    upb_selector_t sel;
  
    if (!check_stack(p)) return false;
  
    /* Start a new parser frame: parser frames correspond one-to-one with
     * handler frames, and string events occur in a sub-frame. */
    inner = start_jsonparser_frame(p);
    sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
    upb_sink_startstr(p->top->sink, sel, 0, &inner->sink);
    inner->m = p->top->m;
    inner->f = p->top->f;
    p->top = inner;
  
    multipart_startaccum(p);
    return true;
  }
  
  static bool lower_camel_push(
      upb_json_parser *p, upb_selector_t sel, const char *ptr, size_t len) {
    const char *limit = ptr + len;
    bool first = true;
    for (;ptr < limit; ptr++) {
      if (*ptr >= 'A' && *ptr <= 'Z' && !first) {
        char lower = tolower(*ptr);
        upb_sink_putstring(p->top->sink, sel, "_", 1, NULL);
        upb_sink_putstring(p->top->sink, sel, &lower, 1, NULL);
      } else {
        upb_sink_putstring(p->top->sink, sel, ptr, 1, NULL);
      }
      first = false;
    }
    return true;
  }
  
  static bool end_fieldmask_path(upb_json_parser *p) {
    upb_selector_t sel;
  
    if (!lower_camel_push(
             p, getsel_for_handlertype(p, UPB_HANDLER_STRING),
             p->accumulated, p->accumulated_len)) {
      return false;
    }
  
    sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
    upb_sink_endstr(p->top->sink, sel);
    p->top--;
  
    multipart_end(p);
    return true;
  }
  
  static void start_member(upb_json_parser *p) {
    UPB_ASSERT(!p->top->f);
    multipart_startaccum(p);
  }
  
  /* Helper: invoked during parse_mapentry() to emit the mapentry message's key
   * field based on the current contents of the accumulate buffer. */
  static bool parse_mapentry_key(upb_json_parser *p) {
  
    size_t len;
    const char *buf = accumulate_getptr(p, &len);
  
    /* Emit the key field. We do a bit of ad-hoc parsing here because the
     * parser state machine has already decided that this is a string field
     * name, and we are reinterpreting it as some arbitrary key type. In
     * particular, integer and bool keys are quoted, so we need to parse the
     * quoted string contents here. */
  
    p->top->f = upb_msgdef_itof(p->top->m, UPB_MAPENTRY_KEY);
    if (p->top->f == NULL) {
      upb_status_seterrmsg(p->status, "mapentry message has no key");
      return false;
    }
    switch (upb_fielddef_type(p->top->f)) {
      case UPB_TYPE_INT32:
      case UPB_TYPE_INT64:
      case UPB_TYPE_UINT32:
      case UPB_TYPE_UINT64:
        /* Invoke end_number. The accum buffer has the number's text already. */
        if (!parse_number(p, true)) {
          return false;
        }
        break;
      case UPB_TYPE_BOOL:
        if (len == 4 && !strncmp(buf, "true", 4)) {
          if (!parser_putbool(p, true)) {
            return false;
          }
        } else if (len == 5 && !strncmp(buf, "false", 5)) {
          if (!parser_putbool(p, false)) {
            return false;
          }
        } else {
          upb_status_seterrmsg(p->status,
                               "Map bool key not 'true' or 'false'");
          return false;
        }
        multipart_end(p);
        break;
      case UPB_TYPE_STRING:
      case UPB_TYPE_BYTES: {
        upb_sink subsink;
        upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
        upb_sink_startstr(p->top->sink, sel, len, &subsink);
        sel = getsel_for_handlertype(p, UPB_HANDLER_STRING);
        upb_sink_putstring(subsink, sel, buf, len, NULL);
        sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
        upb_sink_endstr(subsink, sel);
        multipart_end(p);
        break;
      }
      default:
        upb_status_seterrmsg(p->status, "Invalid field type for map key");
        return false;
    }
  
    return true;
  }
  
  /* Helper: emit one map entry (as a submessage in the map field sequence). This
   * is invoked from end_membername(), at the end of the map entry's key string,
   * with the map key in the accumulate buffer. It parses the key from that
   * buffer, emits the handler calls to start the mapentry submessage (setting up
   * its subframe in the process), and sets up state in the subframe so that the
   * value parser (invoked next) will emit the mapentry's value field and then
   * end the mapentry message. */
  
  static bool handle_mapentry(upb_json_parser *p) {
    const upb_fielddef *mapfield;
    const upb_msgdef *mapentrymsg;
    upb_jsonparser_frame *inner;
    upb_selector_t sel;
  
    /* Map entry: p->top->sink is the seq frame, so we need to start a frame
     * for the mapentry itself, and then set |f| in that frame so that the map
     * value field is parsed, and also set a flag to end the frame after the
     * map-entry value is parsed. */
    if (!check_stack(p)) return false;
  
    mapfield = p->top->mapfield;
    mapentrymsg = upb_fielddef_msgsubdef(mapfield);
  
    inner = start_jsonparser_frame(p);
    p->top->f = mapfield;
    sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSUBMSG);
    upb_sink_startsubmsg(p->top->sink, sel, &inner->sink);
    inner->m = mapentrymsg;
    inner->mapfield = mapfield;
  
    /* Don't set this to true *yet* -- we reuse parsing handlers below to push
     * the key field value to the sink, and these handlers will pop the frame
     * if they see is_mapentry (when invoked by the parser state machine, they
     * would have just seen the map-entry value, not key). */
    inner->is_mapentry = false;
    p->top = inner;
  
    /* send STARTMSG in submsg frame. */
    upb_sink_startmsg(p->top->sink);
  
    parse_mapentry_key(p);
  
    /* Set up the value field to receive the map-entry value. */
    p->top->f = upb_msgdef_itof(p->top->m, UPB_MAPENTRY_VALUE);
    p->top->is_mapentry = true;  /* set up to pop frame after value is parsed. */
    p->top->mapfield = mapfield;
    if (p->top->f == NULL) {
      upb_status_seterrmsg(p->status, "mapentry message has no value");
      return false;
    }
  
    return true;
  }
  
  static bool end_membername(upb_json_parser *p) {
    UPB_ASSERT(!p->top->f);
  
    if (!p->top->m) {
      p->top->is_unknown_field = true;
      multipart_end(p);
      return true;
    }
  
    if (p->top->is_any) {
      return end_any_membername(p);
    } else if (p->top->is_map) {
      return handle_mapentry(p);
    } else {
      size_t len;
      const char *buf = accumulate_getptr(p, &len);
      upb_value v;
  
      if (upb_strtable_lookup2(p->top->name_table, buf, len, &v)) {
        p->top->f = upb_value_getconstptr(v);
        multipart_end(p);
  
        return true;
      } else if (p->ignore_json_unknown) {
        p->top->is_unknown_field = true;
        multipart_end(p);
        return true;
      } else {
        upb_status_seterrf(p->status, "No such field: %.*s\n", (int)len, buf);
        return false;
      }
    }
  }
  
  static bool end_any_membername(upb_json_parser *p) {
    size_t len;
    const char *buf = accumulate_getptr(p, &len);
    upb_value v;
  
    if (len == 5 && strncmp(buf, "@type", len) == 0) {
      upb_strtable_lookup2(p->top->name_table, "type_url", 8, &v);
      p->top->f = upb_value_getconstptr(v);
      multipart_end(p);
      return true;
    } else {
      p->top->is_unknown_field = true;
      multipart_end(p);
      return true;
    }
  }
  
  static void end_member(upb_json_parser *p) {
    /* If we just parsed a map-entry value, end that frame too. */
    if (p->top->is_mapentry) {
      upb_selector_t sel;
      bool ok;
      const upb_fielddef *mapfield;
  
      UPB_ASSERT(p->top > p->stack);
      /* send ENDMSG on submsg. */
      upb_sink_endmsg(p->top->sink, p->status);
      mapfield = p->top->mapfield;
  
      /* send ENDSUBMSG in repeated-field-of-mapentries frame. */
      p->top--;
      ok = upb_handlers_getselector(mapfield, UPB_HANDLER_ENDSUBMSG, &sel);
      UPB_ASSERT(ok);
      upb_sink_endsubmsg(p->top->sink, sel);
    }
  
    p->top->f = NULL;
    p->top->is_unknown_field = false;
  }
  
  static void start_any_member(upb_json_parser *p, const char *ptr) {
    start_member(p);
    json_parser_any_frame_set_after_type_url_start_once(p->top->any_frame, ptr);
  }
  
  static void end_any_member(upb_json_parser *p, const char *ptr) {
    json_parser_any_frame_set_before_type_url_end(p->top->any_frame, ptr);
    end_member(p);
  }
  
  static bool start_subobject(upb_json_parser *p) {
    if (p->top->is_unknown_field) {
      if (!check_stack(p)) return false;
  
      p->top = start_jsonparser_frame(p);
      return true;
    }
  
    if (upb_fielddef_ismap(p->top->f)) {
      upb_jsonparser_frame *inner;
      upb_selector_t sel;
  
      /* Beginning of a map. Start a new parser frame in a repeated-field
       * context. */
      if (!check_stack(p)) return false;
  
      inner = start_jsonparser_frame(p);
      sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSEQ);
      upb_sink_startseq(p->top->sink, sel, &inner->sink);
      inner->m = upb_fielddef_msgsubdef(p->top->f);
      inner->mapfield = p->top->f;
      inner->is_map = true;
      p->top = inner;
  
      return true;
    } else if (upb_fielddef_issubmsg(p->top->f)) {
      upb_jsonparser_frame *inner;
      upb_selector_t sel;
  
      /* Beginning of a subobject. Start a new parser frame in the submsg
       * context. */
      if (!check_stack(p)) return false;
  
      inner = start_jsonparser_frame(p);
      sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSUBMSG);
      upb_sink_startsubmsg(p->top->sink, sel, &inner->sink);
      inner->m = upb_fielddef_msgsubdef(p->top->f);
      set_name_table(p, inner);
      p->top = inner;
  
      if (is_wellknown_msg(p, UPB_WELLKNOWN_ANY)) {
        p->top->is_any = true;
        p->top->any_frame = json_parser_any_frame_new(p);
      } else {
        p->top->is_any = false;
        p->top->any_frame = NULL;
      }
  
      return true;
    } else {
      upb_status_seterrf(p->status,
                         "Object specified for non-message/group field: %s",
                         upb_fielddef_name(p->top->f));
      return false;
    }
  }
  
  static bool start_subobject_full(upb_json_parser *p) {
    if (is_top_level(p)) {
      if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
        start_value_object(p, VALUE_STRUCTVALUE);
        if (!start_subobject(p)) return false;
        start_structvalue_object(p);
      } else if (is_wellknown_msg(p, UPB_WELLKNOWN_STRUCT)) {
        start_structvalue_object(p);
      } else {
        return true;
      }
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_STRUCT)) {
      if (!start_subobject(p)) return false;
      start_structvalue_object(p);
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_VALUE)) {
      if (!start_subobject(p)) return false;
      start_value_object(p, VALUE_STRUCTVALUE);
      if (!start_subobject(p)) return false;
      start_structvalue_object(p);
    }
  
    return start_subobject(p);
  }
  
  static void end_subobject(upb_json_parser *p) {
    if (is_top_level(p)) {
      return;
    }
  
    if (p->top->is_map) {
      upb_selector_t sel;
      p->top--;
      sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSEQ);
      upb_sink_endseq(p->top->sink, sel);
    } else {
      upb_selector_t sel;
      bool is_unknown = p->top->m == NULL;
      p->top--;
      if (!is_unknown) {
        sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSUBMSG);
        upb_sink_endsubmsg(p->top->sink, sel);
      }
    }
  }
  
  static void end_subobject_full(upb_json_parser *p) {
    end_subobject(p);
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_STRUCT)) {
      end_structvalue_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
    }
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
      end_value_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
    }
  }
  
  static bool start_array(upb_json_parser *p) {
    upb_jsonparser_frame *inner;
    upb_selector_t sel;
  
    if (is_top_level(p)) {
      if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
        start_value_object(p, VALUE_LISTVALUE);
        if (!start_subobject(p)) return false;
        start_listvalue_object(p);
      } else if (is_wellknown_msg(p, UPB_WELLKNOWN_LISTVALUE)) {
        start_listvalue_object(p);
      } else {
        return false;
      }
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_LISTVALUE) &&
               (!upb_fielddef_isseq(p->top->f) ||
                p->top->is_repeated)) {
      if (!start_subobject(p)) return false;
      start_listvalue_object(p);
    } else if (is_wellknown_field(p, UPB_WELLKNOWN_VALUE) &&
               (!upb_fielddef_isseq(p->top->f) ||
                p->top->is_repeated)) {
      if (!start_subobject(p)) return false;
      start_value_object(p, VALUE_LISTVALUE);
      if (!start_subobject(p)) return false;
      start_listvalue_object(p);
    }
  
    if (p->top->is_unknown_field) {
      inner = start_jsonparser_frame(p);
      inner->is_unknown_field = true;
      p->top = inner;
  
      return true;
    }
  
    if (!upb_fielddef_isseq(p->top->f)) {
      upb_status_seterrf(p->status,
                         "Array specified for non-repeated field: %s",
                         upb_fielddef_name(p->top->f));
      return false;
    }
  
    if (!check_stack(p)) return false;
  
    inner = start_jsonparser_frame(p);
    sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSEQ);
    upb_sink_startseq(p->top->sink, sel, &inner->sink);
    inner->m = p->top->m;
    inner->f = p->top->f;
    inner->is_repeated = true;
    p->top = inner;
  
    return true;
  }
  
  static void end_array(upb_json_parser *p) {
    upb_selector_t sel;
  
    UPB_ASSERT(p->top > p->stack);
  
    p->top--;
  
    if (p->top->is_unknown_field) {
      return;
    }
  
    sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSEQ);
    upb_sink_endseq(p->top->sink, sel);
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_LISTVALUE)) {
      end_listvalue_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
    }
  
    if (is_wellknown_msg(p, UPB_WELLKNOWN_VALUE)) {
      end_value_object(p);
      if (!is_top_level(p)) {
        end_subobject(p);
      }
    }
  }
  
  static void start_object(upb_json_parser *p) {
    if (!p->top->is_map && p->top->m != NULL) {
      upb_sink_startmsg(p->top->sink);
    }
  }
  
  static void end_object(upb_json_parser *p) {
    if (!p->top->is_map && p->top->m != NULL) {
      upb_sink_endmsg(p->top->sink, p->status);
    }
  }
  
  static void start_any_object(upb_json_parser *p, const char *ptr) {
    start_object(p);
    p->top->any_frame->before_type_url_start = ptr;
    p->top->any_frame->before_type_url_end = ptr;
  }
  
  static bool end_any_object(upb_json_parser *p, const char *ptr) {
    const char *value_membername = "value";
    bool is_well_known_packed = false;
    const char *packed_end = ptr + 1;
    upb_selector_t sel;
    upb_jsonparser_frame *inner;
  
    if (json_parser_any_frame_has_value(p->top->any_frame) &&
        !json_parser_any_frame_has_type_url(p->top->any_frame)) {
      upb_status_seterrmsg(p->status, "No valid type url");
      return false;
    }
  
    /* Well known types data is represented as value field. */
    if (upb_msgdef_wellknowntype(p->top->any_frame->parser->top->m) !=
            UPB_WELLKNOWN_UNSPECIFIED) {
      is_well_known_packed = true;
  
      if (json_parser_any_frame_has_value_before_type_url(p->top->any_frame)) {
        p->top->any_frame->before_type_url_start =
            memchr(p->top->any_frame->before_type_url_start, ':',
                   p->top->any_frame->before_type_url_end -
                   p->top->any_frame->before_type_url_start);
        if (p->top->any_frame->before_type_url_start == NULL) {
          upb_status_seterrmsg(p->status, "invalid data for well known type.");
          return false;
        }
        p->top->any_frame->before_type_url_start++;
      }
  
      if (json_parser_any_frame_has_value_after_type_url(p->top->any_frame)) {
        p->top->any_frame->after_type_url_start =
            memchr(p->top->any_frame->after_type_url_start, ':',
                   (ptr + 1) -
                   p->top->any_frame->after_type_url_start);
        if (p->top->any_frame->after_type_url_start == NULL) {
          upb_status_seterrmsg(p->status, "Invalid data for well known type.");
          return false;
        }
        p->top->any_frame->after_type_url_start++;
        packed_end = ptr;
      }
    }
  
    if (json_parser_any_frame_has_value_before_type_url(p->top->any_frame)) {
      if (!parse(p->top->any_frame->parser, NULL,
                 p->top->any_frame->before_type_url_start,
                 p->top->any_frame->before_type_url_end -
                 p->top->any_frame->before_type_url_start, NULL)) {
        return false;
      }
    } else {
      if (!is_well_known_packed) {
        if (!parse(p->top->any_frame->parser, NULL, "{", 1, NULL)) {
          return false;
        }
      }
    }
  
    if (json_parser_any_frame_has_value_before_type_url(p->top->any_frame) &&
        json_parser_any_frame_has_value_after_type_url(p->top->any_frame)) {
      if (!parse(p->top->any_frame->parser, NULL, ",", 1, NULL)) {
        return false;
      }
    }
  
    if (json_parser_any_frame_has_value_after_type_url(p->top->any_frame)) {
      if (!parse(p->top->any_frame->parser, NULL,
                 p->top->any_frame->after_type_url_start,
                 packed_end - p->top->any_frame->after_type_url_start, NULL)) {
        return false;
      }
    } else {
      if (!is_well_known_packed) {
        if (!parse(p->top->any_frame->parser, NULL, "}", 1, NULL)) {
          return false;
        }
      }
    }
  
    if (!end(p->top->any_frame->parser, NULL)) {
      return false;
    }
  
    p->top->is_any = false;
  
    /* Set value */
    start_member(p);
    capture_begin(p, value_membername);
    capture_end(p, value_membername + 5);
    end_membername(p);
  
    if (!check_stack(p)) return false;
    inner = p->top + 1;
  
    sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
    upb_sink_startstr(p->top->sink, sel, 0, &inner->sink);
    sel = getsel_for_handlertype(p, UPB_HANDLER_STRING);
    upb_sink_putstring(inner->sink, sel, p->top->any_frame->stringsink.ptr,
                       p->top->any_frame->stringsink.len, NULL);
    sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
    upb_sink_endstr(inner->sink, sel);
  
    end_member(p);
  
    end_object(p);
  
    /* Deallocate any parse frame. */
    json_parser_any_frame_free(p->top->any_frame);
  
    return true;
  }
  
  static bool is_string_wrapper(const upb_msgdef *m) {
    upb_wellknowntype_t type = upb_msgdef_wellknowntype(m);
    return type == UPB_WELLKNOWN_STRINGVALUE ||
           type == UPB_WELLKNOWN_BYTESVALUE;
  }
  
  static bool is_fieldmask(const upb_msgdef *m) {
    upb_wellknowntype_t type = upb_msgdef_wellknowntype(m);
    return type == UPB_WELLKNOWN_FIELDMASK;
  }
  
  static void start_fieldmask_object(upb_json_parser *p) {
    const char *membername = "paths";
  
    start_object(p);
  
    /* Set up context for parsing value */
    start_member(p);
    capture_begin(p, membername);
    capture_end(p, membername + 5);
    end_membername(p);
  
    start_array(p);
  }
  
  static void end_fieldmask_object(upb_json_parser *p) {
    end_array(p);
    end_member(p);
    end_object(p);
  }
  
  static void start_wrapper_object(upb_json_parser *p) {
    const char *membername = "value";
  
    start_object(p);
  
    /* Set up context for parsing value */
    start_member(p);
    capture_begin(p, membername);
    capture_end(p, membername + 5);
    end_membername(p);
  }
  
  static void end_wrapper_object(upb_json_parser *p) {
    end_member(p);
    end_object(p);
  }
  
  static void start_value_object(upb_json_parser *p, int value_type) {
    const char *nullmember = "null_value";
    const char *numbermember = "number_value";
    const char *stringmember = "string_value";
    const char *boolmember = "bool_value";
    const char *structmember = "struct_value";
    const char *listmember = "list_value";
    const char *membername = "";
  
    switch (value_type) {
      case VALUE_NULLVALUE:
        membername = nullmember;
        break;
      case VALUE_NUMBERVALUE:
        membername = numbermember;
        break;
      case VALUE_STRINGVALUE:
        membername = stringmember;
        break;
      case VALUE_BOOLVALUE:
        membername = boolmember;
        break;
      case VALUE_STRUCTVALUE:
        membername = structmember;
        break;
      case VALUE_LISTVALUE:
        membername = listmember;
        break;
    }
  
    start_object(p);
  
    /* Set up context for parsing value */
    start_member(p);
    capture_begin(p, membername);
    capture_end(p, membername + strlen(membername));
    end_membername(p);
  }
  
  static void end_value_object(upb_json_parser *p) {
    end_member(p);
    end_object(p);
  }
  
  static void start_listvalue_object(upb_json_parser *p) {
    const char *membername = "values";
  
    start_object(p);
  
    /* Set up context for parsing value */
    start_member(p);
    capture_begin(p, membername);
    capture_end(p, membername + strlen(membername));
    end_membername(p);
  }
  
  static void end_listvalue_object(upb_json_parser *p) {
    end_member(p);
    end_object(p);
  }
  
  static void start_structvalue_object(upb_json_parser *p) {
    const char *membername = "fields";
  
    start_object(p);
  
    /* Set up context for parsing value */
    start_member(p);
    capture_begin(p, membername);
    capture_end(p, membername + strlen(membername));
    end_membername(p);
  }
  
  static void end_structvalue_object(upb_json_parser *p) {
    end_member(p);
    end_object(p);
  }
  
  static bool is_top_level(upb_json_parser *p) {
    return p->top == p->stack && p->top->f == NULL && !p->top->is_unknown_field;
  }
  
  static bool is_wellknown_msg(upb_json_parser *p, upb_wellknowntype_t type) {
    return p->top->m != NULL && upb_msgdef_wellknowntype(p->top->m) == type;
  }
  
  static bool is_wellknown_field(upb_json_parser *p, upb_wellknowntype_t type) {
    return p->top->f != NULL &&
           upb_fielddef_issubmsg(p->top->f) &&
           (upb_msgdef_wellknowntype(upb_fielddef_msgsubdef(p->top->f))
                == type);
  }
  
  static bool does_number_wrapper_start(upb_json_parser *p) {
    return p->top->f != NULL &&
           upb_fielddef_issubmsg(p->top->f) &&
           upb_msgdef_isnumberwrapper(upb_fielddef_msgsubdef(p->top->f));
  }
  
  static bool does_number_wrapper_end(upb_json_parser *p) {
    return p->top->m != NULL && upb_msgdef_isnumberwrapper(p->top->m);
  }
  
  static bool is_number_wrapper_object(upb_json_parser *p) {
    return p->top->m != NULL && upb_msgdef_isnumberwrapper(p->top->m);
  }
  
  static bool does_string_wrapper_start(upb_json_parser *p) {
    return p->top->f != NULL &&
           upb_fielddef_issubmsg(p->top->f) &&
           is_string_wrapper(upb_fielddef_msgsubdef(p->top->f));
  }
  
  static bool does_string_wrapper_end(upb_json_parser *p) {
    return p->top->m != NULL && is_string_wrapper(p->top->m);
  }
  
  static bool is_string_wrapper_object(upb_json_parser *p) {
    return p->top->m != NULL && is_string_wrapper(p->top->m);
  }
  
  static bool does_fieldmask_start(upb_json_parser *p) {
    return p->top->f != NULL &&
           upb_fielddef_issubmsg(p->top->f) &&
           is_fieldmask(upb_fielddef_msgsubdef(p->top->f));
  }
  
  static bool does_fieldmask_end(upb_json_parser *p) {
    return p->top->m != NULL && is_fieldmask(p->top->m);
  }
  
  #define CHECK_RETURN_TOP(x) if (!(x)) goto error
  
  
  /* The actual parser **********************************************************/
  
  /* What follows is the Ragel parser itself.  The language is specified in Ragel
   * and the actions call our C functions above.
   *
   * Ragel has an extensive set of functionality, and we use only a small part of
   * it.  There are many action types but we only use a few:
   *
   *   ">" -- transition into a machine
   *   "%" -- transition out of a machine
   *   "@" -- transition into a final state of a machine.
   *
   * "@" transitions are tricky because a machine can transition into a final
   * state repeatedly.  But in some cases we know this can't happen, for example
   * a string which is delimited by a final '"' can only transition into its
   * final state once, when the closing '"' is seen. */
  
  
  #line 2794 "upb/json/parser.rl"
  
  
  
  #line 2597 "upb/json/parser.c"
  static const char _json_actions[] = {
  	0, 1, 0, 1, 1, 1, 3, 1, 
  	4, 1, 6, 1, 7, 1, 8, 1, 
  	9, 1, 11, 1, 12, 1, 13, 1, 
  	14, 1, 15, 1, 16, 1, 17, 1, 
  	18, 1, 19, 1, 20, 1, 22, 1, 
  	23, 1, 24, 1, 35, 1, 37, 1, 
  	39, 1, 40, 1, 42, 1, 43, 1, 
  	44, 1, 46, 1, 48, 1, 49, 1, 
  	50, 1, 51, 1, 53, 1, 54, 2, 
  	4, 9, 2, 5, 6, 2, 7, 3, 
  	2, 7, 9, 2, 21, 26, 2, 25, 
  	10, 2, 27, 28, 2, 29, 30, 2, 
  	32, 34, 2, 33, 31, 2, 38, 36, 
  	2, 40, 42, 2, 45, 2, 2, 46, 
  	54, 2, 47, 36, 2, 49, 54, 2, 
  	50, 54, 2, 51, 54, 2, 52, 41, 
  	2, 53, 54, 3, 32, 34, 35, 4, 
  	21, 26, 27, 28
  };
  
  static const short _json_key_offsets[] = {
  	0, 0, 12, 13, 18, 23, 28, 29, 
  	30, 31, 32, 33, 34, 35, 36, 37, 
  	38, 43, 44, 48, 53, 58, 63, 67, 
  	71, 74, 77, 79, 83, 87, 89, 91, 
  	96, 98, 100, 109, 115, 121, 127, 133, 
  	135, 139, 142, 144, 146, 149, 150, 154, 
  	156, 158, 160, 162, 163, 165, 167, 168, 
  	170, 172, 173, 175, 177, 178, 180, 182, 
  	183, 185, 187, 191, 193, 195, 196, 197, 
  	198, 199, 201, 206, 208, 210, 212, 221, 
  	222, 222, 222, 227, 232, 237, 238, 239, 
  	240, 241, 241, 242, 243, 244, 244, 245, 
  	246, 247, 247, 252, 253, 257, 262, 267, 
  	272, 276, 276, 279, 282, 285, 288, 291, 
  	294, 294, 294, 294, 294, 294
  };
  
  static const char _json_trans_keys[] = {
  	32, 34, 45, 91, 102, 110, 116, 123, 
  	9, 13, 48, 57, 34, 32, 93, 125, 
  	9, 13, 32, 44, 93, 9, 13, 32, 
  	93, 125, 9, 13, 97, 108, 115, 101, 
  	117, 108, 108, 114, 117, 101, 32, 34, 
  	125, 9, 13, 34, 32, 58, 9, 13, 
  	32, 93, 125, 9, 13, 32, 44, 125, 
  	9, 13, 32, 44, 125, 9, 13, 32, 
  	34, 9, 13, 45, 48, 49, 57, 48, 
  	49, 57, 46, 69, 101, 48, 57, 69, 
  	101, 48, 57, 43, 45, 48, 57, 48, 
  	57, 48, 57, 46, 69, 101, 48, 57, 
  	34, 92, 34, 92, 34, 47, 92, 98, 
  	102, 110, 114, 116, 117, 48, 57, 65, 
  	70, 97, 102, 48, 57, 65, 70, 97, 
  	102, 48, 57, 65, 70, 97, 102, 48, 
  	57, 65, 70, 97, 102, 34, 92, 45, 
  	48, 49, 57, 48, 49, 57, 46, 115, 
  	48, 57, 115, 48, 57, 34, 46, 115, 
  	48, 57, 48, 57, 48, 57, 48, 57, 
  	48, 57, 45, 48, 57, 48, 57, 45, 
  	48, 57, 48, 57, 84, 48, 57, 48, 
  	57, 58, 48, 57, 48, 57, 58, 48, 
  	57, 48, 57, 43, 45, 46, 90, 48, 
  	57, 48, 57, 58, 48, 48, 34, 48, 
  	57, 43, 45, 90, 48, 57, 34, 44, 
  	34, 44, 34, 44, 34, 45, 91, 102, 
  	110, 116, 123, 48, 57, 34, 32, 93, 
  	125, 9, 13, 32, 44, 93, 9, 13, 
  	32, 93, 125, 9, 13, 97, 108, 115, 
  	101, 117, 108, 108, 114, 117, 101, 32, 
  	34, 125, 9, 13, 34, 32, 58, 9, 
  	13, 32, 93, 125, 9, 13, 32, 44, 
  	125, 9, 13, 32, 44, 125, 9, 13, 
  	32, 34, 9, 13, 32, 9, 13, 32, 
  	9, 13, 32, 9, 13, 32, 9, 13, 
  	32, 9, 13, 32, 9, 13, 0
  };
  
  static const char _json_single_lengths[] = {
  	0, 8, 1, 3, 3, 3, 1, 1, 
  	1, 1, 1, 1, 1, 1, 1, 1, 
  	3, 1, 2, 3, 3, 3, 2, 2, 
  	1, 3, 0, 2, 2, 0, 0, 3, 
  	2, 2, 9, 0, 0, 0, 0, 2, 
  	2, 1, 2, 0, 1, 1, 2, 0, 
  	0, 0, 0, 1, 0, 0, 1, 0, 
  	0, 1, 0, 0, 1, 0, 0, 1, 
  	0, 0, 4, 0, 0, 1, 1, 1, 
  	1, 0, 3, 2, 2, 2, 7, 1, 
  	0, 0, 3, 3, 3, 1, 1, 1, 
  	1, 0, 1, 1, 1, 0, 1, 1, 
  	1, 0, 3, 1, 2, 3, 3, 3, 
  	2, 0, 1, 1, 1, 1, 1, 1, 
  	0, 0, 0, 0, 0, 0
  };
  
  static const char _json_range_lengths[] = {
  	0, 2, 0, 1, 1, 1, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	1, 0, 1, 1, 1, 1, 1, 1, 
  	1, 0, 1, 1, 1, 1, 1, 1, 
  	0, 0, 0, 3, 3, 3, 3, 0, 
  	1, 1, 0, 1, 1, 0, 1, 1, 
  	1, 1, 1, 0, 1, 1, 0, 1, 
  	1, 0, 1, 1, 0, 1, 1, 0, 
  	1, 1, 0, 1, 1, 0, 0, 0, 
  	0, 1, 1, 0, 0, 0, 1, 0, 
  	0, 0, 1, 1, 1, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 1, 0, 1, 1, 1, 1, 
  	1, 0, 1, 1, 1, 1, 1, 1, 
  	0, 0, 0, 0, 0, 0
  };
  
  static const short _json_index_offsets[] = {
  	0, 0, 11, 13, 18, 23, 28, 30, 
  	32, 34, 36, 38, 40, 42, 44, 46, 
  	48, 53, 55, 59, 64, 69, 74, 78, 
  	82, 85, 89, 91, 95, 99, 101, 103, 
  	108, 111, 114, 124, 128, 132, 136, 140, 
  	143, 147, 150, 153, 155, 158, 160, 164, 
  	166, 168, 170, 172, 174, 176, 178, 180, 
  	182, 184, 186, 188, 190, 192, 194, 196, 
  	198, 200, 202, 207, 209, 211, 213, 215, 
  	217, 219, 221, 226, 229, 232, 235, 244, 
  	246, 247, 248, 253, 258, 263, 265, 267, 
  	269, 271, 272, 274, 276, 278, 279, 281, 
  	283, 285, 286, 291, 293, 297, 302, 307, 
  	312, 316, 317, 320, 323, 326, 329, 332, 
  	335, 336, 337, 338, 339, 340
  };
  
  static const unsigned char _json_indicies[] = {
  	0, 2, 3, 4, 5, 6, 7, 8, 
  	0, 3, 1, 9, 1, 11, 12, 1, 
  	11, 10, 13, 14, 12, 13, 1, 14, 
  	1, 1, 14, 10, 15, 1, 16, 1, 
  	17, 1, 18, 1, 19, 1, 20, 1, 
  	21, 1, 22, 1, 23, 1, 24, 1, 
  	25, 26, 27, 25, 1, 28, 1, 29, 
  	30, 29, 1, 30, 1, 1, 30, 31, 
  	32, 33, 34, 32, 1, 35, 36, 27, 
  	35, 1, 36, 26, 36, 1, 37, 38, 
  	39, 1, 38, 39, 1, 41, 42, 42, 
  	40, 43, 1, 42, 42, 43, 40, 44, 
  	44, 45, 1, 45, 1, 45, 40, 41, 
  	42, 42, 39, 40, 47, 48, 46, 50, 
  	51, 49, 52, 52, 52, 52, 52, 52, 
  	52, 52, 53, 1, 54, 54, 54, 1, 
  	55, 55, 55, 1, 56, 56, 56, 1, 
  	57, 57, 57, 1, 59, 60, 58, 61, 
  	62, 63, 1, 64, 65, 1, 66, 67, 
  	1, 68, 1, 67, 68, 1, 69, 1, 
  	66, 67, 65, 1, 70, 1, 71, 1, 
  	72, 1, 73, 1, 74, 1, 75, 1, 
  	76, 1, 77, 1, 78, 1, 79, 1, 
  	80, 1, 81, 1, 82, 1, 83, 1, 
  	84, 1, 85, 1, 86, 1, 87, 1, 
  	88, 1, 89, 89, 90, 91, 1, 92, 
  	1, 93, 1, 94, 1, 95, 1, 96, 
  	1, 97, 1, 98, 1, 99, 99, 100, 
  	98, 1, 102, 1, 101, 104, 105, 103, 
  	1, 1, 101, 106, 107, 108, 109, 110, 
  	111, 112, 107, 1, 113, 1, 114, 115, 
  	117, 118, 1, 117, 116, 119, 120, 118, 
  	119, 1, 120, 1, 1, 120, 116, 121, 
  	1, 122, 1, 123, 1, 124, 1, 125, 
  	126, 1, 127, 1, 128, 1, 129, 130, 
  	1, 131, 1, 132, 1, 133, 134, 135, 
  	136, 134, 1, 137, 1, 138, 139, 138, 
  	1, 139, 1, 1, 139, 140, 141, 142, 
  	143, 141, 1, 144, 145, 136, 144, 1, 
  	145, 135, 145, 1, 146, 147, 147, 1, 
  	148, 148, 1, 149, 149, 1, 150, 150, 
  	1, 151, 151, 1, 152, 152, 1, 1, 
  	1, 1, 1, 1, 1, 0
  };
  
  static const char _json_trans_targs[] = {
  	1, 0, 2, 107, 3, 6, 10, 13, 
  	16, 106, 4, 3, 106, 4, 5, 7, 
  	8, 9, 108, 11, 12, 109, 14, 15, 
  	110, 16, 17, 111, 18, 18, 19, 20, 
  	21, 22, 111, 21, 22, 24, 25, 31, 
  	112, 26, 28, 27, 29, 30, 33, 113, 
  	34, 33, 113, 34, 32, 35, 36, 37, 
  	38, 39, 33, 113, 34, 41, 42, 46, 
  	42, 46, 43, 45, 44, 114, 48, 49, 
  	50, 51, 52, 53, 54, 55, 56, 57, 
  	58, 59, 60, 61, 62, 63, 64, 65, 
  	66, 67, 73, 72, 68, 69, 70, 71, 
  	72, 115, 74, 67, 72, 76, 116, 76, 
  	116, 77, 79, 81, 82, 85, 90, 94, 
  	98, 80, 117, 117, 83, 82, 80, 83, 
  	84, 86, 87, 88, 89, 117, 91, 92, 
  	93, 117, 95, 96, 97, 117, 98, 99, 
  	105, 100, 100, 101, 102, 103, 104, 105, 
  	103, 104, 117, 106, 106, 106, 106, 106, 
  	106
  };
  
  static const unsigned char _json_trans_actions[] = {
  	0, 0, 113, 107, 53, 0, 0, 0, 
  	125, 59, 45, 0, 55, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 101, 51, 47, 0, 0, 45, 
  	49, 49, 104, 0, 0, 0, 0, 0, 
  	3, 0, 0, 0, 0, 0, 5, 15, 
  	0, 0, 71, 7, 13, 0, 74, 9, 
  	9, 9, 77, 80, 11, 37, 37, 37, 
  	0, 0, 0, 39, 0, 41, 86, 0, 
  	0, 0, 17, 19, 0, 21, 23, 0, 
  	25, 27, 0, 29, 31, 0, 33, 35, 
  	0, 135, 83, 135, 0, 0, 0, 0, 
  	0, 92, 0, 89, 89, 98, 43, 0, 
  	131, 95, 113, 107, 53, 0, 0, 0, 
  	125, 59, 69, 110, 45, 0, 55, 0, 
  	0, 0, 0, 0, 0, 119, 0, 0, 
  	0, 122, 0, 0, 0, 116, 0, 101, 
  	51, 47, 0, 0, 45, 49, 49, 104, 
  	0, 0, 128, 0, 57, 63, 65, 61, 
  	67
  };
  
  static const unsigned char _json_eof_actions[] = {
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 1, 0, 1, 0, 0, 1, 1, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 0, 0, 0, 0, 0, 
  	0, 0, 0, 57, 63, 65, 61, 67, 
  	0, 0, 0, 0, 0, 0
  };
  
  static const int json_start = 1;
  
  static const int json_en_number_machine = 23;
  static const int json_en_string_machine = 32;
  static const int json_en_duration_machine = 40;
  static const int json_en_timestamp_machine = 47;
  static const int json_en_fieldmask_machine = 75;
  static const int json_en_value_machine = 78;
  static const int json_en_main = 1;
  
  
  #line 2797 "upb/json/parser.rl"
  
  size_t parse(void *closure, const void *hd, const char *buf, size_t size,
               const upb_bufhandle *handle) {
    upb_json_parser *parser = closure;
  
    /* Variables used by Ragel's generated code. */
    int cs = parser->current_state;
    int *stack = parser->parser_stack;
    int top = parser->parser_top;
  
    const char *p = buf;
    const char *pe = buf + size;
    const char *eof = &eof_ch;
  
    parser->handle = handle;
  
    UPB_UNUSED(hd);
    UPB_UNUSED(handle);
  
    capture_resume(parser, buf);
  
    
  #line 2875 "upb/json/parser.c"
  	{
  	int _klen;
  	unsigned int _trans;
  	const char *_acts;
  	unsigned int _nacts;
  	const char *_keys;
  
  	if ( p == pe )
  		goto _test_eof;
  	if ( cs == 0 )
  		goto _out;
  _resume:
  	_keys = _json_trans_keys + _json_key_offsets[cs];
  	_trans = _json_index_offsets[cs];
  
  	_klen = _json_single_lengths[cs];
  	if ( _klen > 0 ) {
  		const char *_lower = _keys;
  		const char *_mid;
  		const char *_upper = _keys + _klen - 1;
  		while (1) {
  			if ( _upper < _lower )
  				break;
  
  			_mid = _lower + ((_upper-_lower) >> 1);
  			if ( (*p) < *_mid )
  				_upper = _mid - 1;
  			else if ( (*p) > *_mid )
  				_lower = _mid + 1;
  			else {
  				_trans += (unsigned int)(_mid - _keys);
  				goto _match;
  			}
  		}
  		_keys += _klen;
  		_trans += _klen;
  	}
  
  	_klen = _json_range_lengths[cs];
  	if ( _klen > 0 ) {
  		const char *_lower = _keys;
  		const char *_mid;
  		const char *_upper = _keys + (_klen<<1) - 2;
  		while (1) {
  			if ( _upper < _lower )
  				break;
  
  			_mid = _lower + (((_upper-_lower) >> 1) & ~1);
  			if ( (*p) < _mid[0] )
  				_upper = _mid - 2;
  			else if ( (*p) > _mid[1] )
  				_lower = _mid + 2;
  			else {
  				_trans += (unsigned int)((_mid - _keys)>>1);
  				goto _match;
  			}
  		}
  		_trans += _klen;
  	}
  
  _match:
  	_trans = _json_indicies[_trans];
  	cs = _json_trans_targs[_trans];
  
  	if ( _json_trans_actions[_trans] == 0 )
  		goto _again;
  
  	_acts = _json_actions + _json_trans_actions[_trans];
  	_nacts = (unsigned int) *_acts++;
  	while ( _nacts-- > 0 )
  	{
  		switch ( *_acts++ )
  		{
  	case 1:
  #line 2602 "upb/json/parser.rl"
  	{ p--; {cs = stack[--top]; goto _again;} }
  	break;
  	case 2:
  #line 2604 "upb/json/parser.rl"
  	{ p--; {stack[top++] = cs; cs = 23;goto _again;} }
  	break;
  	case 3:
  #line 2608 "upb/json/parser.rl"
  	{ start_text(parser, p); }
  	break;
  	case 4:
  #line 2609 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_text(parser, p)); }
  	break;
  	case 5:
  #line 2615 "upb/json/parser.rl"
  	{ start_hex(parser); }
  	break;
  	case 6:
  #line 2616 "upb/json/parser.rl"
  	{ hexdigit(parser, p); }
  	break;
  	case 7:
  #line 2617 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_hex(parser)); }
  	break;
  	case 8:
  #line 2623 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(escape(parser, p)); }
  	break;
  	case 9:
  #line 2629 "upb/json/parser.rl"
  	{ p--; {cs = stack[--top]; goto _again;} }
  	break;
  	case 10:
  #line 2634 "upb/json/parser.rl"
  	{ start_year(parser, p); }
  	break;
  	case 11:
  #line 2635 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_year(parser, p)); }
  	break;
  	case 12:
  #line 2639 "upb/json/parser.rl"
  	{ start_month(parser, p); }
  	break;
  	case 13:
  #line 2640 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_month(parser, p)); }
  	break;
  	case 14:
  #line 2644 "upb/json/parser.rl"
  	{ start_day(parser, p); }
  	break;
  	case 15:
  #line 2645 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_day(parser, p)); }
  	break;
  	case 16:
  #line 2649 "upb/json/parser.rl"
  	{ start_hour(parser, p); }
  	break;
  	case 17:
  #line 2650 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_hour(parser, p)); }
  	break;
  	case 18:
  #line 2654 "upb/json/parser.rl"
  	{ start_minute(parser, p); }
  	break;
  	case 19:
  #line 2655 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_minute(parser, p)); }
  	break;
  	case 20:
  #line 2659 "upb/json/parser.rl"
  	{ start_second(parser, p); }
  	break;
  	case 21:
  #line 2660 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_second(parser, p)); }
  	break;
  	case 22:
  #line 2665 "upb/json/parser.rl"
  	{ start_duration_base(parser, p); }
  	break;
  	case 23:
  #line 2666 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_duration_base(parser, p)); }
  	break;
  	case 24:
  #line 2668 "upb/json/parser.rl"
  	{ p--; {cs = stack[--top]; goto _again;} }
  	break;
  	case 25:
  #line 2673 "upb/json/parser.rl"
  	{ start_timestamp_base(parser); }
  	break;
  	case 26:
  #line 2675 "upb/json/parser.rl"
  	{ start_timestamp_fraction(parser, p); }
  	break;
  	case 27:
  #line 2676 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_timestamp_fraction(parser, p)); }
  	break;
  	case 28:
  #line 2678 "upb/json/parser.rl"
  	{ start_timestamp_zone(parser, p); }
  	break;
  	case 29:
  #line 2679 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_timestamp_zone(parser, p)); }
  	break;
  	case 30:
  #line 2681 "upb/json/parser.rl"
  	{ p--; {cs = stack[--top]; goto _again;} }
  	break;
  	case 31:
  #line 2686 "upb/json/parser.rl"
  	{ start_fieldmask_path_text(parser, p); }
  	break;
  	case 32:
  #line 2687 "upb/json/parser.rl"
  	{ end_fieldmask_path_text(parser, p); }
  	break;
  	case 33:
  #line 2692 "upb/json/parser.rl"
  	{ start_fieldmask_path(parser); }
  	break;
  	case 34:
  #line 2693 "upb/json/parser.rl"
  	{ end_fieldmask_path(parser); }
  	break;
  	case 35:
  #line 2699 "upb/json/parser.rl"
  	{ p--; {cs = stack[--top]; goto _again;} }
  	break;
  	case 36:
  #line 2704 "upb/json/parser.rl"
  	{
          if (is_wellknown_msg(parser, UPB_WELLKNOWN_TIMESTAMP)) {
            {stack[top++] = cs; cs = 47;goto _again;}
          } else if (is_wellknown_msg(parser, UPB_WELLKNOWN_DURATION)) {
            {stack[top++] = cs; cs = 40;goto _again;}
          } else if (is_wellknown_msg(parser, UPB_WELLKNOWN_FIELDMASK)) {
            {stack[top++] = cs; cs = 75;goto _again;}
          } else {
            {stack[top++] = cs; cs = 32;goto _again;}
          }
        }
  	break;
  	case 37:
  #line 2717 "upb/json/parser.rl"
  	{ p--; {stack[top++] = cs; cs = 78;goto _again;} }
  	break;
  	case 38:
  #line 2722 "upb/json/parser.rl"
  	{
          if (is_wellknown_msg(parser, UPB_WELLKNOWN_ANY)) {
            start_any_member(parser, p);
          } else {
            start_member(parser);
          }
        }
  	break;
  	case 39:
  #line 2729 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_membername(parser)); }
  	break;
  	case 40:
  #line 2732 "upb/json/parser.rl"
  	{
          if (is_wellknown_msg(parser, UPB_WELLKNOWN_ANY)) {
            end_any_member(parser, p);
          } else {
            end_member(parser);
          }
        }
  	break;
  	case 41:
  #line 2743 "upb/json/parser.rl"
  	{
          if (is_wellknown_msg(parser, UPB_WELLKNOWN_ANY)) {
            start_any_object(parser, p);
          } else {
            start_object(parser);
          }
        }
  	break;
  	case 42:
  #line 2752 "upb/json/parser.rl"
  	{
          if (is_wellknown_msg(parser, UPB_WELLKNOWN_ANY)) {
            CHECK_RETURN_TOP(end_any_object(parser, p));
          } else {
            end_object(parser);
          }
        }
  	break;
  	case 43:
  #line 2764 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(start_array(parser)); }
  	break;
  	case 44:
  #line 2768 "upb/json/parser.rl"
  	{ end_array(parser); }
  	break;
  	case 45:
  #line 2773 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(start_number(parser, p)); }
  	break;
  	case 46:
  #line 2774 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_number(parser, p)); }
  	break;
  	case 47:
  #line 2776 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(start_stringval(parser)); }
  	break;
  	case 48:
  #line 2777 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_stringval(parser)); }
  	break;
  	case 49:
  #line 2779 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_bool(parser, true)); }
  	break;
  	case 50:
  #line 2781 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_bool(parser, false)); }
  	break;
  	case 51:
  #line 2783 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_null(parser)); }
  	break;
  	case 52:
  #line 2785 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(start_subobject_full(parser)); }
  	break;
  	case 53:
  #line 2786 "upb/json/parser.rl"
  	{ end_subobject_full(parser); }
  	break;
  	case 54:
  #line 2791 "upb/json/parser.rl"
  	{ p--; {cs = stack[--top]; goto _again;} }
  	break;
  #line 3199 "upb/json/parser.c"
  		}
  	}
  
  _again:
  	if ( cs == 0 )
  		goto _out;
  	if ( ++p != pe )
  		goto _resume;
  	_test_eof: {}
  	if ( p == eof )
  	{
  	const char *__acts = _json_actions + _json_eof_actions[cs];
  	unsigned int __nacts = (unsigned int) *__acts++;
  	while ( __nacts-- > 0 ) {
  		switch ( *__acts++ ) {
  	case 0:
  #line 2600 "upb/json/parser.rl"
  	{ p--; {cs = stack[--top]; 	if ( p == pe )
  		goto _test_eof;
  goto _again;} }
  	break;
  	case 46:
  #line 2774 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_number(parser, p)); }
  	break;
  	case 49:
  #line 2779 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_bool(parser, true)); }
  	break;
  	case 50:
  #line 2781 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_bool(parser, false)); }
  	break;
  	case 51:
  #line 2783 "upb/json/parser.rl"
  	{ CHECK_RETURN_TOP(end_null(parser)); }
  	break;
  	case 53:
  #line 2786 "upb/json/parser.rl"
  	{ end_subobject_full(parser); }
  	break;
  #line 3241 "upb/json/parser.c"
  		}
  	}
  	}
  
  	_out: {}
  	}
  
  #line 2819 "upb/json/parser.rl"
  
    if (p != pe) {
      upb_status_seterrf(parser->status, "Parse error at '%.*s'\n", pe - p, p);
    } else {
      capture_suspend(parser, &p);
    }
  
  error:
    /* Save parsing state back to parser. */
    parser->current_state = cs;
    parser->parser_top = top;
  
    return p - buf;
  }
  
  static bool end(void *closure, const void *hd) {
    upb_json_parser *parser = closure;
  
    /* Prevent compile warning on unused static constants. */
    UPB_UNUSED(json_start);
    UPB_UNUSED(json_en_duration_machine);
    UPB_UNUSED(json_en_fieldmask_machine);
    UPB_UNUSED(json_en_number_machine);
    UPB_UNUSED(json_en_string_machine);
    UPB_UNUSED(json_en_timestamp_machine);
    UPB_UNUSED(json_en_value_machine);
    UPB_UNUSED(json_en_main);
  
    parse(parser, hd, &eof_ch, 0, NULL);
  
    return parser->current_state >= 106;
  }
  
  static void json_parser_reset(upb_json_parser *p) {
    int cs;
    int top;
  
    p->top = p->stack;
    init_frame(p->top);
  
    /* Emit Ragel initialization of the parser. */
    
  #line 3292 "upb/json/parser.c"
  	{
  	cs = json_start;
  	top = 0;
  	}
  
  #line 2861 "upb/json/parser.rl"
    p->current_state = cs;
    p->parser_top = top;
    accumulate_clear(p);
    p->multipart_state = MULTIPART_INACTIVE;
    p->capture = NULL;
    p->accumulated = NULL;
  }
  
  static upb_json_parsermethod *parsermethod_new(upb_json_codecache *c,
                                                 const upb_msgdef *md) {
    upb_msg_field_iter i;
    upb_alloc *alloc = upb_arena_alloc(c->arena);
  
    upb_json_parsermethod *m = upb_malloc(alloc, sizeof(*m));
  
    m->cache = c;
  
    upb_byteshandler_init(&m->input_handler_);
    upb_byteshandler_setstring(&m->input_handler_, parse, m);
    upb_byteshandler_setendstr(&m->input_handler_, end, m);
  
    upb_strtable_init2(&m->name_table, UPB_CTYPE_CONSTPTR, alloc);
  
    /* Build name_table */
  
    for(upb_msg_field_begin(&i, md);
        !upb_msg_field_done(&i);
        upb_msg_field_next(&i)) {
      const upb_fielddef *f = upb_msg_iter_field(&i);
      upb_value v = upb_value_constptr(f);
      char *buf;
  
      /* Add an entry for the JSON name. */
      size_t len = upb_fielddef_getjsonname(f, NULL, 0);
      buf = upb_malloc(alloc, len);
      upb_fielddef_getjsonname(f, buf, len);
      upb_strtable_insert3(&m->name_table, buf, strlen(buf), v, alloc);
  
      if (strcmp(buf, upb_fielddef_name(f)) != 0) {
        /* Since the JSON name is different from the regular field name, add an
         * entry for the raw name (compliant proto3 JSON parsers must accept
         * both). */
        const char *name = upb_fielddef_name(f);
        upb_strtable_insert3(&m->name_table, name, strlen(name), v, alloc);
      }
    }
  
    return m;
  }
  
  /* Public API *****************************************************************/
  
  upb_json_parser *upb_json_parser_create(upb_arena *arena,
                                          const upb_json_parsermethod *method,
                                          const upb_symtab* symtab,
                                          upb_sink output,
                                          upb_status *status,
                                          bool ignore_json_unknown) {
  #ifndef NDEBUG
    const size_t size_before = upb_arena_bytesallocated(arena);
  #endif
    upb_json_parser *p = upb_arena_malloc(arena, sizeof(upb_json_parser));
    if (!p) return false;
  
    p->arena = arena;
    p->method = method;
    p->status = status;
    p->limit = p->stack + UPB_JSON_MAX_DEPTH;
    p->accumulate_buf = NULL;
    p->accumulate_buf_size = 0;
    upb_bytessink_reset(&p->input_, &method->input_handler_, p);
  
    json_parser_reset(p);
    p->top->sink = output;
    p->top->m = upb_handlers_msgdef(output.handlers);
    if (is_wellknown_msg(p, UPB_WELLKNOWN_ANY)) {
      p->top->is_any = true;
      p->top->any_frame = json_parser_any_frame_new(p);
    } else {
      p->top->is_any = false;
      p->top->any_frame = NULL;
    }
    set_name_table(p, p->top);
    p->symtab = symtab;
  
    p->ignore_json_unknown = ignore_json_unknown;
  
    /* If this fails, uncomment and increase the value in parser.h. */
    /* fprintf(stderr, "%zd\n", upb_arena_bytesallocated(arena) - size_before); */
    UPB_ASSERT_DEBUGVAR(upb_arena_bytesallocated(arena) - size_before <=
                        UPB_JSON_PARSER_SIZE);
    return p;
  }
  
  upb_bytessink upb_json_parser_input(upb_json_parser *p) {
    return p->input_;
  }
  
  const upb_byteshandler *upb_json_parsermethod_inputhandler(
      const upb_json_parsermethod *m) {
    return &m->input_handler_;
  }
  
  upb_json_codecache *upb_json_codecache_new(void) {
    upb_alloc *alloc;
    upb_json_codecache *c;
  
    c = upb_gmalloc(sizeof(*c));
  
    c->arena = upb_arena_new();
    alloc = upb_arena_alloc(c->arena);
  
    upb_inttable_init2(&c->methods, UPB_CTYPE_CONSTPTR, alloc);
  
    return c;
  }
  
  void upb_json_codecache_free(upb_json_codecache *c) {
    upb_arena_free(c->arena);
    upb_gfree(c);
  }
  
  const upb_json_parsermethod *upb_json_codecache_get(upb_json_codecache *c,
                                                      const upb_msgdef *md) {
    upb_json_parsermethod *m;
    upb_value v;
    upb_msg_field_iter i;
    upb_alloc *alloc = upb_arena_alloc(c->arena);
  
    if (upb_inttable_lookupptr(&c->methods, md, &v)) {
      return upb_value_getconstptr(v);
    }
  
    m = parsermethod_new(c, md);
    v = upb_value_constptr(m);
  
    if (!m) return NULL;
    if (!upb_inttable_insertptr2(&c->methods, md, v, alloc)) return NULL;
  
    /* Populate parser methods for all submessages, so the name tables will
     * be available during parsing. */
    for(upb_msg_field_begin(&i, md);
        !upb_msg_field_done(&i);
        upb_msg_field_next(&i)) {
      upb_fielddef *f = upb_msg_iter_field(&i);
  
      if (upb_fielddef_issubmsg(f)) {
        const upb_msgdef *subdef = upb_fielddef_msgsubdef(f);
        const upb_json_parsermethod *sub_method =
            upb_json_codecache_get(c, subdef);
  
        if (!sub_method) return NULL;
      }
    }
  
    return m;
  }
  /*
  ** This currently uses snprintf() to format primitives, and could be optimized
  ** further.
  */
  
  
  #include <ctype.h>
  #include <stdint.h>
  #include <string.h>
  #include <time.h>
  
  
  struct upb_json_printer {
    upb_sink input_;
    /* BytesSink closure. */
    void *subc_;
    upb_bytessink output_;
  
    /* We track the depth so that we know when to emit startstr/endstr on the
     * output. */
    int depth_;
  
    /* Have we emitted the first element? This state is necessary to emit commas
     * without leaving a trailing comma in arrays/maps. We keep this state per
     * frame depth.
     *
     * Why max_depth * 2? UPB_MAX_HANDLER_DEPTH counts depth as nested messages.
     * We count frames (contexts in which we separate elements by commas) as both
     * repeated fields and messages (maps), and the worst case is a
     * message->repeated field->submessage->repeated field->... nesting. */
    bool first_elem_[UPB_MAX_HANDLER_DEPTH * 2];
  
    /* To print timestamp, printer needs to cache its seconds and nanos values
     * and convert them when ending timestamp message. See comments of
     * printer_sethandlers_timestamp for more detail. */
    int64_t seconds;
    int32_t nanos;
  };
  
  /* StringPiece; a pointer plus a length. */
  typedef struct {
    char *ptr;
    size_t len;
  } strpc;
  
  void freestrpc(void *ptr) {
    strpc *pc = ptr;
    upb_gfree(pc->ptr);
    upb_gfree(pc);
  }
  
  typedef struct {
    bool preserve_fieldnames;
  } upb_json_printercache;
  
  /* Convert fielddef name to JSON name and return as a string piece. */
  strpc *newstrpc(upb_handlers *h, const upb_fielddef *f,
                  bool preserve_fieldnames) {
    /* TODO(haberman): handle malloc failure. */
    strpc *ret = upb_gmalloc(sizeof(*ret));
    if (preserve_fieldnames) {
      ret->ptr = upb_gstrdup(upb_fielddef_name(f));
      ret->len = strlen(ret->ptr);
    } else {
      size_t len;
      ret->len = upb_fielddef_getjsonname(f, NULL, 0);
      ret->ptr = upb_gmalloc(ret->len);
      len = upb_fielddef_getjsonname(f, ret->ptr, ret->len);
      UPB_ASSERT(len == ret->len);
      ret->len--;  /* NULL */
    }
  
    upb_handlers_addcleanup(h, ret, freestrpc);
    return ret;
  }
  
  /* Convert a null-terminated const char* to a string piece. */
  strpc *newstrpc_str(upb_handlers *h, const char * str) {
    strpc * ret = upb_gmalloc(sizeof(*ret));
    ret->ptr = upb_gstrdup(str);
    ret->len = strlen(str);
    upb_handlers_addcleanup(h, ret, freestrpc);
    return ret;
  }
  
  /* ------------ JSON string printing: values, maps, arrays ------------------ */
  
  static void print_data(
      upb_json_printer *p, const char *buf, unsigned int len) {
    /* TODO: Will need to change if we support pushback from the sink. */
    size_t n = upb_bytessink_putbuf(p->output_, p->subc_, buf, len, NULL);
    UPB_ASSERT(n == len);
  }
  
  static void print_comma(upb_json_printer *p) {
    if (!p->first_elem_[p->depth_]) {
      print_data(p, ",", 1);
    }
    p->first_elem_[p->depth_] = false;
  }
  
  /* Helpers that print properly formatted elements to the JSON output stream. */
  
  /* Used for escaping control chars in strings. */
  static const char kControlCharLimit = 0x20;
  
  UPB_INLINE bool is_json_escaped(char c) {
    /* See RFC 4627. */
    unsigned char uc = (unsigned char)c;
    return uc < kControlCharLimit || uc == '"' || uc == '\\';
  }
  
  UPB_INLINE const char* json_nice_escape(char c) {
    switch (c) {
      case '"':  return "\\\"";
      case '\\': return "\\\\";
      case '\b': return "\\b";
      case '\f': return "\\f";
      case '\n': return "\\n";
      case '\r': return "\\r";
      case '\t': return "\\t";
      default:   return NULL;
    }
  }
  
  /* Write a properly escaped string chunk. The surrounding quotes are *not*
   * printed; this is so that the caller has the option of emitting the string
   * content in chunks. */
  static void putstring(upb_json_printer *p, const char *buf, unsigned int len) {
    const char* unescaped_run = NULL;
    unsigned int i;
    for (i = 0; i < len; i++) {
      char c = buf[i];
      /* Handle escaping. */
      if (is_json_escaped(c)) {
        /* Use a "nice" escape, like \n, if one exists for this character. */
        const char* escape = json_nice_escape(c);
        /* If we don't have a specific 'nice' escape code, use a \uXXXX-style
         * escape. */
        char escape_buf[8];
        if (!escape) {
          unsigned char byte = (unsigned char)c;
          _upb_snprintf(escape_buf, sizeof(escape_buf), "\\u%04x", (int)byte);
          escape = escape_buf;
        }
  
        /* N.B. that we assume that the input encoding is equal to the output
         * encoding (both UTF-8 for  now), so for chars >= 0x20 and != \, ", we
         * can simply pass the bytes through. */
  
        /* If there's a current run of unescaped chars, print that run first. */
        if (unescaped_run) {
          print_data(p, unescaped_run, &buf[i] - unescaped_run);
          unescaped_run = NULL;
        }
        /* Then print the escape code. */
        print_data(p, escape, strlen(escape));
      } else {
        /* Add to the current unescaped run of characters. */
        if (unescaped_run == NULL) {
          unescaped_run = &buf[i];
        }
      }
    }
  
    /* If the string ended in a run of unescaped characters, print that last run. */
    if (unescaped_run) {
      print_data(p, unescaped_run, &buf[len] - unescaped_run);
    }
  }
  
  #define CHKLENGTH(x) if (!(x)) return -1;
  
  /* Helpers that format floating point values according to our custom formats.
   * Right now we use %.8g and %.17g for float/double, respectively, to match
   * proto2::util::JsonFormat's defaults.  May want to change this later. */
  
  const char neginf[] = "\"-Infinity\"";
  const char inf[] = "\"Infinity\"";
  
  static size_t fmt_double(double val, char* buf, size_t length) {
    if (val == UPB_INFINITY) {
      CHKLENGTH(length >= strlen(inf));
      strcpy(buf, inf);
      return strlen(inf);
    } else if (val == -UPB_INFINITY) {
      CHKLENGTH(length >= strlen(neginf));
      strcpy(buf, neginf);
      return strlen(neginf);
    } else {
      size_t n = _upb_snprintf(buf, length, "%.17g", val);
      CHKLENGTH(n > 0 && n < length);
      return n;
    }
  }
  
  static size_t fmt_float(float val, char* buf, size_t length) {
    size_t n = _upb_snprintf(buf, length, "%.8g", val);
    CHKLENGTH(n > 0 && n < length);
    return n;
  }
  
  static size_t fmt_bool(bool val, char* buf, size_t length) {
    size_t n = _upb_snprintf(buf, length, "%s", (val ? "true" : "false"));
    CHKLENGTH(n > 0 && n < length);
    return n;
  }
  
  static size_t fmt_int64_as_number(long long val, char* buf, size_t length) {
    size_t n = _upb_snprintf(buf, length, "%lld", val);
    CHKLENGTH(n > 0 && n < length);
    return n;
  }
  
  static size_t fmt_uint64_as_number(
      unsigned long long val, char* buf, size_t length) {
    size_t n = _upb_snprintf(buf, length, "%llu", val);
    CHKLENGTH(n > 0 && n < length);
    return n;
  }
  
  static size_t fmt_int64_as_string(long long val, char* buf, size_t length) {
    size_t n = _upb_snprintf(buf, length, "\"%lld\"", val);
    CHKLENGTH(n > 0 && n < length);
    return n;
  }
  
  static size_t fmt_uint64_as_string(
      unsigned long long val, char* buf, size_t length) {
    size_t n = _upb_snprintf(buf, length, "\"%llu\"", val);
    CHKLENGTH(n > 0 && n < length);
    return n;
  }
  
  /* Print a map key given a field name. Called by scalar field handlers and by
   * startseq for repeated fields. */
  static bool putkey(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    const strpc *key = handler_data;
    print_comma(p);
    print_data(p, "\"", 1);
    putstring(p, key->ptr, key->len);
    print_data(p, "\":", 2);
    return true;
  }
  
  #define CHKFMT(val) if ((val) == (size_t)-1) return false;
  #define CHK(val)    if (!(val)) return false;
  
  #define TYPE_HANDLERS(type, fmt_func)                                        \
    static bool put##type(void *closure, const void *handler_data, type val) { \
      upb_json_printer *p = closure;                                           \
      char data[64];                                                           \
      size_t length = fmt_func(val, data, sizeof(data));                       \
      UPB_UNUSED(handler_data);                                                \
      CHKFMT(length);                                                          \
      print_data(p, data, length);                                             \
      return true;                                                             \
    }                                                                          \
    static bool scalar_##type(void *closure, const void *handler_data,         \
                              type val) {                                      \
      CHK(putkey(closure, handler_data));                                      \
      CHK(put##type(closure, handler_data, val));                              \
      return true;                                                             \
    }                                                                          \
    static bool repeated_##type(void *closure, const void *handler_data,       \
                                type val) {                                    \
      upb_json_printer *p = closure;                                           \
      print_comma(p);                                                          \
      CHK(put##type(closure, handler_data, val));                              \
      return true;                                                             \
    }
  
  #define TYPE_HANDLERS_MAPKEY(type, fmt_func)                                 \
    static bool putmapkey_##type(void *closure, const void *handler_data,      \
                              type val) {                                      \
      upb_json_printer *p = closure;                                           \
      char data[64];                                                           \
      size_t length = fmt_func(val, data, sizeof(data));                       \
      UPB_UNUSED(handler_data);                                                \
      print_data(p, "\"", 1);                                                  \
      print_data(p, data, length);                                             \
      print_data(p, "\":", 2);                                                 \
      return true;                                                             \
    }
  
  TYPE_HANDLERS(double,   fmt_double)
  TYPE_HANDLERS(float,    fmt_float)
  TYPE_HANDLERS(bool,     fmt_bool)
  TYPE_HANDLERS(int32_t,  fmt_int64_as_number)
  TYPE_HANDLERS(uint32_t, fmt_int64_as_number)
  TYPE_HANDLERS(int64_t,  fmt_int64_as_string)
  TYPE_HANDLERS(uint64_t, fmt_uint64_as_string)
  
  /* double and float are not allowed to be map keys. */
  TYPE_HANDLERS_MAPKEY(bool,     fmt_bool)
  TYPE_HANDLERS_MAPKEY(int32_t,  fmt_int64_as_number)
  TYPE_HANDLERS_MAPKEY(uint32_t, fmt_int64_as_number)
  TYPE_HANDLERS_MAPKEY(int64_t,  fmt_int64_as_number)
  TYPE_HANDLERS_MAPKEY(uint64_t, fmt_uint64_as_number)
  
  #undef TYPE_HANDLERS
  #undef TYPE_HANDLERS_MAPKEY
  
  typedef struct {
    void *keyname;
    const upb_enumdef *enumdef;
  } EnumHandlerData;
  
  static bool scalar_enum(void *closure, const void *handler_data,
                          int32_t val) {
    const EnumHandlerData *hd = handler_data;
    upb_json_printer *p = closure;
    const char *symbolic_name;
  
    CHK(putkey(closure, hd->keyname));
  
    symbolic_name = upb_enumdef_iton(hd->enumdef, val);
    if (symbolic_name) {
      print_data(p, "\"", 1);
      putstring(p, symbolic_name, strlen(symbolic_name));
      print_data(p, "\"", 1);
    } else {
      putint32_t(closure, NULL, val);
    }
  
    return true;
  }
  
  static void print_enum_symbolic_name(upb_json_printer *p,
                                       const upb_enumdef *def,
                                       int32_t val) {
    const char *symbolic_name = upb_enumdef_iton(def, val);
    if (symbolic_name) {
      print_data(p, "\"", 1);
      putstring(p, symbolic_name, strlen(symbolic_name));
      print_data(p, "\"", 1);
    } else {
      putint32_t(p, NULL, val);
    }
  }
  
  static bool repeated_enum(void *closure, const void *handler_data,
                            int32_t val) {
    const EnumHandlerData *hd = handler_data;
    upb_json_printer *p = closure;
    print_comma(p);
  
    print_enum_symbolic_name(p, hd->enumdef, val);
  
    return true;
  }
  
  static bool mapvalue_enum(void *closure, const void *handler_data,
                            int32_t val) {
    const EnumHandlerData *hd = handler_data;
    upb_json_printer *p = closure;
  
    print_enum_symbolic_name(p, hd->enumdef, val);
  
    return true;
  }
  
  static void *scalar_startsubmsg(void *closure, const void *handler_data) {
    return putkey(closure, handler_data) ? closure : UPB_BREAK;
  }
  
  static void *repeated_startsubmsg(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    print_comma(p);
    return closure;
  }
  
  static void start_frame(upb_json_printer *p) {
    p->depth_++;
    p->first_elem_[p->depth_] = true;
    print_data(p, "{", 1);
  }
  
  static void end_frame(upb_json_printer *p) {
    print_data(p, "}", 1);
    p->depth_--;
  }
  
  static bool printer_startmsg(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    if (p->depth_ == 0) {
      upb_bytessink_start(p->output_, 0, &p->subc_);
    }
    start_frame(p);
    return true;
  }
  
  static bool printer_endmsg(void *closure, const void *handler_data, upb_status *s) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(s);
    end_frame(p);
    if (p->depth_ == 0) {
      upb_bytessink_end(p->output_);
    }
    return true;
  }
  
  static void *startseq(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    CHK(putkey(closure, handler_data));
    p->depth_++;
    p->first_elem_[p->depth_] = true;
    print_data(p, "[", 1);
    return closure;
  }
  
  static bool endseq(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    print_data(p, "]", 1);
    p->depth_--;
    return true;
  }
  
  static void *startmap(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    CHK(putkey(closure, handler_data));
    p->depth_++;
    p->first_elem_[p->depth_] = true;
    print_data(p, "{", 1);
    return closure;
  }
  
  static bool endmap(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    print_data(p, "}", 1);
    p->depth_--;
    return true;
  }
  
  static size_t putstr(void *closure, const void *handler_data, const char *str,
                       size_t len, const upb_bufhandle *handle) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(handle);
    putstring(p, str, len);
    return len;
  }
  
  /* This has to Base64 encode the bytes, because JSON has no "bytes" type. */
  static size_t putbytes(void *closure, const void *handler_data, const char *str,
                         size_t len, const upb_bufhandle *handle) {
    upb_json_printer *p = closure;
  
    /* This is the regular base64, not the "web-safe" version. */
    static const char base64[] =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
    /* Base64-encode. */
    char data[16000];
    const char *limit = data + sizeof(data);
    const unsigned char *from = (const unsigned char*)str;
    char *to = data;
    size_t remaining = len;
    size_t bytes;
  
    UPB_UNUSED(handler_data);
    UPB_UNUSED(handle);
  
    print_data(p, "\"", 1);
  
    while (remaining > 2) {
      if (limit - to < 4) {
        bytes = to - data;
        putstring(p, data, bytes);
        to = data;
      }
  
      to[0] = base64[from[0] >> 2];
      to[1] = base64[((from[0] & 0x3) << 4) | (from[1] >> 4)];
      to[2] = base64[((from[1] & 0xf) << 2) | (from[2] >> 6)];
      to[3] = base64[from[2] & 0x3f];
  
      remaining -= 3;
      to += 4;
      from += 3;
    }
  
    switch (remaining) {
      case 2:
        to[0] = base64[from[0] >> 2];
        to[1] = base64[((from[0] & 0x3) << 4) | (from[1] >> 4)];
        to[2] = base64[(from[1] & 0xf) << 2];
        to[3] = '=';
        to += 4;
        from += 2;
        break;
      case 1:
        to[0] = base64[from[0] >> 2];
        to[1] = base64[((from[0] & 0x3) << 4)];
        to[2] = '=';
        to[3] = '=';
        to += 4;
        from += 1;
        break;
    }
  
    bytes = to - data;
    putstring(p, data, bytes);
    print_data(p, "\"", 1);
    return len;
  }
  
  static void *scalar_startstr(void *closure, const void *handler_data,
                               size_t size_hint) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(size_hint);
    CHK(putkey(closure, handler_data));
    print_data(p, "\"", 1);
    return p;
  }
  
  static size_t scalar_str(void *closure, const void *handler_data,
                           const char *str, size_t len,
                           const upb_bufhandle *handle) {
    CHK(putstr(closure, handler_data, str, len, handle));
    return len;
  }
  
  static bool scalar_endstr(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    print_data(p, "\"", 1);
    return true;
  }
  
  static void *repeated_startstr(void *closure, const void *handler_data,
                                 size_t size_hint) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(size_hint);
    print_comma(p);
    print_data(p, "\"", 1);
    return p;
  }
  
  static size_t repeated_str(void *closure, const void *handler_data,
                             const char *str, size_t len,
                             const upb_bufhandle *handle) {
    CHK(putstr(closure, handler_data, str, len, handle));
    return len;
  }
  
  static bool repeated_endstr(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    print_data(p, "\"", 1);
    return true;
  }
  
  static void *mapkeyval_startstr(void *closure, const void *handler_data,
                                  size_t size_hint) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(size_hint);
    print_data(p, "\"", 1);
    return p;
  }
  
  static size_t mapkey_str(void *closure, const void *handler_data,
                           const char *str, size_t len,
                           const upb_bufhandle *handle) {
    CHK(putstr(closure, handler_data, str, len, handle));
    return len;
  }
  
  static bool mapkey_endstr(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    print_data(p, "\":", 2);
    return true;
  }
  
  static bool mapvalue_endstr(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    print_data(p, "\"", 1);
    return true;
  }
  
  static size_t scalar_bytes(void *closure, const void *handler_data,
                             const char *str, size_t len,
                             const upb_bufhandle *handle) {
    CHK(putkey(closure, handler_data));
    CHK(putbytes(closure, handler_data, str, len, handle));
    return len;
  }
  
  static size_t repeated_bytes(void *closure, const void *handler_data,
                               const char *str, size_t len,
                               const upb_bufhandle *handle) {
    upb_json_printer *p = closure;
    print_comma(p);
    CHK(putbytes(closure, handler_data, str, len, handle));
    return len;
  }
  
  static size_t mapkey_bytes(void *closure, const void *handler_data,
                             const char *str, size_t len,
                             const upb_bufhandle *handle) {
    upb_json_printer *p = closure;
    CHK(putbytes(closure, handler_data, str, len, handle));
    print_data(p, ":", 1);
    return len;
  }
  
  static void set_enum_hd(upb_handlers *h,
                          const upb_fielddef *f,
                          bool preserve_fieldnames,
                          upb_handlerattr *attr) {
    EnumHandlerData *hd = upb_gmalloc(sizeof(EnumHandlerData));
    hd->enumdef = upb_fielddef_enumsubdef(f);
    hd->keyname = newstrpc(h, f, preserve_fieldnames);
    upb_handlers_addcleanup(h, hd, upb_gfree);
    attr->handler_data = hd;
  }
  
  /* Set up handlers for a mapentry submessage (i.e., an individual key/value pair
   * in a map).
   *
   * TODO: Handle missing key, missing value, out-of-order key/value, or repeated
   * key or value cases properly. The right way to do this is to allocate a
   * temporary structure at the start of a mapentry submessage, store key and
   * value data in it as key and value handlers are called, and then print the
   * key/value pair once at the end of the submessage. If we don't do this, we
   * should at least detect the case and throw an error. However, so far all of
   * our sources that emit mapentry messages do so canonically (with one key
   * field, and then one value field), so this is not a pressing concern at the
   * moment. */
  void printer_sethandlers_mapentry(const void *closure, bool preserve_fieldnames,
                                    upb_handlers *h) {
    const upb_msgdef *md = upb_handlers_msgdef(h);
  
    /* A mapentry message is printed simply as '"key": value'. Rather than
     * special-case key and value for every type below, we just handle both
     * fields explicitly here. */
    const upb_fielddef* key_field = upb_msgdef_itof(md, UPB_MAPENTRY_KEY);
    const upb_fielddef* value_field = upb_msgdef_itof(md, UPB_MAPENTRY_VALUE);
  
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
  
    UPB_UNUSED(closure);
  
    switch (upb_fielddef_type(key_field)) {
      case UPB_TYPE_INT32:
        upb_handlers_setint32(h, key_field, putmapkey_int32_t, &empty_attr);
        break;
      case UPB_TYPE_INT64:
        upb_handlers_setint64(h, key_field, putmapkey_int64_t, &empty_attr);
        break;
      case UPB_TYPE_UINT32:
        upb_handlers_setuint32(h, key_field, putmapkey_uint32_t, &empty_attr);
        break;
      case UPB_TYPE_UINT64:
        upb_handlers_setuint64(h, key_field, putmapkey_uint64_t, &empty_attr);
        break;
      case UPB_TYPE_BOOL:
        upb_handlers_setbool(h, key_field, putmapkey_bool, &empty_attr);
        break;
      case UPB_TYPE_STRING:
        upb_handlers_setstartstr(h, key_field, mapkeyval_startstr, &empty_attr);
        upb_handlers_setstring(h, key_field, mapkey_str, &empty_attr);
        upb_handlers_setendstr(h, key_field, mapkey_endstr, &empty_attr);
        break;
      case UPB_TYPE_BYTES:
        upb_handlers_setstring(h, key_field, mapkey_bytes, &empty_attr);
        break;
      default:
        UPB_ASSERT(false);
        break;
    }
  
    switch (upb_fielddef_type(value_field)) {
      case UPB_TYPE_INT32:
        upb_handlers_setint32(h, value_field, putint32_t, &empty_attr);
        break;
      case UPB_TYPE_INT64:
        upb_handlers_setint64(h, value_field, putint64_t, &empty_attr);
        break;
      case UPB_TYPE_UINT32:
        upb_handlers_setuint32(h, value_field, putuint32_t, &empty_attr);
        break;
      case UPB_TYPE_UINT64:
        upb_handlers_setuint64(h, value_field, putuint64_t, &empty_attr);
        break;
      case UPB_TYPE_BOOL:
        upb_handlers_setbool(h, value_field, putbool, &empty_attr);
        break;
      case UPB_TYPE_FLOAT:
        upb_handlers_setfloat(h, value_field, putfloat, &empty_attr);
        break;
      case UPB_TYPE_DOUBLE:
        upb_handlers_setdouble(h, value_field, putdouble, &empty_attr);
        break;
      case UPB_TYPE_STRING:
        upb_handlers_setstartstr(h, value_field, mapkeyval_startstr, &empty_attr);
        upb_handlers_setstring(h, value_field, putstr, &empty_attr);
        upb_handlers_setendstr(h, value_field, mapvalue_endstr, &empty_attr);
        break;
      case UPB_TYPE_BYTES:
        upb_handlers_setstring(h, value_field, putbytes, &empty_attr);
        break;
      case UPB_TYPE_ENUM: {
        upb_handlerattr enum_attr = UPB_HANDLERATTR_INIT;
        set_enum_hd(h, value_field, preserve_fieldnames, &enum_attr);
        upb_handlers_setint32(h, value_field, mapvalue_enum, &enum_attr);
        break;
      }
      case UPB_TYPE_MESSAGE:
        /* No handler necessary -- the submsg handlers will print the message
         * as appropriate. */
        break;
    }
  }
  
  static bool putseconds(void *closure, const void *handler_data,
                         int64_t seconds) {
    upb_json_printer *p = closure;
    p->seconds = seconds;
    UPB_UNUSED(handler_data);
    return true;
  }
  
  static bool putnanos(void *closure, const void *handler_data,
                       int32_t nanos) {
    upb_json_printer *p = closure;
    p->nanos = nanos;
    UPB_UNUSED(handler_data);
    return true;
  }
  
  static void *scalar_startstr_nokey(void *closure, const void *handler_data,
                                     size_t size_hint) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(size_hint);
    print_data(p, "\"", 1);
    return p;
  }
  
  static size_t putstr_nokey(void *closure, const void *handler_data,
                             const char *str, size_t len,
                             const upb_bufhandle *handle) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(handle);
    print_data(p, "\"", 1);
    putstring(p, str, len);
    print_data(p, "\"", 1);
    return len + 2;
  }
  
  static void *startseq_nokey(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    p->depth_++;
    p->first_elem_[p->depth_] = true;
    print_data(p, "[", 1);
    return closure;
  }
  
  static void *startseq_fieldmask(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    p->depth_++;
    p->first_elem_[p->depth_] = true;
    return closure;
  }
  
  static bool endseq_fieldmask(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    p->depth_--;
    return true;
  }
  
  static void *repeated_startstr_fieldmask(
      void *closure, const void *handler_data,
      size_t size_hint) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(size_hint);
    print_comma(p);
    return p;
  }
  
  static size_t repeated_str_fieldmask(
      void *closure, const void *handler_data,
      const char *str, size_t len,
      const upb_bufhandle *handle) {
    const char* limit = str + len;
    bool upper = false;
    size_t result_len = 0;
    for (; str < limit; str++) {
      if (*str == '_') {
        upper = true;
        continue;
      }
      if (upper && *str >= 'a' && *str <= 'z') {
        char upper_char = toupper(*str);
        CHK(putstr(closure, handler_data, &upper_char, 1, handle));
      } else {
        CHK(putstr(closure, handler_data, str, 1, handle));
      }
      upper = false;
      result_len++;
    }
    return result_len;
  }
  
  static void *startmap_nokey(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    p->depth_++;
    p->first_elem_[p->depth_] = true;
    print_data(p, "{", 1);
    return closure;
  }
  
  static bool putnull(void *closure, const void *handler_data,
                      int32_t null) {
    upb_json_printer *p = closure;
    print_data(p, "null", 4);
    UPB_UNUSED(handler_data);
    UPB_UNUSED(null);
    return true;
  }
  
  static bool printer_startdurationmsg(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    if (p->depth_ == 0) {
      upb_bytessink_start(p->output_, 0, &p->subc_);
    }
    return true;
  }
  
  #define UPB_DURATION_MAX_JSON_LEN 23
  #define UPB_DURATION_MAX_NANO_LEN 9
  
  static bool printer_enddurationmsg(void *closure, const void *handler_data,
                                     upb_status *s) {
    upb_json_printer *p = closure;
    char buffer[UPB_DURATION_MAX_JSON_LEN];
    size_t base_len;
    size_t curr;
    size_t i;
  
    memset(buffer, 0, UPB_DURATION_MAX_JSON_LEN);
  
    if (p->seconds < -315576000000) {
      upb_status_seterrf(s, "error parsing duration: "
                            "minimum acceptable value is "
                            "-315576000000");
      return false;
    }
  
    if (p->seconds > 315576000000) {
      upb_status_seterrf(s, "error serializing duration: "
                            "maximum acceptable value is "
                            "315576000000");
      return false;
    }
  
    _upb_snprintf(buffer, sizeof(buffer), "%ld", (long)p->seconds);
    base_len = strlen(buffer);
  
    if (p->nanos != 0) {
      char nanos_buffer[UPB_DURATION_MAX_NANO_LEN + 3];
      _upb_snprintf(nanos_buffer, sizeof(nanos_buffer), "%.9f",
                    p->nanos / 1000000000.0);
      /* Remove trailing 0. */
      for (i = UPB_DURATION_MAX_NANO_LEN + 2;
           nanos_buffer[i] == '0'; i--) {
        nanos_buffer[i] = 0;
      }
      strcpy(buffer + base_len, nanos_buffer + 1);
    }
  
    curr = strlen(buffer);
    strcpy(buffer + curr, "s");
  
    p->seconds = 0;
    p->nanos = 0;
  
    print_data(p, "\"", 1);
    print_data(p, buffer, strlen(buffer));
    print_data(p, "\"", 1);
  
    if (p->depth_ == 0) {
      upb_bytessink_end(p->output_);
    }
  
    UPB_UNUSED(handler_data);
    return true;
  }
  
  static bool printer_starttimestampmsg(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    if (p->depth_ == 0) {
      upb_bytessink_start(p->output_, 0, &p->subc_);
    }
    return true;
  }
  
  #define UPB_TIMESTAMP_MAX_JSON_LEN 31
  #define UPB_TIMESTAMP_BEFORE_NANO_LEN 19
  #define UPB_TIMESTAMP_MAX_NANO_LEN 9
  
  static bool printer_endtimestampmsg(void *closure, const void *handler_data,
                                      upb_status *s) {
    upb_json_printer *p = closure;
    char buffer[UPB_TIMESTAMP_MAX_JSON_LEN];
    time_t time = p->seconds;
    size_t curr;
    size_t i;
    size_t year_length =
        strftime(buffer, UPB_TIMESTAMP_MAX_JSON_LEN, "%Y", gmtime(&time));
  
    if (p->seconds < -62135596800) {
      upb_status_seterrf(s, "error parsing timestamp: "
                            "minimum acceptable value is "
                            "0001-01-01T00:00:00Z");
      return false;
    }
  
    if (p->seconds > 253402300799) {
      upb_status_seterrf(s, "error parsing timestamp: "
                            "maximum acceptable value is "
                            "9999-12-31T23:59:59Z");
      return false;
    }
  
    /* strftime doesn't guarantee 4 digits for year. Prepend 0 by ourselves. */
    for (i = 0; i < 4 - year_length; i++) {
      buffer[i] = '0';
    }
  
    strftime(buffer + (4 - year_length), UPB_TIMESTAMP_MAX_JSON_LEN,
             "%Y-%m-%dT%H:%M:%S", gmtime(&time));
    if (p->nanos != 0) {
      char nanos_buffer[UPB_TIMESTAMP_MAX_NANO_LEN + 3];
      _upb_snprintf(nanos_buffer, sizeof(nanos_buffer), "%.9f",
                    p->nanos / 1000000000.0);
      /* Remove trailing 0. */
      for (i = UPB_TIMESTAMP_MAX_NANO_LEN + 2;
           nanos_buffer[i] == '0'; i--) {
        nanos_buffer[i] = 0;
      }
      strcpy(buffer + UPB_TIMESTAMP_BEFORE_NANO_LEN, nanos_buffer + 1);
    }
  
    curr = strlen(buffer);
    strcpy(buffer + curr, "Z");
  
    p->seconds = 0;
    p->nanos = 0;
  
    print_data(p, "\"", 1);
    print_data(p, buffer, strlen(buffer));
    print_data(p, "\"", 1);
  
    if (p->depth_ == 0) {
      upb_bytessink_end(p->output_);
    }
  
    UPB_UNUSED(handler_data);
    UPB_UNUSED(s);
    return true;
  }
  
  static bool printer_startmsg_noframe(void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    if (p->depth_ == 0) {
      upb_bytessink_start(p->output_, 0, &p->subc_);
    }
    return true;
  }
  
  static bool printer_endmsg_noframe(
      void *closure, const void *handler_data, upb_status *s) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(s);
    if (p->depth_ == 0) {
      upb_bytessink_end(p->output_);
    }
    return true;
  }
  
  static bool printer_startmsg_fieldmask(
      void *closure, const void *handler_data) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    if (p->depth_ == 0) {
      upb_bytessink_start(p->output_, 0, &p->subc_);
    }
    print_data(p, "\"", 1);
    return true;
  }
  
  static bool printer_endmsg_fieldmask(
      void *closure, const void *handler_data, upb_status *s) {
    upb_json_printer *p = closure;
    UPB_UNUSED(handler_data);
    UPB_UNUSED(s);
    print_data(p, "\"", 1);
    if (p->depth_ == 0) {
      upb_bytessink_end(p->output_);
    }
    return true;
  }
  
  static void *scalar_startstr_onlykey(
      void *closure, const void *handler_data, size_t size_hint) {
    upb_json_printer *p = closure;
    UPB_UNUSED(size_hint);
    CHK(putkey(closure, handler_data));
    return p;
  }
  
  /* Set up handlers for an Any submessage. */
  void printer_sethandlers_any(const void *closure, upb_handlers *h) {
    const upb_msgdef *md = upb_handlers_msgdef(h);
  
    const upb_fielddef* type_field = upb_msgdef_itof(md, UPB_ANY_TYPE);
    const upb_fielddef* value_field = upb_msgdef_itof(md, UPB_ANY_VALUE);
  
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
  
    /* type_url's json name is "@type" */
    upb_handlerattr type_name_attr = UPB_HANDLERATTR_INIT;
    upb_handlerattr value_name_attr = UPB_HANDLERATTR_INIT;
    strpc *type_url_json_name = newstrpc_str(h, "@type");
    strpc *value_json_name = newstrpc_str(h, "value");
  
    type_name_attr.handler_data = type_url_json_name;
    value_name_attr.handler_data = value_json_name;
  
    /* Set up handlers. */
    upb_handlers_setstartmsg(h, printer_startmsg, &empty_attr);
    upb_handlers_setendmsg(h, printer_endmsg, &empty_attr);
  
    upb_handlers_setstartstr(h, type_field, scalar_startstr, &type_name_attr);
    upb_handlers_setstring(h, type_field, scalar_str, &empty_attr);
    upb_handlers_setendstr(h, type_field, scalar_endstr, &empty_attr);
  
    /* This is not the full and correct JSON encoding for the Any value field. It
     * requires further processing by the wrapper code based on the type URL.
     */
    upb_handlers_setstartstr(h, value_field, scalar_startstr_onlykey,
                             &value_name_attr);
  
    UPB_UNUSED(closure);
  }
  
  /* Set up handlers for a fieldmask submessage. */
  void printer_sethandlers_fieldmask(const void *closure, upb_handlers *h) {
    const upb_msgdef *md = upb_handlers_msgdef(h);
    const upb_fielddef* f = upb_msgdef_itof(md, 1);
  
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
  
    upb_handlers_setstartseq(h, f, startseq_fieldmask, &empty_attr);
    upb_handlers_setendseq(h, f, endseq_fieldmask, &empty_attr);
  
    upb_handlers_setstartmsg(h, printer_startmsg_fieldmask, &empty_attr);
    upb_handlers_setendmsg(h, printer_endmsg_fieldmask, &empty_attr);
  
    upb_handlers_setstartstr(h, f, repeated_startstr_fieldmask, &empty_attr);
    upb_handlers_setstring(h, f, repeated_str_fieldmask, &empty_attr);
  
    UPB_UNUSED(closure);
  }
  
  /* Set up handlers for a duration submessage. */
  void printer_sethandlers_duration(const void *closure, upb_handlers *h) {
    const upb_msgdef *md = upb_handlers_msgdef(h);
  
    const upb_fielddef* seconds_field =
        upb_msgdef_itof(md, UPB_DURATION_SECONDS);
    const upb_fielddef* nanos_field =
        upb_msgdef_itof(md, UPB_DURATION_NANOS);
  
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
  
    upb_handlers_setstartmsg(h, printer_startdurationmsg, &empty_attr);
    upb_handlers_setint64(h, seconds_field, putseconds, &empty_attr);
    upb_handlers_setint32(h, nanos_field, putnanos, &empty_attr);
    upb_handlers_setendmsg(h, printer_enddurationmsg, &empty_attr);
  
    UPB_UNUSED(closure);
  }
  
  /* Set up handlers for a timestamp submessage. Instead of printing fields
   * separately, the json representation of timestamp follows RFC 3339 */
  void printer_sethandlers_timestamp(const void *closure, upb_handlers *h) {
    const upb_msgdef *md = upb_handlers_msgdef(h);
  
    const upb_fielddef* seconds_field =
        upb_msgdef_itof(md, UPB_TIMESTAMP_SECONDS);
    const upb_fielddef* nanos_field =
        upb_msgdef_itof(md, UPB_TIMESTAMP_NANOS);
  
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
  
    upb_handlers_setstartmsg(h, printer_starttimestampmsg, &empty_attr);
    upb_handlers_setint64(h, seconds_field, putseconds, &empty_attr);
    upb_handlers_setint32(h, nanos_field, putnanos, &empty_attr);
    upb_handlers_setendmsg(h, printer_endtimestampmsg, &empty_attr);
  
    UPB_UNUSED(closure);
  }
  
  void printer_sethandlers_value(const void *closure, upb_handlers *h) {
    const upb_msgdef *md = upb_handlers_msgdef(h);
    upb_msg_field_iter i;
  
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
  
    upb_handlers_setstartmsg(h, printer_startmsg_noframe, &empty_attr);
    upb_handlers_setendmsg(h, printer_endmsg_noframe, &empty_attr);
  
    upb_msg_field_begin(&i, md);
    for(; !upb_msg_field_done(&i); upb_msg_field_next(&i)) {
      const upb_fielddef *f = upb_msg_iter_field(&i);
  
      switch (upb_fielddef_type(f)) {
        case UPB_TYPE_ENUM:
          upb_handlers_setint32(h, f, putnull, &empty_attr);
          break;
        case UPB_TYPE_DOUBLE:
          upb_handlers_setdouble(h, f, putdouble, &empty_attr);
          break;
        case UPB_TYPE_STRING:
          upb_handlers_setstartstr(h, f, scalar_startstr_nokey, &empty_attr);
          upb_handlers_setstring(h, f, scalar_str, &empty_attr);
          upb_handlers_setendstr(h, f, scalar_endstr, &empty_attr);
          break;
        case UPB_TYPE_BOOL:
          upb_handlers_setbool(h, f, putbool, &empty_attr);
          break;
        case UPB_TYPE_MESSAGE:
          break;
        default:
          UPB_ASSERT(false);
          break;
      }
    }
  
    UPB_UNUSED(closure);
  }
  
  #define WRAPPER_SETHANDLERS(wrapper, type, putmethod)                      \
  void printer_sethandlers_##wrapper(const void *closure, upb_handlers *h) { \
    const upb_msgdef *md = upb_handlers_msgdef(h);                           \
    const upb_fielddef* f = upb_msgdef_itof(md, 1);                          \
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;                \
    upb_handlers_setstartmsg(h, printer_startmsg_noframe, &empty_attr);      \
    upb_handlers_setendmsg(h, printer_endmsg_noframe, &empty_attr);          \
    upb_handlers_set##type(h, f, putmethod, &empty_attr);                    \
    UPB_UNUSED(closure);                                                     \
  }
  
  WRAPPER_SETHANDLERS(doublevalue, double, putdouble)
  WRAPPER_SETHANDLERS(floatvalue,  float,  putfloat)
  WRAPPER_SETHANDLERS(int64value,  int64,  putint64_t)
  WRAPPER_SETHANDLERS(uint64value, uint64, putuint64_t)
  WRAPPER_SETHANDLERS(int32value,  int32,  putint32_t)
  WRAPPER_SETHANDLERS(uint32value, uint32, putuint32_t)
  WRAPPER_SETHANDLERS(boolvalue,   bool,   putbool)
  WRAPPER_SETHANDLERS(stringvalue, string, putstr_nokey)
  WRAPPER_SETHANDLERS(bytesvalue,  string, putbytes)
  
  #undef WRAPPER_SETHANDLERS
  
  void printer_sethandlers_listvalue(const void *closure, upb_handlers *h) {
    const upb_msgdef *md = upb_handlers_msgdef(h);
    const upb_fielddef* f = upb_msgdef_itof(md, 1);
  
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
  
    upb_handlers_setstartseq(h, f, startseq_nokey, &empty_attr);
    upb_handlers_setendseq(h, f, endseq, &empty_attr);
  
    upb_handlers_setstartmsg(h, printer_startmsg_noframe, &empty_attr);
    upb_handlers_setendmsg(h, printer_endmsg_noframe, &empty_attr);
  
    upb_handlers_setstartsubmsg(h, f, repeated_startsubmsg, &empty_attr);
  
    UPB_UNUSED(closure);
  }
  
  void printer_sethandlers_structvalue(const void *closure, upb_handlers *h) {
    const upb_msgdef *md = upb_handlers_msgdef(h);
    const upb_fielddef* f = upb_msgdef_itof(md, 1);
  
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
  
    upb_handlers_setstartseq(h, f, startmap_nokey, &empty_attr);
    upb_handlers_setendseq(h, f, endmap, &empty_attr);
  
    upb_handlers_setstartmsg(h, printer_startmsg_noframe, &empty_attr);
    upb_handlers_setendmsg(h, printer_endmsg_noframe, &empty_attr);
  
    upb_handlers_setstartsubmsg(h, f, repeated_startsubmsg, &empty_attr);
  
    UPB_UNUSED(closure);
  }
  
  void printer_sethandlers(const void *closure, upb_handlers *h) {
    const upb_msgdef *md = upb_handlers_msgdef(h);
    bool is_mapentry = upb_msgdef_mapentry(md);
    upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
    upb_msg_field_iter i;
    const upb_json_printercache *cache = closure;
    const bool preserve_fieldnames = cache->preserve_fieldnames;
  
    if (is_mapentry) {
      /* mapentry messages are sufficiently different that we handle them
       * separately. */
      printer_sethandlers_mapentry(closure, preserve_fieldnames, h);
      return;
    }
  
    switch (upb_msgdef_wellknowntype(md)) {
      case UPB_WELLKNOWN_UNSPECIFIED:
        break;
      case UPB_WELLKNOWN_ANY:
        printer_sethandlers_any(closure, h);
        return;
      case UPB_WELLKNOWN_FIELDMASK:
        printer_sethandlers_fieldmask(closure, h);
        return;
      case UPB_WELLKNOWN_DURATION:
        printer_sethandlers_duration(closure, h);
        return;
      case UPB_WELLKNOWN_TIMESTAMP:
        printer_sethandlers_timestamp(closure, h);
        return;
      case UPB_WELLKNOWN_VALUE:
        printer_sethandlers_value(closure, h);
        return;
      case UPB_WELLKNOWN_LISTVALUE:
        printer_sethandlers_listvalue(closure, h);
        return;
      case UPB_WELLKNOWN_STRUCT:
        printer_sethandlers_structvalue(closure, h);
        return;
  #define WRAPPER(wellknowntype, name)        \
    case wellknowntype:                       \
      printer_sethandlers_##name(closure, h); \
      return;                                 \
  
      WRAPPER(UPB_WELLKNOWN_DOUBLEVALUE, doublevalue);
      WRAPPER(UPB_WELLKNOWN_FLOATVALUE, floatvalue);
      WRAPPER(UPB_WELLKNOWN_INT64VALUE, int64value);
      WRAPPER(UPB_WELLKNOWN_UINT64VALUE, uint64value);
      WRAPPER(UPB_WELLKNOWN_INT32VALUE, int32value);
      WRAPPER(UPB_WELLKNOWN_UINT32VALUE, uint32value);
      WRAPPER(UPB_WELLKNOWN_BOOLVALUE, boolvalue);
      WRAPPER(UPB_WELLKNOWN_STRINGVALUE, stringvalue);
      WRAPPER(UPB_WELLKNOWN_BYTESVALUE, bytesvalue);
  
  #undef WRAPPER
    }
  
    upb_handlers_setstartmsg(h, printer_startmsg, &empty_attr);
    upb_handlers_setendmsg(h, printer_endmsg, &empty_attr);
  
  #define TYPE(type, name, ctype)                                               \
    case type:                                                                  \
      if (upb_fielddef_isseq(f)) {                                              \
        upb_handlers_set##name(h, f, repeated_##ctype, &empty_attr);            \
      } else {                                                                  \
        upb_handlers_set##name(h, f, scalar_##ctype, &name_attr);               \
      }                                                                         \
      break;
  
    upb_msg_field_begin(&i, md);
    for(; !upb_msg_field_done(&i); upb_msg_field_next(&i)) {
      const upb_fielddef *f = upb_msg_iter_field(&i);
  
      upb_handlerattr name_attr = UPB_HANDLERATTR_INIT;
      name_attr.handler_data = newstrpc(h, f, preserve_fieldnames);
  
      if (upb_fielddef_ismap(f)) {
        upb_handlers_setstartseq(h, f, startmap, &name_attr);
        upb_handlers_setendseq(h, f, endmap, &name_attr);
      } else if (upb_fielddef_isseq(f)) {
        upb_handlers_setstartseq(h, f, startseq, &name_attr);
        upb_handlers_setendseq(h, f, endseq, &empty_attr);
      }
  
      switch (upb_fielddef_type(f)) {
        TYPE(UPB_TYPE_FLOAT,  float,  float);
        TYPE(UPB_TYPE_DOUBLE, double, double);
        TYPE(UPB_TYPE_BOOL,   bool,   bool);
        TYPE(UPB_TYPE_INT32,  int32,  int32_t);
        TYPE(UPB_TYPE_UINT32, uint32, uint32_t);
        TYPE(UPB_TYPE_INT64,  int64,  int64_t);
        TYPE(UPB_TYPE_UINT64, uint64, uint64_t);
        case UPB_TYPE_ENUM: {
          /* For now, we always emit symbolic names for enums. We may want an
           * option later to control this behavior, but we will wait for a real
           * need first. */
          upb_handlerattr enum_attr = UPB_HANDLERATTR_INIT;
          set_enum_hd(h, f, preserve_fieldnames, &enum_attr);
  
          if (upb_fielddef_isseq(f)) {
            upb_handlers_setint32(h, f, repeated_enum, &enum_attr);
          } else {
            upb_handlers_setint32(h, f, scalar_enum, &enum_attr);
          }
  
          break;
        }
        case UPB_TYPE_STRING:
          if (upb_fielddef_isseq(f)) {
            upb_handlers_setstartstr(h, f, repeated_startstr, &empty_attr);
            upb_handlers_setstring(h, f, repeated_str, &empty_attr);
            upb_handlers_setendstr(h, f, repeated_endstr, &empty_attr);
          } else {
            upb_handlers_setstartstr(h, f, scalar_startstr, &name_attr);
            upb_handlers_setstring(h, f, scalar_str, &empty_attr);
            upb_handlers_setendstr(h, f, scalar_endstr, &empty_attr);
          }
          break;
        case UPB_TYPE_BYTES:
          /* XXX: this doesn't support strings that span buffers yet. The base64
           * encoder will need to be made resumable for this to work properly. */
          if (upb_fielddef_isseq(f)) {
            upb_handlers_setstring(h, f, repeated_bytes, &empty_attr);
          } else {
            upb_handlers_setstring(h, f, scalar_bytes, &name_attr);
          }
          break;
        case UPB_TYPE_MESSAGE:
          if (upb_fielddef_isseq(f)) {
            upb_handlers_setstartsubmsg(h, f, repeated_startsubmsg, &name_attr);
          } else {
            upb_handlers_setstartsubmsg(h, f, scalar_startsubmsg, &name_attr);
          }
          break;
      }
    }
  
  #undef TYPE
  }
  
  static void json_printer_reset(upb_json_printer *p) {
    p->depth_ = 0;
  }
  
  
  /* Public API *****************************************************************/
  
  upb_json_printer *upb_json_printer_create(upb_arena *a, const upb_handlers *h,
                                            upb_bytessink output) {
  #ifndef NDEBUG
    size_t size_before = upb_arena_bytesallocated(a);
  #endif
  
    upb_json_printer *p = upb_arena_malloc(a, sizeof(upb_json_printer));
    if (!p) return NULL;
  
    p->output_ = output;
    json_printer_reset(p);
    upb_sink_reset(&p->input_, h, p);
    p->seconds = 0;
    p->nanos = 0;
  
    /* If this fails, increase the value in printer.h. */
    UPB_ASSERT_DEBUGVAR(upb_arena_bytesallocated(a) - size_before <=
                        UPB_JSON_PRINTER_SIZE);
    return p;
  }
  
  upb_sink upb_json_printer_input(upb_json_printer *p) {
    return p->input_;
  }
  
  upb_handlercache *upb_json_printer_newcache(bool preserve_proto_fieldnames) {
    upb_json_printercache *cache = upb_gmalloc(sizeof(*cache));
    upb_handlercache *ret = upb_handlercache_new(printer_sethandlers, cache);
  
    cache->preserve_fieldnames = preserve_proto_fieldnames;
    upb_handlercache_addcleanup(ret, cache, upb_gfree);
  
    return ret;
  }
  /* See port_def.inc.  This should #undef all macros #defined there. */
  
  #undef UPB_SIZE
  #undef UPB_FIELD_AT
  #undef UPB_READ_ONEOF
  #undef UPB_WRITE_ONEOF
  #undef UPB_INLINE
  #undef UPB_FORCEINLINE
  #undef UPB_NOINLINE
  #undef UPB_NORETURN
  #undef UPB_MAX
  #undef UPB_MIN
  #undef UPB_UNUSED
  #undef UPB_ASSERT
  #undef UPB_ASSERT_DEBUGVAR
  #undef UPB_UNREACHABLE
  #undef UPB_INFINITY
  #undef UPB_MSVC_VSNPRINTF
  #undef _upb_snprintf
  #undef _upb_vsnprintf
  #undef _upb_va_copy
  