text: /**********************************************************************
    regparse.c -  Oniguruma (regular expression library)
  **********************************************************************/
  /*-
   * Copyright (c) 2002-2017  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  #include "regparse.h"
  #include "st.h"
  
  #ifdef DEBUG_NODE_FREE
  #include <stdio.h>
  #endif
  
  #define WARN_BUFSIZE    256
  
  #define CASE_FOLD_IS_APPLIED_INSIDE_NEGATIVE_CCLASS
  
  
  OnigSyntaxType OnigSyntaxRuby = {
    (( SYN_GNU_REGEX_OP | ONIG_SYN_OP_QMARK_NON_GREEDY |
       ONIG_SYN_OP_ESC_OCTAL3 | ONIG_SYN_OP_ESC_X_HEX2 |
       ONIG_SYN_OP_ESC_X_BRACE_HEX8 | ONIG_SYN_OP_ESC_O_BRACE_OCTAL |
       ONIG_SYN_OP_ESC_CONTROL_CHARS |
       ONIG_SYN_OP_ESC_C_CONTROL )
     & ~ONIG_SYN_OP_ESC_LTGT_WORD_BEGIN_END )
    , ( ONIG_SYN_OP2_QMARK_GROUP_EFFECT |
        ONIG_SYN_OP2_OPTION_RUBY |
        ONIG_SYN_OP2_QMARK_LT_NAMED_GROUP | ONIG_SYN_OP2_ESC_K_NAMED_BACKREF |
        ONIG_SYN_OP2_QMARK_LPAREN_IF_ELSE |
        ONIG_SYN_OP2_QMARK_TILDE_ABSENT_GROUP |
        ONIG_SYN_OP2_ESC_X_Y_GRAPHEME_CLUSTER |
        ONIG_SYN_OP2_ESC_CAPITAL_R_GENERAL_NEWLINE |
        ONIG_SYN_OP2_ESC_CAPITAL_N_O_SUPER_DOT |
        ONIG_SYN_OP2_ESC_CAPITAL_K_KEEP |
        ONIG_SYN_OP2_ESC_G_SUBEXP_CALL |
        ONIG_SYN_OP2_ESC_P_BRACE_CHAR_PROPERTY  |
        ONIG_SYN_OP2_ESC_P_BRACE_CIRCUMFLEX_NOT |
        ONIG_SYN_OP2_PLUS_POSSESSIVE_REPEAT |
        ONIG_SYN_OP2_CCLASS_SET_OP | ONIG_SYN_OP2_ESC_CAPITAL_C_BAR_CONTROL |
        ONIG_SYN_OP2_ESC_CAPITAL_M_BAR_META | ONIG_SYN_OP2_ESC_V_VTAB |
        ONIG_SYN_OP2_ESC_H_XDIGIT )
    , ( SYN_GNU_REGEX_BV | 
        ONIG_SYN_ALLOW_INTERVAL_LOW_ABBREV |
        ONIG_SYN_DIFFERENT_LEN_ALT_LOOK_BEHIND |
        ONIG_SYN_CAPTURE_ONLY_NAMED_GROUP |
        ONIG_SYN_ALLOW_MULTIPLEX_DEFINITION_NAME |
        ONIG_SYN_FIXED_INTERVAL_IS_GREEDY_ONLY |
        ONIG_SYN_WARN_CC_OP_NOT_ESCAPED |
        ONIG_SYN_WARN_REDUNDANT_NESTED_REPEAT )
    , ONIG_OPTION_NONE
    ,
    {
        (OnigCodePoint )'\\'                       /* esc */
      , (OnigCodePoint )ONIG_INEFFECTIVE_META_CHAR /* anychar '.'  */
      , (OnigCodePoint )ONIG_INEFFECTIVE_META_CHAR /* anytime '*'  */
      , (OnigCodePoint )ONIG_INEFFECTIVE_META_CHAR /* zero or one time '?' */
      , (OnigCodePoint )ONIG_INEFFECTIVE_META_CHAR /* one or more time '+' */
      , (OnigCodePoint )ONIG_INEFFECTIVE_META_CHAR /* anychar anytime */
    }
  };
  
  OnigSyntaxType*  OnigDefaultSyntax = ONIG_SYNTAX_RUBY;
  
  extern void onig_null_warn(const char* s ARG_UNUSED) { }
  
  #ifdef DEFAULT_WARN_FUNCTION
  static OnigWarnFunc onig_warn = (OnigWarnFunc )DEFAULT_WARN_FUNCTION;
  #else
  static OnigWarnFunc onig_warn = onig_null_warn;
  #endif
  
  #ifdef DEFAULT_VERB_WARN_FUNCTION
  static OnigWarnFunc onig_verb_warn = (OnigWarnFunc )DEFAULT_VERB_WARN_FUNCTION;
  #else
  static OnigWarnFunc onig_verb_warn = onig_null_warn;
  #endif
  
  extern void onig_set_warn_func(OnigWarnFunc f)
  {
    onig_warn = f;
  }
  
  extern void onig_set_verb_warn_func(OnigWarnFunc f)
  {
    onig_verb_warn = f;
  }
  
  extern void
  onig_warning(const char* s)
  {
    if (onig_warn == onig_null_warn) return ;
  
    (*onig_warn)(s);
  }
  
  #define DEFAULT_MAX_CAPTURE_NUM   32767
  
  static int MaxCaptureNum = DEFAULT_MAX_CAPTURE_NUM;
  
  extern int
  onig_set_capture_num_limit(int num)
  {
    if (num < 0) return -1;
  
    MaxCaptureNum = num;
    return 0;
  }
  
  static unsigned int ParseDepthLimit = DEFAULT_PARSE_DEPTH_LIMIT;
  
  extern unsigned int
  onig_get_parse_depth_limit(void)
  {
    return ParseDepthLimit;
  }
  
  extern int
  onig_set_parse_depth_limit(unsigned int depth)
  {
    if (depth == 0)
      ParseDepthLimit = DEFAULT_PARSE_DEPTH_LIMIT;
    else
      ParseDepthLimit = depth;
    return 0;
  }
  
  
  static void
  bbuf_free(BBuf* bbuf)
  {
    if (IS_NOT_NULL(bbuf)) {
      if (IS_NOT_NULL(bbuf->p)) xfree(bbuf->p);
      xfree(bbuf);
    }
  }
  
  static int
  bbuf_clone(BBuf** rto, BBuf* from)
  {
    int r;
    BBuf *to;
  
    *rto = to = (BBuf* )xmalloc(sizeof(BBuf));
    CHECK_NULL_RETURN_MEMERR(to);
    r = BB_INIT(to, from->alloc);
    if (r != 0) {
      xfree(to->p);
      *rto = 0;
      return r;
    }
    to->used = from->used;
    xmemcpy(to->p, from->p, from->used);
    return 0;
  }
  
  static int backref_rel_to_abs(int rel_no, ScanEnv* env)
  {
    if (rel_no > 0) {
      return env->num_mem + rel_no;
    }
    else {
      return env->num_mem + 1 + rel_no;
    }
  }
  
  #define OPTION_ON(v,f)     ((v) |= (f))
  #define OPTION_OFF(v,f)    ((v) &= ~(f))
  
  #define OPTION_NEGATE(v,f,negative)    (negative) ? ((v) &= ~(f)) : ((v) |= (f))
  
  #define MBCODE_START_POS(enc) \
    (OnigCodePoint )(ONIGENC_MBC_MINLEN(enc) > 1 ? 0 : 0x80)
  
  #define SET_ALL_MULTI_BYTE_RANGE(enc, pbuf) \
    add_code_range_to_buf(pbuf, MBCODE_START_POS(enc), ~((OnigCodePoint )0))
  
  #define ADD_ALL_MULTI_BYTE_RANGE(enc, mbuf) do {\
    if (! ONIGENC_IS_SINGLEBYTE(enc)) {\
      r = SET_ALL_MULTI_BYTE_RANGE(enc, &(mbuf));\
      if (r != 0) return r;\
    }\
  } while (0)
  
  
  #define BITSET_IS_EMPTY(bs,empty) do {\
    int i;\
    empty = 1;\
    for (i = 0; i < (int )BITSET_SIZE; i++) {\
      if ((bs)[i] != 0) {\
        empty = 0; break;\
      }\
    }\
  } while (0)
  
  static void
  bitset_set_range(BitSetRef bs, int from, int to)
  {
    int i;
    for (i = from; i <= to && i < SINGLE_BYTE_SIZE; i++) {
      BITSET_SET_BIT(bs, i);
    }
  }
  
  #if 0
  static void
  bitset_set_all(BitSetRef bs)
  {
    int i;
    for (i = 0; i < BITSET_SIZE; i++) { bs[i] = ~((Bits )0); }
  }
  #endif
  
  static void
  bitset_invert(BitSetRef bs)
  {
    int i;
    for (i = 0; i < (int )BITSET_SIZE; i++) { bs[i] = ~(bs[i]); }
  }
  
  static void
  bitset_invert_to(BitSetRef from, BitSetRef to)
  {
    int i;
    for (i = 0; i < (int )BITSET_SIZE; i++) { to[i] = ~(from[i]); }
  }
  
  static void
  bitset_and(BitSetRef dest, BitSetRef bs)
  {
    int i;
    for (i = 0; i < (int )BITSET_SIZE; i++) { dest[i] &= bs[i]; }
  }
  
  static void
  bitset_or(BitSetRef dest, BitSetRef bs)
  {
    int i;
    for (i = 0; i < (int )BITSET_SIZE; i++) { dest[i] |= bs[i]; }
  }
  
  static void
  bitset_copy(BitSetRef dest, BitSetRef bs)
  {
    int i;
    for (i = 0; i < (int )BITSET_SIZE; i++) { dest[i] = bs[i]; }
  }
  
  extern int
  onig_strncmp(const UChar* s1, const UChar* s2, int n)
  {
    int x;
  
    while (n-- > 0) {
      x = *s2++ - *s1++;
      if (x) return x;
    }
    return 0;
  }
  
  extern void
  onig_strcpy(UChar* dest, const UChar* src, const UChar* end)
  {
    int len = (int)(end - src);
    if (len > 0) {
      xmemcpy(dest, src, len);
      dest[len] = (UChar )0;
    }
  }
  
  static UChar*
  strdup_with_null(OnigEncoding enc, UChar* s, UChar* end)
  {
    int slen, term_len, i;
    UChar *r;
  
    slen = (int)(end - s);
    term_len = ONIGENC_MBC_MINLEN(enc);
  
    r = (UChar* )xmalloc(slen + term_len);
    CHECK_NULL_RETURN(r);
    xmemcpy(r, s, slen);
  
    for (i = 0; i < term_len; i++)
      r[slen + i] = (UChar )0;
  
    return r;
  }
  
  static int
  save_entry(ScanEnv* env, enum SaveType type, int* id)
  {
    int nid = env->save_num;
  
  #if 0
    if (IS_NULL(env->saves)) {
      int n = 10;
      env->saves = (SaveItem* )xmalloc(sizeof(SaveItem) * n);
      CHECK_NULL_RETURN_MEMERR(env->saves);
      env->save_alloc_num = n;
    }
    else if (env->save_alloc_num <= nid) {
      int n = env->save_alloc_num * 2;
      SaveItem* p = (SaveItem* )xrealloc(env->saves, sizeof(SaveItem) * n);
      CHECK_NULL_RETURN_MEMERR(p);
      env->saves = p;
      env->save_alloc_num = n;
    }
  
    env->saves[nid].type = type;
  #endif
  
    env->save_num++;
    *id = nid;
    return 0;
  }
  
  /* scan pattern methods */
  #define PEND_VALUE   0
  
  #define PFETCH_READY  UChar* pfetch_prev
  #define PEND         (p < end ?  0 : 1)
  #define PUNFETCH     p = pfetch_prev
  #define PINC       do { \
    pfetch_prev = p; \
    p += ONIGENC_MBC_ENC_LEN(enc, p); \
  } while (0)
  #define PFETCH(c)  do { \
    c = ONIGENC_MBC_TO_CODE(enc, p, end); \
    pfetch_prev = p; \
    p += ONIGENC_MBC_ENC_LEN(enc, p); \
  } while (0)
  
  #define PINC_S     do { \
    p += ONIGENC_MBC_ENC_LEN(enc, p); \
  } while (0)
  #define PFETCH_S(c) do { \
    c = ONIGENC_MBC_TO_CODE(enc, p, end); \
    p += ONIGENC_MBC_ENC_LEN(enc, p); \
  } while (0)
  
  #define PPEEK        (p < end ? ONIGENC_MBC_TO_CODE(enc, p, end) : PEND_VALUE)
  #define PPEEK_IS(c)  (PPEEK == (OnigCodePoint )c)
  
  static UChar*
  strcat_capa(UChar* dest, UChar* dest_end, const UChar* src, const UChar* src_end,
  	      int capa)
  {
    UChar* r;
  
    if (dest)
      r = (UChar* )xrealloc(dest, capa + 1);
    else
      r = (UChar* )xmalloc(capa + 1);
  
    CHECK_NULL_RETURN(r);
    onig_strcpy(r + (dest_end - dest), src, src_end);
    return r;
  }
  
  /* dest on static area */
  static UChar*
  strcat_capa_from_static(UChar* dest, UChar* dest_end,
  			const UChar* src, const UChar* src_end, int capa)
  {
    UChar* r;
  
    r = (UChar* )xmalloc(capa + 1);
    CHECK_NULL_RETURN(r);
    onig_strcpy(r, dest, dest_end);
    onig_strcpy(r + (dest_end - dest), src, src_end);
    return r;
  }
  
  
  #ifdef USE_ST_LIBRARY
  
  typedef struct {
    UChar* s;
    UChar* end;
  } st_str_end_key;
  
  static int
  str_end_cmp(st_str_end_key* x, st_str_end_key* y)
  {
    UChar *p, *q;
    int c;
  
    if ((x->end - x->s) != (y->end - y->s))
      return 1;
  
    p = x->s;
    q = y->s;
    while (p < x->end) {
      c = (int )*p - (int )*q;
      if (c != 0) return c;
  
      p++; q++;
    }
  
    return 0;
  }
  
  static int
  str_end_hash(st_str_end_key* x)
  {
    UChar *p;
    int val = 0;
  
    p = x->s;
    while (p < x->end) {
      val = val * 997 + (int )*p++;
    }
  
    return val + (val >> 5);
  }
  
  extern hash_table_type*
  onig_st_init_strend_table_with_size(int size)
  {
    static struct st_hash_type hashType = {
      str_end_cmp,
      str_end_hash,
    };
  
    return (hash_table_type* )
             onig_st_init_table_with_size(&hashType, size);
  }
  
  extern int
  onig_st_lookup_strend(hash_table_type* table, const UChar* str_key,
  		      const UChar* end_key, hash_data_type *value)
  {
    st_str_end_key key;
  
    key.s   = (UChar* )str_key;
    key.end = (UChar* )end_key;
  
    return onig_st_lookup(table, (st_data_t )(&key), value);
  }
  
  extern int
  onig_st_insert_strend(hash_table_type* table, const UChar* str_key,
  		      const UChar* end_key, hash_data_type value)
  {
    st_str_end_key* key;
    int result;
  
    key = (st_str_end_key* )xmalloc(sizeof(st_str_end_key));
    CHECK_NULL_RETURN_MEMERR(key);
  
    key->s   = (UChar* )str_key;
    key->end = (UChar* )end_key;
    result = onig_st_insert(table, (st_data_t )key, value);
    if (result) {
      xfree(key);
    }
    return result;
  }
  
  #endif /* USE_ST_LIBRARY */
  
  
  #define INIT_NAME_BACKREFS_ALLOC_NUM   8
  
  typedef struct {
    UChar* name;
    int    name_len;   /* byte length */
    int    back_num;   /* number of backrefs */
    int    back_alloc;
    int    back_ref1;
    int*   back_refs;
  } NameEntry;
  
  #ifdef USE_ST_LIBRARY
  
  typedef st_table  NameTable;
  typedef st_data_t HashDataType;   /* 1.6 st.h doesn't define st_data_t type */
  
  #define NAMEBUF_SIZE    24
  #define NAMEBUF_SIZE_1  25
  
  #ifdef ONIG_DEBUG
  static int
  i_print_name_entry(UChar* key, NameEntry* e, void* arg)
  {
    int i;
    FILE* fp = (FILE* )arg;
  
    fprintf(fp, "%s: ", e->name);
    if (e->back_num == 0)
      fputs("-", fp);
    else if (e->back_num == 1)
      fprintf(fp, "%d", e->back_ref1);
    else {
      for (i = 0; i < e->back_num; i++) {
        if (i > 0) fprintf(fp, ", ");
        fprintf(fp, "%d", e->back_refs[i]);
      }
    }
    fputs("\n", fp);
    return ST_CONTINUE;
  }
  
  extern int
  onig_print_names(FILE* fp, regex_t* reg)
  {
    NameTable* t = (NameTable* )reg->name_table;
  
    if (IS_NOT_NULL(t)) {
      fprintf(fp, "name table\n");
      onig_st_foreach(t, i_print_name_entry, (HashDataType )fp);
      fputs("\n", fp);
    }
    return 0;
  }
  #endif /* ONIG_DEBUG */
  
  static int
  i_free_name_entry(UChar* key, NameEntry* e, void* arg ARG_UNUSED)
  {
    xfree(e->name);
    if (IS_NOT_NULL(e->back_refs)) xfree(e->back_refs);
    xfree(key);
    xfree(e);
    return ST_DELETE;
  }
  
  static int
  names_clear(regex_t* reg)
  {
    NameTable* t = (NameTable* )reg->name_table;
  
    if (IS_NOT_NULL(t)) {
      onig_st_foreach(t, i_free_name_entry, 0);
    }
    return 0;
  }
  
  extern int
  onig_names_free(regex_t* reg)
  {
    int r;
    NameTable* t;
  
    r = names_clear(reg);
    if (r != 0) return r;
  
    t = (NameTable* )reg->name_table;
    if (IS_NOT_NULL(t)) onig_st_free_table(t);
    reg->name_table = (void* )NULL;
    return 0;
  }
  
  static NameEntry*
  name_find(regex_t* reg, const UChar* name, const UChar* name_end)
  {
    NameEntry* e;
    NameTable* t = (NameTable* )reg->name_table;
  
    e = (NameEntry* )NULL;
    if (IS_NOT_NULL(t)) {
      onig_st_lookup_strend(t, name, name_end, (HashDataType* )((void* )(&e)));
    }
    return e;
  }
  
  typedef struct {
    int (*func)(const UChar*, const UChar*,int,int*,regex_t*,void*);
    regex_t* reg;
    void* arg;
    int ret;
    OnigEncoding enc;
  } INamesArg;
  
  static int
  i_names(UChar* key ARG_UNUSED, NameEntry* e, INamesArg* arg)
  {
    int r = (*(arg->func))(e->name,
                           e->name + e->name_len,
                           e->back_num,
                           (e->back_num > 1 ? e->back_refs : &(e->back_ref1)),
                           arg->reg, arg->arg);
    if (r != 0) {
      arg->ret = r;
      return ST_STOP;
    }
    return ST_CONTINUE;
  }
  
  extern int
  onig_foreach_name(regex_t* reg,
    int (*func)(const UChar*, const UChar*,int,int*,regex_t*,void*), void* arg)
  {
    INamesArg narg;
    NameTable* t = (NameTable* )reg->name_table;
  
    narg.ret = 0;
    if (IS_NOT_NULL(t)) {
      narg.func = func;
      narg.reg  = reg;
      narg.arg  = arg;
      narg.enc  = reg->enc; /* should be pattern encoding. */
      onig_st_foreach(t, i_names, (HashDataType )&narg);
    }
    return narg.ret;
  }
  
  static int
  i_renumber_name(UChar* key ARG_UNUSED, NameEntry* e, GroupNumRemap* map)
  {
    int i;
  
    if (e->back_num > 1) {
      for (i = 0; i < e->back_num; i++) {
        e->back_refs[i] = map[e->back_refs[i]].new_val;
      }
    }
    else if (e->back_num == 1) {
      e->back_ref1 = map[e->back_ref1].new_val;
    }
  
    return ST_CONTINUE;
  }
  
  extern int
  onig_renumber_name_table(regex_t* reg, GroupNumRemap* map)
  {
    NameTable* t = (NameTable* )reg->name_table;
  
    if (IS_NOT_NULL(t)) {
      onig_st_foreach(t, i_renumber_name, (HashDataType )map);
    }
    return 0;
  }
  
  
  extern int
  onig_number_of_names(regex_t* reg)
  {
    NameTable* t = (NameTable* )reg->name_table;
  
    if (IS_NOT_NULL(t))
      return t->num_entries;
    else
      return 0;
  }
  
  #else  /* USE_ST_LIBRARY */
  
  #define INIT_NAMES_ALLOC_NUM    8
  
  typedef struct {
    NameEntry* e;
    int        num;
    int        alloc;
  } NameTable;
  
  #ifdef ONIG_DEBUG
  extern int
  onig_print_names(FILE* fp, regex_t* reg)
  {
    int i, j;
    NameEntry* e;
    NameTable* t = (NameTable* )reg->name_table;
  
    if (IS_NOT_NULL(t) && t->num > 0) {
      fprintf(fp, "name table\n");
      for (i = 0; i < t->num; i++) {
        e = &(t->e[i]);
        fprintf(fp, "%s: ", e->name);
        if (e->back_num == 0) {
          fputs("-", fp);
        }
        else if (e->back_num == 1) {
          fprintf(fp, "%d", e->back_ref1);
        }
        else {
          for (j = 0; j < e->back_num; j++) {
            if (j > 0) fprintf(fp, ", ");
            fprintf(fp, "%d", e->back_refs[j]);
          }
        }
        fputs("\n", fp);
      }
      fputs("\n", fp);
    }
    return 0;
  }
  #endif
  
  static int
  names_clear(regex_t* reg)
  {
    int i;
    NameEntry* e;
    NameTable* t = (NameTable* )reg->name_table;
  
    if (IS_NOT_NULL(t)) {
      for (i = 0; i < t->num; i++) {
        e = &(t->e[i]);
        if (IS_NOT_NULL(e->name)) {
          xfree(e->name);
          e->name       = NULL;
          e->name_len   = 0;
          e->back_num   = 0;
          e->back_alloc = 0;
          if (IS_NOT_NULL(e->back_refs)) xfree(e->back_refs);
          e->back_refs = (int* )NULL;
        }
      }
      if (IS_NOT_NULL(t->e)) {
        xfree(t->e);
        t->e = NULL;
      }
      t->num = 0;
    }
    return 0;
  }
  
  extern int
  onig_names_free(regex_t* reg)
  {
    int r;
    NameTable* t;
  
    r = names_clear(reg);
    if (r != 0) return r;
  
    t = (NameTable* )reg->name_table;
    if (IS_NOT_NULL(t)) xfree(t);
    reg->name_table = NULL;
    return 0;
  }
  
  static NameEntry*
  name_find(regex_t* reg, UChar* name, UChar* name_end)
  {
    int i, len;
    NameEntry* e;
    NameTable* t = (NameTable* )reg->name_table;
  
    if (IS_NOT_NULL(t)) {
      len = name_end - name;
      for (i = 0; i < t->num; i++) {
        e = &(t->e[i]);
        if (len == e->name_len && onig_strncmp(name, e->name, len) == 0)
          return e;
      }
    }
    return (NameEntry* )NULL;
  }
  
  extern int
  onig_foreach_name(regex_t* reg,
    int (*func)(const UChar*, const UChar*,int,int*,regex_t*,void*), void* arg)
  {
    int i, r;
    NameEntry* e;
    NameTable* t = (NameTable* )reg->name_table;
  
    if (IS_NOT_NULL(t)) {
      for (i = 0; i < t->num; i++) {
        e = &(t->e[i]);
        r = (*func)(e->name, e->name + e->name_len, e->back_num,
                    (e->back_num > 1 ? e->back_refs : &(e->back_ref1)),
                    reg, arg);
        if (r != 0) return r;
      }
    }
    return 0;
  }
  
  extern int
  onig_number_of_names(regex_t* reg)
  {
    NameTable* t = (NameTable* )reg->name_table;
  
    if (IS_NOT_NULL(t))
      return t->num;
    else
      return 0;
  }
  
  #endif /* else USE_ST_LIBRARY */
  
  static int
  name_add(regex_t* reg, UChar* name, UChar* name_end, int backref, ScanEnv* env)
  {
    int r;
    int alloc;
    NameEntry* e;
    NameTable* t = (NameTable* )reg->name_table;
  
    if (name_end - name <= 0)
      return ONIGERR_EMPTY_GROUP_NAME;
  
    e = name_find(reg, name, name_end);
    if (IS_NULL(e)) {
  #ifdef USE_ST_LIBRARY
      if (IS_NULL(t)) {
        t = onig_st_init_strend_table_with_size(5);
        reg->name_table = (void* )t;
      }
      e = (NameEntry* )xmalloc(sizeof(NameEntry));
      CHECK_NULL_RETURN_MEMERR(e);
  
      e->name = strdup_with_null(reg->enc, name, name_end);
      if (IS_NULL(e->name)) {
        xfree(e);  return ONIGERR_MEMORY;
      }
      r = onig_st_insert_strend(t, e->name, (e->name + (name_end - name)),
                                (HashDataType )e);
      if (r < 0) return r;
  
      e->name_len   = (int)(name_end - name);
      e->back_num   = 0;
      e->back_alloc = 0;
      e->back_refs  = (int* )NULL;
  
  #else
  
      if (IS_NULL(t)) {
        alloc = INIT_NAMES_ALLOC_NUM;
        t = (NameTable* )xmalloc(sizeof(NameTable));
        CHECK_NULL_RETURN_MEMERR(t);
        t->e     = NULL;
        t->alloc = 0;
        t->num   = 0;
  
        t->e = (NameEntry* )xmalloc(sizeof(NameEntry) * alloc);
        if (IS_NULL(t->e)) {
          xfree(t);
          return ONIGERR_MEMORY;
        }
        t->alloc = alloc;
        reg->name_table = t;
        goto clear;
      }
      else if (t->num == t->alloc) {
        int i;
  
        alloc = t->alloc * 2;
        t->e = (NameEntry* )xrealloc(t->e, sizeof(NameEntry) * alloc);
        CHECK_NULL_RETURN_MEMERR(t->e);
        t->alloc = alloc;
  
      clear:
        for (i = t->num; i < t->alloc; i++) {
          t->e[i].name       = NULL;
          t->e[i].name_len   = 0;
          t->e[i].back_num   = 0;
          t->e[i].back_alloc = 0;
          t->e[i].back_refs  = (int* )NULL;
        }
      }
      e = &(t->e[t->num]);
      t->num++;
      e->name = strdup_with_null(reg->enc, name, name_end);
      if (IS_NULL(e->name)) return ONIGERR_MEMORY;
      e->name_len = name_end - name;
  #endif
    }
  
    if (e->back_num >= 1 &&
        ! IS_SYNTAX_BV(env->syntax, ONIG_SYN_ALLOW_MULTIPLEX_DEFINITION_NAME)) {
      onig_scan_env_set_error_string(env, ONIGERR_MULTIPLEX_DEFINED_NAME,
                                     name, name_end);
      return ONIGERR_MULTIPLEX_DEFINED_NAME;
    }
  
    e->back_num++;
    if (e->back_num == 1) {
      e->back_ref1 = backref;
    }
    else {
      if (e->back_num == 2) {
        alloc = INIT_NAME_BACKREFS_ALLOC_NUM;
        e->back_refs = (int* )xmalloc(sizeof(int) * alloc);
        CHECK_NULL_RETURN_MEMERR(e->back_refs);
        e->back_alloc = alloc;
        e->back_refs[0] = e->back_ref1;
        e->back_refs[1] = backref;
      }
      else {
        if (e->back_num > e->back_alloc) {
          alloc = e->back_alloc * 2;
          e->back_refs = (int* )xrealloc(e->back_refs, sizeof(int) * alloc);
          CHECK_NULL_RETURN_MEMERR(e->back_refs);
          e->back_alloc = alloc;
        }
        e->back_refs[e->back_num - 1] = backref;
      }
    }
  
    return 0;
  }
  
  extern int
  onig_name_to_group_numbers(regex_t* reg, const UChar* name,
  			   const UChar* name_end, int** nums)
  {
    NameEntry* e = name_find(reg, name, name_end);
  
    if (IS_NULL(e)) return ONIGERR_UNDEFINED_NAME_REFERENCE;
  
    switch (e->back_num) {
    case 0:
      break;
    case 1:
      *nums = &(e->back_ref1);
      break;
    default:
      *nums = e->back_refs;
      break;
    }
    return e->back_num;
  }
  
  extern int
  onig_name_to_backref_number(regex_t* reg, const UChar* name,
  			    const UChar* name_end, OnigRegion *region)
  {
    int i, n, *nums;
  
    n = onig_name_to_group_numbers(reg, name, name_end, &nums);
    if (n < 0)
      return n;
    else if (n == 0)
      return ONIGERR_PARSER_BUG;
    else if (n == 1)
      return nums[0];
    else {
      if (IS_NOT_NULL(region)) {
        for (i = n - 1; i >= 0; i--) {
          if (region->beg[nums[i]] != ONIG_REGION_NOTPOS)
            return nums[i];
        }
      }
      return nums[n - 1];
    }
  }
  
  extern int
  onig_noname_group_capture_is_active(regex_t* reg)
  {
    if (ONIG_IS_OPTION_ON(reg->options, ONIG_OPTION_DONT_CAPTURE_GROUP))
      return 0;
  
    if (onig_number_of_names(reg) > 0 &&
        IS_SYNTAX_BV(reg->syntax, ONIG_SYN_CAPTURE_ONLY_NAMED_GROUP) &&
        !ONIG_IS_OPTION_ON(reg->options, ONIG_OPTION_CAPTURE_GROUP)) {
      return 0;
    }
  
    return 1;
  }
  
  
  #define INIT_SCANENV_MEMENV_ALLOC_SIZE   16
  
  static void
  scan_env_clear(ScanEnv* env)
  {
    MEM_STATUS_CLEAR(env->capture_history);
    MEM_STATUS_CLEAR(env->bt_mem_start);
    MEM_STATUS_CLEAR(env->bt_mem_end);
    MEM_STATUS_CLEAR(env->backrefed_mem);
    env->error      = (UChar* )NULL;
    env->error_end  = (UChar* )NULL;
    env->num_call   = 0;
  
  #ifdef USE_CALL
    env->unset_addr_list = NULL;
    env->has_call_zero   = 0;
  #endif
  
    env->num_mem    = 0;
    env->num_named  = 0;
    env->mem_alloc  = 0;
    env->mem_env_dynamic = (MemEnv* )NULL;
  
    xmemset(env->mem_env_static, 0, sizeof(env->mem_env_static));
  
  #ifdef USE_COMBINATION_EXPLOSION_CHECK
    env->num_comb_exp_check  = 0;
    env->comb_exp_max_regnum = 0;
    env->curr_max_regnum     = 0;
    env->has_recursion       = 0;
  #endif
    env->parse_depth         = 0;
    env->keep_num            = 0;
    env->save_num            = 0;
    env->save_alloc_num      = 0;
    env->saves               = 0;
  }
  
  static int
  scan_env_add_mem_entry(ScanEnv* env)
  {
    int i, need, alloc;
    MemEnv* p;
  
    need = env->num_mem + 1;
    if (need > MaxCaptureNum && MaxCaptureNum != 0)
      return ONIGERR_TOO_MANY_CAPTURES;
  
    if (need >= SCANENV_MEMENV_SIZE) {
      if (env->mem_alloc <= need) {
        if (IS_NULL(env->mem_env_dynamic)) {
          alloc = INIT_SCANENV_MEMENV_ALLOC_SIZE;
          p = (MemEnv* )xmalloc(sizeof(MemEnv) * alloc);
          CHECK_NULL_RETURN_MEMERR(p);
          xmemcpy(p, env->mem_env_static, sizeof(env->mem_env_static));
        }
        else {
          alloc = env->mem_alloc * 2;
          p = (MemEnv* )xrealloc(env->mem_env_dynamic, sizeof(MemEnv) * alloc);
          CHECK_NULL_RETURN_MEMERR(p);
        }
  
        for (i = env->num_mem + 1; i < alloc; i++) {
          p[i].node = NULL_NODE;
  #if 0
          p[i].in   = 0;
          p[i].recursion = 0;
  #endif
        }
  
        env->mem_env_dynamic = p;
        env->mem_alloc = alloc;
      }
    }
  
    env->num_mem++;
    return env->num_mem;
  }
  
  static int
  scan_env_set_mem_node(ScanEnv* env, int num, Node* node)
  {
    if (env->num_mem >= num)
      SCANENV_MEMENV(env)[num].node = node;
    else
      return ONIGERR_PARSER_BUG;
    return 0;
  }
  
  extern void
  onig_node_free(Node* node)
  {
   start:
    if (IS_NULL(node)) return ;
  
  #ifdef DEBUG_NODE_FREE
    fprintf(stderr, "onig_node_free: %p\n", node);
  #endif
  
    switch (NODE_TYPE(node)) {
    case NODE_STRING:
      if (STR_(node)->capa != 0 &&
          IS_NOT_NULL(STR_(node)->s) && STR_(node)->s != STR_(node)->buf) {
        xfree(STR_(node)->s);
      }
      break;
  
    case NODE_LIST:
    case NODE_ALT:
      onig_node_free(NODE_CAR(node));
      {
        Node* next_node = NODE_CDR(node);
  
        xfree(node);
        node = next_node;
        goto start;
      }
      break;
  
    case NODE_CCLASS:
      {
        CClassNode* cc = CCLASS_(node);
  
        if (cc->mbuf)
          bbuf_free(cc->mbuf);
      }
      break;
  
    case NODE_BACKREF:
      if (IS_NOT_NULL(BACKREF_(node)->back_dynamic))
        xfree(BACKREF_(node)->back_dynamic);
      break;
  
    case NODE_ENCLOSURE:
      if (NODE_BODY(node))
        onig_node_free(NODE_BODY(node));
  
      {
        EnclosureNode* en = ENCLOSURE_(node);
        if (en->type == ENCLOSURE_IF_ELSE) {
          onig_node_free(en->te.Then);
          onig_node_free(en->te.Else);
        }
      }
      break;
  
    case NODE_QUANT:
    case NODE_ANCHOR:
      if (NODE_BODY(node))
        onig_node_free(NODE_BODY(node));
      break;
  
    case NODE_CTYPE:
    case NODE_CALL:
    case NODE_GIMMICK:
      break;
    }
  
    xfree(node);
  }
  
  static void
  cons_node_free_alone(Node* node)
  {
    NODE_CAR(node) = 0;
    NODE_CDR(node) = 0;
    onig_node_free(node);
  }
  
  extern void
  list_node_free_not_car(Node* node)
  {
    Node* next_node;
  
   start:
    if (IS_NULL(node)) return;
  
    next_node = NODE_CDR(node);
    xfree(node);
    node = next_node;
    goto start;
  }
  
  static Node*
  node_new(void)
  {
    Node* node;
  
    node = (Node* )xmalloc(sizeof(Node));
    xmemset(node, 0, sizeof(*node));
  
  #ifdef DEBUG_NODE_FREE
    fprintf(stderr, "node_new: %p\n", node);
  #endif
    return node;
  }
  
  
  static void
  initialize_cclass(CClassNode* cc)
  {
    BITSET_CLEAR(cc->bs);
    cc->flags = 0;
    cc->mbuf  = NULL;
  }
  
  static Node*
  node_new_cclass(void)
  {
    Node* node = node_new();
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_CCLASS);
    initialize_cclass(CCLASS_(node));
    return node;
  }
  
  static Node*
  node_new_ctype(int type, int not, OnigOptionType options)
  {
    Node* node = node_new();
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_CTYPE);
    CTYPE_(node)->ctype   = type;
    CTYPE_(node)->not     = not;
    CTYPE_(node)->options = options;
    CTYPE_(node)->ascii_mode = IS_ASCII_MODE_CTYPE_OPTION(type, options);
    return node;
  }
  
  static Node*
  node_new_anychar(void)
  {
    Node* node = node_new_ctype(CTYPE_ANYCHAR, 0, ONIG_OPTION_NONE);
    return node;
  }
  
  static Node*
  node_new_anychar_with_fixed_option(OnigOptionType option)
  {
    CtypeNode* ct;
    Node* node;
  
    node = node_new_anychar();
    ct = CTYPE_(node);
    ct->options = option;
    NODE_STATUS_ADD(node, NST_FIXED_OPTION);
    return node;
  }
  
  static int
  node_new_no_newline(Node** node, ScanEnv* env)
  {
    Node* n;
  
    n = node_new_anychar_with_fixed_option(ONIG_OPTION_NONE);
    CHECK_NULL_RETURN_MEMERR(n);
    *node = n;
    return 0;
  }
  
  static int
  node_new_true_anychar(Node** node, ScanEnv* env)
  {
    Node* n;
  
    n = node_new_anychar_with_fixed_option(ONIG_OPTION_MULTILINE);
    CHECK_NULL_RETURN_MEMERR(n);
    *node = n;
    return 0;
  }
  
  static Node*
  node_new_list(Node* left, Node* right)
  {
    Node* node = node_new();
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_LIST);
    NODE_CAR(node)  = left;
    NODE_CDR(node) = right;
    return node;
  }
  
  extern Node*
  onig_node_new_list(Node* left, Node* right)
  {
    return node_new_list(left, right);
  }
  
  extern Node*
  onig_node_list_add(Node* list, Node* x)
  {
    Node *n;
  
    n = onig_node_new_list(x, NULL);
    if (IS_NULL(n)) return NULL_NODE;
  
    if (IS_NOT_NULL(list)) {
      while (IS_NOT_NULL(NODE_CDR(list)))
        list = NODE_CDR(list);
  
      NODE_CDR(list) = n;
    }
  
    return n;
  }
  
  extern Node*
  onig_node_new_alt(Node* left, Node* right)
  {
    Node* node = node_new();
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_ALT);
    NODE_CAR(node)  = left;
    NODE_CDR(node) = right;
    return node;
  }
  
  static Node*
  make_list_or_alt(NodeType type, int n, Node* ns[])
  {
    Node* r;
  
    if (n <= 0) return NULL_NODE;
  
    if (n == 1) {
      r = node_new();
      CHECK_NULL_RETURN(r);
      NODE_SET_TYPE(r, type);
      NODE_CAR(r) = ns[0];
      NODE_CDR(r) = NULL_NODE;
    }
    else {
      Node* right;
  
      r = node_new();
      CHECK_NULL_RETURN(r);
  
      right = make_list_or_alt(type, n - 1, ns + 1);
      if (IS_NULL(right)) {
        onig_node_free(r);
        return NULL_NODE;
      }
  
      NODE_SET_TYPE(r, type);
      NODE_CAR(r) = ns[0];
      NODE_CDR(r) = right;
    }
  
    return r;
  }
  
  static Node*
  make_list(int n, Node* ns[])
  {
    return make_list_or_alt(NODE_LIST, n, ns);
  }
  
  static Node*
  make_alt(int n, Node* ns[])
  {
    return make_list_or_alt(NODE_ALT, n, ns);
  }
  
  extern Node*
  onig_node_new_anchor(int type, int ascii_mode)
  {
    Node* node = node_new();
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_ANCHOR);
    ANCHOR_(node)->type       = type;
    ANCHOR_(node)->char_len   = -1;
    ANCHOR_(node)->ascii_mode = ascii_mode;
    return node;
  }
  
  static Node*
  node_new_backref(int back_num, int* backrefs, int by_name,
  #ifdef USE_BACKREF_WITH_LEVEL
  		 int exist_level, int nest_level,
  #endif
  		 ScanEnv* env)
  {
    int i;
    Node* node = node_new();
  
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_BACKREF);
    BACKREF_(node)->back_num = back_num;
    BACKREF_(node)->back_dynamic = (int* )NULL;
    if (by_name != 0)
      NODE_STATUS_ADD(node, NST_BY_NAME);
  
  #ifdef USE_BACKREF_WITH_LEVEL
    if (exist_level != 0) {
      NODE_STATUS_ADD(node, NST_NEST_LEVEL);
      BACKREF_(node)->nest_level  = nest_level;
    }
  #endif
  
    for (i = 0; i < back_num; i++) {
      if (backrefs[i] <= env->num_mem &&
          IS_NULL(SCANENV_MEMENV(env)[backrefs[i]].node)) {
        NODE_STATUS_ADD(node, NST_RECURSION);   /* /...(\1).../ */
        break;
      }
    }
  
    if (back_num <= NODE_BACKREFS_SIZE) {
      for (i = 0; i < back_num; i++)
        BACKREF_(node)->back_static[i] = backrefs[i];
    }
    else {
      int* p = (int* )xmalloc(sizeof(int) * back_num);
      if (IS_NULL(p)) {
        onig_node_free(node);
        return NULL;
      }
      BACKREF_(node)->back_dynamic = p;
      for (i = 0; i < back_num; i++)
        p[i] = backrefs[i];
    }
    return node;
  }
  
  static Node*
  node_new_backref_checker(int back_num, int* backrefs, int by_name,
  #ifdef USE_BACKREF_WITH_LEVEL
  		 int exist_level, int nest_level,
  #endif
  		 ScanEnv* env)
  {
    Node* node;
  
    node = node_new_backref(back_num, backrefs, by_name,
  #ifdef USE_BACKREF_WITH_LEVEL
                            exist_level, nest_level,
  #endif
                            env);
    CHECK_NULL_RETURN(node);
  
    NODE_STATUS_ADD(node, NST_CHECKER);
    return node;
  }
  
  #ifdef USE_CALL
  static Node*
  node_new_call(UChar* name, UChar* name_end, int gnum, int by_number)
  {
    Node* node = node_new();
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_CALL);
    CALL_(node)->by_number   = by_number;
    CALL_(node)->name        = name;
    CALL_(node)->name_end    = name_end;
    CALL_(node)->group_num   = gnum;
    CALL_(node)->entry_count = 1;
    return node;
  }
  #endif
  
  static Node*
  node_new_quantifier(int lower, int upper, int by_number)
  {
    Node* node = node_new();
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_QUANT);
    QUANT_(node)->lower  = lower;
    QUANT_(node)->upper  = upper;
    QUANT_(node)->greedy = 1;
    QUANT_(node)->body_empty_info = QUANT_BODY_IS_NOT_EMPTY;
    QUANT_(node)->head_exact      = NULL_NODE;
    QUANT_(node)->next_head_exact = NULL_NODE;
    QUANT_(node)->is_refered      = 0;
    if (by_number != 0)
      NODE_STATUS_ADD(node, NST_BY_NUMBER);
  
  #ifdef USE_COMBINATION_EXPLOSION_CHECK
    QUANT_(node)->comb_exp_check_num = 0;
  #endif
  
    return node;
  }
  
  static Node*
  node_new_enclosure(enum EnclosureType type)
  {
    Node* node = node_new();
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_ENCLOSURE);
    ENCLOSURE_(node)->type = type;
  
    switch (type) {
    case ENCLOSURE_MEMORY:
      ENCLOSURE_(node)->m.regnum       =  0;
      ENCLOSURE_(node)->m.called_addr  = -1;
      ENCLOSURE_(node)->m.entry_count  =  1;
      ENCLOSURE_(node)->m.called_state =  0;
      break;
  
    case ENCLOSURE_OPTION:
      ENCLOSURE_(node)->o.options =  0;
      break;
  
    case ENCLOSURE_STOP_BACKTRACK:
      break;
  
    case ENCLOSURE_IF_ELSE:
      ENCLOSURE_(node)->te.Then = 0;
      ENCLOSURE_(node)->te.Else = 0;
      break;
    }
  
    ENCLOSURE_(node)->opt_count = 0;
    return node;
  }
  
  extern Node*
  onig_node_new_enclosure(int type)
  {
    return node_new_enclosure(type);
  }
  
  static Node*
  node_new_enclosure_if_else(Node* cond, Node* Then, Node* Else)
  {
    Node* n;
    n = node_new_enclosure(ENCLOSURE_IF_ELSE);
    CHECK_NULL_RETURN(n);
  
    NODE_BODY(n) = cond;
    ENCLOSURE_(n)->te.Then = Then;
    ENCLOSURE_(n)->te.Else = Else;
    return n;
  }
  
  static Node*
  node_new_memory(int is_named)
  {
    Node* node = node_new_enclosure(ENCLOSURE_MEMORY);
    CHECK_NULL_RETURN(node);
    if (is_named != 0)
      NODE_STATUS_ADD(node, NST_NAMED_GROUP);
  
    return node;
  }
  
  static Node*
  node_new_option(OnigOptionType option)
  {
    Node* node = node_new_enclosure(ENCLOSURE_OPTION);
    CHECK_NULL_RETURN(node);
    ENCLOSURE_(node)->o.options = option;
    return node;
  }
  
  static int
  node_new_fail(Node** node, ScanEnv* env)
  {
    *node = node_new();
    CHECK_NULL_RETURN_MEMERR(*node);
  
    NODE_SET_TYPE(*node, NODE_GIMMICK);
    GIMMICK_(*node)->type = GIMMICK_FAIL;
    return ONIG_NORMAL;
  }
  
  static int
  node_new_save_gimmick(Node** node, enum SaveType save_type, ScanEnv* env)
  {
    int id;
    int r;
  
    r = save_entry(env, save_type, &id);
    if (r != ONIG_NORMAL) return r;
  
    *node = node_new();
    CHECK_NULL_RETURN_MEMERR(*node);
  
    NODE_SET_TYPE(*node, NODE_GIMMICK);
    GIMMICK_(*node)->id   = id;
    GIMMICK_(*node)->type = GIMMICK_SAVE;
    GIMMICK_(*node)->detail_type = (int )save_type;
  
    return ONIG_NORMAL;
  }
  
  static int
  node_new_update_var_gimmick(Node** node, enum UpdateVarType update_var_type,
                              int id, ScanEnv* env)
  {
    *node = node_new();
    CHECK_NULL_RETURN_MEMERR(*node);
  
    NODE_SET_TYPE(*node, NODE_GIMMICK);
    GIMMICK_(*node)->id   = id;
    GIMMICK_(*node)->type = GIMMICK_UPDATE_VAR;
    GIMMICK_(*node)->detail_type = (int )update_var_type;
  
    return ONIG_NORMAL;
  }
  
  static int
  node_new_keep(Node** node, ScanEnv* env)
  {
    int r;
  
    r = node_new_save_gimmick(node, SAVE_KEEP, env);
    if (r != 0) return r;
  
    env->keep_num++;
    return ONIG_NORMAL;
  }
  
  static int
  make_extended_grapheme_cluster(Node** node, ScanEnv* env)
  {
    int r;
    int i;
    Node* x;
    Node* ns[2];
  
    /* \X == (?>\O(?:\Y\O)*) */
  
    ns[1] = NULL_NODE;
  
    r = ONIGERR_MEMORY;
    ns[0] = onig_node_new_anchor(ANCHOR_NO_EXTENDED_GRAPHEME_CLUSTER_BOUNDARY, 0);
    if (IS_NULL(ns[0])) goto err;
  
    r = node_new_true_anychar(&ns[1], env);
    if (r != 0) goto err1;
  
    x = make_list(2, ns);
    if (IS_NULL(x)) goto err;
    ns[0] = x;
    ns[1] = NULL_NODE;
  
    x = node_new_quantifier(0, REPEAT_INFINITE, 1);
    if (IS_NULL(x)) goto err;
  
    NODE_BODY(x) = ns[0];
    ns[0] = NULL_NODE;
    ns[1] = x;
  
    r = node_new_true_anychar(&ns[0], env);
    if (r != 0) goto err1;
  
    x = make_list(2, ns);
    if (IS_NULL(x)) goto err;
  
    ns[0] = x;
    ns[1] = NULL_NODE;
  
    x = node_new_enclosure(ENCLOSURE_STOP_BACKTRACK);
    if (IS_NULL(x)) goto err;
  
    NODE_BODY(x) = ns[0];
  
    *node = x;
    return ONIG_NORMAL;
  
   err:
    r = ONIGERR_MEMORY;
   err1:
    for (i = 0; i < 2; i++) onig_node_free(ns[i]);
    return r;
  }
  
  static int
  make_absent_engine(Node** node, int pre_save_right_id, Node* absent,
                     Node* step_one, int lower, int upper, int possessive,
                     int is_range_cutter, ScanEnv* env)
  {
    int r;
    int i;
    int id;
    Node* x;
    Node* ns[4];
  
    for (i = 0; i < 4; i++) ns[i] = NULL_NODE;
  
    ns[1] = absent;
    ns[3] = step_one; // for err
    r = node_new_save_gimmick(&ns[0], SAVE_S, env);
    if (r != 0) goto err;
  
    id = GIMMICK_(ns[0])->id;
    r = node_new_update_var_gimmick(&ns[2], UPDATE_VAR_RIGHT_RANGE_FROM_S_STACK,
                                    id, env);
    if (r != 0) goto err;
  
    r = node_new_fail(&ns[3], env);
    if (r != 0) goto err;
  
    x = make_list(4, ns);
    if (IS_NULL(x)) goto err0;
  
    ns[0] = x;
    ns[1] = step_one;
    ns[2] = ns[3] = NULL_NODE;
  
    x = make_alt(2, ns);
    if (IS_NULL(x)) goto err0;
  
    ns[0] = x;
  
    x = node_new_quantifier(lower, upper, 0);
    if (IS_NULL(x)) goto err0;
  
    NODE_BODY(x) = ns[0];
    ns[0] = x;
  
    if (possessive != 0) {
      x = node_new_enclosure(ENCLOSURE_STOP_BACKTRACK);
      if (IS_NULL(x)) goto err0;
  
      NODE_BODY(x) = ns[0];
      ns[0] = x;
    }
  
    r = node_new_update_var_gimmick(&ns[1], UPDATE_VAR_RIGHT_RANGE_FROM_STACK,
                                    pre_save_right_id, env);
    if (r != 0) goto err;
  
    r = node_new_fail(&ns[2], env);
    if (r != 0) goto err;
  
    x = make_list(2, ns + 1);
    if (IS_NULL(x)) goto err0;
  
    ns[1] = x; ns[2] = NULL_NODE;
  
    x = make_alt(2, ns);
    if (IS_NULL(x)) goto err0;
  
    if (is_range_cutter != 0)
      NODE_STATUS_ADD(x, NST_SUPER);
  
    *node = x;
    return ONIG_NORMAL;
  
   err0:
    r = ONIGERR_MEMORY;
   err:
    for (i = 0; i < 4; i++) onig_node_free(ns[i]);
    return r;
  }
  
  static int
  make_absent_tail(Node** node1, Node** node2, int pre_save_right_id,
                   ScanEnv* env)
  {
    int r;
    int id;
    Node* save;
    Node* x;
    Node* ns[2];
  
    *node1 = *node2 = NULL_NODE;
    save = ns[0] = ns[1] = NULL_NODE;
  
    r = node_new_save_gimmick(&save, SAVE_RIGHT_RANGE, env);
    if (r != 0) goto err;
  
    id = GIMMICK_(save)->id;
    r = node_new_update_var_gimmick(&ns[0], UPDATE_VAR_RIGHT_RANGE_FROM_STACK,
                                    id, env);
    if (r != 0) goto err;
  
    r = node_new_fail(&ns[1], env);
    if (r != 0) goto err;
  
    x = make_list(2, ns);
    if (IS_NULL(x)) goto err0;
  
    ns[0] = NULL_NODE; ns[1] = x;
  
    r = node_new_update_var_gimmick(&ns[0], UPDATE_VAR_RIGHT_RANGE_FROM_STACK,
                                    pre_save_right_id, env);
    if (r != 0) goto err;
  
    x = make_alt(2, ns);
    if (IS_NULL(x)) goto err0;
  
    *node1 = save;
    *node2 = x;
    return ONIG_NORMAL;
  
   err0:
    r = ONIGERR_MEMORY;
   err:
    onig_node_free(save);
    onig_node_free(ns[0]);
    onig_node_free(ns[1]);
    return r;
  }
  
  static int
  make_range_clear(Node** node, ScanEnv* env)
  {
    int r;
    int id;
    Node* save;
    Node* x;
    Node* ns[2];
  
    *node = NULL_NODE;
    save = ns[0] = ns[1] = NULL_NODE;
  
    r = node_new_save_gimmick(&save, SAVE_RIGHT_RANGE, env);
    if (r != 0) goto err;
  
    id = GIMMICK_(save)->id;
    r = node_new_update_var_gimmick(&ns[0], UPDATE_VAR_RIGHT_RANGE_FROM_STACK,
                                    id, env);
    if (r != 0) goto err;
  
    r = node_new_fail(&ns[1], env);
    if (r != 0) goto err;
  
    x = make_list(2, ns);
    if (IS_NULL(x)) goto err0;
  
    ns[0] = NULL_NODE; ns[1] = x;
  
    r = node_new_update_var_gimmick(&ns[0], UPDATE_VAR_RIGHT_RANGE_INIT, 0, env);
    if (r != 0) goto err;
  
    x = make_alt(2, ns);
    if (IS_NULL(x)) goto err0;
  
    NODE_STATUS_ADD(x, NST_SUPER);
  
    ns[0] = save;
    ns[1] = x;
    save = NULL_NODE;
    x = make_list(2, ns);
    if (IS_NULL(x)) goto err0;
  
    *node = x;
    return ONIG_NORMAL;
  
   err0:
    r = ONIGERR_MEMORY;
   err:
    onig_node_free(save);
    onig_node_free(ns[0]);
    onig_node_free(ns[1]);
    return r;
  }
  
  static int
  is_simple_one_char_repeat(Node* node, Node** rquant, Node** rbody,
                            int* is_possessive, ScanEnv* env)
  {
    Node* quant;
    Node* body;
  
    *rquant = *rbody = 0;
    *is_possessive = 0;
  
    if (NODE_TYPE(node) == NODE_QUANT) {
      quant = node;
    }
    else {
      if (NODE_TYPE(node) == NODE_ENCLOSURE) {
        EnclosureNode* en = ENCLOSURE_(node);
        if (en->type == ENCLOSURE_STOP_BACKTRACK) {
          *is_possessive = 1;
          quant = NODE_ENCLOSURE_BODY(en);
          if (NODE_TYPE(quant) != NODE_QUANT)
            return 0;
        }
        else
          return 0;
      }
      else
        return 0;
    }
  
    if (QUANT_(quant)->greedy == 0)
      return 0;
  
    body = NODE_BODY(quant);
    switch (NODE_TYPE(body)) {
    case NODE_STRING:
      {
        int len;
        StrNode* sn = STR_(body);
        UChar *s = sn->s;
  
        len = 0;
        while (s < sn->end) {
          s += enclen(env->enc, s);
          len++;
        }
        if (len != 1)
          return 0;
      }
  
    case NODE_CCLASS:
      break;
  
    default:
      return 0;
      break;
    }
  
    if (node != quant) {
      NODE_BODY(node) = 0;
      onig_node_free(node);
    }
    NODE_BODY(quant) = NULL_NODE;
    *rquant = quant;
    *rbody  = body;
    return 1;
  }
  
  static int
  make_absent_tree_for_simple_one_char_repeat(Node** node, Node* absent, Node* quant,
                                              Node* body, int possessive, ScanEnv* env)
  {
    int r;
    int i;
    int id1;
    int lower, upper;
    Node* x;
    Node* ns[4];
  
    *node = NULL_NODE;
    r = ONIGERR_MEMORY;
    ns[0] = ns[1] = NULL_NODE;
    ns[2] = body;
    ns[3] = absent;
  
    lower = QUANT_(quant)->lower;
    upper = QUANT_(quant)->upper;
    onig_node_free(quant);
  
    r = node_new_save_gimmick(&ns[0], SAVE_RIGHT_RANGE, env);
    if (r != 0) goto err;
  
    id1 = GIMMICK_(ns[0])->id;
  
    r = make_absent_engine(&ns[1], id1, absent, body, lower, upper, possessive,
                           0, env);
    if (r != 0) goto err;
  
    ns[2] = ns[3] = NULL_NODE;
  
    r = node_new_update_var_gimmick(&ns[2], UPDATE_VAR_RIGHT_RANGE_FROM_STACK,
                                    id1, env);
    if (r != 0) goto err;
  
    x = make_list(3, ns);
    if (IS_NULL(x)) goto err0;
  
    *node = x;
    return ONIG_NORMAL;
  
   err0:
    r = ONIGERR_MEMORY;
   err:
    for (i = 0; i < 4; i++) onig_node_free(ns[i]);
    return r;
  }
  
  static int
  make_absent_tree(Node** node, Node* absent, Node* expr, int is_range_cutter,
                   ScanEnv* env)
  {
    int r;
    int i;
    int id1, id2;
    int possessive;
    Node* x;
    Node* ns[7];
  
    r = ONIGERR_MEMORY;
    for (i = 0; i < 7; i++) ns[i] = NULL_NODE;
    ns[4] = expr; ns[5] = absent;
  
    if (is_range_cutter == 0) {
      Node* quant;
      Node* body;
  
      if (expr == NULL_NODE) {
        /* default expr \O* */
        quant = node_new_quantifier(0, REPEAT_INFINITE, 0);
        if (IS_NULL(quant)) goto err0;
  
        r = node_new_true_anychar(&body, env);
        if (r != 0) {
          onig_node_free(quant);
          goto err;
        }
        possessive = 0;
        goto simple;
      }
      else {
        if (is_simple_one_char_repeat(expr, &quant, &body, &possessive, env)) {
        simple:
          r = make_absent_tree_for_simple_one_char_repeat(node, absent, quant,
                                                          body, possessive, env);
          if (r != 0) {
            ns[4] = NULL_NODE;
            onig_node_free(quant);
            onig_node_free(body);
            goto err;
          }
  
          return ONIG_NORMAL;
        }
      }
    }
  
    r = node_new_save_gimmick(&ns[0], SAVE_RIGHT_RANGE, env);
    if (r != 0) goto err;
  
    id1 = GIMMICK_(ns[0])->id;
  
    r = node_new_save_gimmick(&ns[1], SAVE_S, env);
    if (r != 0) goto err;
  
    id2 = GIMMICK_(ns[1])->id;
  
    r = node_new_true_anychar(&ns[3], env);
    if (r != 0) goto err;
  
    possessive = 1;
    r = make_absent_engine(&ns[2], id1, absent, ns[3], 0, REPEAT_INFINITE,
                           possessive, is_range_cutter, env);
    if (r != 0) goto err;
  
    ns[3] = NULL_NODE;
    ns[5] = NULL_NODE;
  
    r = node_new_update_var_gimmick(&ns[3], UPDATE_VAR_S_FROM_STACK, id2, env);
    if (r != 0) goto err;
  
    if (is_range_cutter != 0) {
      x = make_list(4, ns);
      if (IS_NULL(x)) goto err0;
    }
    else {
      r = make_absent_tail(&ns[5], &ns[6], id1, env);
      if (r != 0) goto err;
    
      x = make_list(7, ns);
      if (IS_NULL(x)) goto err0;
    }
  
    *node = x;
    return ONIG_NORMAL;
  
   err0:
    r = ONIGERR_MEMORY;
   err:
    for (i = 0; i < 7; i++) onig_node_free(ns[i]);
    return r;  
  }
  
  extern int
  onig_node_str_cat(Node* node, const UChar* s, const UChar* end)
  {
    int addlen = (int)(end - s);
  
    if (addlen > 0) {
      int len  = (int)(STR_(node)->end - STR_(node)->s);
  
      if (STR_(node)->capa > 0 || (len + addlen > NODE_STRING_BUF_SIZE - 1)) {
        UChar* p;
        int capa = len + addlen + NODE_STRING_MARGIN;
  
        if (capa <= STR_(node)->capa) {
          onig_strcpy(STR_(node)->s + len, s, end);
        }
        else {
          if (STR_(node)->s == STR_(node)->buf)
            p = strcat_capa_from_static(STR_(node)->s, STR_(node)->end,
                                        s, end, capa);
          else
            p = strcat_capa(STR_(node)->s, STR_(node)->end, s, end, capa);
  
          CHECK_NULL_RETURN_MEMERR(p);
          STR_(node)->s    = p;
          STR_(node)->capa = capa;
        }
      }
      else {
        onig_strcpy(STR_(node)->s + len, s, end);
      }
      STR_(node)->end = STR_(node)->s + len + addlen;
    }
  
    return 0;
  }
  
  extern int
  onig_node_str_set(Node* node, const UChar* s, const UChar* end)
  {
    onig_node_str_clear(node);
    return onig_node_str_cat(node, s, end);
  }
  
  static int
  node_str_cat_char(Node* node, UChar c)
  {
    UChar s[1];
  
    s[0] = c;
    return onig_node_str_cat(node, s, s + 1);
  }
  
  extern void
  onig_node_conv_to_str_node(Node* node, int flag)
  {
    NODE_SET_TYPE(node, NODE_STRING);
    STR_(node)->flag = flag;
    STR_(node)->capa = 0;
    STR_(node)->s    = STR_(node)->buf;
    STR_(node)->end  = STR_(node)->buf;
  }
  
  extern void
  onig_node_str_clear(Node* node)
  {
    if (STR_(node)->capa != 0 &&
        IS_NOT_NULL(STR_(node)->s) && STR_(node)->s != STR_(node)->buf) {
      xfree(STR_(node)->s);
    }
  
    STR_(node)->capa = 0;
    STR_(node)->flag = 0;
    STR_(node)->s    = STR_(node)->buf;
    STR_(node)->end  = STR_(node)->buf;
  }
  
  static Node*
  node_new_str(const UChar* s, const UChar* end)
  {
    Node* node = node_new();
    CHECK_NULL_RETURN(node);
  
    NODE_SET_TYPE(node, NODE_STRING);
    STR_(node)->capa = 0;
    STR_(node)->flag = 0;
    STR_(node)->s    = STR_(node)->buf;
    STR_(node)->end  = STR_(node)->buf;
    if (onig_node_str_cat(node, s, end)) {
      onig_node_free(node);
      return NULL;
    }
    return node;
  }
  
  extern Node*
  onig_node_new_str(const UChar* s, const UChar* end)
  {
    return node_new_str(s, end);
  }
  
  static Node*
  node_new_str_raw(UChar* s, UChar* end)
  {
    Node* node = node_new_str(s, end);
    NODE_STRING_SET_RAW(node);
    return node;
  }
  
  static Node*
  node_new_empty(void)
  {
    return node_new_str(NULL, NULL);
  }
  
  static Node*
  node_new_str_raw_char(UChar c)
  {
    UChar p[1];
  
    p[0] = c;
    return node_new_str_raw(p, p + 1);
  }
  
  static Node*
  str_node_split_last_char(StrNode* sn, OnigEncoding enc)
  {
    const UChar *p;
    Node* n = NULL_NODE;
  
    if (sn->end > sn->s) {
      p = onigenc_get_prev_char_head(enc, sn->s, sn->end);
      if (p && p > sn->s) { /* can be split. */
        n = node_new_str(p, sn->end);
        if ((sn->flag & STRING_RAW) != 0)
          NODE_STRING_SET_RAW(n);
  
        sn->end = (UChar* )p;
      }
    }
    return n;
  }
  
  static int
  str_node_can_be_split(StrNode* sn, OnigEncoding enc)
  {
    if (sn->end > sn->s) {
      return ((enclen(enc, sn->s) < sn->end - sn->s)  ?  1 : 0);
    }
    return 0;
  }
  
  #ifdef USE_PAD_TO_SHORT_BYTE_CHAR
  static int
  node_str_head_pad(StrNode* sn, int num, UChar val)
  {
    UChar buf[NODE_STRING_BUF_SIZE];
    int i, len;
  
    len = sn->end - sn->s;
    onig_strcpy(buf, sn->s, sn->end);
    onig_strcpy(&(sn->s[num]), buf, buf + len);
    sn->end += num;
  
    for (i = 0; i < num; i++) {
      sn->s[i] = val;
    }
  }
  #endif
  
  extern int
  onig_scan_unsigned_number(UChar** src, const UChar* end, OnigEncoding enc)
  {
    unsigned int num, val;
    OnigCodePoint c;
    UChar* p = *src;
    PFETCH_READY;
  
    num = 0;
    while (! PEND) {
      PFETCH(c);
      if (IS_CODE_DIGIT_ASCII(enc, c)) {
        val = (unsigned int )DIGITVAL(c);
        if ((INT_MAX_LIMIT - val) / 10UL < num)
          return -1;  /* overflow */
  
        num = num * 10 + val;
      }
      else {
        PUNFETCH;
        break;
      }
    }
    *src = p;
    return num;
  }
  
  static int
  scan_unsigned_hexadecimal_number(UChar** src, UChar* end, int maxlen,
                                   OnigEncoding enc)
  {
    OnigCodePoint c;
    unsigned int num, val;
    UChar* p = *src;
    PFETCH_READY;
  
    num = 0;
    while (! PEND && maxlen-- != 0) {
      PFETCH(c);
      if (IS_CODE_XDIGIT_ASCII(enc, c)) {
        val = (unsigned int )XDIGITVAL(enc,c);
        if ((INT_MAX_LIMIT - val) / 16UL < num)
          return -1;  /* overflow */
  
        num = (num << 4) + XDIGITVAL(enc,c);
      }
      else {
        PUNFETCH;
        break;
      }
    }
    *src = p;
    return num;
  }
  
  static int
  scan_unsigned_octal_number(UChar** src, UChar* end, int maxlen,
                             OnigEncoding enc)
  {
    OnigCodePoint c;
    unsigned int num, val;
    UChar* p = *src;
    PFETCH_READY;
  
    num = 0;
    while (! PEND && maxlen-- != 0) {
      PFETCH(c);
      if (IS_CODE_DIGIT_ASCII(enc, c) && c < '8') {
        val = ODIGITVAL(c);
        if ((INT_MAX_LIMIT - val) / 8UL < num)
          return -1;  /* overflow */
  
        num = (num << 3) + val;
      }
      else {
        PUNFETCH;
        break;
      }
    }
    *src = p;
    return num;
  }
  
  
  #define BB_WRITE_CODE_POINT(bbuf,pos,code) \
      BB_WRITE(bbuf, pos, &(code), SIZE_CODE_POINT)
  
  /* data format:
       [n][from-1][to-1][from-2][to-2] ... [from-n][to-n]
       (all data size is OnigCodePoint)
   */
  static int
  new_code_range(BBuf** pbuf)
  {
  #define INIT_MULTI_BYTE_RANGE_SIZE  (SIZE_CODE_POINT * 5)
    int r;
    OnigCodePoint n;
    BBuf* bbuf;
  
    bbuf = *pbuf = (BBuf* )xmalloc(sizeof(BBuf));
    CHECK_NULL_RETURN_MEMERR(bbuf);
    r = BB_INIT(bbuf, INIT_MULTI_BYTE_RANGE_SIZE);
    if (r != 0) {
      xfree(bbuf);
      *pbuf = 0;
      return r;
    }
  
    n = 0;
    BB_WRITE_CODE_POINT(bbuf, 0, n);
    return 0;
  }
  
  static int
  add_code_range_to_buf(BBuf** pbuf, OnigCodePoint from, OnigCodePoint to)
  {
    int r, inc_n, pos;
    int low, high, bound, x;
    OnigCodePoint n, *data;
    BBuf* bbuf;
  
    if (from > to) {
      n = from; from = to; to = n;
    }
  
    if (IS_NULL(*pbuf)) {
      r = new_code_range(pbuf);
      if (r != 0) return r;
      bbuf = *pbuf;
      n = 0;
    }
    else {
      bbuf = *pbuf;
      GET_CODE_POINT(n, bbuf->p);
    }
    data = (OnigCodePoint* )(bbuf->p);
    data++;
  
    for (low = 0, bound = n; low < bound; ) {
      x = (low + bound) >> 1;
      if (from > data[x*2 + 1])
        low = x + 1;
      else
        bound = x;
    }
  
    high = (to == ~((OnigCodePoint )0)) ? n : low;
    for (bound = n; high < bound; ) {
      x = (high + bound) >> 1;
      if (to + 1 >= data[x*2])
        high = x + 1;
      else
        bound = x;
    }
  
    inc_n = low + 1 - high;
    if (n + inc_n > ONIG_MAX_MULTI_BYTE_RANGES_NUM)
      return ONIGERR_TOO_MANY_MULTI_BYTE_RANGES;
  
    if (inc_n != 1) {
      if (from > data[low*2])
        from = data[low*2];
      if (to < data[(high - 1)*2 + 1])
        to = data[(high - 1)*2 + 1];
    }
  
    if (inc_n != 0 && (OnigCodePoint )high < n) {
      int from_pos = SIZE_CODE_POINT * (1 + high * 2);
      int to_pos   = SIZE_CODE_POINT * (1 + (low + 1) * 2);
      int size = (n - high) * 2 * SIZE_CODE_POINT;
  
      if (inc_n > 0) {
        BB_MOVE_RIGHT(bbuf, from_pos, to_pos, size);
      }
      else {
        BB_MOVE_LEFT_REDUCE(bbuf, from_pos, to_pos);
      }
    }
  
    pos = SIZE_CODE_POINT * (1 + low * 2);
    BB_ENSURE_SIZE(bbuf, pos + SIZE_CODE_POINT * 2);
    BB_WRITE_CODE_POINT(bbuf, pos, from);
    BB_WRITE_CODE_POINT(bbuf, pos + SIZE_CODE_POINT, to);
    n += inc_n;
    BB_WRITE_CODE_POINT(bbuf, 0, n);
  
    return 0;
  }
  
  static int
  add_code_range(BBuf** pbuf, ScanEnv* env, OnigCodePoint from, OnigCodePoint to)
  {
    if (from > to) {
      if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_ALLOW_EMPTY_RANGE_IN_CC))
        return 0;
      else
        return ONIGERR_EMPTY_RANGE_IN_CHAR_CLASS;
    }
  
    return add_code_range_to_buf(pbuf, from, to);
  }
  
  static int
  not_code_range_buf(OnigEncoding enc, BBuf* bbuf, BBuf** pbuf)
  {
    int r, i, n;
    OnigCodePoint pre, from, *data, to = 0;
  
    *pbuf = (BBuf* )NULL;
    if (IS_NULL(bbuf)) {
    set_all:
      return SET_ALL_MULTI_BYTE_RANGE(enc, pbuf);
    }
  
    data = (OnigCodePoint* )(bbuf->p);
    GET_CODE_POINT(n, data);
    data++;
    if (n <= 0) goto set_all;
  
    r = 0;
    pre = MBCODE_START_POS(enc);
    for (i = 0; i < n; i++) {
      from = data[i*2];
      to   = data[i*2+1];
      if (pre <= from - 1) {
        r = add_code_range_to_buf(pbuf, pre, from - 1);
        if (r != 0) return r;
      }
      if (to == ~((OnigCodePoint )0)) break;
      pre = to + 1;
    }
    if (to < ~((OnigCodePoint )0)) {
      r = add_code_range_to_buf(pbuf, to + 1, ~((OnigCodePoint )0));
    }
    return r;
  }
  
  #define SWAP_BB_NOT(bbuf1, not1, bbuf2, not2) do {\
    BBuf *tbuf; \
    int  tnot; \
    tnot = not1;  not1  = not2;  not2  = tnot; \
    tbuf = bbuf1; bbuf1 = bbuf2; bbuf2 = tbuf; \
  } while (0)
  
  static int
  or_code_range_buf(OnigEncoding enc, BBuf* bbuf1, int not1,
                    BBuf* bbuf2, int not2, BBuf** pbuf)
  {
    int r;
    OnigCodePoint i, n1, *data1;
    OnigCodePoint from, to;
  
    *pbuf = (BBuf* )NULL;
    if (IS_NULL(bbuf1) && IS_NULL(bbuf2)) {
      if (not1 != 0 || not2 != 0)
        return SET_ALL_MULTI_BYTE_RANGE(enc, pbuf);
      return 0;
    }
  
    r = 0;
    if (IS_NULL(bbuf2))
      SWAP_BB_NOT(bbuf1, not1, bbuf2, not2);
  
    if (IS_NULL(bbuf1)) {
      if (not1 != 0) {
        return SET_ALL_MULTI_BYTE_RANGE(enc, pbuf);
      }
      else {
        if (not2 == 0) {
          return bbuf_clone(pbuf, bbuf2);
        }
        else {
          return not_code_range_buf(enc, bbuf2, pbuf);
        }
      }
    }
  
    if (not1 != 0)
      SWAP_BB_NOT(bbuf1, not1, bbuf2, not2);
  
    data1 = (OnigCodePoint* )(bbuf1->p);
    GET_CODE_POINT(n1, data1);
    data1++;
  
    if (not2 == 0 && not1 == 0) { /* 1 OR 2 */
      r = bbuf_clone(pbuf, bbuf2);
    }
    else if (not1 == 0) { /* 1 OR (not 2) */
      r = not_code_range_buf(enc, bbuf2, pbuf);
    }
    if (r != 0) return r;
  
    for (i = 0; i < n1; i++) {
      from = data1[i*2];
      to   = data1[i*2+1];
      r = add_code_range_to_buf(pbuf, from, to);
      if (r != 0) return r;
    }
    return 0;
  }
  
  static int
  and_code_range1(BBuf** pbuf, OnigCodePoint from1, OnigCodePoint to1,
                  OnigCodePoint* data, int n)
  {
    int i, r;
    OnigCodePoint from2, to2;
  
    for (i = 0; i < n; i++) {
      from2 = data[i*2];
      to2   = data[i*2+1];
      if (from2 < from1) {
        if (to2 < from1) continue;
        else {
          from1 = to2 + 1;
        }
      }
      else if (from2 <= to1) {
        if (to2 < to1) {
          if (from1 <= from2 - 1) {
            r = add_code_range_to_buf(pbuf, from1, from2-1);
            if (r != 0) return r;
          }
          from1 = to2 + 1;
        }
        else {
          to1 = from2 - 1;
        }
      }
      else {
        from1 = from2;
      }
      if (from1 > to1) break;
    }
    if (from1 <= to1) {
      r = add_code_range_to_buf(pbuf, from1, to1);
      if (r != 0) return r;
    }
    return 0;
  }
  
  static int
  and_code_range_buf(BBuf* bbuf1, int not1, BBuf* bbuf2, int not2, BBuf** pbuf)
  {
    int r;
    OnigCodePoint i, j, n1, n2, *data1, *data2;
    OnigCodePoint from, to, from1, to1, from2, to2;
  
    *pbuf = (BBuf* )NULL;
    if (IS_NULL(bbuf1)) {
      if (not1 != 0 && IS_NOT_NULL(bbuf2)) /* not1 != 0 -> not2 == 0 */
        return bbuf_clone(pbuf, bbuf2);
      return 0;
    }
    else if (IS_NULL(bbuf2)) {
      if (not2 != 0)
        return bbuf_clone(pbuf, bbuf1);
      return 0;
    }
  
    if (not1 != 0)
      SWAP_BB_NOT(bbuf1, not1, bbuf2, not2);
  
    data1 = (OnigCodePoint* )(bbuf1->p);
    data2 = (OnigCodePoint* )(bbuf2->p);
    GET_CODE_POINT(n1, data1);
    GET_CODE_POINT(n2, data2);
    data1++;
    data2++;
  
    if (not2 == 0 && not1 == 0) { /* 1 AND 2 */
      for (i = 0; i < n1; i++) {
        from1 = data1[i*2];
        to1   = data1[i*2+1];
        for (j = 0; j < n2; j++) {
          from2 = data2[j*2];
          to2   = data2[j*2+1];
          if (from2 > to1) break;
          if (to2 < from1) continue;
          from = MAX(from1, from2);
          to   = MIN(to1, to2);
          r = add_code_range_to_buf(pbuf, from, to);
          if (r != 0) return r;
        }
      }
    }
    else if (not1 == 0) { /* 1 AND (not 2) */
      for (i = 0; i < n1; i++) {
        from1 = data1[i*2];
        to1   = data1[i*2+1];
        r = and_code_range1(pbuf, from1, to1, data2, n2);
        if (r != 0) return r;
      }
    }
  
    return 0;
  }
  
  static int
  and_cclass(CClassNode* dest, CClassNode* cc, OnigEncoding enc)
  {
    int r, not1, not2;
    BBuf *buf1, *buf2, *pbuf;
    BitSetRef bsr1, bsr2;
    BitSet bs1, bs2;
  
    not1 = IS_NCCLASS_NOT(dest);
    bsr1 = dest->bs;
    buf1 = dest->mbuf;
    not2 = IS_NCCLASS_NOT(cc);
    bsr2 = cc->bs;
    buf2 = cc->mbuf;
  
    if (not1 != 0) {
      bitset_invert_to(bsr1, bs1);
      bsr1 = bs1;
    }
    if (not2 != 0) {
      bitset_invert_to(bsr2, bs2);
      bsr2 = bs2;
    }
    bitset_and(bsr1, bsr2);
    if (bsr1 != dest->bs) {
      bitset_copy(dest->bs, bsr1);
    }
    if (not1 != 0) {
      bitset_invert(dest->bs);
    }
  
    if (! ONIGENC_IS_SINGLEBYTE(enc)) {
      if (not1 != 0 && not2 != 0) {
        r = or_code_range_buf(enc, buf1, 0, buf2, 0, &pbuf);
      }
      else {
        r = and_code_range_buf(buf1, not1, buf2, not2, &pbuf);
        if (r == 0 && not1 != 0) {
          BBuf *tbuf;
          r = not_code_range_buf(enc, pbuf, &tbuf);
          if (r != 0) {
            bbuf_free(pbuf);
            return r;
          }
          bbuf_free(pbuf);
          pbuf = tbuf;
        }
      }
      if (r != 0) return r;
  
      dest->mbuf = pbuf;
      bbuf_free(buf1);
      return r;
    }
    return 0;
  }
  
  static int
  or_cclass(CClassNode* dest, CClassNode* cc, OnigEncoding enc)
  {
    int r, not1, not2;
    BBuf *buf1, *buf2, *pbuf;
    BitSetRef bsr1, bsr2;
    BitSet bs1, bs2;
  
    not1 = IS_NCCLASS_NOT(dest);
    bsr1 = dest->bs;
    buf1 = dest->mbuf;
    not2 = IS_NCCLASS_NOT(cc);
    bsr2 = cc->bs;
    buf2 = cc->mbuf;
  
    if (not1 != 0) {
      bitset_invert_to(bsr1, bs1);
      bsr1 = bs1;
    }
    if (not2 != 0) {
      bitset_invert_to(bsr2, bs2);
      bsr2 = bs2;
    }
    bitset_or(bsr1, bsr2);
    if (bsr1 != dest->bs) {
      bitset_copy(dest->bs, bsr1);
    }
    if (not1 != 0) {
      bitset_invert(dest->bs);
    }
  
    if (! ONIGENC_IS_SINGLEBYTE(enc)) {
      if (not1 != 0 && not2 != 0) {
        r = and_code_range_buf(buf1, 0, buf2, 0, &pbuf);
      }
      else {
        r = or_code_range_buf(enc, buf1, not1, buf2, not2, &pbuf);
        if (r == 0 && not1 != 0) {
          BBuf *tbuf;
          r = not_code_range_buf(enc, pbuf, &tbuf);
          if (r != 0) {
            bbuf_free(pbuf);
            return r;
          }
          bbuf_free(pbuf);
          pbuf = tbuf;
        }
      }
      if (r != 0) return r;
  
      dest->mbuf = pbuf;
      bbuf_free(buf1);
      return r;
    }
    else
      return 0;
  }
  
  static OnigCodePoint
  conv_backslash_value(OnigCodePoint c, ScanEnv* env)
  {
    if (IS_SYNTAX_OP(env->syntax, ONIG_SYN_OP_ESC_CONTROL_CHARS)) {
      switch (c) {
      case 'n': return '\n';
      case 't': return '\t';
      case 'r': return '\r';
      case 'f': return '\f';
      case 'a': return '\007';
      case 'b': return '\010';
      case 'e': return '\033';
      case 'v':
        if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_ESC_V_VTAB))
          return '\v';
        break;
  
      default:
        break;
      }
    }
    return c;
  }
  
  static int
  is_invalid_quantifier_target(Node* node)
  {
    switch (NODE_TYPE(node)) {
    case NODE_ANCHOR:
    case NODE_GIMMICK:
      return 1;
      break;
  
    case NODE_ENCLOSURE:
      /* allow enclosed elements */
      /* return is_invalid_quantifier_target(NODE_BODY(node)); */
      break;
  
    case NODE_LIST:
      do {
        if (! is_invalid_quantifier_target(NODE_CAR(node))) return 0;
      } while (IS_NOT_NULL(node = NODE_CDR(node)));
      return 0;
      break;
  
    case NODE_ALT:
      do {
        if (is_invalid_quantifier_target(NODE_CAR(node))) return 1;
      } while (IS_NOT_NULL(node = NODE_CDR(node)));
      break;
  
    default:
      break;
    }
    return 0;
  }
  
  /* ?:0, *:1, +:2, ??:3, *?:4, +?:5 */
  static int
  popular_quantifier_num(QuantNode* q)
  {
    if (q->greedy) {
      if (q->lower == 0) {
        if (q->upper == 1) return 0;
        else if (IS_REPEAT_INFINITE(q->upper)) return 1;
      }
      else if (q->lower == 1) {
        if (IS_REPEAT_INFINITE(q->upper)) return 2;
      }
    }
    else {
      if (q->lower == 0) {
        if (q->upper == 1) return 3;
        else if (IS_REPEAT_INFINITE(q->upper)) return 4;
      }
      else if (q->lower == 1) {
        if (IS_REPEAT_INFINITE(q->upper)) return 5;
      }
    }
    return -1;
  }
  
  
  enum ReduceType {
    RQ_ASIS = 0, /* as is */
    RQ_DEL  = 1, /* delete parent */
    RQ_A,        /* to '*'    */
    RQ_AQ,       /* to '*?'   */
    RQ_QQ,       /* to '??'   */
    RQ_P_QQ,     /* to '+)??' */
    RQ_PQ_Q      /* to '+?)?' */
  };
  
  static enum ReduceType ReduceTypeTable[6][6] = {
    {RQ_DEL,  RQ_A,    RQ_A,   RQ_QQ,   RQ_AQ,   RQ_ASIS}, /* '?'  */
    {RQ_DEL,  RQ_DEL,  RQ_DEL, RQ_P_QQ, RQ_P_QQ, RQ_DEL},  /* '*'  */
    {RQ_A,    RQ_A,    RQ_DEL, RQ_ASIS, RQ_P_QQ, RQ_DEL},  /* '+'  */
    {RQ_DEL,  RQ_AQ,   RQ_AQ,  RQ_DEL,  RQ_AQ,   RQ_AQ},   /* '??' */
    {RQ_DEL,  RQ_DEL,  RQ_DEL, RQ_DEL,  RQ_DEL,  RQ_DEL},  /* '*?' */
    {RQ_ASIS, RQ_PQ_Q, RQ_DEL, RQ_AQ,   RQ_AQ,   RQ_DEL}   /* '+?' */
  };
  
  extern void
  onig_reduce_nested_quantifier(Node* pnode, Node* cnode)
  {
    int pnum, cnum;
    QuantNode *p, *c;
  
    p = QUANT_(pnode);
    c = QUANT_(cnode);
    pnum = popular_quantifier_num(p);
    cnum = popular_quantifier_num(c);
    if (pnum < 0 || cnum < 0) return ;
  
    switch(ReduceTypeTable[cnum][pnum]) {
    case RQ_DEL:
      *pnode = *cnode;
      break;
    case RQ_A:
      NODE_BODY(pnode) = NODE_BODY(cnode);
      p->lower  = 0;  p->upper = REPEAT_INFINITE;  p->greedy = 1;
      break;
    case RQ_AQ:
      NODE_BODY(pnode) = NODE_BODY(cnode);
      p->lower  = 0;  p->upper = REPEAT_INFINITE;  p->greedy = 0;
      break;
    case RQ_QQ:
      NODE_BODY(pnode) = NODE_BODY(cnode);
      p->lower  = 0;  p->upper = 1;  p->greedy = 0;
      break;
    case RQ_P_QQ:
      NODE_BODY(pnode) = cnode;
      p->lower  = 0;  p->upper = 1;  p->greedy = 0;
      c->lower  = 1;  c->upper = REPEAT_INFINITE;  c->greedy = 1;
      return ;
      break;
    case RQ_PQ_Q:
      NODE_BODY(pnode) = cnode;
      p->lower  = 0;  p->upper = 1;  p->greedy = 1;
      c->lower  = 1;  c->upper = REPEAT_INFINITE;  c->greedy = 0;
      return ;
      break;
    case RQ_ASIS:
      NODE_BODY(pnode) = cnode;
      return ;
      break;
    }
  
    NODE_BODY(cnode) = NULL_NODE;
    onig_node_free(cnode);
  }
  
  static int
  node_new_general_newline(Node** node, ScanEnv* env)
  {
    int r;
    int dlen, alen;
    UChar buf[ONIGENC_CODE_TO_MBC_MAXLEN * 2];
    Node* crnl;
    Node* ncc;
    Node* x;
    CClassNode* cc;
  
    dlen = ONIGENC_CODE_TO_MBC(env->enc, 0x0d, buf);
    if (dlen < 0) return dlen;
    alen = ONIGENC_CODE_TO_MBC(env->enc, 0x0a, buf + dlen);
    if (alen < 0) return alen;
  
    crnl = node_new_str_raw(buf, buf + dlen + alen);
    CHECK_NULL_RETURN_MEMERR(crnl);
  
    ncc = node_new_cclass();
    if (IS_NULL(ncc)) goto err2;
  
    cc = CCLASS_(ncc);
    if (dlen == 1) {
      bitset_set_range(cc->bs, 0x0a, 0x0d);
    }
    else {
      r = add_code_range(&(cc->mbuf), env, 0x0a, 0x0d);
      if (r != 0) {
      err1:
        onig_node_free(ncc);
      err2:
        onig_node_free(crnl);
        return ONIGERR_MEMORY;
      }
    }
  
    if (ONIGENC_IS_UNICODE_ENCODING(env->enc)) {
      r = add_code_range(&(cc->mbuf), env, 0x85, 0x85);
      if (r != 0) goto err1;
      r = add_code_range(&(cc->mbuf), env, 0x2028, 0x2029);
      if (r != 0) goto err1;
    }
  
    x = node_new_enclosure_if_else(crnl, 0, ncc);
    if (IS_NULL(x)) goto err1;
  
    *node = x;
    return 0;
  }
  
  enum TokenSyms {
    TK_EOT      = 0,   /* end of token */
    TK_RAW_BYTE = 1,
    TK_CHAR,
    TK_STRING,
    TK_CODE_POINT,
    TK_ANYCHAR,
    TK_CHAR_TYPE,
    TK_BACKREF,
    TK_CALL,
    TK_ANCHOR,
    TK_OP_REPEAT,
    TK_INTERVAL,
    TK_ANYCHAR_ANYTIME,  /* SQL '%' == .* */
    TK_ALT,
    TK_SUBEXP_OPEN,
    TK_SUBEXP_CLOSE,
    TK_CC_OPEN,
    TK_QUOTE_OPEN,
    TK_CHAR_PROPERTY,    /* \p{...}, \P{...} */
    TK_KEEP,             /* \K */
    TK_GENERAL_NEWLINE,  /* \R */
    TK_NO_NEWLINE,       /* \N */
    TK_TRUE_ANYCHAR,     /* \O */
    TK_EXTENDED_GRAPHEME_CLUSTER, /* \X */
  
    /* in cc */
    TK_CC_CLOSE,
    TK_CC_RANGE,
    TK_POSIX_BRACKET_OPEN,
    TK_CC_AND,             /* && */
    TK_CC_CC_OPEN          /* [ */
  };
  
  typedef struct {
    enum TokenSyms type;
    int escaped;
    int base;   /* is number: 8, 16 (used in [....]) */
    UChar* backp;
    union {
      UChar* s;
      int   c;
      OnigCodePoint code;
      int   anchor;
      int   subtype;
      struct {
        int lower;
        int upper;
        int greedy;
        int possessive;
      } repeat;
      struct {
        int  num;
        int  ref1;
        int* refs;
        int  by_name;
  #ifdef USE_BACKREF_WITH_LEVEL
        int  exist_level;
        int  level;   /* \k<name+n> */
  #endif
      } backref;
      struct {
        UChar* name;
        UChar* name_end;
        int    gnum;
        int    by_number;
      } call;
      struct {
        int ctype;
        int not;
      } prop;
    } u;
  } OnigToken;
  
  
  static int
  fetch_range_quantifier(UChar** src, UChar* end, OnigToken* tok, ScanEnv* env)
  {
    int low, up, syn_allow, non_low = 0;
    int r = 0;
    OnigCodePoint c;
    OnigEncoding enc = env->enc;
    UChar* p = *src;
    PFETCH_READY;
  
    syn_allow = IS_SYNTAX_BV(env->syntax, ONIG_SYN_ALLOW_INVALID_INTERVAL);
  
    if (PEND) {
      if (syn_allow)
        return 1;  /* "....{" : OK! */
      else
        return ONIGERR_END_PATTERN_AT_LEFT_BRACE;  /* "....{" syntax error */
    }
  
    if (! syn_allow) {
      c = PPEEK;
      if (c == ')' || c == '(' || c == '|') {
        return ONIGERR_END_PATTERN_AT_LEFT_BRACE;
      }
    }
  
    low = onig_scan_unsigned_number(&p, end, env->enc);
    if (low < 0) return ONIGERR_TOO_BIG_NUMBER_FOR_REPEAT_RANGE;
    if (low > ONIG_MAX_REPEAT_NUM)
      return ONIGERR_TOO_BIG_NUMBER_FOR_REPEAT_RANGE;
  
    if (p == *src) { /* can't read low */
      if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_ALLOW_INTERVAL_LOW_ABBREV)) {
        /* allow {,n} as {0,n} */
        low = 0;
        non_low = 1;
      }
      else
        goto invalid;
    }
  
    if (PEND) goto invalid;
    PFETCH(c);
    if (c == ',') {
      UChar* prev = p;
      up = onig_scan_unsigned_number(&p, end, env->enc);
      if (up < 0) return ONIGERR_TOO_BIG_NUMBER_FOR_REPEAT_RANGE;
      if (up > ONIG_MAX_REPEAT_NUM)
        return ONIGERR_TOO_BIG_NUMBER_FOR_REPEAT_RANGE;
  
      if (p == prev) {
        if (non_low != 0)
          goto invalid;
        up = REPEAT_INFINITE;  /* {n,} : {n,infinite} */
      }
    }
    else {
      if (non_low != 0)
        goto invalid;
  
      PUNFETCH;
      up = low;  /* {n} : exact n times */
      r = 2;     /* fixed */
    }
  
    if (PEND) goto invalid;
    PFETCH(c);
    if (IS_SYNTAX_OP(env->syntax, ONIG_SYN_OP_ESC_BRACE_INTERVAL)) {
      if (c != MC_ESC(env->syntax)) goto invalid;
      PFETCH(c);
    }
    if (c != '}') goto invalid;
  
    if (!IS_REPEAT_INFINITE(up) && low > up) {
      return ONIGERR_UPPER_SMALLER_THAN_LOWER_IN_REPEAT_RANGE;
    }
  
    tok->type = TK_INTERVAL;
    tok->u.repeat.lower = low;
    tok->u.repeat.upper = up;
    *src = p;
    return r; /* 0: normal {n,m}, 2: fixed {n} */
  
   invalid:
    if (syn_allow) {
      /* *src = p; */ /* !!! Don't do this line !!! */
      return 1;  /* OK */
    }
    else
      return ONIGERR_INVALID_REPEAT_RANGE_PATTERN;
  }
  
  /* \M-, \C-, \c, or \... */
  static int
  fetch_escaped_value(UChar** src, UChar* end, ScanEnv* env, OnigCodePoint* val)
  {
    int v;
    OnigCodePoint c;
    OnigEncoding enc = env->enc;
    UChar* p = *src;
  
    if (PEND) return ONIGERR_END_PATTERN_AT_ESCAPE;
  
    PFETCH_S(c);
    switch (c) {
    case 'M':
      if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_ESC_CAPITAL_M_BAR_META)) {
        if (PEND) return ONIGERR_END_PATTERN_AT_META;
        PFETCH_S(c);
        if (c != '-') return ONIGERR_META_CODE_SYNTAX;
        if (PEND) return ONIGERR_END_PATTERN_AT_META;
        PFETCH_S(c);
        if (c == MC_ESC(env->syntax)) {
          v = fetch_escaped_value(&p, end, env, &c);
          if (v < 0) return v;
        }
        c = ((c & 0xff) | 0x80);
      }
      else
        goto backslash;
      break;
  
    case 'C':
      if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_ESC_CAPITAL_C_BAR_CONTROL)) {
        if (PEND) return ONIGERR_END_PATTERN_AT_CONTROL;
        PFETCH_S(c);
        if (c != '-') return ONIGERR_CONTROL_CODE_SYNTAX;
        goto control;
      }
      else
        goto backslash;
  
    case 'c':
      if (IS_SYNTAX_OP(env->syntax, ONIG_SYN_OP_ESC_C_CONTROL)) {
      control:
        if (PEND) return ONIGERR_END_PATTERN_AT_CONTROL;
        PFETCH_S(c);
        if (c == '?') {
          c = 0177;
        }
        else {
          if (c == MC_ESC(env->syntax)) {
            v = fetch_escaped_value(&p, end, env, &c);
            if (v < 0) return v;
          }
          c &= 0x9f;
        }
        break;
      }
      /* fall through */
  
    default:
      {
      backslash:
        c = conv_backslash_value(c, env);
      }
      break;
    }
  
    *src = p;
    *val = c;
    return 0;
  }
  
  static int fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env);
  
  static OnigCodePoint
  get_name_end_code_point(OnigCodePoint start)
  {
    switch (start) {
    case '<':  return (OnigCodePoint )'>';  break;
    case '\'': return (OnigCodePoint )'\''; break;
    case '(':  return (OnigCodePoint )')';  break;
    default:
      break;
    }
  
    return (OnigCodePoint )0;
  }
  
  enum REF_NUM {
    IS_NOT_NUM = 0,
    IS_ABS_NUM = 1,
    IS_REL_NUM = 2
  };
  
  #ifdef USE_BACKREF_WITH_LEVEL
  /*
     \k<name+n>, \k<name-n>
     \k<num+n>,  \k<num-n>
     \k<-num+n>, \k<-num-n>
     \k<+num+n>, \k<+num-n>
  */
  static int
  fetch_name_with_level(OnigCodePoint start_code, UChar** src, UChar* end,
                        UChar** rname_end, ScanEnv* env,
                        int* rback_num, int* rlevel, enum REF_NUM* num_type)
  {
    int r, sign, exist_level;
    int digit_count;
    OnigCodePoint end_code;
    OnigCodePoint c = 0;
    OnigEncoding enc = env->enc;
    UChar *name_end;
    UChar *pnum_head;
    UChar *p = *src;
    PFETCH_READY;
  
    *rback_num = 0;
    exist_level = 0;
    *num_type = IS_NOT_NUM;
    sign = 1;
    pnum_head = *src;
  
    end_code = get_name_end_code_point(start_code);
  
    digit_count = 0;
    name_end = end;
    r = 0;
    if (PEND) {
      return ONIGERR_EMPTY_GROUP_NAME;
    }
    else {
      PFETCH(c);
      if (c == end_code)
        return ONIGERR_EMPTY_GROUP_NAME;
  
      if (IS_CODE_DIGIT_ASCII(enc, c)) {
        *num_type = IS_ABS_NUM;
        digit_count++;
      }
      else if (c == '-') {
        *num_type = IS_REL_NUM;
        sign = -1;
        pnum_head = p;
      }
      else if (c == '+') {
        *num_type = IS_REL_NUM;
        sign = 1;
        pnum_head = p;
      }
      else if (!ONIGENC_IS_CODE_WORD(enc, c)) {
        r = ONIGERR_INVALID_CHAR_IN_GROUP_NAME;
      }
    }
  
    while (!PEND) {
      name_end = p;
      PFETCH(c);
      if (c == end_code || c == ')' || c == '+' || c == '-') {
        if (*num_type != IS_NOT_NUM && digit_count == 0)
          r = ONIGERR_INVALID_GROUP_NAME;
        break;
      }
  
      if (*num_type != IS_NOT_NUM) {
        if (IS_CODE_DIGIT_ASCII(enc, c)) {
          digit_count++;
        }
        else {
          r = ONIGERR_INVALID_GROUP_NAME;
          *num_type = IS_NOT_NUM;
        }
      }
      else if (!ONIGENC_IS_CODE_WORD(enc, c)) {
        r = ONIGERR_INVALID_CHAR_IN_GROUP_NAME;
      }
    }
  
    if (r == 0 && c != end_code) {
      if (c == '+' || c == '-') {
        int level;
        int flag = (c == '-' ? -1 : 1);
  
        if (PEND) {
          r = ONIGERR_INVALID_CHAR_IN_GROUP_NAME;
          goto end;
        }
        PFETCH(c);
        if (! IS_CODE_DIGIT_ASCII(enc, c)) goto err;
        PUNFETCH;
        level = onig_scan_unsigned_number(&p, end, enc);
        if (level < 0) return ONIGERR_TOO_BIG_NUMBER;
        *rlevel = (level * flag);
        exist_level = 1;
  
        if (!PEND) {
          PFETCH(c);
          if (c == end_code)
            goto end;
        }
      }
  
    err:
      name_end = end;
    err2:
      r = ONIGERR_INVALID_GROUP_NAME;
    }
  
   end:
    if (r == 0) {
      if (*num_type != IS_NOT_NUM) {
        *rback_num = onig_scan_unsigned_number(&pnum_head, name_end, enc);
        if (*rback_num < 0) return ONIGERR_TOO_BIG_NUMBER;
        else if (*rback_num == 0) {
          if (*num_type == IS_REL_NUM)
            goto err2;
        }
  
        *rback_num *= sign;
      }
  
      *rname_end = name_end;
      *src = p;
      return (exist_level ? 1 : 0);
    }
    else {
      onig_scan_env_set_error_string(env, r, *src, name_end);
      return r;
    }
  }
  #endif /* USE_BACKREF_WITH_LEVEL */
  
  /*
    ref: 0 -> define name    (don't allow number name)
         1 -> reference name (allow number name)
  */
  static int
  fetch_name(OnigCodePoint start_code, UChar** src, UChar* end,
             UChar** rname_end, ScanEnv* env, int* rback_num,
             enum REF_NUM* num_type, int ref)
  {
    int r, sign;
    int digit_count;
    OnigCodePoint end_code;
    OnigCodePoint c = 0;
    OnigEncoding enc = env->enc;
    UChar *name_end;
    UChar *pnum_head;
    UChar *p = *src;
  
    *rback_num = 0;
  
    end_code = get_name_end_code_point(start_code);
  
    digit_count = 0;
    name_end = end;
    pnum_head = *src;
    r = 0;
    *num_type = IS_NOT_NUM;
    sign = 1;
    if (PEND) {
      return ONIGERR_EMPTY_GROUP_NAME;
    }
    else {
      PFETCH_S(c);
      if (c == end_code)
        return ONIGERR_EMPTY_GROUP_NAME;
  
      if (IS_CODE_DIGIT_ASCII(enc, c)) {
        if (ref == 1)
          *num_type = IS_ABS_NUM;
        else {
          r = ONIGERR_INVALID_GROUP_NAME;
        }
        digit_count++;
      }
      else if (c == '-') {
        if (ref == 1) {
          *num_type = IS_REL_NUM;
          sign = -1;
          pnum_head = p;
        }
        else {
          r = ONIGERR_INVALID_GROUP_NAME;
        }
      }
      else if (c == '+') {
        if (ref == 1) {
          *num_type = IS_REL_NUM;
          sign = 1;
          pnum_head = p;
        }
        else {
          r = ONIGERR_INVALID_GROUP_NAME;
        }
      }
      else if (!ONIGENC_IS_CODE_WORD(enc, c)) {
        r = ONIGERR_INVALID_CHAR_IN_GROUP_NAME;
      }
    }
  
    if (r == 0) {
      while (!PEND) {
        name_end = p;
        PFETCH_S(c);
        if (c == end_code || c == ')') {
          if (*num_type != IS_NOT_NUM && digit_count == 0)
            r = ONIGERR_INVALID_GROUP_NAME;
          break;
        }
  
        if (*num_type != IS_NOT_NUM) {
          if (IS_CODE_DIGIT_ASCII(enc, c)) {
            digit_count++;
          }
          else {
            if (!ONIGENC_IS_CODE_WORD(enc, c))
              r = ONIGERR_INVALID_CHAR_IN_GROUP_NAME;
            else
              r = ONIGERR_INVALID_GROUP_NAME;
  
            *num_type = IS_NOT_NUM;
          }
        }
        else {
          if (!ONIGENC_IS_CODE_WORD(enc, c)) {
            r = ONIGERR_INVALID_CHAR_IN_GROUP_NAME;
          }
        }
      }
  
      if (c != end_code) {
        r = ONIGERR_INVALID_GROUP_NAME;
        goto err;
      }
  
      if (*num_type != IS_NOT_NUM) {
        *rback_num = onig_scan_unsigned_number(&pnum_head, name_end, enc);
        if (*rback_num < 0) return ONIGERR_TOO_BIG_NUMBER;
        else if (*rback_num == 0) {
          if (*num_type == IS_REL_NUM) {
            r = ONIGERR_INVALID_GROUP_NAME;
            goto err;
          }
        }
  
        *rback_num *= sign;
      }
  
      *rname_end = name_end;
      *src = p;
      return 0;
    }
    else {
      while (!PEND) {
        name_end = p;
        PFETCH_S(c);
        if (c == end_code || c == ')')
          break;
      }
      if (PEND)
        name_end = end;
  
    err:
      onig_scan_env_set_error_string(env, r, *src, name_end);
      return r;
    }
  }
  
  static void
  CC_ESC_WARN(ScanEnv* env, UChar *c)
  {
    if (onig_warn == onig_null_warn) return ;
  
    if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_WARN_CC_OP_NOT_ESCAPED) &&
        IS_SYNTAX_BV(env->syntax, ONIG_SYN_BACKSLASH_ESCAPE_IN_CC)) {
      UChar buf[WARN_BUFSIZE];
      onig_snprintf_with_pattern(buf, WARN_BUFSIZE, env->enc,
  		env->pattern, env->pattern_end,
                  (UChar* )"character class has '%s' without escape", c);
      (*onig_warn)((char* )buf);
    }
  }
  
  static void
  CLOSE_BRACKET_WITHOUT_ESC_WARN(ScanEnv* env, UChar* c)
  {
    if (onig_warn == onig_null_warn) return ;
  
    if (IS_SYNTAX_BV((env)->syntax, ONIG_SYN_WARN_CC_OP_NOT_ESCAPED)) {
      UChar buf[WARN_BUFSIZE];
      onig_snprintf_with_pattern(buf, WARN_BUFSIZE, (env)->enc,
  		(env)->pattern, (env)->pattern_end,
  		(UChar* )"regular expression has '%s' without escape", c);
      (*onig_warn)((char* )buf);
    }
  }
  
  static UChar*
  find_str_position(OnigCodePoint s[], int n, UChar* from, UChar* to,
                    UChar **next, OnigEncoding enc)
  {
    int i;
    OnigCodePoint x;
    UChar *q;
    UChar *p = from;
    
    while (p < to) {
      x = ONIGENC_MBC_TO_CODE(enc, p, to);
      q = p + enclen(enc, p);
      if (x == s[0]) {
        for (i = 1; i < n && q < to; i++) {
          x = ONIGENC_MBC_TO_CODE(enc, q, to);
          if (x != s[i]) break;
          q += enclen(enc, q);
        }
        if (i >= n) {
          if (IS_NOT_NULL(next))
            *next = q;
          return p;
        }
      }
      p = q;
    }
    return NULL_UCHARP;
  }
  
  static int
  str_exist_check_with_esc(OnigCodePoint s[], int n, UChar* from, UChar* to,
                           OnigCodePoint bad, OnigEncoding enc, OnigSyntaxType* syn)
  {
    int i, in_esc;
    OnigCodePoint x;
    UChar *q;
    UChar *p = from;
  
    in_esc = 0;
    while (p < to) {
      if (in_esc) {
        in_esc = 0;
        p += enclen(enc, p);
      }
      else {
        x = ONIGENC_MBC_TO_CODE(enc, p, to);
        q = p + enclen(enc, p);
        if (x == s[0]) {
          for (i = 1; i < n && q < to; i++) {
            x = ONIGENC_MBC_TO_CODE(enc, q, to);
            if (x != s[i]) break;
            q += enclen(enc, q);
          }
          if (i >= n) return 1;
          p += enclen(enc, p);
        }
        else {
          x = ONIGENC_MBC_TO_CODE(enc, p, to);
          if (x == bad) return 0;
          else if (x == MC_ESC(syn)) in_esc = 1;
          p = q;
        }
      }
    }
    return 0;
  }
  
  static int
  fetch_token_in_cc(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
  {
    int num;
    OnigCodePoint c, c2;
    OnigSyntaxType* syn = env->syntax;
    OnigEncoding enc = env->enc;
    UChar* prev;
    UChar* p = *src;
    PFETCH_READY;
  
    if (PEND) {
      tok->type = TK_EOT;
      return tok->type;
    }
  
    PFETCH(c);
    tok->type = TK_CHAR;
    tok->base = 0;
    tok->u.c  = c;
    tok->escaped = 0;
  
    if (c == ']') {
      tok->type = TK_CC_CLOSE;
    }
    else if (c == '-') {
      tok->type = TK_CC_RANGE;
    }
    else if (c == MC_ESC(syn)) {
      if (! IS_SYNTAX_BV(syn, ONIG_SYN_BACKSLASH_ESCAPE_IN_CC))
        goto end;
  
      if (PEND) return ONIGERR_END_PATTERN_AT_ESCAPE;
  
      PFETCH(c);
      tok->escaped = 1;
      tok->u.c = c;
      switch (c) {
      case 'w':
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_WORD;
        tok->u.prop.not   = 0;
        break;
      case 'W':
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_WORD;
        tok->u.prop.not   = 1;
        break;
      case 'd':
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_DIGIT;
        tok->u.prop.not   = 0;
        break;
      case 'D':
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_DIGIT;
        tok->u.prop.not   = 1;
        break;
      case 's':
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_SPACE;
        tok->u.prop.not   = 0;
        break;
      case 'S':
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_SPACE;
        tok->u.prop.not   = 1;
        break;
      case 'h':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_H_XDIGIT)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_XDIGIT;
        tok->u.prop.not   = 0;
        break;
      case 'H':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_H_XDIGIT)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_XDIGIT;
        tok->u.prop.not   = 1;
        break;
  
      case 'p':
      case 'P':
        if (PEND) break;
  
        c2 = PPEEK;
        if (c2 == '{' &&
            IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_P_BRACE_CHAR_PROPERTY)) {
          PINC;
          tok->type = TK_CHAR_PROPERTY;
          tok->u.prop.not = (c == 'P' ? 1 : 0);
  
          if (!PEND && IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_P_BRACE_CIRCUMFLEX_NOT)) {
            PFETCH(c2);
            if (c2 == '^') {
              tok->u.prop.not = (tok->u.prop.not == 0 ? 1 : 0);
            }
            else
              PUNFETCH;
          }
        }
        break;
  
      case 'o':
        if (PEND) break;
  
        prev = p;
        if (PPEEK_IS('{') && IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_O_BRACE_OCTAL)) {
          PINC;
          num = scan_unsigned_octal_number(&p, end, 11, enc);
          if (num < 0) return ONIGERR_TOO_BIG_WIDE_CHAR_VALUE;
          if (!PEND) {
            c2 = PPEEK;
            if (IS_CODE_DIGIT_ASCII(enc, c2))
              return ONIGERR_TOO_LONG_WIDE_CHAR_VALUE;
          }
  
          if (p > prev + enclen(enc, prev) && !PEND && (PPEEK_IS('}'))) {
            PINC;
            tok->type   = TK_CODE_POINT;
            tok->base   = 8;
            tok->u.code = (OnigCodePoint )num;
          }
          else {
            /* can't read nothing or invalid format */
            p = prev;
          }
        }
        break;
  
      case 'x':
        if (PEND) break;
  
        prev = p;
        if (PPEEK_IS('{') && IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_X_BRACE_HEX8)) {
          PINC;
          num = scan_unsigned_hexadecimal_number(&p, end, 8, enc);
          if (num < 0) return ONIGERR_TOO_BIG_WIDE_CHAR_VALUE;
          if (!PEND) {
            c2 = PPEEK;
            if (IS_CODE_XDIGIT_ASCII(enc, c2))
              return ONIGERR_TOO_LONG_WIDE_CHAR_VALUE;
          }
  
          if (p > prev + enclen(enc, prev) && !PEND && (PPEEK_IS('}'))) {
            PINC;
            tok->type   = TK_CODE_POINT;
            tok->base   = 16;
            tok->u.code = (OnigCodePoint )num;
          }
          else {
            /* can't read nothing or invalid format */
            p = prev;
          }
        }
        else if (IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_X_HEX2)) {
          num = scan_unsigned_hexadecimal_number(&p, end, 2, enc);
          if (num < 0) return ONIGERR_TOO_BIG_NUMBER;
          if (p == prev) {  /* can't read nothing. */
            num = 0; /* but, it's not error */
          }
          tok->type = TK_RAW_BYTE;
          tok->base = 16;
          tok->u.c  = num;
        }
        break;
  
      case 'u':
        if (PEND) break;
  
        prev = p;
        if (IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_U_HEX4)) {
          num = scan_unsigned_hexadecimal_number(&p, end, 4, enc);
          if (num < 0) return ONIGERR_TOO_BIG_NUMBER;
          if (p == prev) {  /* can't read nothing. */
            num = 0; /* but, it's not error */
          }
          tok->type   = TK_CODE_POINT;
          tok->base   = 16;
          tok->u.code = (OnigCodePoint )num;
        }
        break;
  
      case '0':
      case '1': case '2': case '3': case '4': case '5': case '6': case '7':
        if (IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_OCTAL3)) {
          PUNFETCH;
          prev = p;
          num = scan_unsigned_octal_number(&p, end, 3, enc);
          if (num < 0 || num >= 256) return ONIGERR_TOO_BIG_NUMBER;
          if (p == prev) {  /* can't read nothing. */
            num = 0; /* but, it's not error */
          }
          tok->type = TK_RAW_BYTE;
          tok->base = 8;
          tok->u.c  = num;
        }
        break;
  
      default:
        PUNFETCH;
        num = fetch_escaped_value(&p, end, env, &c2);
        if (num < 0) return num;
        if (tok->u.c != c2) {
          tok->u.code = c2;
          tok->type   = TK_CODE_POINT;
        }
        break;
      }
    }
    else if (c == '[') {
      if (IS_SYNTAX_OP(syn, ONIG_SYN_OP_POSIX_BRACKET) && (PPEEK_IS(':'))) {
        OnigCodePoint send[] = { (OnigCodePoint )':', (OnigCodePoint )']' };
        tok->backp = p; /* point at '[' is read */
        PINC;
        if (str_exist_check_with_esc(send, 2, p, end,
                                     (OnigCodePoint )']', enc, syn)) {
          tok->type = TK_POSIX_BRACKET_OPEN;
        }
        else {
          PUNFETCH;
          goto cc_in_cc;
        }
      }
      else {
      cc_in_cc:
        if (IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_CCLASS_SET_OP)) {
          tok->type = TK_CC_CC_OPEN;
        }
        else {
          CC_ESC_WARN(env, (UChar* )"[");
        }
      }
    }
    else if (c == '&') {
      if (IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_CCLASS_SET_OP) &&
          !PEND && (PPEEK_IS('&'))) {
        PINC;
        tok->type = TK_CC_AND;
      }
    }
  
   end:
    *src = p;
    return tok->type;
  }
  
  static int
  fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
  {
    int r, num;
    OnigCodePoint c;
    OnigEncoding enc = env->enc;
    OnigSyntaxType* syn = env->syntax;
    UChar* prev;
    UChar* p = *src;
    PFETCH_READY;
  
   start:
    if (PEND) {
      tok->type = TK_EOT;
      return tok->type;
    }
  
    tok->type  = TK_STRING;
    tok->base  = 0;
    tok->backp = p;
  
    PFETCH(c);
    if (IS_MC_ESC_CODE(c, syn)) {
      if (PEND) return ONIGERR_END_PATTERN_AT_ESCAPE;
  
      tok->backp = p;
      PFETCH(c);
  
      tok->u.c = c;
      tok->escaped = 1;
      switch (c) {
      case '*':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_ASTERISK_ZERO_INF)) break;
        tok->type = TK_OP_REPEAT;
        tok->u.repeat.lower = 0;
        tok->u.repeat.upper = REPEAT_INFINITE;
        goto greedy_check;
        break;
  
      case '+':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_PLUS_ONE_INF)) break;
        tok->type = TK_OP_REPEAT;
        tok->u.repeat.lower = 1;
        tok->u.repeat.upper = REPEAT_INFINITE;
        goto greedy_check;
        break;
  
      case '?':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_QMARK_ZERO_ONE)) break;
        tok->type = TK_OP_REPEAT;
        tok->u.repeat.lower = 0;
        tok->u.repeat.upper = 1;
      greedy_check:
        if (!PEND && PPEEK_IS('?') &&
            IS_SYNTAX_OP(syn, ONIG_SYN_OP_QMARK_NON_GREEDY)) {
          PFETCH(c);
          tok->u.repeat.greedy     = 0;
          tok->u.repeat.possessive = 0;
        }
        else {
        possessive_check:
          if (!PEND && PPEEK_IS('+') &&
              ((IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_PLUS_POSSESSIVE_REPEAT) &&
                tok->type != TK_INTERVAL)  ||
               (IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_PLUS_POSSESSIVE_INTERVAL) &&
                tok->type == TK_INTERVAL))) {
            PFETCH(c);
            tok->u.repeat.greedy     = 1;
            tok->u.repeat.possessive = 1;
          }
          else {
            tok->u.repeat.greedy     = 1;
            tok->u.repeat.possessive = 0;
          }
        }
        break;
  
      case '{':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_BRACE_INTERVAL)) break;
        r = fetch_range_quantifier(&p, end, tok, env);
        if (r < 0) return r;  /* error */
        if (r == 0) goto greedy_check;
        else if (r == 2) { /* {n} */
          if (IS_SYNTAX_BV(syn, ONIG_SYN_FIXED_INTERVAL_IS_GREEDY_ONLY))
            goto possessive_check;
  
          goto greedy_check;
        }
        /* r == 1 : normal char */
        break;
  
      case '|':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_VBAR_ALT)) break;
        tok->type = TK_ALT;
        break;
  
      case '(':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_LPAREN_SUBEXP)) break;
        tok->type = TK_SUBEXP_OPEN;
        break;
  
      case ')':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_LPAREN_SUBEXP)) break;
        tok->type = TK_SUBEXP_CLOSE;
        break;
  
      case 'w':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_W_WORD)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_WORD;
        tok->u.prop.not   = 0;
        break;
  
      case 'W':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_W_WORD)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_WORD;
        tok->u.prop.not   = 1;
        break;
  
      case 'b':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_B_WORD_BOUND)) break;
        tok->type = TK_ANCHOR;
        tok->u.anchor = ANCHOR_WORD_BOUNDARY;
        break;
  
      case 'B':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_B_WORD_BOUND)) break;
        tok->type = TK_ANCHOR;
        tok->u.anchor = ANCHOR_NO_WORD_BOUNDARY;
        break;
  
      case 'y':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP2_ESC_X_Y_GRAPHEME_CLUSTER)) break;
        tok->type = TK_ANCHOR;
        tok->u.anchor = ANCHOR_EXTENDED_GRAPHEME_CLUSTER_BOUNDARY;
        break;
  
      case 'Y':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP2_ESC_X_Y_GRAPHEME_CLUSTER)) break;
        tok->type = TK_ANCHOR;
        tok->u.anchor = ANCHOR_NO_EXTENDED_GRAPHEME_CLUSTER_BOUNDARY;
        break;
  
  #ifdef USE_WORD_BEGIN_END
      case '<':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_LTGT_WORD_BEGIN_END)) break;
        tok->type = TK_ANCHOR;
        tok->u.anchor = ANCHOR_WORD_BEGIN;
        break;
  
      case '>':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_LTGT_WORD_BEGIN_END)) break;
        tok->type = TK_ANCHOR;
        tok->u.anchor = ANCHOR_WORD_END;
        break;
  #endif
  
      case 's':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_S_WHITE_SPACE)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_SPACE;
        tok->u.prop.not   = 0;
        break;
  
      case 'S':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_S_WHITE_SPACE)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_SPACE;
        tok->u.prop.not   = 1;
        break;
  
      case 'd':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_D_DIGIT)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_DIGIT;
        tok->u.prop.not   = 0;
        break;
  
      case 'D':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_D_DIGIT)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_DIGIT;
        tok->u.prop.not   = 1;
        break;
  
      case 'h':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_H_XDIGIT)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_XDIGIT;
        tok->u.prop.not   = 0;
        break;
  
      case 'H':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_H_XDIGIT)) break;
        tok->type = TK_CHAR_TYPE;
        tok->u.prop.ctype = ONIGENC_CTYPE_XDIGIT;
        tok->u.prop.not   = 1;
        break;
  
      case 'K':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_CAPITAL_K_KEEP)) break;
        tok->type = TK_KEEP;
        break;
  
      case 'R':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_CAPITAL_R_GENERAL_NEWLINE)) break;
        tok->type = TK_GENERAL_NEWLINE;
        break;
  
      case 'N':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_CAPITAL_N_O_SUPER_DOT)) break;
        tok->type = TK_NO_NEWLINE;
        break;
  
      case 'O':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_CAPITAL_N_O_SUPER_DOT)) break;
        tok->type = TK_TRUE_ANYCHAR;
        break;
  
      case 'X':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_X_Y_GRAPHEME_CLUSTER)) break;
        tok->type = TK_EXTENDED_GRAPHEME_CLUSTER;
        break;
  
      case 'A':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_AZ_BUF_ANCHOR)) break;
      begin_buf:
        tok->type = TK_ANCHOR;
        tok->u.subtype = ANCHOR_BEGIN_BUF;
        break;
  
      case 'Z':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_AZ_BUF_ANCHOR)) break;
        tok->type = TK_ANCHOR;
        tok->u.subtype = ANCHOR_SEMI_END_BUF;
        break;
  
      case 'z':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_AZ_BUF_ANCHOR)) break;
      end_buf:
        tok->type = TK_ANCHOR;
        tok->u.subtype = ANCHOR_END_BUF;
        break;
  
      case 'G':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_CAPITAL_G_BEGIN_ANCHOR)) break;
        tok->type = TK_ANCHOR;
        tok->u.subtype = ANCHOR_BEGIN_POSITION;
        break;
  
      case '`':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_GNU_BUF_ANCHOR)) break;
        goto begin_buf;
        break;
  
      case '\'':
        if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_GNU_BUF_ANCHOR)) break;
        goto end_buf;
        break;
  
      case 'o':
        if (PEND) break;
  
        prev = p;
        if (PPEEK_IS('{') && IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_O_BRACE_OCTAL)) {
          PINC;
          num = scan_unsigned_octal_number(&p, end, 11, enc);
          if (num < 0) return ONIGERR_TOO_BIG_WIDE_CHAR_VALUE;
          if (!PEND) {
            if (IS_CODE_DIGIT_ASCII(enc, PPEEK))
              return ONIGERR_TOO_LONG_WIDE_CHAR_VALUE;
          }
  
          if ((p > prev + enclen(enc, prev)) && !PEND && PPEEK_IS('}')) {
            PINC;
            tok->type   = TK_CODE_POINT;
            tok->u.code = (OnigCodePoint )num;
          }
          else {
            /* can't read nothing or invalid format */
            p = prev;
          }
        }
        break;
  
      case 'x':
        if (PEND) break;
  
        prev = p;
        if (PPEEK_IS('{') && IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_X_BRACE_HEX8)) {
          PINC;
          num = scan_unsigned_hexadecimal_number(&p, end, 8, enc);
          if (num < 0) return ONIGERR_TOO_BIG_WIDE_CHAR_VALUE;
          if (!PEND) {
            if (IS_CODE_XDIGIT_ASCII(enc, PPEEK))
              return ONIGERR_TOO_LONG_WIDE_CHAR_VALUE;
          }
  
          if ((p > prev + enclen(enc, prev)) && !PEND && PPEEK_IS('}')) {
            PINC;
            tok->type   = TK_CODE_POINT;
            tok->u.code = (OnigCodePoint )num;
          }
          else {
            /* can't read nothing or invalid format */
            p = prev;
          }
        }
        else if (IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_X_HEX2)) {
          num = scan_unsigned_hexadecimal_number(&p, end, 2, enc);
          if (num < 0) return ONIGERR_TOO_BIG_NUMBER;
          if (p == prev) {  /* can't read nothing. */
            num = 0; /* but, it's not error */
          }
          tok->type = TK_RAW_BYTE;
          tok->base = 16;
          tok->u.c  = num;
        }
        break;
  
      case 'u':
        if (PEND) break;
  
        prev = p;
        if (IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_U_HEX4)) {
          num = scan_unsigned_hexadecimal_number(&p, end, 4, enc);
          if (num < 0) return ONIGERR_TOO_BIG_NUMBER;
          if (p == prev) {  /* can't read nothing. */
            num = 0; /* but, it's not error */
          }
          tok->type   = TK_CODE_POINT;
          tok->base   = 16;
          tok->u.code = (OnigCodePoint )num;
        }
        break;
  
      case '1': case '2': case '3': case '4':
      case '5': case '6': case '7': case '8': case '9':
        PUNFETCH;
        prev = p;
        num = onig_scan_unsigned_number(&p, end, enc);
        if (num < 0 || num > ONIG_MAX_BACKREF_NUM) {
          goto skip_backref;
        }
  
        if (IS_SYNTAX_OP(syn, ONIG_SYN_OP_DECIMAL_BACKREF) && 
            (num <= env->num_mem || num <= 9)) { /* This spec. from GNU regex */
          if (IS_SYNTAX_BV(syn, ONIG_SYN_STRICT_CHECK_BACKREF)) {
            if (num > env->num_mem || IS_NULL(SCANENV_MEMENV(env)[num].node))
              return ONIGERR_INVALID_BACKREF;
          }
  
          tok->type = TK_BACKREF;
          tok->u.backref.num     = 1;
          tok->u.backref.ref1    = num;
          tok->u.backref.by_name = 0;
  #ifdef USE_BACKREF_WITH_LEVEL
          tok->u.backref.exist_level = 0;
  #endif
          break;
        }
  
      skip_backref:
        if (c == '8' || c == '9') {
          /* normal char */
          p = prev; PINC;
          break;
        }
  
        p = prev;
        /* fall through */
      case '0':
        if (IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_OCTAL3)) {
          prev = p;
          num = scan_unsigned_octal_number(&p, end, (c == '0' ? 2:3), enc);
          if (num < 0 || num >= 256) return ONIGERR_TOO_BIG_NUMBER;
          if (p == prev) {  /* can't read nothing. */
            num = 0; /* but, it's not error */
          }
          tok->type = TK_RAW_BYTE;
          tok->base = 8;
          tok->u.c  = num;
        }
        else if (c != '0') {
          PINC;
        }
        break;
  
      case 'k':
        if (!PEND && IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_K_NAMED_BACKREF)) {
          PFETCH(c);
          if (c == '<' || c == '\'') {
            UChar* name_end;
            int* backs;
            int back_num;
            enum REF_NUM num_type;
  
            prev = p;
  
  #ifdef USE_BACKREF_WITH_LEVEL
            name_end = NULL_UCHARP; /* no need. escape gcc warning. */
            r = fetch_name_with_level((OnigCodePoint )c, &p, end, &name_end,
                                   env, &back_num, &tok->u.backref.level, &num_type);
            if (r == 1) tok->u.backref.exist_level = 1;
            else        tok->u.backref.exist_level = 0;
  #else
            r = fetch_name(c, &p, end, &name_end, env, &back_num, &num_type, 1);
  #endif
            if (r < 0) return r;
  
            if (num_type != IS_NOT_NUM) {
              if (num_type == IS_REL_NUM) {
                back_num = backref_rel_to_abs(back_num, env);
              }
              if (back_num <= 0)
                return ONIGERR_INVALID_BACKREF;
  
              if (IS_SYNTAX_BV(syn, ONIG_SYN_STRICT_CHECK_BACKREF)) {
                if (back_num > env->num_mem ||
                    IS_NULL(SCANENV_MEMENV(env)[back_num].node))
                  return ONIGERR_INVALID_BACKREF;
              }
              tok->type = TK_BACKREF;
              tok->u.backref.by_name = 0;
              tok->u.backref.num  = 1;
              tok->u.backref.ref1 = back_num;
            }
            else {
              num = onig_name_to_group_numbers(env->reg, prev, name_end, &backs);
              if (num <= 0) {
                onig_scan_env_set_error_string(env,
                          ONIGERR_UNDEFINED_NAME_REFERENCE, prev, name_end);
                return ONIGERR_UNDEFINED_NAME_REFERENCE;
              }
              if (IS_SYNTAX_BV(syn, ONIG_SYN_STRICT_CHECK_BACKREF)) {
                int i;
                for (i = 0; i < num; i++) {
                  if (backs[i] > env->num_mem ||
                      IS_NULL(SCANENV_MEMENV(env)[backs[i]].node))
                    return ONIGERR_INVALID_BACKREF;
                }
              }
  
              tok->type = TK_BACKREF;
              tok->u.backref.by_name = 1;
              if (num == 1) {
                tok->u.backref.num  = 1;
                tok->u.backref.ref1 = backs[0];
              }
              else {
                tok->u.backref.num  = num;
                tok->u.backref.refs = backs;
              }
            }
          }
          else
            PUNFETCH;
        }
        break;
  
  #ifdef USE_CALL
      case 'g':
        if (!PEND && IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_G_SUBEXP_CALL)) {
          PFETCH(c);
          if (c == '<' || c == '\'') {
            int gnum;
            UChar* name_end;
            enum REF_NUM num_type;
  
            prev = p;
            r = fetch_name((OnigCodePoint )c, &p, end, &name_end, env,
                           &gnum, &num_type, 1);
            if (r < 0) return r;
  
            if (num_type != IS_NOT_NUM) {
              if (num_type == IS_REL_NUM) {
                gnum = backref_rel_to_abs(gnum, env);
                if (gnum < 0)
                  return ONIGERR_UNDEFINED_GROUP_REFERENCE;
              }
              tok->u.call.by_number = 1;
              tok->u.call.gnum      = gnum;
            }
            else {
              tok->u.call.by_number = 0;
              tok->u.call.gnum      = 0;
            }
  
            tok->type = TK_CALL;
            tok->u.call.name     = prev;
            tok->u.call.name_end = name_end;
          }
          else
            PUNFETCH;
        }
        break;
  #endif
  
      case 'Q':
        if (IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_CAPITAL_Q_QUOTE)) {
          tok->type = TK_QUOTE_OPEN;
        }
        break;
  
      case 'p':
      case 'P':
        if (!PEND && PPEEK_IS('{') &&
            IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_P_BRACE_CHAR_PROPERTY)) {
          PINC;
          tok->type = TK_CHAR_PROPERTY;
          tok->u.prop.not = (c == 'P' ? 1 : 0);
  
          if (!PEND &&
              IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_P_BRACE_CIRCUMFLEX_NOT)) {
            PFETCH(c);
            if (c == '^') {
              tok->u.prop.not = (tok->u.prop.not == 0 ? 1 : 0);
            }
            else
              PUNFETCH;
          }
        }
        break;
  
      default:
        {
          OnigCodePoint c2;
  
          PUNFETCH;
          num = fetch_escaped_value(&p, end, env, &c2);
          if (num < 0) return num;
          /* set_raw: */
          if (tok->u.c != c2) {
            tok->type = TK_CODE_POINT;
            tok->u.code = c2;
          }
          else { /* string */
            p = tok->backp + enclen(enc, tok->backp);
          }
        }
        break;
      }
    }
    else {
      tok->u.c = c;
      tok->escaped = 0;
  
  #ifdef USE_VARIABLE_META_CHARS
      if ((c != ONIG_INEFFECTIVE_META_CHAR) &&
          IS_SYNTAX_OP(syn, ONIG_SYN_OP_VARIABLE_META_CHARACTERS)) {
        if (c == MC_ANYCHAR(syn))
          goto any_char;
        else if (c == MC_ANYTIME(syn))
          goto anytime;
        else if (c == MC_ZERO_OR_ONE_TIME(syn))
          goto zero_or_one_time;
        else if (c == MC_ONE_OR_MORE_TIME(syn))
          goto one_or_more_time;
        else if (c == MC_ANYCHAR_ANYTIME(syn)) {
          tok->type = TK_ANYCHAR_ANYTIME;
          goto out;
        }
      }
  #endif
  
      switch (c) {
      case '.':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_DOT_ANYCHAR)) break;
  #ifdef USE_VARIABLE_META_CHARS
      any_char:
  #endif
        tok->type = TK_ANYCHAR;
        break;
  
      case '*':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ASTERISK_ZERO_INF)) break;
  #ifdef USE_VARIABLE_META_CHARS
      anytime:
  #endif
        tok->type = TK_OP_REPEAT;
        tok->u.repeat.lower = 0;
        tok->u.repeat.upper = REPEAT_INFINITE;
        goto greedy_check;
        break;
  
      case '+':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_PLUS_ONE_INF)) break;
  #ifdef USE_VARIABLE_META_CHARS
      one_or_more_time:
  #endif
        tok->type = TK_OP_REPEAT;
        tok->u.repeat.lower = 1;
        tok->u.repeat.upper = REPEAT_INFINITE;
        goto greedy_check;
        break;
  
      case '?':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_QMARK_ZERO_ONE)) break;
  #ifdef USE_VARIABLE_META_CHARS
      zero_or_one_time:
  #endif
        tok->type = TK_OP_REPEAT;
        tok->u.repeat.lower = 0;
        tok->u.repeat.upper = 1;
        goto greedy_check;
        break;
  
      case '{':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_BRACE_INTERVAL)) break;
        r = fetch_range_quantifier(&p, end, tok, env);
        if (r < 0) return r;  /* error */
        if (r == 0) goto greedy_check;
        else if (r == 2) { /* {n} */
          if (IS_SYNTAX_BV(syn, ONIG_SYN_FIXED_INTERVAL_IS_GREEDY_ONLY))
            goto possessive_check;
  
          goto greedy_check;
        }
        /* r == 1 : normal char */
        break;
  
      case '|':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_VBAR_ALT)) break;
        tok->type = TK_ALT;
        break;
  
      case '(':
        if (!PEND && PPEEK_IS('?') &&
            IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_QMARK_GROUP_EFFECT)) {
          PINC;
          if (!PEND && PPEEK_IS('#')) {
            PFETCH(c);
            while (1) {
              if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
              PFETCH(c);
              if (c == MC_ESC(syn)) {
                if (!PEND) PFETCH(c);
              }
              else {
                if (c == ')') break;
              }
            }
            goto start;
          }
          PUNFETCH;
        }
  
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_LPAREN_SUBEXP)) break;
        tok->type = TK_SUBEXP_OPEN;
        break;
  
      case ')':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_LPAREN_SUBEXP)) break;
        tok->type = TK_SUBEXP_CLOSE;
        break;
  
      case '^':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_LINE_ANCHOR)) break;
        tok->type = TK_ANCHOR;
        tok->u.subtype = (IS_SINGLELINE(env->options)
  			? ANCHOR_BEGIN_BUF : ANCHOR_BEGIN_LINE);
        break;
  
      case '$':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_LINE_ANCHOR)) break;
        tok->type = TK_ANCHOR;
        tok->u.subtype = (IS_SINGLELINE(env->options)
  			? ANCHOR_SEMI_END_BUF : ANCHOR_END_LINE);
        break;
  
      case '[':
        if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_BRACKET_CC)) break;
        tok->type = TK_CC_OPEN;
        break;
  
      case ']':
        if (*src > env->pattern)   /* /].../ is allowed. */
          CLOSE_BRACKET_WITHOUT_ESC_WARN(env, (UChar* )"]");
        break;
  
      case '#':
        if (IS_EXTEND(env->options)) {
          while (!PEND) {
            PFETCH(c);
            if (ONIGENC_IS_CODE_NEWLINE(enc, c))
              break;
          }
          goto start;
          break;
        }
        break;
  
      case ' ': case '\t': case '\n': case '\r': case '\f':
        if (IS_EXTEND(env->options))
          goto start;
        break;
  
      default:
        /* string */
        break;
      }
    }
  
  #ifdef USE_VARIABLE_META_CHARS
   out:
  #endif
    *src = p;
    return tok->type;
  }
  
  static int
  add_ctype_to_cc_by_range(CClassNode* cc, int ctype ARG_UNUSED, int not,
                           OnigEncoding enc ARG_UNUSED, OnigCodePoint sb_out,
                           const OnigCodePoint mbr[])
  {
    int i, r;
    OnigCodePoint j;
  
    int n = ONIGENC_CODE_RANGE_NUM(mbr);
  
    if (not == 0) {
      for (i = 0; i < n; i++) {
        for (j  = ONIGENC_CODE_RANGE_FROM(mbr, i);
             j <= ONIGENC_CODE_RANGE_TO(mbr, i); j++) {
          if (j >= sb_out) {
            if (j > ONIGENC_CODE_RANGE_FROM(mbr, i)) {
              r = add_code_range_to_buf(&(cc->mbuf), j,
                                        ONIGENC_CODE_RANGE_TO(mbr, i));
              if (r != 0) return r;
              i++;
            }
  
            goto sb_end;
          }
          BITSET_SET_BIT(cc->bs, j);
        }
      }
  
    sb_end:
      for ( ; i < n; i++) {
        r = add_code_range_to_buf(&(cc->mbuf),
                                  ONIGENC_CODE_RANGE_FROM(mbr, i),
                                  ONIGENC_CODE_RANGE_TO(mbr, i));
        if (r != 0) return r;
      }
    }
    else {
      OnigCodePoint prev = 0;
  
      for (i = 0; i < n; i++) {
        for (j = prev; j < ONIGENC_CODE_RANGE_FROM(mbr, i); j++) {
          if (j >= sb_out) {
            goto sb_end2;
          }
          BITSET_SET_BIT(cc->bs, j);
        }
        prev = ONIGENC_CODE_RANGE_TO(mbr, i) + 1;
      }
      for (j = prev; j < sb_out; j++) {
        BITSET_SET_BIT(cc->bs, j);
      }
  
    sb_end2:
      prev = sb_out;
  
      for (i = 0; i < n; i++) {
        if (prev < ONIGENC_CODE_RANGE_FROM(mbr, i)) {
          r = add_code_range_to_buf(&(cc->mbuf), prev,
                                    ONIGENC_CODE_RANGE_FROM(mbr, i) - 1);
          if (r != 0) return r;
        }
        prev = ONIGENC_CODE_RANGE_TO(mbr, i) + 1;
        if (prev == 0) goto end;
      }
  
      r = add_code_range_to_buf(&(cc->mbuf), prev, MAX_CODE_POINT);
      if (r != 0) return r;
    }
  
   end:
    return 0;
  }
  
  static int
  add_ctype_to_cc_by_range_limit(CClassNode* cc, int ctype ARG_UNUSED, int not,
                                 OnigEncoding enc ARG_UNUSED,
                                 OnigCodePoint sb_out,
                                 const OnigCodePoint mbr[], OnigCodePoint limit)
  {
    int i, r;
    OnigCodePoint j;
    OnigCodePoint from;
    OnigCodePoint to;
  
    int n = ONIGENC_CODE_RANGE_NUM(mbr);
  
    if (not == 0) {
      for (i = 0; i < n; i++) {
        for (j  = ONIGENC_CODE_RANGE_FROM(mbr, i);
             j <= ONIGENC_CODE_RANGE_TO(mbr, i); j++) {
          if (j > limit) goto end;
          if (j >= sb_out) {
            if (j > ONIGENC_CODE_RANGE_FROM(mbr, i)) {
              to = ONIGENC_CODE_RANGE_TO(mbr, i);
              if (to > limit) to = limit;
              r = add_code_range_to_buf(&(cc->mbuf), j, to);
              if (r != 0) return r;
              i++;
            }
  
            goto sb_end;
          }
          BITSET_SET_BIT(cc->bs, j);
        }
      }
  
    sb_end:
      for ( ; i < n; i++) {
        from = ONIGENC_CODE_RANGE_FROM(mbr, i);
        to   = ONIGENC_CODE_RANGE_TO(mbr, i);
        if (from > limit) break;
        if (to   > limit) to = limit;
        r = add_code_range_to_buf(&(cc->mbuf), from, to);
        if (r != 0) return r;
      }
    }
    else {
      OnigCodePoint prev = 0;
  
      for (i = 0; i < n; i++) {
        from = ONIGENC_CODE_RANGE_FROM(mbr, i);
        if (from > limit) {
          for (j = prev; j < sb_out; j++) {
            BITSET_SET_BIT(cc->bs, j);
          }
          goto sb_end2;
        }
        for (j = prev; j < from; j++) {
          if (j >= sb_out) goto sb_end2;
          BITSET_SET_BIT(cc->bs, j);
        }
        prev = ONIGENC_CODE_RANGE_TO(mbr, i);
        if (prev > limit) prev = limit;
        prev++;
        if (prev == 0) goto end;
      }
      for (j = prev; j < sb_out; j++) {
        BITSET_SET_BIT(cc->bs, j);
      }
  
    sb_end2:
      prev = sb_out;
  
      for (i = 0; i < n; i++) {
        from = ONIGENC_CODE_RANGE_FROM(mbr, i);
        if (from > limit) goto last;
  
        if (prev < from) {
          r = add_code_range_to_buf(&(cc->mbuf), prev, from - 1);
          if (r != 0) return r;
        }
        prev = ONIGENC_CODE_RANGE_TO(mbr, i);
        if (prev > limit) prev = limit;
        prev++;
        if (prev == 0) goto end;
      }
  
    last:
      r = add_code_range_to_buf(&(cc->mbuf), prev, MAX_CODE_POINT);
      if (r != 0) return r;
    }
  
   end:
    return 0;
  }
  
  static int
  add_ctype_to_cc(CClassNode* cc, int ctype, int not, ScanEnv* env)
  {
  #define ASCII_LIMIT    127
  
    int c, r;
    int ascii_mode;
    const OnigCodePoint *ranges;
    OnigCodePoint limit;
    OnigCodePoint sb_out;
    OnigEncoding enc = env->enc;
  
    ascii_mode = IS_ASCII_MODE_CTYPE_OPTION(ctype, env->options);
  
    r = ONIGENC_GET_CTYPE_CODE_RANGE(enc, ctype, &sb_out, &ranges);
    if (r == 0) {
      if (ascii_mode == 0)
        r = add_ctype_to_cc_by_range(cc, ctype, not, env->enc, sb_out, ranges);
      else
        r = add_ctype_to_cc_by_range_limit(cc, ctype, not, env->enc, sb_out,
                                           ranges, ASCII_LIMIT);
      return r;
    }
    else if (r != ONIG_NO_SUPPORT_CONFIG) {
      return r;
    }
  
    r = 0;
    limit = ascii_mode ? ASCII_LIMIT : SINGLE_BYTE_SIZE;
  
    switch (ctype) {
    case ONIGENC_CTYPE_ALPHA:
    case ONIGENC_CTYPE_BLANK:
    case ONIGENC_CTYPE_CNTRL:
    case ONIGENC_CTYPE_DIGIT:
    case ONIGENC_CTYPE_LOWER:
    case ONIGENC_CTYPE_PUNCT:
    case ONIGENC_CTYPE_SPACE:
    case ONIGENC_CTYPE_UPPER:
    case ONIGENC_CTYPE_XDIGIT:
    case ONIGENC_CTYPE_ASCII:
    case ONIGENC_CTYPE_ALNUM:
      if (not != 0) {
        for (c = 0; c < limit; c++) {
          if (! ONIGENC_IS_CODE_CTYPE(enc, (OnigCodePoint )c, ctype))
            BITSET_SET_BIT(cc->bs, c);
        }
        for (c = limit; c < SINGLE_BYTE_SIZE; c++) {
          BITSET_SET_BIT(cc->bs, c);
        }
  
        ADD_ALL_MULTI_BYTE_RANGE(enc, cc->mbuf);
      }
      else {
        for (c = 0; c < limit; c++) {
          if (ONIGENC_IS_CODE_CTYPE(enc, (OnigCodePoint )c, ctype))
            BITSET_SET_BIT(cc->bs, c);
        }
      }
      break;
  
    case ONIGENC_CTYPE_GRAPH:
    case ONIGENC_CTYPE_PRINT:
    case ONIGENC_CTYPE_WORD:
      if (not != 0) {
        for (c = 0; c < limit; c++) {
          if (ONIGENC_CODE_TO_MBCLEN(enc, c) > 0 /* check invalid code point */
              && ! ONIGENC_IS_CODE_CTYPE(enc, (OnigCodePoint )c, ctype))
            BITSET_SET_BIT(cc->bs, c);
        }
        for (c = limit; c < SINGLE_BYTE_SIZE; c++) {
          if (ONIGENC_CODE_TO_MBCLEN(enc, c) > 0)
            BITSET_SET_BIT(cc->bs, c);
        }
      }
      else {
        for (c = 0; c < limit; c++) {
          if (ONIGENC_IS_CODE_CTYPE(enc, (OnigCodePoint )c, ctype))
            BITSET_SET_BIT(cc->bs, c);
        }
        if (ascii_mode == 0)
          ADD_ALL_MULTI_BYTE_RANGE(enc, cc->mbuf);
      }
      break;
  
    default:
      return ONIGERR_PARSER_BUG;
      break;
    }
  
    return r;
  }
  
  static int
  parse_posix_bracket(CClassNode* cc, UChar** src, UChar* end, ScanEnv* env)
  {
  #define POSIX_BRACKET_CHECK_LIMIT_LENGTH  20
  #define POSIX_BRACKET_NAME_MIN_LEN         4
  
    static PosixBracketEntryType PBS[] = {
      { (UChar* )"alnum",  ONIGENC_CTYPE_ALNUM,  5 },
      { (UChar* )"alpha",  ONIGENC_CTYPE_ALPHA,  5 },
      { (UChar* )"blank",  ONIGENC_CTYPE_BLANK,  5 },
      { (UChar* )"cntrl",  ONIGENC_CTYPE_CNTRL,  5 },
      { (UChar* )"digit",  ONIGENC_CTYPE_DIGIT,  5 },
      { (UChar* )"graph",  ONIGENC_CTYPE_GRAPH,  5 },
      { (UChar* )"lower",  ONIGENC_CTYPE_LOWER,  5 },
      { (UChar* )"print",  ONIGENC_CTYPE_PRINT,  5 },
      { (UChar* )"punct",  ONIGENC_CTYPE_PUNCT,  5 },
      { (UChar* )"space",  ONIGENC_CTYPE_SPACE,  5 },
      { (UChar* )"upper",  ONIGENC_CTYPE_UPPER,  5 },
      { (UChar* )"xdigit", ONIGENC_CTYPE_XDIGIT, 6 },
      { (UChar* )"ascii",  ONIGENC_CTYPE_ASCII,  5 },
      { (UChar* )"word",   ONIGENC_CTYPE_WORD,   4 },
      { (UChar* )NULL,     -1, 0 }
    };
  
    PosixBracketEntryType *pb;
    int not, i, r;
    OnigCodePoint c;
    OnigEncoding enc = env->enc;
    UChar *p = *src;
  
    if (PPEEK_IS('^')) {
      PINC_S;
      not = 1;
    }
    else
      not = 0;
  
    if (onigenc_strlen(enc, p, end) < POSIX_BRACKET_NAME_MIN_LEN + 3)
      goto not_posix_bracket;
  
    for (pb = PBS; IS_NOT_NULL(pb->name); pb++) {
      if (onigenc_with_ascii_strncmp(enc, p, end, pb->name, pb->len) == 0) {
        p = (UChar* )onigenc_step(enc, p, end, pb->len);
        if (onigenc_with_ascii_strncmp(enc, p, end, (UChar* )":]", 2) != 0)
          return ONIGERR_INVALID_POSIX_BRACKET_TYPE;
  
        r = add_ctype_to_cc(cc, pb->ctype, not, env);
        if (r != 0) return r;
  
        PINC_S; PINC_S;
        *src = p;
        return 0;
      }
    }
  
   not_posix_bracket:
    c = 0;
    i = 0;
    while (!PEND && ((c = PPEEK) != ':') && c != ']') {
      PINC_S;
      if (++i > POSIX_BRACKET_CHECK_LIMIT_LENGTH) break;
    }
    if (c == ':' && ! PEND) {
      PINC_S;
      if (! PEND) {
        PFETCH_S(c);
        if (c == ']')
          return ONIGERR_INVALID_POSIX_BRACKET_TYPE;
      }
    }
  
    return 1;  /* 1: is not POSIX bracket, but no error. */
  }
  
  static int
  fetch_char_property_to_ctype(UChar** src, UChar* end, ScanEnv* env)
  {
    int r;
    OnigCodePoint c;
    OnigEncoding enc = env->enc;
    UChar *prev, *start, *p = *src;
  
    r = 0;
    start = prev = p;
  
    while (!PEND) {
      prev = p;
      PFETCH_S(c);
      if (c == '}') {
        r = ONIGENC_PROPERTY_NAME_TO_CTYPE(enc, start, prev);
        if (r < 0) break;
  
        *src = p;
        return r;
      }
      else if (c == '(' || c == ')' || c == '{' || c == '|') {
        r = ONIGERR_INVALID_CHAR_PROPERTY_NAME;
        break;
      }
    }
  
    onig_scan_env_set_error_string(env, r, *src, prev);
    return r;
  }
  
  static int
  parse_char_property(Node** np, OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
  {
    int r, ctype;
    CClassNode* cc;
  
    ctype = fetch_char_property_to_ctype(src, end, env);
    if (ctype < 0) return ctype;
  
    *np = node_new_cclass();
    CHECK_NULL_RETURN_MEMERR(*np);
    cc = CCLASS_(*np);
    r = add_ctype_to_cc(cc, ctype, 0, env);
    if (r != 0) return r;
    if (tok->u.prop.not != 0) NCCLASS_SET_NOT(cc);
  
    return 0;
  }
  
  
  enum CCSTATE {
    CCS_VALUE,
    CCS_RANGE,
    CCS_COMPLETE,
    CCS_START
  };
  
  enum CCVALTYPE {
    CCV_SB,
    CCV_CODE_POINT,
    CCV_CLASS
  };
  
  static int
  next_state_class(CClassNode* cc, OnigCodePoint* vs, enum CCVALTYPE* type,
                   enum CCSTATE* state, ScanEnv* env)
  {
    int r;
  
    if (*state == CCS_RANGE)
      return ONIGERR_CHAR_CLASS_VALUE_AT_END_OF_RANGE;
  
    if (*state == CCS_VALUE && *type != CCV_CLASS) {
      if (*type == CCV_SB)
        BITSET_SET_BIT(cc->bs, (int )(*vs));
      else if (*type == CCV_CODE_POINT) {
        r = add_code_range(&(cc->mbuf), env, *vs, *vs);
        if (r < 0) return r;
      }
    }
  
    *state = CCS_VALUE;
    *type  = CCV_CLASS;
    return 0;
  }
  
  static int
  next_state_val(CClassNode* cc, OnigCodePoint *from, OnigCodePoint to,
                 int* from_israw, int to_israw,
                 enum CCVALTYPE intype, enum CCVALTYPE* type,
                 enum CCSTATE* state, ScanEnv* env)
  {
    int r;
  
    switch (*state) {
    case CCS_VALUE:
      if (*type == CCV_SB) {
        if (*from > 0xff)
            return ONIGERR_INVALID_CODE_POINT_VALUE;
  
        BITSET_SET_BIT(cc->bs, (int )(*from));
      }
      else if (*type == CCV_CODE_POINT) {
        r = add_code_range(&(cc->mbuf), env, *from, *from);
        if (r < 0) return r;
      }
      break;
  
    case CCS_RANGE:
      if (intype == *type) {
        if (intype == CCV_SB) {
          if (*from > 0xff || to > 0xff)
            return ONIGERR_INVALID_CODE_POINT_VALUE;
  
          if (*from > to) {
            if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_ALLOW_EMPTY_RANGE_IN_CC))
              goto ccs_range_end;
            else
              return ONIGERR_EMPTY_RANGE_IN_CHAR_CLASS;
          }
          bitset_set_range(cc->bs, (int )*from, (int )to);
        }
        else {
          r = add_code_range(&(cc->mbuf), env, *from, to);
          if (r < 0) return r;
        }
      }
      else {
        if (*from > to) {
          if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_ALLOW_EMPTY_RANGE_IN_CC))
            goto ccs_range_end;
          else
            return ONIGERR_EMPTY_RANGE_IN_CHAR_CLASS;
        }
        bitset_set_range(cc->bs, (int )*from, (int )(to < 0xff ? to : 0xff));
        r = add_code_range(&(cc->mbuf), env, (OnigCodePoint )*from, to);
        if (r < 0) return r;
      }
    ccs_range_end:
      *state = CCS_COMPLETE;
      break;
  
    case CCS_COMPLETE:
    case CCS_START:
      *state = CCS_VALUE;
      break;
  
    default:
      break;
    }
  
    *from_israw = to_israw;
    *from       = to;
    *type       = intype;
    return 0;
  }
  
  static int
  code_exist_check(OnigCodePoint c, UChar* from, UChar* end, int ignore_escaped,
                   ScanEnv* env)
  {
    int in_esc;
    OnigCodePoint code;
    OnigEncoding enc = env->enc;
    UChar* p = from;
  
    in_esc = 0;
    while (! PEND) {
      if (ignore_escaped && in_esc) {
        in_esc = 0;
      }
      else {
        PFETCH_S(code);
        if (code == c) return 1;
        if (code == MC_ESC(env->syntax)) in_esc = 1;
      }
    }
    return 0;
  }
  
  static int
  parse_char_class(Node** np, OnigToken* tok, UChar** src, UChar* end,
  		 ScanEnv* env)
  {
    int r, neg, len, fetched, and_start;
    OnigCodePoint v, vs;
    UChar *p;
    Node* node;
    CClassNode *cc, *prev_cc;
    CClassNode work_cc;
  
    enum CCSTATE state;
    enum CCVALTYPE val_type, in_type;
    int val_israw, in_israw;
  
    *np = NULL_NODE;
    env->parse_depth++;
    if (env->parse_depth > ParseDepthLimit)
      return ONIGERR_PARSE_DEPTH_LIMIT_OVER;
    prev_cc = (CClassNode* )NULL;
    r = fetch_token_in_cc(tok, src, end, env);
    if (r == TK_CHAR && tok->u.c == '^' && tok->escaped == 0) {
      neg = 1;
      r = fetch_token_in_cc(tok, src, end, env);
    }
    else {
      neg = 0;
    }
  
    if (r < 0) return r;
    if (r == TK_CC_CLOSE) {
      if (! code_exist_check((OnigCodePoint )']',
                             *src, env->pattern_end, 1, env))
        return ONIGERR_EMPTY_CHAR_CLASS;
  
      CC_ESC_WARN(env, (UChar* )"]");
      r = tok->type = TK_CHAR;  /* allow []...] */
    }
  
    *np = node = node_new_cclass();
    CHECK_NULL_RETURN_MEMERR(node);
    cc = CCLASS_(node);
  
    and_start = 0;
    state = CCS_START;
    p = *src;
    while (r != TK_CC_CLOSE) {
      fetched = 0;
      switch (r) {
      case TK_CHAR:
      any_char_in:
        len = ONIGENC_CODE_TO_MBCLEN(env->enc, tok->u.c);
        if (len > 1) {
          in_type = CCV_CODE_POINT;
        }
        else if (len < 0) {
          r = len;
          goto err;
        }
        else {
          /* sb_char: */
          in_type = CCV_SB;
        }
        v = (OnigCodePoint )tok->u.c;
        in_israw = 0;
        goto val_entry2;
        break;
  
      case TK_RAW_BYTE:
        /* tok->base != 0 : octal or hexadec. */
        if (! ONIGENC_IS_SINGLEBYTE(env->enc) && tok->base != 0) {
          UChar buf[ONIGENC_CODE_TO_MBC_MAXLEN];
          UChar* bufe = buf + ONIGENC_CODE_TO_MBC_MAXLEN;
          UChar* psave = p;
          int i, base = tok->base;
  
          buf[0] = tok->u.c;
          for (i = 1; i < ONIGENC_MBC_MAXLEN(env->enc); i++) {
            r = fetch_token_in_cc(tok, &p, end, env);
            if (r < 0) goto err;
            if (r != TK_RAW_BYTE || tok->base != base) {
              fetched = 1;
              break;
            }
            buf[i] = tok->u.c;
          }
  
          if (i < ONIGENC_MBC_MINLEN(env->enc)) {
            r = ONIGERR_TOO_SHORT_MULTI_BYTE_STRING;
            goto err;
          }
  
          len = enclen(env->enc, buf);
          if (i < len) {
            r = ONIGERR_TOO_SHORT_MULTI_BYTE_STRING;
            goto err;
          }
          else if (i > len) { /* fetch back */
            p = psave;
            for (i = 1; i < len; i++) {
              r = fetch_token_in_cc(tok, &p, end, env);
            }
            fetched = 0;
          }
  
          if (i == 1) {
            v = (OnigCodePoint )buf[0];
            goto raw_single;
          }
          else {
            v = ONIGENC_MBC_TO_CODE(env->enc, buf, bufe);
            in_type = CCV_CODE_POINT;
          }
        }
        else {
          v = (OnigCodePoint )tok->u.c;
        raw_single:
          in_type = CCV_SB;
        }
        in_israw = 1;
        goto val_entry2;
        break;
  
      case TK_CODE_POINT:
        v = tok->u.code;
        in_israw = 1;
      val_entry:
        len = ONIGENC_CODE_TO_MBCLEN(env->enc, v);
        if (len < 0) {
          r = len;
          goto err;
        }
        in_type = (len == 1 ? CCV_SB : CCV_CODE_POINT);
      val_entry2:
        r = next_state_val(cc, &vs, v, &val_israw, in_israw, in_type, &val_type,
  			 &state, env);
        if (r != 0) goto err;
        break;
  
      case TK_POSIX_BRACKET_OPEN:
        r = parse_posix_bracket(cc, &p, end, env);
        if (r < 0) goto err;
        if (r == 1) {  /* is not POSIX bracket */
          CC_ESC_WARN(env, (UChar* )"[");
          p = tok->backp;
          v = (OnigCodePoint )tok->u.c;
          in_israw = 0;
          goto val_entry;
        }
        goto next_class;
        break;
  
      case TK_CHAR_TYPE:
        r = add_ctype_to_cc(cc, tok->u.prop.ctype, tok->u.prop.not, env);
        if (r != 0) goto err;
  
      next_class:
        r = next_state_class(cc, &vs, &val_type, &state, env);
        if (r != 0) goto err;
        break;
  
      case TK_CHAR_PROPERTY:
        {
          int ctype = fetch_char_property_to_ctype(&p, end, env);
          if (ctype < 0) {
            r = ctype;
            goto err;
          }
          r = add_ctype_to_cc(cc, ctype, tok->u.prop.not, env);
          if (r != 0) goto err;
          goto next_class;
        }
        break;
  
      case TK_CC_RANGE:
        if (state == CCS_VALUE) {
          r = fetch_token_in_cc(tok, &p, end, env);
          if (r < 0) goto err;
          fetched = 1;
          if (r == TK_CC_CLOSE) { /* allow [x-] */
          range_end_val:
            v = (OnigCodePoint )'-';
            in_israw = 0;
            goto val_entry;
          }
          else if (r == TK_CC_AND) {
            CC_ESC_WARN(env, (UChar* )"-");
            goto range_end_val;
          }
  
          if (val_type == CCV_CLASS) {
            r = ONIGERR_UNMATCHED_RANGE_SPECIFIER_IN_CHAR_CLASS;
            goto err;
          }
  
          state = CCS_RANGE;
        }
        else if (state == CCS_START) {
          /* [-xa] is allowed */
          v = (OnigCodePoint )tok->u.c;
          in_israw = 0;
  
          r = fetch_token_in_cc(tok, &p, end, env);
          if (r < 0) goto err;
          fetched = 1;
          /* [--x] or [a&&-x] is warned. */
          if (r == TK_CC_RANGE || and_start != 0)
            CC_ESC_WARN(env, (UChar* )"-");
  
          goto val_entry;
        }
        else if (state == CCS_RANGE) {
          CC_ESC_WARN(env, (UChar* )"-");
          goto any_char_in;  /* [!--x] is allowed */
        }
        else { /* CCS_COMPLETE */
          r = fetch_token_in_cc(tok, &p, end, env);
          if (r < 0) goto err;
          fetched = 1;
          if (r == TK_CC_CLOSE) goto range_end_val; /* allow [a-b-] */
          else if (r == TK_CC_AND) {
            CC_ESC_WARN(env, (UChar* )"-");
            goto range_end_val;
          }
  	
          if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_ALLOW_DOUBLE_RANGE_OP_IN_CC)) {
            CC_ESC_WARN(env, (UChar* )"-");
            goto range_end_val;   /* [0-9-a] is allowed as [0-9\-a] */
          }
          r = ONIGERR_UNMATCHED_RANGE_SPECIFIER_IN_CHAR_CLASS;
          goto err;
        }
        break;
  
      case TK_CC_CC_OPEN: /* [ */
        {
          Node *anode;
          CClassNode* acc;
  
          r = parse_char_class(&anode, tok, &p, end, env);
          if (r != 0) {
            onig_node_free(anode);
            goto cc_open_err;
          }
          acc = CCLASS_(anode);
          r = or_cclass(cc, acc, env->enc);
          onig_node_free(anode);
  
        cc_open_err:
          if (r != 0) goto err;
        }
        break;
  
      case TK_CC_AND: /* && */
        {
          if (state == CCS_VALUE) {
            r = next_state_val(cc, &vs, 0, &val_israw, 0, val_type,
                               &val_type, &state, env);
            if (r != 0) goto err;
          }
          /* initialize local variables */
          and_start = 1;
          state = CCS_START;
  
          if (IS_NOT_NULL(prev_cc)) {
            r = and_cclass(prev_cc, cc, env->enc);
            if (r != 0) goto err;
            bbuf_free(cc->mbuf);
          }
          else {
            prev_cc = cc;
            cc = &work_cc;
          }
          initialize_cclass(cc);
        }
        break;
  
      case TK_EOT:
        r = ONIGERR_PREMATURE_END_OF_CHAR_CLASS;
        goto err;
        break;
      default:
        r = ONIGERR_PARSER_BUG;
        goto err;
        break;
      }
  
      if (fetched)
        r = tok->type;
      else {
        r = fetch_token_in_cc(tok, &p, end, env);
        if (r < 0) goto err;
      }
    }
  
    if (state == CCS_VALUE) {
      r = next_state_val(cc, &vs, 0, &val_israw, 0, val_type,
  		       &val_type, &state, env);
      if (r != 0) goto err;
    }
  
    if (IS_NOT_NULL(prev_cc)) {
      r = and_cclass(prev_cc, cc, env->enc);
      if (r != 0) goto err;
      bbuf_free(cc->mbuf);
      cc = prev_cc;
    }
  
    if (neg != 0)
      NCCLASS_SET_NOT(cc);
    else
      NCCLASS_CLEAR_NOT(cc);
    if (IS_NCCLASS_NOT(cc) &&
        IS_SYNTAX_BV(env->syntax, ONIG_SYN_NOT_NEWLINE_IN_NEGATIVE_CC)) {
      int is_empty = (IS_NULL(cc->mbuf) ? 1 : 0);
      if (is_empty != 0)
        BITSET_IS_EMPTY(cc->bs, is_empty);
  
      if (is_empty == 0) {
  #define NEWLINE_CODE    0x0a
  
        if (ONIGENC_IS_CODE_NEWLINE(env->enc, NEWLINE_CODE)) {
          if (ONIGENC_CODE_TO_MBCLEN(env->enc, NEWLINE_CODE) == 1)
            BITSET_SET_BIT(cc->bs, NEWLINE_CODE);
          else
            add_code_range(&(cc->mbuf), env, NEWLINE_CODE, NEWLINE_CODE);
        }
      }
    }
    *src = p;
    env->parse_depth--;
    return 0;
  
   err:
    if (cc != CCLASS_(*np))
      bbuf_free(cc->mbuf);
    return r;
  }
  
  static int parse_subexp(Node** top, OnigToken* tok, int term,
                          UChar** src, UChar* end, ScanEnv* env);
  
  static int
  parse_enclosure(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
                  ScanEnv* env)
  {
    int r, num;
    Node *target;
    OnigOptionType option;
    OnigCodePoint c;
    int list_capture;
    OnigEncoding enc = env->enc;
  
    UChar* p = *src;
    PFETCH_READY;
  
    *np = NULL;
    if (PEND) return ONIGERR_END_PATTERN_WITH_UNMATCHED_PARENTHESIS;
  
    option = env->options;
    if (PPEEK_IS('?') &&
        IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_QMARK_GROUP_EFFECT)) {
      PINC;
      if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
  
      PFETCH(c);
      switch (c) {
      case ':':   /* (?:...) grouping only */
      group:
        r = fetch_token(tok, &p, end, env);
        if (r < 0) return r;
        r = parse_subexp(np, tok, term, &p, end, env);
        if (r < 0) return r;
        *src = p;
        return 1; /* group */
        break;
  
      case '=':
        *np = onig_node_new_anchor(ANCHOR_PREC_READ, 0);
        break;
      case '!':  /*         preceding read */
        *np = onig_node_new_anchor(ANCHOR_PREC_READ_NOT, 0);
        break;
      case '>':            /* (?>...) stop backtrack */
        *np = node_new_enclosure(ENCLOSURE_STOP_BACKTRACK);
        break;
  
      case '\'':
        if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_QMARK_LT_NAMED_GROUP)) {
          goto named_group1;
        }
        else
          return ONIGERR_UNDEFINED_GROUP_OPTION;
        break;
  
      case '<':   /* look behind (?<=...), (?<!...) */
        if (PEND) return ONIGERR_END_PATTERN_WITH_UNMATCHED_PARENTHESIS;
        PFETCH(c);
        if (c == '=')
          *np = onig_node_new_anchor(ANCHOR_LOOK_BEHIND, 0);
        else if (c == '!')
          *np = onig_node_new_anchor(ANCHOR_LOOK_BEHIND_NOT, 0);
        else {
          if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_QMARK_LT_NAMED_GROUP)) {
            UChar *name;
            UChar *name_end;
            enum REF_NUM num_type;
  
            PUNFETCH;
            c = '<';
  
          named_group1:
            list_capture = 0;
  
          named_group2:
            name = p;
            r = fetch_name((OnigCodePoint )c, &p, end, &name_end, env, &num,
                           &num_type, 0);
            if (r < 0) return r;
  
            num = scan_env_add_mem_entry(env);
            if (num < 0) return num;
            if (list_capture != 0 && num >= (int )MEM_STATUS_BITS_NUM)
              return ONIGERR_GROUP_NUMBER_OVER_FOR_CAPTURE_HISTORY;
  
            r = name_add(env->reg, name, name_end, num, env);
            if (r != 0) return r;
            *np = node_new_memory(1);
            CHECK_NULL_RETURN_MEMERR(*np);
            ENCLOSURE_(*np)->m.regnum = num;
            if (list_capture != 0)
              MEM_STATUS_ON_SIMPLE(env->capture_history, num);
            env->num_named++;
          }
          else {
            return ONIGERR_UNDEFINED_GROUP_OPTION;
          }
        }
        break;
  
      case '~':
        if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_QMARK_TILDE_ABSENT_GROUP)) {
          Node* absent;
          Node* expr;
          int head_bar;
          int is_range_cutter;
  
          if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
  
          if (PPEEK_IS('|')) { // (?~|generator|absent)
            PINC;
            if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
  
            head_bar = 1;
            if (PPEEK_IS(')')) { // (?~|)  : range clear
              PINC;
              r = make_range_clear(np, env);
              if (r != 0) return r;
              goto end;
            }
          }
          else
            head_bar = 0;
  
          r = fetch_token(tok, &p, end, env);
          if (r < 0) return r;
          r = parse_subexp(&absent, tok, term, &p, end, env);
          if (r < 0) {
            onig_node_free(absent);
            return r;
          }
  
          expr = NULL_NODE;
          is_range_cutter = 0;
          if (head_bar != 0) {
            Node* top = absent;
            if (NODE_TYPE(top) != NODE_ALT || IS_NULL(NODE_CDR(top))) {
              expr = NULL_NODE;
              is_range_cutter = 1;
              //return ONIGERR_INVALID_ABSENT_GROUP_GENERATOR_PATTERN;
            }
            else {
              absent = NODE_CAR(top);
              expr   = NODE_CDR(top);
              NODE_CAR(top) = NULL_NODE;
              NODE_CDR(top) = NULL_NODE;
              onig_node_free(top);
              if (IS_NULL(NODE_CDR(expr))) {
                top = expr;
                expr = NODE_CAR(top);
                NODE_CAR(top) = NULL_NODE;
                onig_node_free(top);
              }
            }
          }
  
          r = make_absent_tree(np, absent, expr, is_range_cutter, env);
          if (r != 0) {
            return r;
          }
          goto end;
        }
        else {
          return ONIGERR_UNDEFINED_GROUP_OPTION;
        }
        break;
  
      case '(':
        /* (?()...) */
        if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_QMARK_LPAREN_IF_ELSE)) {
          UChar *prev;
          Node* condition;
          int condition_is_checker;
  
          if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
          PFETCH(c);
          if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
  
          if (IS_CODE_DIGIT_ASCII(enc, c)
              || c == '-' || c == '+' || c == '<' || c == '\'') {
            UChar* name_end;
            int back_num;
            int exist_level;
            int level;
            enum REF_NUM num_type;
            int is_enclosed;
  
            is_enclosed = (c == '<' || c == '\'') ? 1 : 0;
            if (! is_enclosed)
              PUNFETCH;
            prev = p;
            exist_level = 0;
  #ifdef USE_BACKREF_WITH_LEVEL
            name_end = NULL_UCHARP; /* no need. escape gcc warning. */
            r = fetch_name_with_level(
                      (OnigCodePoint )(is_enclosed != 0 ? c : '('),
                      &p, end, &name_end,
                      env, &back_num, &level, &num_type);
            if (r == 1) exist_level = 1;
  #else
            r = fetch_name((OnigCodePoint )(is_enclosed != 0 ? c : '('),
                           &p, end, &name_end, env, &back_num, &num_type, 1);
  #endif
            if (r < 0) {
              if (is_enclosed == 0) {
                goto any_condition;
              }
              else
                return r;
            }
  
            condition_is_checker = 1;
            if (num_type != IS_NOT_NUM) {
              if (num_type == IS_REL_NUM) {
                back_num = backref_rel_to_abs(back_num, env);
              }
              if (back_num <= 0)
                return ONIGERR_INVALID_BACKREF;
  
              if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_STRICT_CHECK_BACKREF)) {
                if (back_num > env->num_mem ||
                    IS_NULL(SCANENV_MEMENV(env)[back_num].node))
                  return ONIGERR_INVALID_BACKREF;
              }
  
              condition = node_new_backref_checker(1, &back_num, 0,
  #ifdef USE_BACKREF_WITH_LEVEL
                                                   exist_level, level,
  #endif
                                                   env);
            }
            else {
              int num;
              int* backs;
  
              num = onig_name_to_group_numbers(env->reg, prev, name_end, &backs);
              if (num <= 0) {
                onig_scan_env_set_error_string(env,
                          ONIGERR_UNDEFINED_NAME_REFERENCE, prev, name_end);
                return ONIGERR_UNDEFINED_NAME_REFERENCE;
              }
              if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_STRICT_CHECK_BACKREF)) {
                int i;
                for (i = 0; i < num; i++) {
                  if (backs[i] > env->num_mem ||
                      IS_NULL(SCANENV_MEMENV(env)[backs[i]].node))
                    return ONIGERR_INVALID_BACKREF;
                }
              }
  
              condition = node_new_backref_checker(num, backs, 1,
  #ifdef USE_BACKREF_WITH_LEVEL
                                                   exist_level, level,
  #endif
                                                   env);
            }
  
            if (is_enclosed != 0) {
              if (PEND) goto err_if_else;
              PFETCH(c);
              if (c != ')') goto err_if_else;
            }
          }
          else {
          any_condition:
            PUNFETCH;
            condition_is_checker = 0;
            r = fetch_token(tok, &p, end, env);
            if (r < 0) return r;
            r = parse_subexp(&condition, tok, term, &p, end, env);
            if (r < 0) {
              onig_node_free(condition);
              return r;
            }
          }
  
          CHECK_NULL_RETURN_MEMERR(condition);
  
          if (PEND) {
          err_if_else:
            onig_node_free(condition);
            return ONIGERR_END_PATTERN_IN_GROUP;
          }
  
          if (PPEEK_IS(')')) { /* case: empty body: make backref checker */
            if (condition_is_checker == 0) {
              onig_node_free(condition);
              return ONIGERR_INVALID_IF_ELSE_SYNTAX;
            }
            PFETCH(c);
            *np = condition;
          }
          else { /* if-else */
            int then_is_empty;
            Node *Then, *Else;
  
            if (PPEEK_IS('|')) {
              PFETCH(c);
              Then = 0;
              then_is_empty = 1;
            }
            else
              then_is_empty = 0;
  
            r = fetch_token(tok, &p, end, env);
            if (r < 0) {
              onig_node_free(condition);
              return r;
            }
            r = parse_subexp(&target, tok, term, &p, end, env);
            if (r < 0) {
              onig_node_free(condition);
              onig_node_free(target);
              return r;
            }
  
            if (then_is_empty != 0) {
              Else = target;
            }
            else {
              if (NODE_TYPE(target) == NODE_ALT) {
                Then = NODE_CAR(target);
                if (NODE_CDR(NODE_CDR(target)) == NULL_NODE) {
                  Else = NODE_CAR(NODE_CDR(target));
                  cons_node_free_alone(NODE_CDR(target));
                }
                else {
                  Else = NODE_CDR(target);
                }
                cons_node_free_alone(target);
              }
              else {
                Then = target;
                Else = 0;
              }
            }
  
            *np = node_new_enclosure_if_else(condition, Then, Else);
            if (IS_NULL(*np)) {
              onig_node_free(condition);
              onig_node_free(Then);
              onig_node_free(Else);
              return ONIGERR_MEMORY;
            }
          }
          goto end;
        }
        else {
          return ONIGERR_UNDEFINED_GROUP_OPTION;
        }
        break;
  
      case '@':
        if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_ATMARK_CAPTURE_HISTORY)) {
          if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_QMARK_LT_NAMED_GROUP)) {
            PFETCH(c);
            if (c == '<' || c == '\'') {
              list_capture = 1;
              goto named_group2; /* (?@<name>...) */
            }
            PUNFETCH;
          }
  
          *np = node_new_memory(0);
          CHECK_NULL_RETURN_MEMERR(*np);
          num = scan_env_add_mem_entry(env);
          if (num < 0) {
            return num;
          }
          else if (num >= (int )MEM_STATUS_BITS_NUM) {
            return ONIGERR_GROUP_NUMBER_OVER_FOR_CAPTURE_HISTORY;
          }
          ENCLOSURE_(*np)->m.regnum = num;
          MEM_STATUS_ON_SIMPLE(env->capture_history, num);
        }
        else {
          return ONIGERR_UNDEFINED_GROUP_OPTION;
        }
        break;
  
  #ifdef USE_POSIXLINE_OPTION
      case 'p':
  #endif
      case '-': case 'i': case 'm': case 's': case 'x':
      case 'W': case 'D': case 'S': case 'P':
        {
          int neg = 0;
  
          while (1) {
            switch (c) {
            case ':':
            case ')':
              break;
  
            case '-':  neg = 1; break;
            case 'x':  OPTION_NEGATE(option, ONIG_OPTION_EXTEND,     neg); break;
            case 'i':  OPTION_NEGATE(option, ONIG_OPTION_IGNORECASE, neg); break;
            case 's':
              if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_OPTION_PERL)) {
                OPTION_NEGATE(option, ONIG_OPTION_MULTILINE,  neg);
              }
              else
                return ONIGERR_UNDEFINED_GROUP_OPTION;
              break;
  
            case 'm':
              if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_OPTION_PERL)) {
                OPTION_NEGATE(option, ONIG_OPTION_SINGLELINE, (neg == 0 ? 1 : 0));
              }
              else if (IS_SYNTAX_OP2(env->syntax, ONIG_SYN_OP2_OPTION_RUBY)) {
                OPTION_NEGATE(option, ONIG_OPTION_MULTILINE,  neg);
              }
              else
                return ONIGERR_UNDEFINED_GROUP_OPTION;
              break;
  #ifdef USE_POSIXLINE_OPTION
            case 'p':
              OPTION_NEGATE(option, ONIG_OPTION_MULTILINE|ONIG_OPTION_SINGLELINE, neg);
              break;
  #endif
            case 'W': OPTION_NEGATE(option, ONIG_OPTION_WORD_IS_ASCII, neg); break;
            case 'D': OPTION_NEGATE(option, ONIG_OPTION_DIGIT_IS_ASCII, neg); break;
            case 'S': OPTION_NEGATE(option, ONIG_OPTION_SPACE_IS_ASCII, neg); break;
            case 'P': OPTION_NEGATE(option, ONIG_OPTION_POSIX_IS_ASCII, neg); break;
  
            default:
              return ONIGERR_UNDEFINED_GROUP_OPTION;
            }
  
            if (c == ')') {
              *np = node_new_option(option);
              CHECK_NULL_RETURN_MEMERR(*np);
              *src = p;
              return 2; /* option only */
            }
            else if (c == ':') {
              OnigOptionType prev = env->options;
  
              env->options = option;
              r = fetch_token(tok, &p, end, env);
              if (r < 0) return r;
              r = parse_subexp(&target, tok, term, &p, end, env);
              env->options = prev;
              if (r < 0) {
                onig_node_free(target);
                return r;
              }
              *np = node_new_option(option);
              CHECK_NULL_RETURN_MEMERR(*np);
              NODE_BODY(*np) = target;
              *src = p;
              return 0;
            }
  
            if (PEND) return ONIGERR_END_PATTERN_IN_GROUP;
            PFETCH(c);
          }
        }
        break;
  
      default:
        return ONIGERR_UNDEFINED_GROUP_OPTION;
      }
    }
    else {
      if (ONIG_IS_OPTION_ON(env->options, ONIG_OPTION_DONT_CAPTURE_GROUP))
        goto group;
  
      *np = node_new_memory(0);
      CHECK_NULL_RETURN_MEMERR(*np);
      num = scan_env_add_mem_entry(env);
      if (num < 0) return num;
      ENCLOSURE_(*np)->m.regnum = num;
    }
  
    CHECK_NULL_RETURN_MEMERR(*np);
    r = fetch_token(tok, &p, end, env);
    if (r < 0) return r;
    r = parse_subexp(&target, tok, term, &p, end, env);
    if (r < 0) {
      onig_node_free(target);
      return r;
    }
  
    NODE_BODY(*np) = target;
  
    if (NODE_TYPE(*np) == NODE_ENCLOSURE) {
      if (ENCLOSURE_(*np)->type == ENCLOSURE_MEMORY) {
        /* Don't move this to previous of parse_subexp() */
        r = scan_env_set_mem_node(env, ENCLOSURE_(*np)->m.regnum, *np);
        if (r != 0) return r;
      }
    }
  
   end:
    *src = p;
    return 0;
  }
  
  static const char* PopularQStr[] = {
    "?", "*", "+", "??", "*?", "+?"
  };
  
  static const char* ReduceQStr[] = {
    "", "", "*", "*?", "??", "+ and ??", "+? and ?"
  };
  
  static int
  set_quantifier(Node* qnode, Node* target, int group, ScanEnv* env)
  {
    QuantNode* qn;
  
    qn = QUANT_(qnode);
    if (qn->lower == 1 && qn->upper == 1)
      return 1;
  
    switch (NODE_TYPE(target)) {
    case NODE_STRING:
      if (! group) {
        StrNode* sn = STR_(target);
        if (str_node_can_be_split(sn, env->enc)) {
          Node* n = str_node_split_last_char(sn, env->enc);
          if (IS_NOT_NULL(n)) {
            NODE_BODY(qnode) = n;
            return 2;
          }
        }
      }
      break;
  
    case NODE_QUANT:
      { /* check redundant double repeat. */
        /* verbose warn (?:.?)? etc... but not warn (.?)? etc... */
        QuantNode* qnt   = QUANT_(target);
        int nestq_num   = popular_quantifier_num(qn);
        int targetq_num = popular_quantifier_num(qnt);
  
  #ifdef USE_WARNING_REDUNDANT_NESTED_REPEAT_OPERATOR
        if (! NODE_IS_BY_NUMBER(qnode) && ! NODE_IS_BY_NUMBER(target) &&
            IS_SYNTAX_BV(env->syntax, ONIG_SYN_WARN_REDUNDANT_NESTED_REPEAT)) {
          UChar buf[WARN_BUFSIZE];
  
          switch(ReduceTypeTable[targetq_num][nestq_num]) {
          case RQ_ASIS:
            break;
  
          case RQ_DEL:
            if (onig_verb_warn != onig_null_warn) {
              onig_snprintf_with_pattern(buf, WARN_BUFSIZE, env->enc,
                                    env->pattern, env->pattern_end,
                                    (UChar* )"redundant nested repeat operator");
              (*onig_verb_warn)((char* )buf);
            }
            goto warn_exit;
            break;
  
          default:
            if (onig_verb_warn != onig_null_warn) {
              onig_snprintf_with_pattern(buf, WARN_BUFSIZE, env->enc,
                                         env->pattern, env->pattern_end,
              (UChar* )"nested repeat operator %s and %s was replaced with '%s'",
              PopularQStr[targetq_num], PopularQStr[nestq_num],
              ReduceQStr[ReduceTypeTable[targetq_num][nestq_num]]);
              (*onig_verb_warn)((char* )buf);
            }
            goto warn_exit;
            break;
          }
        }
  
      warn_exit:
  #endif
        if (targetq_num >= 0) {
          if (nestq_num >= 0) {
            onig_reduce_nested_quantifier(qnode, target);
            goto q_exit;
          }
          else if (targetq_num == 1 || targetq_num == 2) { /* * or + */
            /* (?:a*){n,m}, (?:a+){n,m} => (?:a*){n,n}, (?:a+){n,n} */
            if (! IS_REPEAT_INFINITE(qn->upper) && qn->upper > 1 && qn->greedy) {
              qn->upper = (qn->lower == 0 ? 1 : qn->lower);
            }
          }
        }
      }
      break;
  
    default:
      break;
    }
  
    NODE_BODY(qnode) = target;
   q_exit:
    return 0;
  }
  
  
  #ifndef CASE_FOLD_IS_APPLIED_INSIDE_NEGATIVE_CCLASS
  static int
  clear_not_flag_cclass(CClassNode* cc, OnigEncoding enc)
  {
    BBuf *tbuf;
    int r;
  
    if (IS_NCCLASS_NOT(cc)) {
      bitset_invert(cc->bs);
  
      if (! ONIGENC_IS_SINGLEBYTE(enc)) {
        r = not_code_range_buf(enc, cc->mbuf, &tbuf);
        if (r != 0) return r;
  
        bbuf_free(cc->mbuf);
        cc->mbuf = tbuf;
      }
  
      NCCLASS_CLEAR_NOT(cc);
    }
  
    return 0;
  }
  #endif /* CASE_FOLD_IS_APPLIED_INSIDE_NEGATIVE_CCLASS */
  
  typedef struct {
    ScanEnv*    env;
    CClassNode* cc;
    Node*       alt_root;
    Node**      ptail;
  } IApplyCaseFoldArg;
  
  static int
  i_apply_case_fold(OnigCodePoint from, OnigCodePoint to[], int to_len, void* arg)
  {
    IApplyCaseFoldArg* iarg;
    ScanEnv* env;
    CClassNode* cc;
    BitSetRef bs;
  
    iarg = (IApplyCaseFoldArg* )arg;
    env = iarg->env;
    cc  = iarg->cc;
    bs = cc->bs;
  
    if (to_len == 1) {
      int is_in = onig_is_code_in_cc(env->enc, from, cc);
  #ifdef CASE_FOLD_IS_APPLIED_INSIDE_NEGATIVE_CCLASS
      if ((is_in != 0 && !IS_NCCLASS_NOT(cc)) ||
          (is_in == 0 &&  IS_NCCLASS_NOT(cc))) {
        if (ONIGENC_MBC_MINLEN(env->enc) > 1 || *to >= SINGLE_BYTE_SIZE) {
          add_code_range(&(cc->mbuf), env, *to, *to);
        }
        else {
          BITSET_SET_BIT(bs, *to);
        }
      }
  #else
      if (is_in != 0) {
        if (ONIGENC_MBC_MINLEN(env->enc) > 1 || *to >= SINGLE_BYTE_SIZE) {
          if (IS_NCCLASS_NOT(cc)) clear_not_flag_cclass(cc, env->enc);
          add_code_range(&(cc->mbuf), env, *to, *to);
        }
        else {
          if (IS_NCCLASS_NOT(cc)) {
            BITSET_CLEAR_BIT(bs, *to);
          }
          else
            BITSET_SET_BIT(bs, *to);
        }
      }
  #endif /* CASE_FOLD_IS_APPLIED_INSIDE_NEGATIVE_CCLASS */
    }
    else {
      int r, i, len;
      UChar buf[ONIGENC_CODE_TO_MBC_MAXLEN];
      Node *snode = NULL_NODE;
  
      if (onig_is_code_in_cc(env->enc, from, cc)
  #ifdef CASE_FOLD_IS_APPLIED_INSIDE_NEGATIVE_CCLASS
  	&& !IS_NCCLASS_NOT(cc)
  #endif
          ) {
        for (i = 0; i < to_len; i++) {
          len = ONIGENC_CODE_TO_MBC(env->enc, to[i], buf);
          if (i == 0) {
            snode = onig_node_new_str(buf, buf + len);
            CHECK_NULL_RETURN_MEMERR(snode);
  
            /* char-class expanded multi-char only
               compare with string folded at match time. */
            NODE_STRING_SET_AMBIG(snode);
          }
          else {
            r = onig_node_str_cat(snode, buf, buf + len);
            if (r < 0) {
              onig_node_free(snode);
              return r;
            }
          }
        }
  
        *(iarg->ptail) = onig_node_new_alt(snode, NULL_NODE);
        CHECK_NULL_RETURN_MEMERR(*(iarg->ptail));
        iarg->ptail = &(NODE_CDR((*(iarg->ptail))));
      }
    }
  
    return 0;
  }
  
  static int
  parse_exp(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
            ScanEnv* env)
  {
    int r, len, group = 0;
    Node* qn;
    Node** targetp;
  
    *np = NULL;
    if (tok->type == (enum TokenSyms )term)
      goto end_of_token;
  
    switch (tok->type) {
    case TK_ALT:
    case TK_EOT:
    end_of_token:
    *np = node_new_empty();
    return tok->type;
    break;
  
    case TK_SUBEXP_OPEN:
      r = parse_enclosure(np, tok, TK_SUBEXP_CLOSE, src, end, env);
      if (r < 0) return r;
      if (r == 1) group = 1;
      else if (r == 2) { /* option only */
        Node* target;
        OnigOptionType prev = env->options;
  
        env->options = ENCLOSURE_(*np)->o.options;
        r = fetch_token(tok, src, end, env);
        if (r < 0) return r;
        r = parse_subexp(&target, tok, term, src, end, env);
        env->options = prev;
        if (r < 0) {
          onig_node_free(target);
          return r;
        }
        NODE_BODY(*np) = target;
        return tok->type;
      }
      break;
  
    case TK_SUBEXP_CLOSE:
      if (! IS_SYNTAX_BV(env->syntax, ONIG_SYN_ALLOW_UNMATCHED_CLOSE_SUBEXP))
        return ONIGERR_UNMATCHED_CLOSE_PARENTHESIS;
  
      if (tok->escaped) goto tk_raw_byte;
      else goto tk_byte;
      break;
  
    case TK_STRING:
    tk_byte:
      {
        *np = node_new_str(tok->backp, *src);
        CHECK_NULL_RETURN_MEMERR(*np);
  
        while (1) {
          r = fetch_token(tok, src, end, env);
          if (r < 0) return r;
          if (r != TK_STRING) break;
  
          r = onig_node_str_cat(*np, tok->backp, *src);
          if (r < 0) return r;
        }
  
      string_end:
        targetp = np;
        goto repeat;
      }
      break;
  
    case TK_RAW_BYTE:
    tk_raw_byte:
      {
        *np = node_new_str_raw_char((UChar )tok->u.c);
        CHECK_NULL_RETURN_MEMERR(*np);
        len = 1;
        while (1) {
          if (len >= ONIGENC_MBC_MINLEN(env->enc)) {
            if (len == enclen(env->enc, STR_(*np)->s)) {//should not enclen_end()
              r = fetch_token(tok, src, end, env);
              NODE_STRING_CLEAR_RAW(*np);
              goto string_end;
            }
          }
  
          r = fetch_token(tok, src, end, env);
          if (r < 0) return r;
          if (r != TK_RAW_BYTE) {
            /* Don't use this, it is wrong for little endian encodings. */
  #ifdef USE_PAD_TO_SHORT_BYTE_CHAR
            int rem;
            if (len < ONIGENC_MBC_MINLEN(env->enc)) {
              rem = ONIGENC_MBC_MINLEN(env->enc) - len;
              (void )node_str_head_pad(STR_(*np), rem, (UChar )0);
              if (len + rem == enclen(env->enc, STR_(*np)->s)) {
                NODE_STRING_CLEAR_RAW(*np);
                goto string_end;
              }
            }
  #endif
            return ONIGERR_TOO_SHORT_MULTI_BYTE_STRING;
          }
  
          r = node_str_cat_char(*np, (UChar )tok->u.c);
          if (r < 0) return r;
  
          len++;
        }
      }
      break;
  
    case TK_CODE_POINT:
      {
        UChar buf[ONIGENC_CODE_TO_MBC_MAXLEN];
        int num = ONIGENC_CODE_TO_MBC(env->enc, tok->u.code, buf);
        if (num < 0) return num;
  #ifdef NUMBERED_CHAR_IS_NOT_CASE_AMBIG
        *np = node_new_str_raw(buf, buf + num);
  #else
        *np = node_new_str(buf, buf + num);
  #endif
        CHECK_NULL_RETURN_MEMERR(*np);
      }
      break;
  
    case TK_QUOTE_OPEN:
      {
        OnigCodePoint end_op[2];
        UChar *qstart, *qend, *nextp;
  
        end_op[0] = (OnigCodePoint )MC_ESC(env->syntax);
        end_op[1] = (OnigCodePoint )'E';
        qstart = *src;
        qend = find_str_position(end_op, 2, qstart, end, &nextp, env->enc);
        if (IS_NULL(qend)) {
          nextp = qend = end;
        }
        *np = node_new_str(qstart, qend);
        CHECK_NULL_RETURN_MEMERR(*np);
        *src = nextp;
      }
      break;
  
    case TK_CHAR_TYPE:
      {
        switch (tok->u.prop.ctype) {
        case ONIGENC_CTYPE_WORD:
          *np = node_new_ctype(tok->u.prop.ctype, tok->u.prop.not, env->options);
          CHECK_NULL_RETURN_MEMERR(*np);
          break;
  
        case ONIGENC_CTYPE_SPACE:
        case ONIGENC_CTYPE_DIGIT:
        case ONIGENC_CTYPE_XDIGIT:
          {
            CClassNode* cc;
  
            *np = node_new_cclass();
            CHECK_NULL_RETURN_MEMERR(*np);
            cc = CCLASS_(*np);
            add_ctype_to_cc(cc, tok->u.prop.ctype, 0, env);
            if (tok->u.prop.not != 0) NCCLASS_SET_NOT(cc);
          }
          break;
  
        default:
          return ONIGERR_PARSER_BUG;
          break;
        }
      }
      break;
  
    case TK_CHAR_PROPERTY:
      r = parse_char_property(np, tok, src, end, env);
      if (r != 0) return r;
      break;
  
    case TK_CC_OPEN:
      {
        CClassNode* cc;
  
        r = parse_char_class(np, tok, src, end, env);
        if (r != 0) return r;
  
        cc = CCLASS_(*np);
        if (IS_IGNORECASE(env->options)) {
          IApplyCaseFoldArg iarg;
  
          iarg.env      = env;
          iarg.cc       = cc;
          iarg.alt_root = NULL_NODE;
          iarg.ptail    = &(iarg.alt_root);
  
          r = ONIGENC_APPLY_ALL_CASE_FOLD(env->enc, env->case_fold_flag,
                                          i_apply_case_fold, &iarg);
          if (r != 0) {
            onig_node_free(iarg.alt_root);
            return r;
          }
          if (IS_NOT_NULL(iarg.alt_root)) {
            Node* work = onig_node_new_alt(*np, iarg.alt_root);
            if (IS_NULL(work)) {
              onig_node_free(iarg.alt_root);
              return ONIGERR_MEMORY;
            }
            *np = work;
          }
        }
      }
      break;
  
    case TK_ANYCHAR:
      *np = node_new_anychar();
      CHECK_NULL_RETURN_MEMERR(*np);
      break;
  
    case TK_ANYCHAR_ANYTIME:
      *np = node_new_anychar();
      CHECK_NULL_RETURN_MEMERR(*np);
      qn = node_new_quantifier(0, REPEAT_INFINITE, 0);
      CHECK_NULL_RETURN_MEMERR(qn);
      NODE_BODY(qn) = *np;
      *np = qn;
      break;
  
    case TK_BACKREF:
      len = tok->u.backref.num;
      *np = node_new_backref(len,
                    (len > 1 ? tok->u.backref.refs : &(tok->u.backref.ref1)),
                    tok->u.backref.by_name,
  #ifdef USE_BACKREF_WITH_LEVEL
  			   tok->u.backref.exist_level,
  			   tok->u.backref.level,
  #endif
  			   env);
      CHECK_NULL_RETURN_MEMERR(*np);
      break;
  
  #ifdef USE_CALL
    case TK_CALL:
      {
        int gnum = tok->u.call.gnum;
  
        *np = node_new_call(tok->u.call.name, tok->u.call.name_end,
                            gnum, tok->u.call.by_number);
        CHECK_NULL_RETURN_MEMERR(*np);
        env->num_call++;
        if (tok->u.call.by_number != 0 && gnum == 0) {
          env->has_call_zero = 1;
        }
      }
      break;
  #endif
  
    case TK_ANCHOR:
      {
        int ascii_mode =
          IS_WORD_ASCII(env->options) && IS_WORD_ANCHOR_TYPE(tok->u.anchor) ? 1 : 0;
        *np = onig_node_new_anchor(tok->u.anchor, ascii_mode);
      }
      break;
  
    case TK_OP_REPEAT:
    case TK_INTERVAL:
      if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_CONTEXT_INDEP_REPEAT_OPS)) {
        if (IS_SYNTAX_BV(env->syntax, ONIG_SYN_CONTEXT_INVALID_REPEAT_OPS))
          return ONIGERR_TARGET_OF_REPEAT_OPERATOR_NOT_SPECIFIED;
        else
          *np = node_new_empty();
      }
      else {
        goto tk_byte;
      }
      break;
  
    case TK_KEEP:
      r = node_new_keep(np, env);
      if (r < 0) return r;
      break;
  
    case TK_GENERAL_NEWLINE:
      r = node_new_general_newline(np, env);
      if (r < 0) return r;
      break;
  
    case TK_NO_NEWLINE:
      r = node_new_no_newline(np, env);
      if (r < 0) return r;
      break;
  
    case TK_TRUE_ANYCHAR:
      r = node_new_true_anychar(np, env);
      if (r < 0) return r;
      break;
  
    case TK_EXTENDED_GRAPHEME_CLUSTER:
      r = make_extended_grapheme_cluster(np, env);
      if (r < 0) return r;
      break;
  
    default:
      return ONIGERR_PARSER_BUG;
      break;
    }
  
    {
      targetp = np;
  
    re_entry:
      r = fetch_token(tok, src, end, env);
      if (r < 0) return r;
  
    repeat:
      if (r == TK_OP_REPEAT || r == TK_INTERVAL) {
        if (is_invalid_quantifier_target(*targetp))
          return ONIGERR_TARGET_OF_REPEAT_OPERATOR_INVALID;
  
        qn = node_new_quantifier(tok->u.repeat.lower, tok->u.repeat.upper,
                                 (r == TK_INTERVAL ? 1 : 0));
        CHECK_NULL_RETURN_MEMERR(qn);
        QUANT_(qn)->greedy = tok->u.repeat.greedy;
        r = set_quantifier(qn, *targetp, group, env);
        if (r < 0) {
          onig_node_free(qn);
          return r;
        }
  
        if (tok->u.repeat.possessive != 0) {
          Node* en;
          en = node_new_enclosure(ENCLOSURE_STOP_BACKTRACK);
          if (IS_NULL(en)) {
            onig_node_free(qn);
            return ONIGERR_MEMORY;
          }
          NODE_BODY(en) = qn;
          qn = en;
        }
  
        if (r == 0) {
          *targetp = qn;
        }
        else if (r == 1) {
          onig_node_free(qn);
        }
        else if (r == 2) { /* split case: /abc+/ */
          Node *tmp;
  
          *targetp = node_new_list(*targetp, NULL);
          if (IS_NULL(*targetp)) {
            onig_node_free(qn);
            return ONIGERR_MEMORY;
          }
          tmp = NODE_CDR(*targetp) = node_new_list(qn, NULL);
          if (IS_NULL(tmp)) {
            onig_node_free(qn);
            return ONIGERR_MEMORY;
          }
          targetp = &(NODE_CAR(tmp));
        }
        goto re_entry;
      }
    }
  
    return r;
  }
  
  static int
  parse_branch(Node** top, OnigToken* tok, int term, UChar** src, UChar* end,
               ScanEnv* env)
  {
    int r;
    Node *node, **headp;
  
    *top = NULL;
    r = parse_exp(&node, tok, term, src, end, env);
    if (r < 0) {
      onig_node_free(node);
      return r;
    }
  
    if (r == TK_EOT || r == term || r == TK_ALT) {
      *top = node;
    }
    else {
      *top  = node_new_list(node, NULL);
      headp = &(NODE_CDR(*top));
      while (r != TK_EOT && r != term && r != TK_ALT) {
        r = parse_exp(&node, tok, term, src, end, env);
        if (r < 0) {
          onig_node_free(node);
          return r;
        }
  
        if (NODE_TYPE(node) == NODE_LIST) {
          *headp = node;
          while (IS_NOT_NULL(NODE_CDR(node))) node = NODE_CDR(node);
          headp = &(NODE_CDR(node));
        }
        else {
          *headp = node_new_list(node, NULL);
          headp = &(NODE_CDR(*headp));
        }
      }
    }
  
    return r;
  }
  
  /* term_tok: TK_EOT or TK_SUBEXP_CLOSE */
  static int
  parse_subexp(Node** top, OnigToken* tok, int term, UChar** src, UChar* end,
               ScanEnv* env)
  {
    int r;
    Node *node, **headp;
  
    *top = NULL;
    env->parse_depth++;
    if (env->parse_depth > ParseDepthLimit)
      return ONIGERR_PARSE_DEPTH_LIMIT_OVER;
    r = parse_branch(&node, tok, term, src, end, env);
    if (r < 0) {
      onig_node_free(node);
      return r;
    }
  
    if (r == term) {
      *top = node;
    }
    else if (r == TK_ALT) {
      *top  = onig_node_new_alt(node, NULL);
      headp = &(NODE_CDR(*top));
      while (r == TK_ALT) {
        r = fetch_token(tok, src, end, env);
        if (r < 0) return r;
        r = parse_branch(&node, tok, term, src, end, env);
        if (r < 0) {
          onig_node_free(node);
          return r;
        }
        *headp = onig_node_new_alt(node, NULL);
        headp = &(NODE_CDR(*headp));
      }
  
      if (tok->type != (enum TokenSyms )term)
        goto err;
    }
    else {
      onig_node_free(node);
    err:
      if (term == TK_SUBEXP_CLOSE)
        return ONIGERR_END_PATTERN_WITH_UNMATCHED_PARENTHESIS;
      else
        return ONIGERR_PARSER_BUG;
    }
  
    env->parse_depth--;
    return r;
  }
  
  static int
  parse_regexp(Node** top, UChar** src, UChar* end, ScanEnv* env)
  {
    int r;
    OnigToken tok;
  
    r = fetch_token(&tok, src, end, env);
    if (r < 0) return r;
    r = parse_subexp(top, &tok, TK_EOT, src, end, env);
    if (r < 0) return r;
  
    return 0;
  }
  
  #ifdef USE_CALL
  static int
  make_call_zero_body(Node* node, ScanEnv* env, Node** rnode)
  {
    int r;
  
    Node* x = node_new_memory(0 /* 0: is not named */);
    CHECK_NULL_RETURN_MEMERR(x);
  
    NODE_BODY(x) = node;
    ENCLOSURE_(x)->m.regnum = 0;
    r = scan_env_set_mem_node(env, 0, x);
    if (r != 0) {
      onig_node_free(x);
      return r;
    }
  
    *rnode = x;
    return 0;
  }
  #endif
  
  extern int
  onig_parse_tree(Node** root, const UChar* pattern, const UChar* end,
                  regex_t* reg, ScanEnv* env)
  {
    int r;
    UChar* p;
  
    names_clear(reg);
  
    scan_env_clear(env);
    env->options        = reg->options;
    env->case_fold_flag = reg->case_fold_flag;
    env->enc            = reg->enc;
    env->syntax         = reg->syntax;
    env->pattern        = (UChar* )pattern;
    env->pattern_end    = (UChar* )end;
    env->reg            = reg;
  
    *root = NULL;
  
    if (! ONIGENC_IS_VALID_MBC_STRING(env->enc, pattern, end))
      return ONIGERR_INVALID_WIDE_CHAR_VALUE;
  
    p = (UChar* )pattern;
    r = parse_regexp(root, &p, (UChar* )end, env);
  
  #ifdef USE_CALL
    if (r != 0) return r;
  
    if (env->has_call_zero != 0) {
      Node* zero_node;
      r = make_call_zero_body(*root, env, &zero_node);
      if (r != 0) return r;
  
      *root = zero_node;
    }
  #endif
  
    reg->num_mem = env->num_mem;
    return r;
  }
  
  extern void
  onig_scan_env_set_error_string(ScanEnv* env, int ecode ARG_UNUSED,
                                 UChar* arg, UChar* arg_end)
  {
    env->error     = arg;
    env->error_end = arg_end;
  }
  