text: /****************************************************************************
  **
  ** Copyright (C) 2017 Intel Corporation
  **
  ** Permission is hereby granted, free of charge, to any person obtaining a copy
  ** of this software and associated documentation files (the "Software"), to deal
  ** in the Software without restriction, including without limitation the rights
  ** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  ** copies of the Software, and to permit persons to whom the Software is
  ** furnished to do so, subject to the following conditions:
  **
  ** The above copyright notice and this permission notice shall be included in
  ** all copies or substantial portions of the Software.
  **
  ** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  ** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  ** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  ** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  ** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  ** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  ** THE SOFTWARE.
  **
  ****************************************************************************/
  
  #pragma GCC diagnostic push
  #pragma GCC diagnostic ignored "-Wbad-function-cast"
  #pragma clang diagnostic ignored "-Wimplicit-fallthrough"
  #pragma clang diagnostic ignored "-Wdocumentation"
  #pragma GCC diagnostic ignored "-Wconversion"
  #pragma GCC diagnostic ignored "-Wsign-conversion"
  #pragma GCC diagnostic ignored "-Wunused-macros"
  
  #ifndef _BSD_SOURCE
      #define _BSD_SOURCE 1
  #endif
  #ifndef _DEFAULT_SOURCE
      #define _DEFAULT_SOURCE 1
  #endif
  #ifndef __STDC_LIMIT_MACROS
      #define __STDC_LIMIT_MACROS 1
  #endif
  
  #include "cbor.h"
  #include "cborinternal_p.h"
  #include "compilersupport_p.h"
  
  #include <string.h>
  
  /**
   * \defgroup CborParsing Parsing CBOR streams
   * \brief Group of functions used to parse CBOR streams.
   *
   * TinyCBOR provides functions for pull-based stream parsing of a CBOR-encoded
   * payload. The main data type for the parsing is a CborValue, which behaves
   * like an iterator and can be used to extract the encoded data. It is first
   * initialized with a call to cbor_parser_init() and is usually used to extract
   * exactly one item, most often an array or map.
   *
   * Nested CborValue objects can be parsed using cbor_value_enter_container().
   * Each call to cbor_value_enter_container() must be matched by a call to
   * cbor_value_leave_container(), with the exact same parameters.
   *
   * The example below initializes a CborParser object, begins the parsing with a
   * CborValue and decodes a single integer:
   *
   * \code
   * int extract_int(const uint8_t *buffer, size_t len)
   * {
   *     CborParser parser;
   *     CborValue value;
   *     int result;
   *     cbor_parser_init(buffer, len, 0, &parser, &value);
   *     cbor_value_get_int(&value, &result);
   *     return result;
   * }
   * \endcode
   *
   * The code above does no error checking, which means it assumes the data comes
   * from a source trusted to send one properly-encoded integer. The following
   * example does the exact same operation, but includes error checking and
   * returns 0 on parsing failure:
   *
   * \code
   * int extract_int(const uint8_t *buffer, size_t len)
   * {
   *     CborParser parser;
   *     CborValue value;
   *     int result;
   *     if (cbor_parser_init(buffer, len, 0, &parser, &value) != CborNoError)
   *         return 0;
   *     if (!cbor_value_is_integer(&value) ||
   *             cbor_value_get_int(&value, &result) != CborNoError)
   *         return 0;
   *     return result;
   * }
   * \endcode
   *
   * Note, in the example above, that one can't distinguish a parsing failure
   * from an encoded value of zero. Reporting a parsing error is left as an
   * exercise to the reader.
   *
   * The code above does not execute a range-check either: it is possible that
   * the value decoded from the CBOR stream encodes a number larger than what can
   * be represented in a variable of type \c{int}. If detecting that case is
   * important, the code should call cbor_value_get_int_checked() instead.
   *
   * <h3 class="groupheader">Memory and parsing constraints</h3>
   *
   * TinyCBOR is designed to run with little memory and with minimal overhead.
   * Except where otherwise noted, the parser functions always run on constant
   * time (O(1)), do not recurse and never allocate memory (thus, stack usage is
   * bounded and is O(1)).
   *
   * <h3 class="groupheader">Error handling and preconditions</h3>
   *
   * All functions operating on a CborValue return a CborError condition, with
   * CborNoError standing for the normal situation in which no parsing error
   * occurred. All functions may return parsing errors in case the stream cannot
   * be decoded properly, be it due to corrupted data or due to reaching the end
   * of the input buffer.
   *
   * Error conditions must not be ignored. All decoder functions have undefined
   * behavior if called after an error has been reported, and may crash.
   *
   * Some functions are also documented to have preconditions, like
   * cbor_value_get_int() requiring that the input be an integral value.
   * Violation of preconditions also results in undefined behavior and the
   * program may crash.
   */
  
  /**
   * \addtogroup CborParsing
   * @{
   */
  
  /**
   * \struct CborValue
   *
   * This type contains one value parsed from the CBOR stream. Each CborValue
   * behaves as an iterator in a StAX-style parser.
   *
   * \if privatedocs
   * Implementation details: the CborValue contains these fields:
   * \list
   *   \li ptr: pointer to the actual data
   *   \li flags: flags from the decoder
   *   \li extra: partially decoded integer value (0, 1 or 2 bytes)
   *   \li remaining: remaining items in this collection after this item or
   * UINT32_MAX if length is unknown \endlist \endif
   */
  
  static inline uint16_t get16(const uint8_t* ptr)
  {
      uint16_t result;
      memcpy(&result, ptr, sizeof(result));
      return cbor_ntohs(result);
  }
  
  static inline uint32_t get32(const uint8_t* ptr)
  {
      uint32_t result;
      memcpy(&result, ptr, sizeof(result));
      return cbor_ntohl(result);
  }
  
  static inline uint64_t get64(const uint8_t* ptr)
  {
      uint64_t result;
      memcpy(&result, ptr, sizeof(result));
      return cbor_ntohll(result);
  }
  
  CborError CBOR_INTERNAL_API_CC _cbor_value_extract_number(const uint8_t** ptr,
                                                            const uint8_t* end,
                                                            uint64_t* len)
  {
      size_t bytesNeeded;
      uint8_t additional_information = **ptr & SmallValueMask;
      ++*ptr;
      if (additional_information < Value8Bit)
      {
          *len = additional_information;
          return CborNoError;
      }
      if (unlikely(additional_information > Value64Bit))
          return CborErrorIllegalNumber;
  
      bytesNeeded = (size_t)(1 << (additional_information - Value8Bit));
      if (unlikely(bytesNeeded > (size_t)(end - *ptr)))
      {
          return CborErrorUnexpectedEOF;
      }
      else if (bytesNeeded == 1)
      {
          *len = (uint8_t)(*ptr)[0];
      }
      else if (bytesNeeded == 2)
      {
          *len = get16(*ptr);
      }
      else if (bytesNeeded == 4)
      {
          *len = get32(*ptr);
      }
      else
      {
          *len = get64(*ptr);
      }
      *ptr += bytesNeeded;
      return CborNoError;
  }
  
  static CborError
  extract_length(const CborParser* parser, const uint8_t** ptr, size_t* len)
  {
      uint64_t v;
      CborError err = _cbor_value_extract_number(ptr, parser->end, &v);
      if (err)
      {
          *len = 0;
          return err;
      }
  
      *len = (size_t) v;
      if (v != *len)
          return CborErrorDataTooLarge;
      return CborNoError;
  }
  
  static bool is_fixed_type(uint8_t type)
  {
      return type != CborTextStringType && type != CborByteStringType &&
             type != CborArrayType && type != CborMapType;
  }
  
  static CborError preparse_value(CborValue* it)
  {
      enum
      {
          /* flags to keep */
          FlagsToKeep =
              CborIteratorFlag_ContainerIsMap | CborIteratorFlag_NextIsMapKey
      };
      const CborParser* parser = it->parser;
      it->type = CborInvalidType;
  
      /* are we at the end? */
      if (it->ptr == parser->end)
          return CborErrorUnexpectedEOF;
  
      uint8_t descriptor = *it->ptr;
      uint8_t type = descriptor & MajorTypeMask;
      it->type = type;
      it->flags &= FlagsToKeep;
      it->extra = (descriptor &= SmallValueMask);
  
      if (descriptor > Value64Bit)
      {
          if (unlikely(descriptor != IndefiniteLength))
              return type == CborSimpleType ? CborErrorUnknownType :
                                              CborErrorIllegalNumber;
          if (likely(!is_fixed_type(type)))
          {
              /* special case */
              it->flags |= CborIteratorFlag_UnknownLength;
              it->type = type;
              return CborNoError;
          }
          return type == CborSimpleType ? CborErrorUnexpectedBreak :
                                          CborErrorIllegalNumber;
      }
  
      size_t bytesNeeded =
          descriptor < Value8Bit ? 0 : (1 << (descriptor - Value8Bit));
      if (bytesNeeded + 1 > (size_t)(parser->end - it->ptr))
          return CborErrorUnexpectedEOF;
  
      uint8_t majortype = type >> MajorTypeShift;
      if (majortype == NegativeIntegerType)
      {
          it->flags |= CborIteratorFlag_NegativeInteger;
          it->type = CborIntegerType;
      }
      else if (majortype == SimpleTypesType)
      {
          switch (descriptor)
          {
              case FalseValue:
                  it->extra = false;
                  it->type = CborBooleanType;
                  break;
  
              case SinglePrecisionFloat:
              case DoublePrecisionFloat:
                  it->flags |= CborIteratorFlag_IntegerValueTooLarge;
                  /* fall through */
              case TrueValue:
              case NullValue:
              case UndefinedValue:
              case HalfPrecisionFloat:
                  it->type = *it->ptr;
                  break;
  
              case SimpleTypeInNextByte:
                  it->extra = (uint8_t) it->ptr[1];
  #ifndef CBOR_PARSER_NO_STRICT_CHECKS
                  if (unlikely(it->extra < 32))
                  {
                      it->type = CborInvalidType;
                      return CborErrorIllegalSimpleType;
                  }
  #endif
                  break;
  
              case 28:
              case 29:
              case 30:
              case Break:
                  /* Intentional fallthrough */
                  // Angaza: Add default case
              default:
                  cbor_assert(false); /* these conditions can't be reached */
                  return CborErrorUnexpectedBreak;
          }
          return CborNoError;
      }
  
      /* try to decode up to 16 bits */
      if (descriptor < Value8Bit)
          return CborNoError;
  
      if (descriptor == Value8Bit)
          it->extra = (uint8_t) it->ptr[1];
      else if (descriptor == Value16Bit)
          it->extra = get16(it->ptr + 1);
      else
          it->flags |= CborIteratorFlag_IntegerValueTooLarge; /* Value32Bit or
                                                                 Value64Bit */
      return CborNoError;
  }
  
  static CborError preparse_next_value_nodecrement(CborValue* it)
  {
      if (it->remaining == UINT32_MAX && it->ptr != it->parser->end &&
          *it->ptr == (uint8_t) BreakByte)
      {
          /* end of map or array */
          if ((it->flags & CborIteratorFlag_ContainerIsMap &&
               it->flags & CborIteratorFlag_NextIsMapKey) ||
              it->type == CborTagType)
          {
              /* but we weren't expecting it! */
              return CborErrorUnexpectedBreak;
          }
          ++it->ptr;
          it->type = CborInvalidType;
          it->remaining = 0;
          return CborNoError;
      }
  
      return preparse_value(it);
  }
  
  static CborError preparse_next_value(CborValue* it)
  {
      /* tags don't count towards item totals or whether we've successfully
       * read a map's key or value */
      bool itemCounts = it->type != CborTagType;
  
      if (it->remaining != UINT32_MAX)
      {
          if (itemCounts && --it->remaining == 0)
          {
              it->type = CborInvalidType;
              return CborNoError;
          }
      }
      if (itemCounts)
      {
          /* toggle the flag indicating whether this was a map key */
          it->flags ^= CborIteratorFlag_NextIsMapKey;
      }
      return preparse_next_value_nodecrement(it);
  }
  
  static CborError advance_internal(CborValue* it)
  {
      uint64_t length;
      CborError err =
          _cbor_value_extract_number(&it->ptr, it->parser->end, &length);
      cbor_assert(err == CborNoError);
  
      if (it->type == CborByteStringType || it->type == CborTextStringType)
      {
          cbor_assert(length == (size_t) length);
          cbor_assert((it->flags & CborIteratorFlag_UnknownLength) == 0);
          it->ptr += length;
      }
  
      return preparse_next_value(it);
  }
  
  /** \internal
   *
   * Decodes the CBOR integer value when it is larger than the 16 bits available
   * in value->extra. This function requires that value->flags have the
   * CborIteratorFlag_IntegerValueTooLarge flag set.
   *
   * This function is also used to extract single- and double-precision floating
   * point values (SinglePrecisionFloat == Value32Bit and DoublePrecisionFloat ==
   * Value64Bit).
   */
  uint64_t _cbor_value_decode_int64_internal(const CborValue* value)
  {
      cbor_assert(value->flags & CborIteratorFlag_IntegerValueTooLarge ||
                  value->type == CborFloatType || value->type == CborDoubleType);
  
      /* since the additional information can only be Value32Bit or Value64Bit,
       * we just need to test for the one bit those two options differ */
      cbor_assert((*value->ptr & SmallValueMask) == Value32Bit ||
                  (*value->ptr & SmallValueMask) == Value64Bit);
      if ((*value->ptr & 1) == (Value32Bit & 1))
          return get32(value->ptr + 1);
  
      cbor_assert((*value->ptr & SmallValueMask) == Value64Bit);
      return get64(value->ptr + 1);
  }
  
  /**
   * Initializes the CBOR parser for parsing \a size bytes beginning at \a
   * buffer. Parsing will use flags set in \a flags. The iterator to the first
   * element is returned in \a it.
   *
   * The \a parser structure needs to remain valid throughout the decoding
   * process. It is not thread-safe to share one CborParser among multiple
   * threads iterating at the same time, but the object can be copied so multiple
   * threads can iterate.
   */
  CborError cbor_parser_init(const uint8_t* buffer,
                             size_t size,
                             uint32_t flags,
                             CborParser* parser,
                             CborValue* it)
  {
      memset(parser, 0, sizeof(*parser));
      parser->end = buffer + size;
      parser->flags = flags;
      it->parser = parser;
      it->ptr = buffer;
      it->remaining =
          1; /* there's one type altogether, usually an array or map */
      it->flags = 0;
      return preparse_value(it);
  }
  
  /**
   * \fn bool cbor_value_at_end(const CborValue *it)
   *
   * Returns true if \a it has reached the end of the iteration, usually when
   * advancing after the last item in an array or map.
   *
   * In the case of the outermost CborValue object, this function returns true
   * after decoding a single element. A pointer to the first byte of the
   * remaining data (if any) can be obtained with cbor_value_get_next_byte().
   *
   * \sa cbor_value_advance(), cbor_value_is_valid(), cbor_value_get_next_byte()
   */
  
  /**
   * \fn const uint8_t *cbor_value_get_next_byte(const CborValue *it)
   *
   * Returns a pointer to the next byte that would be decoded if this CborValue
   * object were advanced.
   *
   * This function is useful if cbor_value_at_end() returns true for the
   * outermost CborValue: the pointer returned is the first byte of the data
   * remaining in the buffer, if any. Code can decide whether to begin decoding a
   * new CBOR data stream from this point, or parse some other data appended to
   * the same buffer.
   *
   * This function may be used even after a parsing error. If that occurred,
   * then this function returns a pointer to where the parsing error occurred.
   * Note that the error recovery is not precise and the pointer may not indicate
   * the exact byte containing bad data.
   *
   * \sa cbor_value_at_end()
   */
  
  /**
   * \fn bool cbor_value_is_valid(const CborValue *it)
   *
   * Returns true if the iterator \a it contains a valid value. Invalid iterators
   * happen when iteration reaches the end of a container (see \ref
   * cbor_value_at_end()) or when a search function resulted in no matches.
   *
   * \sa cbor_value_advance(), cbor_value_at_end(), cbor_value_get_type()
   */
  
  /**
   * Performs a basic validation of the CBOR stream pointed by \a it and returns
   * the error it found. If no error was found, it returns CborNoError and the
   * application can iterate over the items with certainty that no other errors
   * will appear during parsing.
   *
   * A basic validation checks for:
   * \list
   *   \li absence of undefined additional information bytes;
   *   \li well-formedness of all numbers, lengths, and simple values;
   *   \li string contents match reported sizes;
   *   \li arrays and maps contain the number of elements they are reported to
   * have; \endlist
   *
   * For further checks, see cbor_value_validate().
   *
   * This function has the same timing and memory requirements as
   * cbor_value_advance().
   *
   * \sa cbor_value_validate(), cbor_value_advance()
   */
  CborError cbor_value_validate_basic(const CborValue* it)
  {
      CborValue value = *it;
      return cbor_value_advance(&value);
  }
  
  /**
   * Advances the CBOR value \a it by one fixed-size position. Fixed-size types
   * are: integers, tags, simple types (including boolean, null and undefined
   * values) and floating point types.
   *
   * If the type is not of fixed size, this function has undefined behavior. Code
   * must be sure that the current type is one of the fixed-size types before
   * calling this function. This function is provided because it can guarantee
   * that it runs in constant time (O(1)).
   *
   * If the caller is not able to determine whether the type is fixed or not, code
   * can use the cbor_value_advance() function instead.
   *
   * \sa cbor_value_at_end(), cbor_value_advance(), cbor_value_enter_container(), cbor_value_leave_container()
   */
  CborError cbor_value_advance_fixed(CborValue* it)
  {
      cbor_assert(it->type != CborInvalidType);
      cbor_assert(is_fixed_type(it->type));
      if (!it->remaining)
          return CborErrorAdvancePastEOF;
      return advance_internal(it);
  }
  
  static CborError advance_recursive(CborValue* it, int nestingLevel)
  {
      CborError err;
      CborValue recursed;
  
      if (is_fixed_type(it->type))
          return advance_internal(it);
  
      if (!cbor_value_is_container(it))
      {
          size_t len = SIZE_MAX;
          return _cbor_value_copy_string(it, NULL, &len, it);
      }
  
      /* map or array */
      if (nestingLevel == 0)
          return CborErrorNestingTooDeep;
  
      err = cbor_value_enter_container(it, &recursed);
      if (err)
          return err;
      while (!cbor_value_at_end(&recursed))
      {
          err = advance_recursive(&recursed, nestingLevel - 1);
          if (err)
              return err;
      }
      return cbor_value_leave_container(it, &recursed);
  }
  
  /**
   * Advances the CBOR value \a it by one element, skipping over containers.
   * Unlike cbor_value_advance_fixed(), this function can be called on a CBOR
   * value of any type. However, if the type is a container (map or array) or a
   * string with a chunked payload, this function will not run in constant time
   * and will recurse into itself (it will run on O(n) time for the number of
   * elements or chunks and will use O(n) memory for the number of nested
   * containers).
   *
   * The number of recursions can be limited at compile time to avoid stack
   * exhaustion in constrained systems.
   *
   * \sa cbor_value_at_end(), cbor_value_advance_fixed(), cbor_value_enter_container(), cbor_value_leave_container()
   */
  CborError cbor_value_advance(CborValue* it)
  {
      cbor_assert(it->type != CborInvalidType);
      if (!it->remaining)
          return CborErrorAdvancePastEOF;
      return advance_recursive(it, CBOR_PARSER_MAX_RECURSIONS);
  }
  
  /**
   * \fn bool cbor_value_is_tag(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR tag.
   *
   * \sa cbor_value_get_tag(), cbor_value_skip_tag()
   */
  
  /**
   * \fn CborError cbor_value_get_tag(const CborValue *value, CborTag *result)
   *
   * Retrieves the CBOR tag value that \a value points to and stores it in \a
   * result. If the iterator \a value does not point to a CBOR tag value, the
   * behavior is undefined, so checking with \ref cbor_value_get_type or with
   * \ref cbor_value_is_tag is recommended.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_tag()
   */
  
  /**
   * Advances the CBOR value \a it until it no longer points to a tag. If \a it is
   * already not pointing to a tag, then this function returns it unchanged.
   *
   * This function does not run in constant time: it will run on O(n) for n being
   * the number of tags. It does use constant memory (O(1) memory requirements).
   *
   * \sa cbor_value_advance_fixed(), cbor_value_advance()
   */
  CborError cbor_value_skip_tag(CborValue* it)
  {
      while (cbor_value_is_tag(it))
      {
          CborError err = cbor_value_advance_fixed(it);
          if (err)
              return err;
      }
      return CborNoError;
  }
  
  /**
   * \fn bool cbor_value_is_container(const CborValue *it)
   *
   * Returns true if the \a it value is a container and requires recursion in
   * order to decode (maps and arrays), false otherwise.
   */
  
  /**
   * Creates a CborValue iterator pointing to the first element of the container
   * represented by \a it and saves it in \a recursed. The \a it container object
   * needs to be kept and passed again to cbor_value_leave_container() in order
   * to continue iterating past this container.
   *
   * The \a it CborValue iterator must point to a container.
   *
   * \sa cbor_value_is_container(), cbor_value_leave_container(), cbor_value_advance()
   */
  CborError cbor_value_enter_container(const CborValue* it, CborValue* recursed)
  {
      cbor_static_assert(CborIteratorFlag_ContainerIsMap ==
                         (CborMapType & ~CborArrayType));
      cbor_assert(cbor_value_is_container(it));
      *recursed = *it;
  
      if (it->flags & CborIteratorFlag_UnknownLength)
      {
          recursed->remaining = UINT32_MAX;
          ++recursed->ptr;
      }
      else
      {
          uint64_t len;
          CborError err = _cbor_value_extract_number(
              &recursed->ptr, recursed->parser->end, &len);
          cbor_assert(err == CborNoError);
  
          recursed->remaining = (uint32_t) len;
          if (recursed->remaining != len || len == UINT32_MAX)
          {
              /* back track the pointer to indicate where the error occurred */
              recursed->ptr = it->ptr;
              return CborErrorDataTooLarge;
          }
          if (recursed->type == CborMapType)
          {
              /* maps have keys and values, so we need to multiply by 2 */
              if (recursed->remaining > UINT32_MAX / 2)
              {
                  /* back track the pointer to indicate where the error occurred
                   */
                  recursed->ptr = it->ptr;
                  return CborErrorDataTooLarge;
              }
              recursed->remaining *= 2;
          }
          if (len == 0)
          {
              /* the case of the empty container */
              recursed->type = CborInvalidType;
              return CborNoError;
          }
      }
      recursed->flags = (recursed->type & CborIteratorFlag_ContainerIsMap);
      return preparse_next_value_nodecrement(recursed);
  }
  
  /**
   * Updates \a it to point to the next element after the container. The \a
   * recursed object needs to point to the element obtained either by advancing
   * the last element of the container (via cbor_value_advance(),
   * cbor_value_advance_fixed(), a nested cbor_value_leave_container(), or the \c
   * next pointer from cbor_value_copy_string() or cbor_value_dup_string()).
   *
   * The \a it and \a recursed parameters must be the exact same as passed to
   * cbor_value_enter_container().
   *
   * \sa cbor_value_enter_container(), cbor_value_at_end()
   */
  CborError cbor_value_leave_container(CborValue* it, const CborValue* recursed)
  {
      cbor_assert(cbor_value_is_container(it));
      cbor_assert(recursed->type == CborInvalidType);
      it->ptr = recursed->ptr;
      return preparse_next_value(it);
  }
  
  /**
   * \fn CborType cbor_value_get_type(const CborValue *value)
   *
   * Returns the type of the CBOR value that the iterator \a value points to. If
   * \a value does not point to a valid value, this function returns \ref
   * CborInvalidType.
   *
   * TinyCBOR also provides functions to test directly if a given CborValue object
   * is of a given type, like cbor_value_is_text_string() and
   * cbor_value_is_null().
   *
   * \sa cbor_value_is_valid()
   */
  
  /**
   * \fn bool cbor_value_is_null(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR null
   * type.
   *
   * \sa cbor_value_is_valid(), cbor_value_is_undefined()
   */
  
  /**
   * \fn bool cbor_value_is_undefined(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR undefined
   * type.
   *
   * \sa cbor_value_is_valid(), cbor_value_is_null()
   */
  
  /**
   * \fn bool cbor_value_is_boolean(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR boolean
   * type (true or false).
   *
   * \sa cbor_value_is_valid(), cbor_value_get_boolean()
   */
  
  /**
   * \fn CborError cbor_value_get_boolean(const CborValue *value, bool *result)
   *
   * Retrieves the boolean value that \a value points to and stores it in \a
   * result. If the iterator \a value does not point to a boolean value, the
   * behavior is undefined, so checking with \ref cbor_value_get_type or with
   * \ref cbor_value_is_boolean is recommended.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_boolean()
   */
  
  /**
   * \fn bool cbor_value_is_simple_type(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR Simple
   * Type type (other than true, false, null and undefined).
   *
   * \sa cbor_value_is_valid(), cbor_value_get_simple_type()
   */
  
  /**
   * \fn CborError cbor_value_get_simple_type(const CborValue *value, uint8_t *result)
   *
   * Retrieves the CBOR Simple Type value that \a value points to and stores it
   * in \a result. If the iterator \a value does not point to a simple_type
   * value, the behavior is undefined, so checking with \ref cbor_value_get_type
   * or with \ref cbor_value_is_simple_type is recommended.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_simple_type()
   */
  
  /**
   * \fn bool cbor_value_is_integer(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR integer
   * type.
   *
   * \sa cbor_value_is_valid(), cbor_value_get_int, cbor_value_get_int64, cbor_value_get_uint64, cbor_value_get_raw_integer
   */
  
  /**
   * \fn bool cbor_value_is_unsigned_integer(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR unsigned
   * integer type (positive values or zero).
   *
   * \sa cbor_value_is_valid(), cbor_value_get_uint64()
   */
  
  /**
   * \fn bool cbor_value_is_negative_integer(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR negative
   * integer type.
   *
   * \sa cbor_value_is_valid(), cbor_value_get_int, cbor_value_get_int64, cbor_value_get_raw_integer
   */
  
  /**
   * \fn CborError cbor_value_get_int(const CborValue *value, int *result)
   *
   * Retrieves the CBOR integer value that \a value points to and stores it in \a
   * result. If the iterator \a value does not point to an integer value, the
   * behavior is undefined, so checking with \ref cbor_value_get_type or with
   * \ref cbor_value_is_integer is recommended.
   *
   * Note that this function does not do range-checking: integral values that do
   * not fit in a variable of type \c{int} are silently truncated to fit. Use
   * cbor_value_get_int_checked() if that is not acceptable.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer()
   */
  
  /**
   * \fn CborError cbor_value_get_int64(const CborValue *value, int64_t *result)
   *
   * Retrieves the CBOR integer value that \a value points to and stores it in \a
   * result. If the iterator \a value does not point to an integer value, the
   * behavior is undefined, so checking with \ref cbor_value_get_type or with
   * \ref cbor_value_is_integer is recommended.
   *
   * Note that this function does not do range-checking: integral values that do
   * not fit in a variable of type \c{int64_t} are silently truncated to fit. Use
   * cbor_value_get_int64_checked() that is not acceptable.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer()
   */
  
  /**
   * \fn CborError cbor_value_get_uint64(const CborValue *value, uint64_t *result)
   *
   * Retrieves the CBOR integer value that \a value points to and stores it in \a
   * result. If the iterator \a value does not point to an unsigned integer
   * value, the behavior is undefined, so checking with \ref cbor_value_get_type
   * or with \ref cbor_value_is_unsigned_integer is recommended.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_unsigned_integer()
   */
  
  /**
   * \fn CborError cbor_value_get_raw_integer(const CborValue *value, uint64_t *result)
   *
   * Retrieves the CBOR integer value that \a value points to and stores it in \a
   * result. If the iterator \a value does not point to an integer value, the
   * behavior is undefined, so checking with \ref cbor_value_get_type or with
   * \ref cbor_value_is_integer is recommended.
   *
   * This function is provided because CBOR negative integers can assume values
   * that cannot be represented with normal 64-bit integer variables.
   *
   * If the integer is unsigned (that is, if cbor_value_is_unsigned_integer()
   * returns true), then \a result will contain the actual value. If the integer
   * is negative, then \a result will contain the absolute value of that integer,
   * minus one. That is, \c {actual = -result - 1}. On architectures using two's
   * complement for representation of negative integers, it is equivalent to say
   * that \a result will contain the bitwise negation of the actual value.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer()
   */
  
  /**
   * Retrieves the CBOR integer value that \a value points to and stores it in \a
   * result. If the iterator \a value does not point to an integer value, the
   * behavior is undefined, so checking with \ref cbor_value_get_type or with
   * \ref cbor_value_is_integer is recommended.
   *
   * Unlike \ref cbor_value_get_int64(), this function performs a check to see if
   * the stored integer fits in \a result without data loss. If the number is
   * outside the valid range for the data type, this function returns the
   * recoverable error CborErrorDataTooLarge. In that case, use either
   * cbor_value_get_uint64() (if the number is positive) or
   * cbor_value_get_raw_integer().
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer(), cbor_value_get_int64()
   */
  CborError cbor_value_get_int64_checked(const CborValue* value, int64_t* result)
  {
      uint64_t v;
      cbor_assert(cbor_value_is_integer(value));
      v = _cbor_value_extract_int64_helper(value);
  
      /* Check before converting, as the standard says (C11 6.3.1.3 paragraph 3):
       * "[if] the new type is signed and the value cannot be represented in it;
       * either the result is implementation-defined or an implementation-defined
       * signal is raised."
       *
       * The range for int64_t is -2^63 to 2^63-1 (int64_t is required to be
       * two's complement, C11 7.20.1.1 paragraph 3), which in CBOR is
       * represented the same way, differing only on the "sign bit" (the major
       * type).
       */
  
      if (unlikely(v > (uint64_t) INT64_MAX))
          return CborErrorDataTooLarge;
  
  // warning: Loss of precision in implicit conversion
  #ifndef __clang_analyzer__
      *result = v;
  #endif
      if (value->flags & CborIteratorFlag_NegativeInteger)
          *result = -*result - 1;
      return CborNoError;
  }
  
  /**
   * Retrieves the CBOR integer value that \a value points to and stores it in \a
   * result. If the iterator \a value does not point to an integer value, the
   * behavior is undefined, so checking with \ref cbor_value_get_type or with
   * \ref cbor_value_is_integer is recommended.
   *
   * Unlike \ref cbor_value_get_int(), this function performs a check to see if
   * the stored integer fits in \a result without data loss. If the number is
   * outside the valid range for the data type, this function returns the
   * recoverable error CborErrorDataTooLarge. In that case, use one of the other
   * integer functions to obtain the value.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer(), cbor_value_get_int64(),
   *     cbor_value_get_uint64(), cbor_value_get_int64_checked(),
   * cbor_value_get_raw_integer()
   */
  CborError cbor_value_get_int_checked(const CborValue* value, int* result)
  {
      uint64_t v;
      cbor_assert(cbor_value_is_integer(value));
      v = _cbor_value_extract_int64_helper(value);
  
      /* Check before converting, as the standard says (C11 6.3.1.3 paragraph 3):
       * "[if] the new type is signed and the value cannot be represented in it;
       * either the result is implementation-defined or an implementation-defined
       * signal is raised."
       *
       * But we can convert from signed to unsigned without fault (paragraph 2).
       *
       * The range for int is implementation-defined and int is not guaranteed to
       * use two's complement representation (although int32_t is).
       */
  
      if (value->flags & CborIteratorFlag_NegativeInteger)
      {
          if (unlikely(v > (unsigned) -(INT_MIN + 1)))
              return CborErrorDataTooLarge;
  
          *result = (int) v;
          *result = -*result - 1;
      }
      else
      {
          if (unlikely(v > (uint64_t) INT_MAX))
              return CborErrorDataTooLarge;
  
          *result = (int) v;
      }
      return CborNoError;
  }
  
  /**
   * \fn bool cbor_value_is_length_known(const CborValue *value)
   *
   * Returns true if the length of this type is known without calculation. That
   * is, if the length of this CBOR string, map or array is encoded in the data
   * stream, this function returns true. If the length is not encoded, it returns
   * false.
   *
   * If the length is known, code can call cbor_value_get_string_length(),
   * cbor_value_get_array_length() or cbor_value_get_map_length() to obtain the
   * length. If the length is not known but is necessary, code can use the
   * cbor_value_calculate_string_length() function (no equivalent function is
   * provided for maps and arrays).
   */
  
  /**
   * \fn bool cbor_value_is_text_string(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR text
   * string. CBOR text strings are UTF-8 encoded and usually contain
   * human-readable text.
   *
   * \sa cbor_value_is_valid(), cbor_value_get_string_length(), cbor_value_calculate_string_length(),
   *     cbor_value_copy_text_string(), cbor_value_dup_text_string()
   */
  
  /**
   * \fn bool cbor_value_is_byte_string(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR text
   * string. CBOR byte strings are binary data with no specified encoding or
   * format.
   *
   * \sa cbor_value_is_valid(), cbor_value_get_string_length(), cbor_value_calculate_string_length(),
   *     cbor_value_copy_byte_string(), cbor_value_dup_byte_string()
   */
  
  /**
   * \fn CborError cbor_value_get_string_length(const CborValue *value, size_t *length)
   *
   * Extracts the length of the byte or text string that \a value points to and
   * stores it in \a result. If the iterator \a value does not point to a text
   * string or a byte string, the behaviour is undefined, so checking with \ref
   * cbor_value_get_type, with \ref cbor_value_is_text_string or \ref
   * cbor_value_is_byte_string is recommended.
   *
   * If the length of this string is not encoded in the CBOR data stream, this
   * function will return the recoverable error CborErrorUnknownLength. You may
   * also check whether that is the case by using cbor_value_is_length_known().
   *
   * If the length of the string is required but the length was not encoded, use
   * cbor_value_calculate_string_length(), but note that that function does not
   * run in constant time.
   *
   * \note On 32-bit platforms, this function will return error condition of \ref
   * CborErrorDataTooLarge if the stream indicates a length that is too big to
   * fit in 32-bit.
   *
   * \sa cbor_value_is_valid(), cbor_value_is_length_known(), cbor_value_calculate_string_length()
   */
  
  /**
   * Calculates the length of the byte or text string that \a value points to and
   * stores it in \a len. If the iterator \a value does not point to a text
   * string or a byte string, the behaviour is undefined, so checking with \ref
   * cbor_value_get_type, with \ref cbor_value_is_text_string or \ref
   * cbor_value_is_byte_string is recommended.
   *
   * This function is different from cbor_value_get_string_length() in that it
   * calculates the length even for strings sent in chunks. For that reason, this
   * function may not run in constant time (it will run in O(n) time on the
   * number of chunks). It does use constant memory (O(1)).
   *
   * \note On 32-bit platforms, this function will return error condition of \ref
   * CborErrorDataTooLarge if the stream indicates a length that is too big to
   * fit in 32-bit.
   *
   * \sa cbor_value_get_string_length(), cbor_value_copy_text_string(), cbor_value_copy_byte_string(), cbor_value_is_length_known()
   */
  CborError cbor_value_calculate_string_length(const CborValue* value,
                                               size_t* len)
  {
      *len = SIZE_MAX;
      return _cbor_value_copy_string(value, NULL, len, NULL);
  }
  
  static inline void prepare_string_iteration(CborValue* it)
  {
      if (!cbor_value_is_length_known(it))
      {
          /* chunked string: we're before the first chunk;
           * advance to the first chunk */
          ++it->ptr;
          it->flags |= CborIteratorFlag_IteratingStringChunks;
      }
  }
  
  CborError CBOR_INTERNAL_API_CC
  _cbor_value_prepare_string_iteration(CborValue* it)
  {
      cbor_assert((it->flags & CborIteratorFlag_IteratingStringChunks) == 0);
      prepare_string_iteration(it);
  
      /* are we at the end? */
      if (it->ptr == it->parser->end)
          return CborErrorUnexpectedEOF;
      return CborNoError;
  }
  
  static CborError
  get_string_chunk(CborValue* it, const void** bufferptr, size_t* len)
  {
      CborError err;
  
      /* Possible states:
       * length known | iterating | meaning
       *     no       |    no     | before the first chunk of a chunked string
       *     yes      |    no     | at a non-chunked string
       *     no       |    yes    | second or later chunk
       *     yes      |    yes    | after a non-chunked string
       */
      if (it->flags & CborIteratorFlag_IteratingStringChunks)
      {
          /* already iterating */
          if (cbor_value_is_length_known(it))
          {
              /* if the length was known, it wasn't chunked, so finish iteration
               */
              goto last_chunk;
          }
      }
      else
      {
          prepare_string_iteration(it);
      }
  
      /* are we at the end? */
      if (it->ptr == it->parser->end)
          return CborErrorUnexpectedEOF;
  
      if (*it->ptr == BreakByte)
      {
          /* last chunk */
          ++it->ptr;
      last_chunk:
          *bufferptr = NULL;
          *len = 0;
          return preparse_next_value(it);
      }
      else if ((uint8_t)(*it->ptr & MajorTypeMask) == it->type)
      {
          err = extract_length(it->parser, &it->ptr, len);
          if (err)
              return err;
          if (*len > (size_t)(it->parser->end - it->ptr))
              return CborErrorUnexpectedEOF;
  
          *bufferptr = it->ptr;
          it->ptr += *len;
      }
      else
      {
          return CborErrorIllegalType;
      }
  
      it->flags |= CborIteratorFlag_IteratingStringChunks;
      return CborNoError;
  }
  
  CborError CBOR_INTERNAL_API_CC
  _cbor_value_get_string_chunk(const CborValue* value,
                               const void** bufferptr,
                               size_t* len,
                               CborValue* next)
  {
      CborValue tmp;
      if (!next)
          next = &tmp;
      *next = *value;
      return get_string_chunk(next, bufferptr, len);
  }
  
  /* We return uintptr_t so that we can pass memcpy directly as the iteration
   * function. The choice is to optimize for memcpy, which is used in the base
   * parser API (cbor_value_copy_string), while memcmp is used in convenience API
   * only. */
  typedef uintptr_t (*IterateFunction)(char*, const uint8_t*, size_t);
  
  static uintptr_t iterate_noop(char* dest, const uint8_t* src, size_t len)
  {
      (void) dest;
      (void) src;
      (void) len;
      return true;
  }
  
  static uintptr_t iterate_memcmp(char* s1, const uint8_t* s2, size_t len)
  {
      return memcmp(s1, (const char*) s2, len) == 0;
  }
  
  static uintptr_t iterate_memcpy(char* dest, const uint8_t* src, size_t len)
  {
      return (uintptr_t) memcpy(dest, src, len);
  }
  
  static CborError iterate_string_chunks(const CborValue* value,
                                         char* buffer,
                                         size_t* buflen,
                                         bool* result,
                                         CborValue* next,
                                         IterateFunction func)
  {
      CborError err;
      CborValue tmp;
      size_t total = 0;
      const void* ptr;
  
      cbor_assert(cbor_value_is_byte_string(value) ||
                  cbor_value_is_text_string(value));
      if (!next)
          next = &tmp;
      *next = *value;
      *result = true;
  
      while (1)
      {
          size_t newTotal;
          size_t chunkLen;
          err = get_string_chunk(next, &ptr, &chunkLen);
          if (err)
              return err;
          if (!ptr)
              break;
  
          if (unlikely(add_check_overflow(total, chunkLen, &newTotal)))
              return CborErrorDataTooLarge;
  
          if (*result && *buflen >= newTotal)
              *result = !!func(buffer + total, (const uint8_t*) ptr, chunkLen);
          else
              *result = false;
  
          total = newTotal;
      }
  
      /* is there enough room for the ending NUL byte? */
      if (*result && *buflen > total)
      {
          uint8_t nul[] = {0};
          *result = !!func(buffer + total, nul, 1);
      }
      *buflen = total;
      return CborNoError;
  }
  
  /**
   * \fn CborError cbor_value_copy_text_string(const CborValue *value, char *buffer, size_t *buflen, CborValue *next)
   *
   * Copies the string pointed to by \a value into the buffer provided at \a
   * buffer of \a buflen bytes. If \a buffer is a NULL pointer, this function will
   * not copy anything and will only update the \a next value.
   *
   * If the iterator \a value does not point to a text string, the behaviour is
   * undefined, so checking with \ref cbor_value_get_type or \ref
   * cbor_value_is_text_string is recommended.
   *
   * If the provided buffer length was too small, this function returns an error
   * condition of \ref CborErrorOutOfMemory. If you need to calculate the length
   * of the string in order to preallocate a buffer, use
   * cbor_value_calculate_string_length().
   *
   * On success, this function sets the number of bytes copied to \c{*buflen}. If
   * the buffer is large enough, this function will insert a null byte after the
   * last copied byte, to facilitate manipulation of text strings. That byte is
   * not included in the returned value of \c{*buflen}. If there was no space for
   * the terminating null, no error is returned, so callers must check the value
   * of *buflen after the call, before relying on the '\0'; if it has not been
   * changed by the call, there is no '\0'-termination on the buffer's contents.
   *
   * The \a next pointer, if not null, will be updated to point to the next item
   * after this string. If \a value points to the last item, then \a next will be
   * invalid.
   *
   * This function may not run in constant time (it will run in O(n) time on the
   * number of chunks). It requires constant memory (O(1)).
   *
   * \note This function does not perform UTF-8 validation on the incoming text
   * string.
   *
   * \sa cbor_value_get_text_string_chunk() cbor_value_dup_text_string(), cbor_value_copy_byte_string(), cbor_value_get_string_length(), cbor_value_calculate_string_length()
   */
  
  /**
   * \fn CborError cbor_value_copy_byte_string(const CborValue *value, uint8_t *buffer, size_t *buflen, CborValue *next)
   *
   * Copies the string pointed by \a value into the buffer provided at \a buffer
   * of \a buflen bytes. If \a buffer is a NULL pointer, this function will not
   * copy anything and will only update the \a next value.
   *
   * If the iterator \a value does not point to a byte string, the behaviour is
   * undefined, so checking with \ref cbor_value_get_type or \ref
   * cbor_value_is_byte_string is recommended.
   *
   * If the provided buffer length was too small, this function returns an error
   * condition of \ref CborErrorOutOfMemory. If you need to calculate the length
   * of the string in order to preallocate a buffer, use
   * cbor_value_calculate_string_length().
   *
   * On success, this function sets the number of bytes copied to \c{*buflen}. If
   * the buffer is large enough, this function will insert a null byte after the
   * last copied byte, to facilitate manipulation of null-terminated strings.
   * That byte is not included in the returned value of \c{*buflen}.
   *
   * The \a next pointer, if not null, will be updated to point to the next item
   * after this string. If \a value points to the last item, then \a next will be
   * invalid.
   *
   * This function may not run in constant time (it will run in O(n) time on the
   * number of chunks). It requires constant memory (O(1)).
   *
   * \sa cbor_value_get_byte_string_chunk(), cbor_value_dup_text_string(), cbor_value_copy_text_string(), cbor_value_get_string_length(), cbor_value_calculate_string_length()
   */
  
  CborError _cbor_value_copy_string(const CborValue* value,
                                    void* buffer,
                                    size_t* buflen,
                                    CborValue* next)
  {
      bool copied_all;
      CborError err =
          iterate_string_chunks(value,
                                (char*) buffer,
                                buflen,
                                &copied_all,
                                next,
                                buffer ? iterate_memcpy : iterate_noop);
      return err ? err : copied_all ? CborNoError : CborErrorOutOfMemory;
  }
  
  /**
   * Compares the entry \a value with the string \a string and stores the result
   * in \a result. If the value is different from \a string \a result will
   * contain \c false.
   *
   * The entry at \a value may be a tagged string. If \a value is not a string or
   * a tagged string, the comparison result will be false.
   *
   * CBOR requires text strings to be encoded in UTF-8, but this function does
   * not validate either the strings in the stream or the string \a string to be
   * matched. Moreover, comparison is done on strict codepoint comparison,
   * without any Unicode normalization.
   *
   * This function may not run in constant time (it will run in O(n) time on the
   * number of chunks). It requires constant memory (O(1)).
   *
   * \sa cbor_value_skip_tag(), cbor_value_copy_text_string()
   */
  CborError cbor_value_text_string_equals(const CborValue* value,
                                          const char* string,
                                          bool* result)
  {
      size_t len;
      CborValue copy = *value;
      CborError err = cbor_value_skip_tag(&copy);
      if (err)
          return err;
      if (!cbor_value_is_text_string(&copy))
      {
          *result = false;
          return CborNoError;
      }
  
      len = strlen(string);
      return iterate_string_chunks(
          &copy, CONST_CAST(char*, string), &len, result, NULL, iterate_memcmp);
  }
  
  /**
   * \fn bool cbor_value_is_array(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR array.
   *
   * \sa cbor_value_is_valid(), cbor_value_is_map()
   */
  
  /**
   * \fn CborError cbor_value_get_array_length(const CborValue *value, size_t *length)
   *
   * Extracts the length of the CBOR array that \a value points to and stores it
   * in \a result. If the iterator \a value does not point to a CBOR array, the
   * behaviour is undefined, so checking with \ref cbor_value_get_type or \ref
   * cbor_value_is_array is recommended.
   *
   * If the length of this array is not encoded in the CBOR data stream, this
   * function will return the recoverable error CborErrorUnknownLength. You may
   * also check whether that is the case by using cbor_value_is_length_known().
   *
   * \note On 32-bit platforms, this function will return error condition of \ref
   * CborErrorDataTooLarge if the stream indicates a length that is too big to
   * fit in 32-bit.
   *
   * \sa cbor_value_is_valid(), cbor_value_is_length_known()
   */
  
  /**
   * \fn bool cbor_value_is_map(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR map.
   *
   * \sa cbor_value_is_valid(), cbor_value_is_array()
   */
  
  /**
   * \fn CborError cbor_value_get_map_length(const CborValue *value, size_t *length)
   *
   * Extracts the length of the CBOR map that \a value points to and stores it in
   * \a result. If the iterator \a value does not point to a CBOR map, the
   * behaviour is undefined, so checking with \ref cbor_value_get_type or \ref
   * cbor_value_is_map is recommended.
   *
   * If the length of this map is not encoded in the CBOR data stream, this
   * function will return the recoverable error CborErrorUnknownLength. You may
   * also check whether that is the case by using cbor_value_is_length_known().
   *
   * \note On 32-bit platforms, this function will return error condition of \ref
   * CborErrorDataTooLarge if the stream indicates a length that is too big to
   * fit in 32-bit.
   *
   * \sa cbor_value_is_valid(), cbor_value_is_length_known()
   */
  
  /**
   * Attempts to find the value in map \a map that corresponds to the text string
   * entry \a string. If the iterator \a value does not point to a CBOR map, the
   * behaviour is undefined, so checking with \ref cbor_value_get_type or \ref
   * cbor_value_is_map is recommended.
   *
   * If the item is found, it is stored in \a result. If no item is found
   * matching the key, then \a result will contain an element of type \ref
   * CborInvalidType. Matching is performed using
   * cbor_value_text_string_equals(), so tagged strings will also match.
   *
   * This function has a time complexity of O(n) where n is the number of
   * elements in the map to be searched. In addition, this function is has O(n)
   * memory requirement based on the number of nested containers (maps or arrays)
   * found as elements of this map.
   *
   * \sa cbor_value_is_valid(), cbor_value_text_string_equals(), cbor_value_advance()
   */
  CborError cbor_value_map_find_value(const CborValue* map,
                                      const char* string,
                                      CborValue* element)
  {
      CborError err;
      size_t len = strlen(string);
      cbor_assert(cbor_value_is_map(map));
      err = cbor_value_enter_container(map, element);
      if (err)
          goto error;
  
      while (!cbor_value_at_end(element))
      {
          /* find the non-tag so we can compare */
          err = cbor_value_skip_tag(element);
          if (err)
              goto error;
          if (cbor_value_is_text_string(element))
          {
              bool equals;
              size_t dummyLen = len;
              err = iterate_string_chunks(element,
                                          CONST_CAST(char*, string),
                                          &dummyLen,
                                          &equals,
                                          element,
                                          iterate_memcmp);
              if (err)
                  goto error;
              if (equals)
                  return preparse_value(element);
          }
          else
          {
              /* skip this key */
              err = cbor_value_advance(element);
              if (err)
                  goto error;
          }
  
          /* skip this value */
          err = cbor_value_skip_tag(element);
          if (err)
              goto error;
          err = cbor_value_advance(element);
          if (err)
              goto error;
      }
  
      /* not found */
      element->type = CborInvalidType;
      return CborNoError;
  
  error:
      element->type = CborInvalidType;
      return err;
  }
  
  /**
   * \fn bool cbor_value_is_float(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR
   * single-precision floating point (32-bit).
   *
   * \sa cbor_value_is_valid(), cbor_value_is_double(), cbor_value_is_half_float()
   */
  
  /**
   * \fn CborError cbor_value_get_float(const CborValue *value, float *result)
   *
   * Retrieves the CBOR single-precision floating point (32-bit) value that \a
   * value points to and stores it in \a result. If the iterator \a value does
   * not point to a single-precision floating point value, the behavior is
   * undefined, so checking with \ref cbor_value_get_type or with \ref
   * cbor_value_is_float is recommended.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_float(), cbor_value_get_double()
   */
  
  /**
   * \fn bool cbor_value_is_double(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR
   * double-precision floating point (64-bit).
   *
   * \sa cbor_value_is_valid(), cbor_value_is_float(), cbor_value_is_half_float()
   */
  
  /**
   * \fn CborError cbor_value_get_double(const CborValue *value, float *result)
   *
   * Retrieves the CBOR double-precision floating point (64-bit) value that \a
   * value points to and stores it in \a result. If the iterator \a value does
   * not point to a double-precision floating point value, the behavior is
   * undefined, so checking with \ref cbor_value_get_type or with \ref
   * cbor_value_is_double is recommended.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_double(), cbor_value_get_float()
   */
  
  /**
   * \fn bool cbor_value_is_half_float(const CborValue *value)
   *
   * Returns true if the iterator \a value is valid and points to a CBOR
   * single-precision floating point (16-bit).
   *
   * \sa cbor_value_is_valid(), cbor_value_is_double(), cbor_value_is_float()
   */
  
  /**
   * Retrieves the CBOR half-precision floating point (16-bit) value that \a
   * value points to and stores it in \a result. If the iterator \a value does
   * not point to a half-precision floating point value, the behavior is
   * undefined, so checking with \ref cbor_value_get_type or with \ref
   * cbor_value_is_half_float is recommended.
   *
   * Note: since the C language does not have a standard type for half-precision
   * floating point, this function takes a \c{void *} as a parameter for the
   * storage area, which must be at least 16 bits wide.
   *
   * \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_half_float(), cbor_value_get_float()
   */
  CborError cbor_value_get_half_float(const CborValue* value, void* result)
  {
      uint16_t v;
      cbor_assert(cbor_value_is_half_float(value));
  
      /* size has been computed already */
      v = get16(value->ptr + 1);
      memcpy(result, &v, sizeof(v));
      return CborNoError;
  }
  
  #pragma GCC diagnostic pop
  
  /** @} */
  