/**************************************************************************** ** ** 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. ** ****************************************************************************/ #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 /** * \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. * *

Memory and parsing constraints

* * 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)). * *

Error handling and preconditions

* * 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) { const CborParser *parser = it->parser; /* 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 = 0; 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: 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 */ ++it->ptr; it->type = CborInvalidType; it->remaining = 0; return CborNoError; } return preparse_value(it); } static CborError preparse_next_value(CborValue *it) { if (it->remaining != UINT32_MAX) { /* don't decrement the item count if the current item is tag: they don't count */ if (it->type != CborTagType && --it->remaining == 0) { it->type = CborInvalidType; return CborNoError; } } 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 */ 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_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; } } 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; *result = v; 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(©); if (err) return err; if (!cbor_value_is_text_string(©)) { *result = false; return CborNoError; } len = strlen(string); return iterate_string_chunks(©, 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; } /** @} */