/* * Copyright (c) 2020 Nordic Semiconductor ASA * * SPDX-License-Identifier: Apache-2.0 */ #ifndef ZCBOR_DECODE_H__ #define ZCBOR_DECODE_H__ #include #include #include #include "zcbor_common.h" #ifdef __cplusplus extern "C" { #endif /** The zcbor_decode library provides functions for decoding CBOR data elements. * * See The README for an introduction to CBOR, including the meaning of pint, * nint, bstr etc. */ /** See @ref zcbor_new_state() */ void zcbor_new_decode_state(zcbor_state_t *state_array, size_t n_states, const uint8_t *payload, size_t payload_len, size_t elem_count, uint8_t *elem_state, size_t elem_state_bytes); /** Convenience macro for declaring and initializing a decoding state with backups. * * This gives you a state variable named @p name. The variable functions like * a pointer. * * @param[in] name The name of the new state variable. * @param[in] num_backups The number of backup slots to keep in the state. * @param[in] payload The payload to work on. * @param[in] payload_size The size (in bytes) of @p payload. * @param[in] elem_count The starting elem_count (typically 1). * @param[in] n_flags For use if ZCBOR_MAP_SMART_SEARCH is enabled, ignored otherwise. * The total number of unordered map search flags needed. * I.e. the largest number of elements expected in an unordered map, * including elements in nested unordered maps. */ #define ZCBOR_STATE_D(name, num_backups, payload, payload_size, elem_count, n_flags) \ zcbor_state_t name[((num_backups) + 2 + ZCBOR_FLAG_STATES(n_flags))]; \ do { \ zcbor_new_decode_state(name, ZCBOR_ARRAY_SIZE(name), payload, payload_size, elem_count, \ (uint8_t *)&name[(num_backups) + 1], ZCBOR_FLAG_STATES(n_flags) * sizeof(zcbor_state_t)); \ } while(0) /** The following applies to all _decode() functions listed directly below. * * @param[inout] state The current state of the decoding. * @param[out] result Where to place the decoded value. * @param[in] result_size (if present) Size in bytes of the memory at @p result * * @retval true If the value was decoded correctly. * @retval false If the value has the wrong type, the payload overflowed, the * element count was exhausted, or the value was larger than can * fit in the result variable. * Use zcbor_peek_error() to see the error code. */ bool zcbor_int32_decode(zcbor_state_t *state, int32_t *result); /* pint/nint */ bool zcbor_int64_decode(zcbor_state_t *state, int64_t *result); /* pint/nint */ bool zcbor_uint32_decode(zcbor_state_t *state, uint32_t *result); /* pint */ bool zcbor_uint64_decode(zcbor_state_t *state, uint64_t *result); /* pint */ bool zcbor_size_decode(zcbor_state_t *state, size_t *result); /* pint */ bool zcbor_int_decode(zcbor_state_t *state, void *result, size_t result_size); /* pint/nint */ bool zcbor_uint_decode(zcbor_state_t *state, void *result, size_t result_size); /* pint */ bool zcbor_bstr_decode(zcbor_state_t *state, struct zcbor_string *result); /* bstr */ bool zcbor_tstr_decode(zcbor_state_t *state, struct zcbor_string *result); /* tstr */ bool zcbor_tag_decode(zcbor_state_t *state, uint32_t *result); /* CBOR tag */ bool zcbor_simple_decode(zcbor_state_t *state, uint8_t *result); /* CBOR simple value */ bool zcbor_bool_decode(zcbor_state_t *state, bool *result); /* boolean CBOR simple value */ bool zcbor_float16_decode(zcbor_state_t *state, float *result); /* IEEE754 float16 */ bool zcbor_float16_bytes_decode(zcbor_state_t *state, uint16_t *result); /* IEEE754 float16 raw bytes */ bool zcbor_float16_32_decode(zcbor_state_t *state, float *result); /* IEEE754 float16 or float32 */ bool zcbor_float32_decode(zcbor_state_t *state, float *result); /* IEEE754 float32 */ bool zcbor_float32_64_decode(zcbor_state_t *state, double *result); /* IEEE754 float32 or float64 */ bool zcbor_float64_decode(zcbor_state_t *state, double *result); /* IEEE754 float64 */ bool zcbor_float_decode(zcbor_state_t *state, double *result); /* IEEE754 float16, float32, or float64 */ /** The following applies to all _expect() and _pexpect() functions listed directly below. * * @param[inout] state The current state of the decoding. * @param[in] expected The expected value. * * @retval true If the result was decoded correctly and has the expected value. * @retval false If the decoding failed or the result doesn't have the * expected value. * Use zcbor_peek_error() to see the error code. */ bool zcbor_int32_expect(zcbor_state_t *state, int32_t expected); /* pint/nint */ bool zcbor_int64_expect(zcbor_state_t *state, int64_t expected); /* pint/nint */ bool zcbor_uint32_expect(zcbor_state_t *state, uint32_t expected); /* pint */ bool zcbor_uint64_expect(zcbor_state_t *state, uint64_t expected); /* pint */ bool zcbor_size_expect(zcbor_state_t *state, size_t expected); /* pint */ bool zcbor_bstr_expect(zcbor_state_t *state, struct zcbor_string *expected); /* bstr */ bool zcbor_tstr_expect(zcbor_state_t *state, struct zcbor_string *expected); /* tstr */ bool zcbor_tag_expect(zcbor_state_t *state, uint32_t expected); /* CBOR tag */ bool zcbor_simple_expect(zcbor_state_t *state, uint8_t expected); /* CBOR simple value */ bool zcbor_bool_expect(zcbor_state_t *state, bool expected); /* boolean CBOR simple value */ bool zcbor_nil_expect(zcbor_state_t *state, void *unused); /* 'nil' CBOR simple value */ bool zcbor_undefined_expect(zcbor_state_t *state, void *unused); /* 'undefined' CBOR simple value */ bool zcbor_float16_expect(zcbor_state_t *state, float expected); /* IEEE754 float16 */ bool zcbor_float16_bytes_expect(zcbor_state_t *state, uint16_t expected); /* IEEE754 float16 raw bytes */ bool zcbor_float16_32_expect(zcbor_state_t *state, float expected); /* IEEE754 float16 or float32 */ bool zcbor_float32_expect(zcbor_state_t *state, float expected); /* IEEE754 float32 */ bool zcbor_float32_64_expect(zcbor_state_t *state, double expected); /* IEEE754 float32 or float64 */ bool zcbor_float64_expect(zcbor_state_t *state, double expected); /* IEEE754 float64 */ bool zcbor_float_expect(zcbor_state_t *state, double expected); /* IEEE754 float16, float32, or float64 */ /** Like the _expect() functions but the value is passed through a pointer. * (for use as a zcbor_decoder_t function) */ bool zcbor_int32_pexpect(zcbor_state_t *state, int32_t *expected); /* pint/nint */ bool zcbor_int64_pexpect(zcbor_state_t *state, int64_t *expected); /* pint/nint */ bool zcbor_uint32_pexpect(zcbor_state_t *state, uint32_t *expected); /* pint */ bool zcbor_uint64_pexpect(zcbor_state_t *state, uint64_t *expected); /* pint */ bool zcbor_size_pexpect(zcbor_state_t *state, size_t *expected); /* pint */ bool zcbor_tag_pexpect(zcbor_state_t *state, uint32_t *expected); /* CBOR tag */ bool zcbor_simple_pexpect(zcbor_state_t *state, uint8_t *expected); /* CBOR simple value */ bool zcbor_bool_pexpect(zcbor_state_t *state, bool *expected); /* boolean CBOR simple value */ bool zcbor_float16_pexpect(zcbor_state_t *state, float *expected); /* IEEE754 float16 */ bool zcbor_float16_bytes_pexpect(zcbor_state_t *state, uint16_t *expected); /* IEEE754 float16 raw bytes */ bool zcbor_float16_32_pexpect(zcbor_state_t *state, float *expected); /* IEEE754 float16 or float32 */ bool zcbor_float32_pexpect(zcbor_state_t *state, float *expected); /* IEEE754 float32 */ bool zcbor_float32_64_pexpect(zcbor_state_t *state, double *expected); /* IEEE754 float32 or float64 */ bool zcbor_float64_pexpect(zcbor_state_t *state, double *expected); /* IEEE754 float64 */ bool zcbor_float_pexpect(zcbor_state_t *state, double *expected); /* IEEE754 float16, float32, or float64 */ /** Consume and expect a pint/nint with a certain value, within a union. * * Calls @ref zcbor_union_elem_code then @ref zcbor_[u]int[32|64]_expect. */ bool zcbor_int32_expect_union(zcbor_state_t *state, int32_t expected); bool zcbor_int64_expect_union(zcbor_state_t *state, int64_t expected); bool zcbor_uint32_expect_union(zcbor_state_t *state, uint32_t expected); bool zcbor_uint64_expect_union(zcbor_state_t *state, uint64_t expected); /** Decode and consume a list/map header. * * The contents of the list can be decoded via subsequent function calls. * A state backup is created to keep track of the element count. * Call @ref zcbor_list_end_decode / @ref zcbor_map_end_decode when done * decoding the contents of the list/map * * @retval true Header decoded correctly * @retval false Header decoded incorrectly, or backup failed. */ bool zcbor_list_start_decode(zcbor_state_t *state); bool zcbor_map_start_decode(zcbor_state_t *state); bool zcbor_unordered_map_start_decode(zcbor_state_t *state); /** Search for a key in a map. * * The CBOR spec allows elements (key-value pairs) in maps to appear in any order. * This function should be used when the order of elements is unknown. * * This must only be used while inside a map that has been entered via * @ref zcbor_unordered_map_start_decode. Use @ref zcbor_unordered_map_end_decode * when leaving the map. * * This function searches for keys. When this function returns successfully, * the @p state is pointing to the value corresponding to the found key. * Therefore, to be able to call this function again, the value must first be * decoded or skipped. * * When searching unordered maps, the found elements must be kept track of. * By default, this function automatically keeps track, which means it keeps a * running count of the number of found elements, which is checked when exiting * the map. You can do this manually instead, see @ref zcbor_elem_processed and * @ref manually_process_elem. If ZCBOR_MAP_SMART_SEARCH is defined, a flag is * kept for each element, instead of a rolling count. * * @note Unless ZCBOR_MAP_SMART_SEARCH is defined, * elements are not individually marked as processed, so they may * be returned again in a subsequent call to this function, if it is * matched by the @p key_decoder of that call. Because of this, you should * only use this function when you know the @p key_decoder matches no more * than one of the keys. Typically this means all keys are known strings * or integers, i.e. the @p key_decoder is typically a _pexpect() function. * * When searching for strings, there are convenience functions available, * see the zcbor_search_key_* functions. * * @param[in] key_decoder A decoding function that will be tried against all * keys in the map until it returns true, at which point * @ref zcbor_unordered_map_search will return true. * For example, a zcbor_*_pexpect() function. * @param[inout] state The current state of decoding. Must be currently decoding * the contents of a map, and pointing to one (any) of the * keys, not one of the values. If successful, the @p state * will be pointing to the value corresponding to the * matched key. If unsuccessful, the @p state will be * unchanged. * @param[inout] key_result This will be passed as the second argument to the * @p key_decoder. * * @retval true If the key was found, i.e. @p key_decoder returned true. * @retval false If the key was not found after searching all map elements. * Or the map was pointing to a value (not a key). * Or an unexpected error happened while skipping elements or * jumping from the end of the map to the start. */ bool zcbor_unordered_map_search(zcbor_decoder_t key_decoder, zcbor_state_t *state, void *key_result); /** Find a specific bstr/tstr key as part of a map with unknown element order. * * Uses @ref zcbor_unordered_map_search under the hood. Please refer to those docs * for the conditions under which this can be called. * Refer to the docs for zcbor_(t|b)str_expect_* (e.g. @ref zcbor_bstr_expect_ptr) * for parameter docs. */ bool zcbor_search_key_bstr_ptr(zcbor_state_t *state, char const *ptr, size_t len); bool zcbor_search_key_tstr_ptr(zcbor_state_t *state, char const *ptr, size_t len); bool zcbor_search_key_bstr_term(zcbor_state_t *state, char const *str, size_t maxlen); bool zcbor_search_key_tstr_term(zcbor_state_t *state, char const *str, size_t maxlen); #define zcbor_search_key_bstr_lit(state, str) zcbor_search_key_bstr_ptr(state, str, sizeof(str) - 1) #define zcbor_search_key_tstr_lit(state, str) zcbor_search_key_tstr_ptr(state, str, sizeof(str) - 1) #define zcbor_search_key_bstr_arr(state, str) zcbor_search_key_bstr_ptr(state, str, (sizeof(str))) #define zcbor_search_key_tstr_arr(state, str) zcbor_search_key_tstr_ptr(state, str, (sizeof(str))) /** (Optional) Call this function to mark an (unordered map) element as processed. * * @note This should not be called unless the @ref manually_process_elem flag is set. * By default, i.e. when @ref manually_process_elem is not set, this function is * called internally by @ref zcbor_unordered_map_search whenever a key is found. * * By default, this function increments the internal count @ref map_elems_processed. * * If ZCBOR_MAP_SMART_SEARCH is defined, this function instead clears a flag for the * element (key-value pair) that is currently being processed, or that has just been * processed, meaning the element won't be found again via @ref zcbor_unordered_map_search. * * @ref zcbor_unordered_map_end_decode will fail if @ref map_elems_processed does not * match the number of elements in the map, or if any of the map element's flag is set. */ bool zcbor_elem_processed(zcbor_state_t *state); /** Finalize decoding a list/map * * Check that the list/map had the correct number of elements, and restore the * previous element count from the backup. * * Use @ref zcbor_list_map_end_force_decode to forcibly consume the backup if * something has gone wrong. * * In all successful cases, the state is returned pointing to the byte/element * after the list/map in the payload. * * @retval true Everything ok. * @retval false Element count not correct. */ bool zcbor_list_end_decode(zcbor_state_t *state); bool zcbor_map_end_decode(zcbor_state_t *state); bool zcbor_unordered_map_end_decode(zcbor_state_t *state); bool zcbor_list_map_end_force_decode(zcbor_state_t *state); /** Find whether the state is at the end of a list or map. */ bool zcbor_array_at_end(zcbor_state_t *state); /** Skip a single element, regardless of type and value. * * This means if the element is a map or list, this function will recursively * skip all its contents. * This function will also skip any tags preceeding the element. * * @param[inout] state The current state of the decoding. * @param[in] unused Unused parameter to maintain signature parity with * @ref zcbor_decoder_t. */ bool zcbor_any_skip(zcbor_state_t *state, void *unused); /** Decode 0 or more elements with the same type and constraints. * * The decoded values will appear consecutively in the @p result array. * * The following is an example of decoding a list containing 3 INTS followed by * 0 to 2 bstrs: * * @code{c} * uint32_t ints[3]; * struct zcbor_string bstrs[2]; * uint32_t num_decode; * bool res; * * res = zcbor_list_start_decode(state); * res = res && zcbor_multi_decode(3, 3, &num_decode, zcbor_uint32_decode, * state, ints, sizeof(ints[0])); * res = res && zcbor_multi_decode(0, 2, &num_decode, zcbor_bstr_decode, * state, bstrs, sizeof(bstrs[0])); * res = res && zcbor_list_end_decode(state); * // check res * @endcode * * The @ref zcbor_decoder_t type is designed to be compatible with all single- * value decoder functions in this library, e.g. @ref zcbor_uint32_decode, * @ref zcbor_tstr_expect, @ref zcbor_nil_expect, etc. For _expect() functions, * @p result will be used as a value instead of an array/pointer, so * @p result_len will determine how much the value changes for each call. * To decode the same value multiple times, use a @p result_len of 0. * This function can also be used with custom decoder functions, such as those * generated by the zcbor.py script, which for example decodes larger chunks of * the data at once. * * @param[in] min_decode The minimum acceptable number of elements. * @param[in] max_decode The maximum acceptable number of elements. * @param[out] num_decode The actual number of elements decoded. * @param[in] decoder The decoder function to call under the hood. This * function will be called with the provided arguments * repeatedly until the function fails (returns false) * or until it has been called @p max_decode times. * The result pointer is moved @p result_len bytes for * each call to @p decoder, i.e. @p result refers to * an array of result variables. * Should not be an _expect() function, use * _pexpect() instead. * @param[out] result Where to place the decoded values. Must be an array * of at least @p max_decode elements. * @param[in] result_len The length of each result variable. Must be the * length of the individual elements of @p result. * * @retval true If at least @p min_decode variables were correctly decoded. * @retval false If @p decoder failed before having decoded @p min_decode * values. */ bool zcbor_multi_decode(size_t min_decode, size_t max_decode, size_t *num_decode, zcbor_decoder_t decoder, zcbor_state_t *state, void *result, size_t result_len); /** Attempt to decode a value that might not be present in the data. * * Works like @ref zcbor_multi_decode, with @p present as num_decode. * Will return true, even if the data is not present. * * @param[out] present Whether or not the data was present and successfully decoded. * @param[in] decoder The decoder to attempt. * @param[out] result The result, if present. * * @return Should always return true. */ bool zcbor_present_decode(bool *present, zcbor_decoder_t decoder, zcbor_state_t *state, void *result); /** Supplementary string (bstr/tstr) decoding functions: */ /** Consume and expect a bstr/tstr with the value of the provided char/uint8_t array. * * @param[inout] state The current state of the decoding. * @param[in] str The value to expect. A pointer to the string/array. * _term() uses strnlen(), so @p str must be null-terminated. * _lit() uses sizeof()-1, so @p str must be a (null-terminated) string literal. * _arr() uses sizeof(), so @p str must be a uint8_t array (not null-terminated). * @param[in] len (if present) The length of the string pointed to by @p str * @param[in] maxlen (if present) The maximum length of the string pointed to by @p str. * This value is passed to strnlen. */ bool zcbor_bstr_expect_ptr(zcbor_state_t *state, char const *ptr, size_t len); bool zcbor_tstr_expect_ptr(zcbor_state_t *state, char const *ptr, size_t len); bool zcbor_bstr_expect_term(zcbor_state_t *state, char const *str, size_t maxlen); bool zcbor_tstr_expect_term(zcbor_state_t *state, char const *str, size_t maxlen); #define zcbor_bstr_expect_lit(state, str) zcbor_bstr_expect_ptr(state, str, sizeof(str) - 1) #define zcbor_tstr_expect_lit(state, str) zcbor_tstr_expect_ptr(state, str, sizeof(str) - 1) #define zcbor_bstr_expect_arr(state, str) zcbor_bstr_expect_ptr(state, str, sizeof(str)) #define zcbor_tstr_expect_arr(state, str) zcbor_tstr_expect_ptr(state, str, sizeof(str)) /** Decode and consume a bstr header. * * The rest of the string can be decoded as CBOR. * A state backup is created to keep track of the element count. * Call @ref zcbor_bstr_end_decode when done decoding the contents of the bstr. * * @param[inout] state The current state of the decoding. * @param[out] result The resulting string, for reference. The string should be decoded via * functions from this API since state is pointing to the start of the string, * not the end. * * @retval true Header decoded correctly * @retval false Header decoded incorrectly, or backup failed, or payload is not large enough * to contain the contents of the string. Use @ref zcbor_bstr_start_decode_fragment * for decoding fragmented payloads. */ bool zcbor_bstr_start_decode(zcbor_state_t *state, struct zcbor_string *result); /** Finalize decoding a CBOR-encoded bstr. * * Restore element count from backup. */ bool zcbor_bstr_end_decode(zcbor_state_t *state); /** Supplementary string (bstr/tstr) decoding functions for fragmented payloads: */ /** Start decoding a bstr/tstr, even if the payload contains only part of it. * * This must be followed by a call to @ref zcbor_update_state, which can be * followed by a call to @ref zcbor_next_fragment. Do not call this function * again on subsequent fragments of the same string. * * This consumes the remaining payload as long as it belongs to the string. */ bool zcbor_bstr_decode_fragment(zcbor_state_t *state, struct zcbor_string_fragment *result); bool zcbor_tstr_decode_fragment(zcbor_state_t *state, struct zcbor_string_fragment *result); /** Extract the next fragment of a string. * * Use this function to extract all but the first fragment. */ void zcbor_next_fragment(zcbor_state_t *state, struct zcbor_string_fragment *prev_fragment, struct zcbor_string_fragment *result); /** Decode and consume a bstr header, assuming the payload does not contain the whole bstr. * * The rest of the string can be decoded as CBOR. * A state backup is created to keep track of the element count. * Call @ref zcbor_update_state followed by @ref zcbor_bstr_next_fragment when * the current payload has been exhausted. * Call @ref zcbor_bstr_end_decode when done decoding the contents of the bstr. */ bool zcbor_bstr_start_decode_fragment(zcbor_state_t *state, struct zcbor_string_fragment *result); /** Start decoding the next fragment of a string. * * Use this function to extract all but the first fragment of a CBOR-encoded * bstr. */ void zcbor_bstr_next_fragment(zcbor_state_t *state, struct zcbor_string_fragment *prev_fragment, struct zcbor_string_fragment *result); /** Can be used on any fragment to tell if it is the final fragment of the string. */ bool zcbor_is_last_fragment(const struct zcbor_string_fragment *fragment); #ifdef __cplusplus } #endif #endif /* ZCBOR_DECODE_H__ */