mcuboot/boot/zcbor/include/zcbor_decode.h

453 lines
23 KiB
C

/*
* This file has been copied from the zcbor library.
* Commit zcbor 0.8.1
*/
/*
* Copyright (c) 2020 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef ZCBOR_DECODE_H__
#define ZCBOR_DECODE_H__
#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>
#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__ */