blob: 04cabc623058613ff19ff01b3376576d73d59580 [file] [log] [blame]
// Copyright 2021 Google LLC
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
struct CborIn {
const uint8_t* buffer;
size_t buffer_size;
size_t cursor;
enum CborReadResult {
// The end of the input was reached before the token was fully read.
// A malformed or unsupported token was found.
// The requested token was not found.
// Initializes an input stream for reading CBOR tokens.
static inline void CborInInit(const uint8_t* buffer, size_t buffer_size,
struct CborIn* in) {
in->buffer = buffer;
in->buffer_size = buffer_size;
in->cursor = 0;
// Returns the number of bytes that have been read from the input.
static inline size_t CborInOffset(const struct CborIn* in) {
return in->cursor;
// Returns whether the input stream has been fully consumed.
static inline bool CborInAtEnd(const struct CborIn* in) {
return in->cursor == in->buffer_size;
// These functions read simple CBOR tokens from the input stream. Interpreting
// the greater structure of the data left to the caller and it is expected that
// these functions are just being used to validate and extract data from a known
// structure.
enum CborReadResult CborReadInt(struct CborIn* in, int64_t* val);
enum CborReadResult CborReadUint(struct CborIn* in, uint64_t* val);
enum CborReadResult CborReadBstr(struct CborIn* in, size_t* data_size,
const uint8_t** data);
enum CborReadResult CborReadTstr(struct CborIn* in, size_t* size,
const char** str);
enum CborReadResult CborReadArray(struct CborIn* in, size_t* num_elements);
enum CborReadResult CborReadMap(struct CborIn* in, size_t* num_pairs);
enum CborReadResult CborReadFalse(struct CborIn* in);
enum CborReadResult CborReadTrue(struct CborIn* in);
enum CborReadResult CborReadNull(struct CborIn* in);
// Returns CBOR_READ_RESULT_OK even if the value read does not correspond to
// a valid tag. See
// for a registry of reserved and invalid tag values.
enum CborReadResult CborReadTag(struct CborIn* in, uint64_t* tag);
// Skips over the next CBOR item in the input. The item may contain nested
// items, in the case of an array, map, or tag, and this function will attempt
// to descend and skip all nested items in order to skip the parent item. There
// is a limit on the level of nesting, after which this function will fail with
enum CborReadResult CborReadSkip(struct CborIn* in);
#ifdef __cplusplus
} // extern "C"