/* SPDX-License-Identifier: GPL-3.0-or-later
 * Copyright © 2022 The TokTok team.
 */

#ifndef C_TOXCORE_TOXCORE_BIN_UNPACK_H
#define C_TOXCORE_TOXCORE_BIN_UNPACK_H

#include <stdbool.h>
#include <stdint.h>

#include "attributes.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @brief Binary deserialisation object.
 */
typedef struct Bin_Unpack Bin_Unpack;

/** @brief Allocate a new unpacker object.
 *
 * @param buf The byte array to unpack values from.
 * @param buf_size The size of the byte array.
 *
 * @retval nullptr on allocation failure.
 */
non_null()
Bin_Unpack *bin_unpack_new(const uint8_t *buf, uint32_t buf_size);

/** @brief Deallocates an unpacker object.
 *
 * Does not deallocate the buffer inside.
 */
nullable(1)
void bin_unpack_free(Bin_Unpack *bu);

/** @brief Start unpacking a MessagePack array.
 *
 * A call to this function must be followed by exactly `size` calls to other functions below.
 *
 * @param size Will contain the number of array elements following the array marker.
 */
non_null() bool bin_unpack_array(Bin_Unpack *bu, uint32_t *size);

/** @brief Start unpacking a fixed size MessagePack array.
 *
 * @retval false if the packed array size is not exactly the required size.
 */
non_null() bool bin_unpack_array_fixed(Bin_Unpack *bu, uint32_t required_size);

/** @brief Unpack a MessagePack bool. */
non_null() bool bin_unpack_bool(Bin_Unpack *bu, bool *val);
/** @brief Unpack a MessagePack positive int into a `uint8_t`. */
non_null() bool bin_unpack_u08(Bin_Unpack *bu, uint8_t *val);
/** @brief Unpack a MessagePack positive int into a `uint16_t`. */
non_null() bool bin_unpack_u16(Bin_Unpack *bu, uint16_t *val);
/** @brief Unpack a MessagePack positive int into a `uint32_t`. */
non_null() bool bin_unpack_u32(Bin_Unpack *bu, uint32_t *val);
/** @brief Unpack a MessagePack positive int into a `uint64_t`. */
non_null() bool bin_unpack_u64(Bin_Unpack *bu, uint64_t *val);
/** @brief Unpack a Messagepack nil value. */
non_null() bool bin_unpack_nil(Bin_Unpack *bu);

/** @brief Unpack a MessagePack bin into a newly allocated byte array.
 *
 * Allocates a new byte array and stores it into `data_ptr` with its length stored in
 * `data_length_ptr`. This function requires that the unpacking buffer has at least as many bytes
 * remaining to be unpacked as the bin claims to need, so it's not possible to cause an arbitrarily
 * large allocation unless the input array was already that large.
 */
non_null() bool bin_unpack_bin(Bin_Unpack *bu, uint8_t **data_ptr, uint32_t *data_length_ptr);
/** @brief Unpack a MessagePack bin of a fixed length into a pre-allocated byte array.
 *
 * Unlike the function above, this function does not allocate any memory, but requires the size to
 * be known up front.
 */
non_null() bool bin_unpack_bin_fixed(Bin_Unpack *bu, uint8_t *data, uint32_t data_length);

/** @brief Start unpacking a custom binary representation.
 *
 * A call to this function must be followed by exactly `size` bytes packed by functions below.
 */
non_null() bool bin_unpack_bin_size(Bin_Unpack *bu, uint32_t *size);

/** @brief Read a `uint8_t` directly from the unpacker, consuming 1 byte. */
non_null() bool bin_unpack_u08_b(Bin_Unpack *bu, uint8_t *val);
/** @brief Read a `uint16_t` as big endian 16 bit int, consuming 2 bytes. */
non_null() bool bin_unpack_u16_b(Bin_Unpack *bu, uint16_t *val);
/** @brief Read a `uint32_t` as big endian 32 bit int, consuming 4 bytes. */
non_null() bool bin_unpack_u32_b(Bin_Unpack *bu, uint32_t *val);
/** @brief Read a `uint64_t` as big endian 64 bit int, consuming 8 bytes. */
non_null() bool bin_unpack_u64_b(Bin_Unpack *bu, uint64_t *val);

/** @brief Read a byte array directly from the packer, consuming `length` bytes. */
non_null() bool bin_unpack_bin_b(Bin_Unpack *bu, uint8_t *data, uint32_t length);

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // C_TOXCORE_TOXCORE_BIN_UNPACK_H