/* SPDX-License-Identifier: GPL-3.0-or-later

 * Copyright © 2016-2020 The TokTok team.

 * Copyright © 2014 Tox project.

 */

#include "state.h"

#include <string.h>

#include "ccompat.h"

#include "logger.h"

/** state load/save */

int state_load(const Logger *_Nonnull log, state_load_cb *_Nonnull state_load_callback, void *_Nonnull outer,

               const uint8_t *_Nonnull data, uint32_t length, uint16_t cookie_inner)

{

    if (state_load_callback == nullptr || data == nullptr) {

        LOGGER_ERROR(log, "state_load() called with invalid args.");

        return -1;

    }

    const uint32_t size_head = sizeof(uint32_t) * 2;

    while (length >= size_head) {

        uint32_t length_sub;

        lendian_bytes_to_host32(&length_sub, data);

        uint32_t cookie_type;

        lendian_bytes_to_host32(&cookie_type, data + sizeof(uint32_t));

        data += size_head;

        length -= size_head;

        if (length < length_sub) {

            /* file truncated */

            LOGGER_ERROR(log, "state file too short: %u < %u", length, length_sub);

            return -1;

        }

        if (lendian_to_host16(cookie_type >> 16) != cookie_inner) {

            /* something is not matching up in a bad way, give up */

            LOGGER_ERROR(log, "state file garbled: %04x != %04x", cookie_type >> 16, cookie_inner);

            return -1;

        }

        const uint16_t type = lendian_to_host16(cookie_type & 0xFFFF);

        switch (state_load_callback(outer, data, length_sub, type)) {

            case STATE_LOAD_STATUS_CONTINUE: {

                data += length_sub;

                length -= length_sub;

                break;

            }

            case STATE_LOAD_STATUS_ERROR: {

                LOGGER_ERROR(log, "Error occcured in state file (type: 0x%02x).", type);

                return -1;

            }

            case STATE_LOAD_STATUS_END: {

                return 0;

            }

        }

    }

    if (length != 0) {

        LOGGER_ERROR(log, "unparsed data in state file of length %u", length);

        return -1;

    }

    return 0;

}

uint8_t *_Nonnull state_write_section_header(uint8_t *_Nonnull data, uint16_t cookie_type, uint32_t len, uint32_t section_type)

{

    host_to_lendian_bytes32(data, len);

    data += sizeof(uint32_t);

    host_to_lendian_bytes32(data, (host_to_lendian16(cookie_type) << 16) | host_to_lendian16(section_type));

    data += sizeof(uint32_t);

    return data;

}

uint16_t lendian_to_host16(uint16_t lendian)

{

#ifdef WORDS_BIGENDIAN

    return (lendian << 8) | (lendian >> 8);

#else

    return lendian;

#endif /* WORDS_BIGENDIAN */

}

uint16_t host_to_lendian16(uint16_t host)

{

    return lendian_to_host16(host);

}

void host_to_lendian_bytes64(uint8_t *_Nonnull dest, uint64_t num)

{

#ifdef WORDS_BIGENDIAN

    num = ((num << 8) & 0xFF00FF00FF00FF00) | ((num >> 8) & 0xFF00FF00FF00FF);

    num = ((num << 16) & 0xFFFF0000FFFF0000) | ((num >> 16) & 0xFFFF0000FFFF);

    num = (num << 32) | (num >> 32);

#endif /* WORDS_BIGENDIAN */

    memcpy(dest, &num, sizeof(uint64_t));

}

void lendian_bytes_to_host64(uint64_t *_Nonnull dest, const uint8_t *_Nonnull lendian)

{

    uint64_t d;

    memcpy(&d, lendian, sizeof(uint64_t));

#ifdef WORDS_BIGENDIAN

    d = ((d << 8) & 0xFF00FF00FF00FF00) | ((d >> 8) & 0xFF00FF00FF00FF);

    d = ((d << 16) & 0xFFFF0000FFFF0000) | ((d >> 16) & 0xFFFF0000FFFF);

    d = (d << 32) | (d >> 32);

#endif /* WORDS_BIGENDIAN */

    *dest = d;

}

void host_to_lendian_bytes32(uint8_t *_Nonnull dest, uint32_t num)

{

#ifdef WORDS_BIGENDIAN

    num = ((num << 8) & 0xFF00FF00) | ((num >> 8) & 0xFF00FF);

    num = (num << 16) | (num >> 16);

#endif /* WORDS_BIGENDIAN */

    memcpy(dest, &num, sizeof(uint32_t));

}

void lendian_bytes_to_host32(uint32_t *_Nonnull dest, const uint8_t *_Nonnull lendian)

{

    uint32_t d;

    memcpy(&d, lendian, sizeof(uint32_t));

#ifdef WORDS_BIGENDIAN

    d = ((d << 8) & 0xFF00FF00) | ((d >> 8) & 0xFF00FF);

    d = (d << 16) | (d >> 16);

#endif /* WORDS_BIGENDIAN */

    *dest = d;

}

void host_to_lendian_bytes16(uint8_t *_Nonnull dest, uint16_t num)

{

#ifdef WORDS_BIGENDIAN

    num = (num << 8) | (num >> 8);

#endif /* WORDS_BIGENDIAN */

    memcpy(dest, &num, sizeof(uint16_t));

}

void lendian_bytes_to_host16(uint16_t *_Nonnull dest, const uint8_t *_Nonnull lendian)

{

    uint16_t d;

    memcpy(&d, lendian, sizeof(uint16_t));

#ifdef WORDS_BIGENDIAN

    d = (d << 8) | (d >> 8);

#endif /* WORDS_BIGENDIAN */

    *dest = d;

}