/*

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include <stddef.h>

#include <stdint.h>

#include "libavutil/mem.h"

#include "atsc_a53.h"

#include "get_bits.h"

int ff_alloc_a53_sei(const AVFrame *frame, size_t prefix_len,

                     void **data, size_t *sei_size)

{

    AVFrameSideData *side_data = NULL;

    uint8_t *sei_data;

    if (frame)

        side_data = av_frame_get_side_data(frame, AV_FRAME_DATA_A53_CC);

    if (!side_data) {

        *data = NULL;

        return 0;

    }

    *sei_size = side_data->size + 11;

    *data = av_mallocz(*sei_size + prefix_len);

    if (!*data)

        return AVERROR(ENOMEM);

    sei_data = (uint8_t*)*data + prefix_len;

    // country code

    sei_data[0] = 181;

    sei_data[1] = 0;

    sei_data[2] = 49;

    /**

     * 'GA94' is standard in North America for ATSC, but hard coding

     * this style may not be the right thing to do -- other formats

     * do exist. This information is not available in the side_data

     * so we are going with this right now.

     */

    AV_WL32(sei_data + 3, MKTAG('G', 'A', '9', '4'));

    sei_data[7] = 3;

    sei_data[8] = ((side_data->size/3) & 0x1f) | 0x40;

    sei_data[9] = 0;

    memcpy(sei_data + 10, side_data->data, side_data->size);

    sei_data[side_data->size+10] = 255;

    return 0;

}

int ff_parse_a53_cc(AVBufferRef **pbuf, const uint8_t *data, int size)

{

    AVBufferRef *buf = *pbuf;

    GetBitContext gb;

    size_t new_size, old_size = buf ? buf->size : 0;

    int ret, cc_count;

    if (size < 3)

        return AVERROR_INVALIDDATA;

    ret = init_get_bits8(&gb, data, size);

    if (ret < 0)

        return ret;

    if (get_bits(&gb, 8) != 0x3) // user_data_type_code

        return 0;

    skip_bits(&gb, 1); // reserved

    if (!get_bits(&gb, 1)) // process_cc_data_flag

        return 0;

    skip_bits(&gb, 1); // zero bit

    cc_count = get_bits(&gb, 5);

    if (!cc_count)

        return 0;

    skip_bits(&gb, 8); // reserved

    /* 3 bytes per CC plus one byte marker_bits at the end */

    if (cc_count * 3 >= (get_bits_left(&gb) >> 3))

        return AVERROR_INVALIDDATA;

    new_size = (old_size + cc_count * 3);

    if (new_size > INT_MAX)

        return AVERROR_INVALIDDATA;

    /* Allow merging of the cc data from two fields. */

    ret = av_buffer_realloc(pbuf, new_size);

    if (ret < 0)

        return ret;

    buf = *pbuf;

    /* Use of av_buffer_realloc assumes buffer is writeable */

    for (int i = 0; i < cc_count; i++) {

        buf->data[old_size++] = get_bits(&gb, 8);

        buf->data[old_size++] = get_bits(&gb, 8);

        buf->data[old_size++] = get_bits(&gb, 8);

    }

    return cc_count;

}