/*

 * gsm 06.10 decoder

 * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>

 *

 * 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

 */

/**

 * @file

 * GSM decoder

 */

#include "config_components.h"

#include "libavutil/attributes.h"

#include "libavutil/channel_layout.h"

#include "avcodec.h"

#include "codec_internal.h"

#include "decode.h"

#include "get_bits.h"

#include "msgsmdec.h"

#include "gsmdec_template.c"

static av_cold int gsm_init(AVCodecContext *avctx)

{

    av_channel_layout_uninit(&avctx->ch_layout);

    avctx->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;

    if (!avctx->sample_rate)

        avctx->sample_rate = 8000;

    avctx->sample_fmt     = AV_SAMPLE_FMT_S16;

    switch (avctx->codec_id) {

    case AV_CODEC_ID_GSM:

        avctx->frame_size  = GSM_FRAME_SIZE;

        avctx->block_align = GSM_BLOCK_SIZE;

        break;

    case AV_CODEC_ID_GSM_MS:

        avctx->frame_size  = 2 * GSM_FRAME_SIZE;

        if (!avctx->block_align)

            avctx->block_align = GSM_MS_BLOCK_SIZE;

        else

            if (avctx->block_align < MSN_MIN_BLOCK_SIZE ||

                avctx->block_align > GSM_MS_BLOCK_SIZE  ||

                (avctx->block_align - MSN_MIN_BLOCK_SIZE) % 3) {

                av_log(avctx, AV_LOG_ERROR, "Invalid block alignment %d\n",

                       avctx->block_align);

                return AVERROR_INVALIDDATA;

            }

    }

    return 0;

}

static int gsm_decode_frame(AVCodecContext *avctx, AVFrame *frame,

                            int *got_frame_ptr, AVPacket *avpkt)

{

    int res;

    GetBitContext gb;

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    int16_t *samples;

    if (buf_size < avctx->block_align) {

        av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");

        return AVERROR_INVALIDDATA;

    }

    /* get output buffer */

    frame->nb_samples = avctx->frame_size;

    if ((res = ff_get_buffer(avctx, frame, 0)) < 0)

        return res;

    samples = (int16_t *)frame->data[0];

    switch (avctx->codec_id) {

    case AV_CODEC_ID_GSM:

        init_get_bits(&gb, buf, buf_size * 8);

        if (get_bits(&gb, 4) != 0xd)

            av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");

        res = gsm_decode_block(avctx, samples, &gb, GSM_13000);

        if (res < 0)

            return res;

        break;

    case AV_CODEC_ID_GSM_MS:

        res = ff_msgsm_decode_block(avctx, samples, buf,

                                    (GSM_MS_BLOCK_SIZE - avctx->block_align) / 3);

        if (res < 0)

            return res;

    }

    *got_frame_ptr = 1;

    return avctx->block_align;

}

static av_cold void gsm_flush(AVCodecContext *avctx)

{

    GSMContext *s = avctx->priv_data;

    memset(s, 0, sizeof(*s));

}

#if CONFIG_GSM_DECODER

const FFCodec ff_gsm_decoder = {

    .p.name         = "gsm",

    CODEC_LONG_NAME("GSM"),

    .p.type         = AVMEDIA_TYPE_AUDIO,

    .p.id           = AV_CODEC_ID_GSM,

    .priv_data_size = sizeof(GSMContext),

    .init           = gsm_init,

    FF_CODEC_DECODE_CB(gsm_decode_frame),

    .flush          = gsm_flush,

    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,

};

#endif

#if CONFIG_GSM_MS_DECODER

const FFCodec ff_gsm_ms_decoder = {

    .p.name         = "gsm_ms",

    CODEC_LONG_NAME("GSM Microsoft variant"),

    .p.type         = AVMEDIA_TYPE_AUDIO,

    .p.id           = AV_CODEC_ID_GSM_MS,

    .priv_data_size = sizeof(GSMContext),

    .init           = gsm_init,

    FF_CODEC_DECODE_CB(gsm_decode_frame),

    .flush          = gsm_flush,

    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,

};

#endif