/*
  * 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 "libavutil/channel_layout.h"

 #include "avcodec.h"
 #include "get_bits.h"

 #include "internal.h"

 #include "msgsmdec.h"

 #include "gsmdec_template.c"

 
 static av_cold int gsm_init(AVCodecContext *avctx)
 {

     avctx->channels       = 1;
     avctx->channel_layout = AV_CH_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, void *data,

                             int *got_frame_ptr, AVPacket *avpkt)

 {

     AVFrame *frame = data;

     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 void gsm_flush(AVCodecContext *avctx)
 {
     GSMContext *s = avctx->priv_data;
     memset(s, 0, sizeof(*s));
 }
 

 #if CONFIG_GSM_DECODER

 AVCodec ff_gsm_decoder = {

     .name           = "gsm",

     .long_name      = NULL_IF_CONFIG_SMALL("GSM"),

     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_GSM,

     .priv_data_size = sizeof(GSMContext),
     .init           = gsm_init,
     .decode         = gsm_decode_frame,

     .flush          = gsm_flush,

     .capabilities   = AV_CODEC_CAP_DR1,

 };

 #endif
 #if CONFIG_GSM_MS_DECODER

 AVCodec ff_gsm_ms_decoder = {

     .name           = "gsm_ms",

     .long_name      = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),

     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_GSM_MS,

     .priv_data_size = sizeof(GSMContext),
     .init           = gsm_init,
     .decode         = gsm_decode_frame,

     .flush          = gsm_flush,

     .capabilities   = AV_CODEC_CAP_DR1,

 };

 #endif