/*
  * FLAC common code
  * Copyright (c) 2009 Justin Ruggles
  *
  * 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 "libavutil/channel_layout.h"

 #include "libavutil/crc.h"

 #include "libavutil/log.h"
 #include "bytestream.h"
 #include "get_bits.h"

 #include "flac.h"

 #include "flacdata.h"
 
 static const int8_t sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 0 };
 

 static const uint64_t flac_channel_layouts[8] = {

     AV_CH_LAYOUT_MONO,
     AV_CH_LAYOUT_STEREO,
     AV_CH_LAYOUT_SURROUND,
     AV_CH_LAYOUT_QUAD,
     AV_CH_LAYOUT_5POINT0,

     AV_CH_LAYOUT_5POINT1,
     AV_CH_LAYOUT_6POINT1,
     AV_CH_LAYOUT_7POINT1

 };
 

 static int64_t get_utf8(GetBitContext *gb)
 {
     int64_t val;
     GET_UTF8(val, get_bits(gb, 8), return -1;)
     return val;
 }
 
 int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,

                                 FLACFrameInfo *fi, int log_level_offset)

 {
     int bs_code, sr_code, bps_code;
 
     /* frame sync code */

     if ((get_bits(gb, 15) & 0x7FFF) != 0x7FFC) {

         av_log(avctx, AV_LOG_ERROR + log_level_offset, "invalid sync code\n");

         return AVERROR_INVALIDDATA;

     }
 
     /* variable block size stream code */

     fi->is_var_size = get_bits1(gb);

 
     /* block size and sample rate codes */
     bs_code = get_bits(gb, 4);
     sr_code = get_bits(gb, 4);
 
     /* channels and decorrelation */
     fi->ch_mode = get_bits(gb, 4);
     if (fi->ch_mode < FLAC_MAX_CHANNELS) {
         fi->channels = fi->ch_mode + 1;
         fi->ch_mode = FLAC_CHMODE_INDEPENDENT;

     } else if (fi->ch_mode < FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE) {

         fi->channels = 2;

         fi->ch_mode -= FLAC_MAX_CHANNELS - 1;

     } else {

         av_log(avctx, AV_LOG_ERROR + log_level_offset,
                "invalid channel mode: %d\n", fi->ch_mode);

         return AVERROR_INVALIDDATA;

     }
 
     /* bits per sample */
     bps_code = get_bits(gb, 3);
     if (bps_code == 3 || bps_code == 7) {

         av_log(avctx, AV_LOG_ERROR + log_level_offset,
                "invalid sample size code (%d)\n",

                bps_code);

         return AVERROR_INVALIDDATA;

     }
     fi->bps = sample_size_table[bps_code];
 
     /* reserved bit */
     if (get_bits1(gb)) {

         av_log(avctx, AV_LOG_ERROR + log_level_offset,
                "broken stream, invalid padding\n");

         return AVERROR_INVALIDDATA;

     }
 
     /* sample or frame count */

     fi->frame_or_sample_num = get_utf8(gb);
     if (fi->frame_or_sample_num < 0) {

         av_log(avctx, AV_LOG_ERROR + log_level_offset,
                "sample/frame number invalid; utf8 fscked\n");

         return AVERROR_INVALIDDATA;

     }
 
     /* blocksize */
     if (bs_code == 0) {

         av_log(avctx, AV_LOG_ERROR + log_level_offset,
                "reserved blocksize code: 0\n");

         return AVERROR_INVALIDDATA;

     } else if (bs_code == 6) {
         fi->blocksize = get_bits(gb, 8) + 1;
     } else if (bs_code == 7) {
         fi->blocksize = get_bits(gb, 16) + 1;
     } else {
         fi->blocksize = ff_flac_blocksize_table[bs_code];
     }
 
     /* sample rate */
     if (sr_code < 12) {
         fi->samplerate = ff_flac_sample_rate_table[sr_code];
     } else if (sr_code == 12) {
         fi->samplerate = get_bits(gb, 8) * 1000;
     } else if (sr_code == 13) {
         fi->samplerate = get_bits(gb, 16);
     } else if (sr_code == 14) {
         fi->samplerate = get_bits(gb, 16) * 10;
     } else {

         av_log(avctx, AV_LOG_ERROR + log_level_offset,
                "illegal sample rate code %d\n",

                sr_code);

         return AVERROR_INVALIDDATA;

     }
 
     /* header CRC-8 check */
     skip_bits(gb, 8);
     if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer,
                get_bits_count(gb)/8)) {

         av_log(avctx, AV_LOG_ERROR + log_level_offset,
                "header crc mismatch\n");

         return AVERROR_INVALIDDATA;

     }
 
     return 0;
 }

 
 int ff_flac_get_max_frame_size(int blocksize, int ch, int bps)
 {
     /* Technically, there is no limit to FLAC frame size, but an encoder
        should not write a frame that is larger than if verbatim encoding mode
        were to be used. */
 
     int count;
 
     count = 16;                  /* frame header */
     count += ch * ((7+bps+7)/8); /* subframe headers */
     if (ch == 2) {
         /* for stereo, need to account for using decorrelation */
         count += (( 2*bps+1) * blocksize + 7) / 8;
     } else {
         count += ( ch*bps    * blocksize + 7) / 8;
     }
     count += 2; /* frame footer */
 
     return count;
 }

 int ff_flac_is_extradata_valid(AVCodecContext *avctx,

                                enum FLACExtradataFormat *format,
                                uint8_t **streaminfo_start)
 {
     if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) {
         av_log(avctx, AV_LOG_ERROR, "extradata NULL or too small.\n");
         return 0;
     }
     if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) {
         /* extradata contains STREAMINFO only */
         if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) {
             av_log(avctx, AV_LOG_WARNING, "extradata contains %d bytes too many.\n",
                    FLAC_STREAMINFO_SIZE-avctx->extradata_size);
         }
         *format = FLAC_EXTRADATA_FORMAT_STREAMINFO;
         *streaminfo_start = avctx->extradata;
     } else {
         if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) {
             av_log(avctx, AV_LOG_ERROR, "extradata too small.\n");
             return 0;
         }
         *format = FLAC_EXTRADATA_FORMAT_FULL_HEADER;
         *streaminfo_start = &avctx->extradata[8];
     }
     return 1;
 }
 

 void ff_flac_set_channel_layout(AVCodecContext *avctx)
 {
     if (avctx->channels <= FF_ARRAY_ELEMS(flac_channel_layouts))
         avctx->channel_layout = flac_channel_layouts[avctx->channels - 1];
     else
         avctx->channel_layout = 0;
 }
 

 int ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,

                               const uint8_t *buffer)
 {
     GetBitContext gb;
     init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
 
     skip_bits(&gb, 16); /* skip min blocksize */
     s->max_blocksize = get_bits(&gb, 16);
     if (s->max_blocksize < FLAC_MIN_BLOCKSIZE) {
         av_log(avctx, AV_LOG_WARNING, "invalid max blocksize: %d\n",
                s->max_blocksize);
         s->max_blocksize = 16;

         return AVERROR_INVALIDDATA;

     }
 
     skip_bits(&gb, 24); /* skip min frame size */
     s->max_framesize = get_bits_long(&gb, 24);
 
     s->samplerate = get_bits_long(&gb, 20);
     s->channels = get_bits(&gb, 3) + 1;
     s->bps = get_bits(&gb, 5) + 1;
 

     if (s->bps < 4) {
         av_log(avctx, AV_LOG_ERROR, "invalid bps: %d\n", s->bps);
         s->bps = 16;

         return AVERROR_INVALIDDATA;

     }
 

     avctx->channels = s->channels;
     avctx->sample_rate = s->samplerate;
     avctx->bits_per_raw_sample = s->bps;

 
     if (!avctx->channel_layout ||
         av_get_channel_layout_nb_channels(avctx->channel_layout) != avctx->channels)
         ff_flac_set_channel_layout(avctx);

     s->samples = get_bits64(&gb, 36);

 
     skip_bits_long(&gb, 64); /* md5 sum */
     skip_bits_long(&gb, 64); /* md5 sum */

 
     return 0;

 }