/*
  * Musepack SV8 demuxer
  * Copyright (c) 2007 Konstantin Shishkov
  *
  * 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 "libavcodec/get_bits.h"

 #include "libavcodec/unary.h"

 #include "apetag.h"

 #include "avformat.h"

 #include "internal.h"

 #include "avio_internal.h"

 
 /// Two-byte MPC tag
 #define MKMPCTAG(a, b) (a | (b << 8))
 
 #define TAG_MPCK MKTAG('M','P','C','K')
 
 /// Reserved MPC tags
 enum MPCPacketTags{
     TAG_STREAMHDR   = MKMPCTAG('S','H'),
     TAG_STREAMEND   = MKMPCTAG('S','E'),
 
     TAG_AUDIOPACKET = MKMPCTAG('A','P'),
 
     TAG_SEEKTBLOFF  = MKMPCTAG('S','O'),
     TAG_SEEKTABLE   = MKMPCTAG('S','T'),
 
     TAG_REPLAYGAIN  = MKMPCTAG('R','G'),
     TAG_ENCINFO     = MKMPCTAG('E','I'),
 };
 
 static const int mpc8_rate[8] = { 44100, 48000, 37800, 32000, -1, -1, -1, -1 };
 
 typedef struct {
     int ver;
     int64_t header_pos;
     int64_t samples;

 
     int64_t apetag_start;

 } MPCContext;
 

 static inline int64_t bs_get_v(const uint8_t **bs)

 {

     uint64_t v = 0;

     int br = 0;
     int c;
 
     do {
         c = **bs; (*bs)++;
         v <<= 7;
         v |= c & 0x7F;
         br++;
         if (br > 10)
             return -1;
     } while (c & 0x80);
 
     return v - br;
 }
 

 static int mpc8_probe(AVProbeData *p)
 {

     const uint8_t *bs = p->buf + 4;
     const uint8_t *bs_end = bs + p->buf_size;

     int64_t size;
 

     if (p->buf_size < 16)
         return 0;
     if (AV_RL32(p->buf) != TAG_MPCK)
         return 0;

     while (bs < bs_end + 3) {
         int header_found = (bs[0] == 'S' && bs[1] == 'H');
         if (bs[0] < 'A' || bs[0] > 'Z' || bs[1] < 'A' || bs[1] > 'Z')

             return 0;

         bs += 2;
         size = bs_get_v(&bs);
         if (size < 2)

             return 0;

         if (size >= bs_end - bs + 2)

             return AVPROBE_SCORE_MAX / 4 - 1; //seems to be valid MPC but no header yet
         if (header_found) {

             if (size < 11 || size > 28)
                 return 0;
             if (!AV_RL32(bs)) //zero CRC is invalid
                 return 0;
             return AVPROBE_SCORE_MAX;

         } else {
             bs += size - 2;
         }

     }

     return 0;

 }
 
 static inline int64_t gb_get_v(GetBitContext *gb)
 {

     uint64_t v = 0;

     int bits = 0;
     while(get_bits1(gb) && bits < 64-7){
         v <<= 7;
         v |= get_bits(gb, 7);
         bits += 7;
     }
     v <<= 7;
     v |= get_bits(gb, 7);
 
     return v;
 }
 

 static void mpc8_get_chunk_header(AVIOContext *pb, int *tag, int64_t *size)

 {
     int64_t pos;

     pos = avio_tell(pb);

     *tag = avio_rl16(pb);

     *size = ffio_read_varlen(pb);

     *size -= avio_tell(pb) - pos;

 }
 
 static void mpc8_parse_seektable(AVFormatContext *s, int64_t off)
 {
     MPCContext *c = s->priv_data;
     int tag;
     int64_t size, pos, ppos[2];
     uint8_t *buf;
     int i, t, seekd;
     GetBitContext gb;
 

     if (s->nb_streams == 0) {
         av_log(s, AV_LOG_ERROR, "No stream added before parsing seek table\n");
         return;
     }
 

     avio_seek(s->pb, off, SEEK_SET);

     mpc8_get_chunk_header(s->pb, &tag, &size);

     if(tag != TAG_SEEKTABLE){
         av_log(s, AV_LOG_ERROR, "No seek table at given position\n");
         return;
     }

     if (size > INT_MAX/10 || size<=0) {

         av_log(s, AV_LOG_ERROR, "Bad seek table size\n");

         return;
     }

     if(!(buf = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE)))

         return;

     avio_read(s->pb, buf, size);

     init_get_bits(&gb, buf, size * 8);
     size = gb_get_v(&gb);
     if(size > UINT_MAX/4 || size > c->samples/1152){
         av_log(s, AV_LOG_ERROR, "Seek table is too big\n");
         return;
     }
     seekd = get_bits(&gb, 4);
     for(i = 0; i < 2; i++){
         pos = gb_get_v(&gb) + c->header_pos;
         ppos[1 - i] = pos;
         av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME);
     }
     for(; i < size; i++){
         t = get_unary(&gb, 1, 33) << 12;
         t += get_bits(&gb, 12);
         if(t & 1)
             t = -(t & ~1);
         pos = (t >> 1) + ppos[0]*2 - ppos[1];
         av_add_index_entry(s->streams[0], pos, i << seekd, 0, 0, AVINDEX_KEYFRAME);
         ppos[1] = ppos[0];
         ppos[0] = pos;
     }
     av_free(buf);
 }
 
 static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size)
 {

     AVIOContext *pb = s->pb;

     int64_t pos, off;
 
     switch(tag){
     case TAG_SEEKTBLOFF:

         pos = avio_tell(pb) + size;

         off = ffio_read_varlen(pb);

         mpc8_parse_seektable(s, chunk_pos + off);

         avio_seek(pb, pos, SEEK_SET);

         break;
     default:

         avio_skip(pb, size);

     }
 }
 

 static int mpc8_read_header(AVFormatContext *s)

 {
     MPCContext *c = s->priv_data;

     AVIOContext *pb = s->pb;

     AVStream *st;
     int tag = 0;
     int64_t size, pos;
 

     c->header_pos = avio_tell(pb);

     if(avio_rl32(pb) != TAG_MPCK){

         av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n");

         return AVERROR_INVALIDDATA;

     }
 
     while(!url_feof(pb)){

         pos = avio_tell(pb);

         mpc8_get_chunk_header(pb, &tag, &size);

         if (size < 0) {
             av_log(s, AV_LOG_ERROR, "Invalid chunk length\n");
             return AVERROR_INVALIDDATA;
         }

         if(tag == TAG_STREAMHDR)
             break;
         mpc8_handle_chunk(s, tag, pos, size);
     }
     if(tag != TAG_STREAMHDR){
         av_log(s, AV_LOG_ERROR, "Stream header not found\n");

         return AVERROR_INVALIDDATA;

     }

     pos = avio_tell(pb);

     avio_skip(pb, 4); //CRC

     c->ver = avio_r8(pb);

     if(c->ver != 8){
         av_log(s, AV_LOG_ERROR, "Unknown stream version %d\n", c->ver);

         return AVERROR_PATCHWELCOME;

     }

     c->samples = ffio_read_varlen(pb);
     ffio_read_varlen(pb); //silence samples at the beginning

     st = avformat_new_stream(s, NULL);

     if (!st)
         return AVERROR(ENOMEM);

     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

     st->codec->codec_id = AV_CODEC_ID_MUSEPACK8;

     st->codec->bits_per_coded_sample = 16;

 
     st->codec->extradata_size = 2;
     st->codec->extradata = av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);

     avio_read(pb, st->codec->extradata, st->codec->extradata_size);

 
     st->codec->channels = (st->codec->extradata[1] >> 4) + 1;
     st->codec->sample_rate = mpc8_rate[st->codec->extradata[0] >> 5];

     avpriv_set_pts_info(st, 32, 1152  << (st->codec->extradata[1]&3)*2, st->codec->sample_rate);

     st->start_time = 0;

     st->duration = c->samples / (1152 << (st->codec->extradata[1]&3)*2);

     size -= avio_tell(pb) - pos;

     if (size > 0)
         avio_skip(pb, size);

     if (pb->seekable) {
         int64_t pos = avio_tell(s->pb);

         c->apetag_start = ff_ape_parse_tag(s);

         avio_seek(s->pb, pos, SEEK_SET);
     }
 

     return 0;
 }
 
 static int mpc8_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     MPCContext *c = s->priv_data;
     int tag;
     int64_t pos, size;
 

     while(!url_feof(s->pb)){

         pos = avio_tell(s->pb);

 
         /* don't return bogus packets with the ape tag data */
         if (c->apetag_start && pos >= c->apetag_start)
             return AVERROR_EOF;
 

         mpc8_get_chunk_header(s->pb, &tag, &size);

         if (size < 0)
             return -1;

         if(tag == TAG_AUDIOPACKET){

             if(av_get_packet(s->pb, pkt, size) < 0)

                 return AVERROR(ENOMEM);
             pkt->stream_index = 0;

             pkt->duration     = 1;

             return 0;
         }
         if(tag == TAG_STREAMEND)
             return AVERROR(EIO);
         mpc8_handle_chunk(s, tag, pos, size);
     }

     return AVERROR_EOF;

 }
 
 static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 {
     AVStream *st = s->streams[stream_index];
     int index = av_index_search_timestamp(st, timestamp, flags);
 
     if(index < 0) return -1;

     if (avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET) < 0)
         return -1;

     ff_update_cur_dts(s, st, st->index_entries[index].timestamp);

     return 0;
 }
 
 

 AVInputFormat ff_mpc8_demuxer = {

     .name           = "mpc8",
     .long_name      = NULL_IF_CONFIG_SMALL("Musepack SV8"),
     .priv_data_size = sizeof(MPCContext),
     .read_probe     = mpc8_probe,
     .read_header    = mpc8_read_header,
     .read_packet    = mpc8_read_packet,
     .read_seek      = mpc8_read_seek,

 };