text: /*
   * Core Audio Format demuxer
   * Copyright (c) 2007 Justin Ruggles
   * Copyright (c) 2009 Peter Ross
   *
   * 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
   * Core Audio Format demuxer
   */
  
  #include <inttypes.h>
  
  #include "avformat.h"
  #include "internal.h"
  #include "isom.h"
  #include "mov_chan.h"
  #include "libavutil/intreadwrite.h"
  #include "libavutil/intfloat.h"
  #include "libavutil/dict.h"
  #include "caf.h"
  
  typedef struct CafContext {
      int bytes_per_packet;           ///< bytes in a packet, or 0 if variable
      int frames_per_packet;          ///< frames in a packet, or 0 if variable
      int64_t num_bytes;              ///< total number of bytes in stream
  
      int64_t packet_cnt;             ///< packet counter
      int64_t frame_cnt;              ///< frame counter
  
      int64_t data_start;             ///< data start position, in bytes
      int64_t data_size;              ///< raw data size, in bytes
  } CafContext;
  
  static int probe(const AVProbeData *p)
  {
      if (AV_RB32(p->buf) == MKBETAG('c','a','f','f') && AV_RB16(&p->buf[4]) == 1)
          return AVPROBE_SCORE_MAX;
      return 0;
  }
  
  /** Read audio description chunk */
  static int read_desc_chunk(AVFormatContext *s)
  {
      AVIOContext *pb = s->pb;
      CafContext *caf = s->priv_data;
      AVStream *st;
      int flags;
  
      /* new audio stream */
      st = avformat_new_stream(s, NULL);
      if (!st)
          return AVERROR(ENOMEM);
  
      /* parse format description */
      st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
      st->codecpar->sample_rate = av_clipd(av_int2double(avio_rb64(pb)), 0, INT_MAX);
      st->codecpar->codec_tag   = avio_rl32(pb);
      flags = avio_rb32(pb);
      caf->bytes_per_packet  = avio_rb32(pb);
      st->codecpar->block_align = caf->bytes_per_packet;
      caf->frames_per_packet = avio_rb32(pb);
      st->codecpar->channels    = avio_rb32(pb);
      st->codecpar->bits_per_coded_sample = avio_rb32(pb);
  
      if (caf->bytes_per_packet < 0 || caf->frames_per_packet < 0)
          return AVERROR_INVALIDDATA;
  
      /* calculate bit rate for constant size packets */
      if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
          st->codecpar->bit_rate = (uint64_t)st->codecpar->sample_rate * (uint64_t)caf->bytes_per_packet * 8
                                   / (uint64_t)caf->frames_per_packet;
      } else {
          st->codecpar->bit_rate = 0;
      }
  
      /* determine codec */
      if (st->codecpar->codec_tag == MKTAG('l','p','c','m'))
          st->codecpar->codec_id = ff_mov_get_lpcm_codec_id(st->codecpar->bits_per_coded_sample, (flags ^ 0x2) | 0x4);
      else
          st->codecpar->codec_id = ff_codec_get_id(ff_codec_caf_tags, st->codecpar->codec_tag);
      return 0;
  }
  
  /** Read magic cookie chunk */
  static int read_kuki_chunk(AVFormatContext *s, int64_t size)
  {
      AVIOContext *pb = s->pb;
      AVStream *st      = s->streams[0];
      int ret;
  
      if (size < 0 || size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE)
          return -1;
  
      if (st->codecpar->codec_id == AV_CODEC_ID_AAC) {
          /* The magic cookie format for AAC is an mp4 esds atom.
             The lavc AAC decoder requires the data from the codec specific
             description as extradata input. */
          int strt, skip;
  
          strt = avio_tell(pb);
          ff_mov_read_esds(s, pb);
          skip = size - (avio_tell(pb) - strt);
          if (skip < 0 || !st->codecpar->extradata ||
              st->codecpar->codec_id != AV_CODEC_ID_AAC) {
              av_log(s, AV_LOG_ERROR, "invalid AAC magic cookie\n");
              return AVERROR_INVALIDDATA;
          }
          avio_skip(pb, skip);
      } else if (st->codecpar->codec_id == AV_CODEC_ID_ALAC) {
  #define ALAC_PREAMBLE 12
  #define ALAC_HEADER   36
  #define ALAC_NEW_KUKI 24
          uint8_t preamble[12];
          if (size < ALAC_NEW_KUKI) {
              av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
              avio_skip(pb, size);
              return AVERROR_INVALIDDATA;
          }
          if (avio_read(pb, preamble, ALAC_PREAMBLE) != ALAC_PREAMBLE) {
              av_log(s, AV_LOG_ERROR, "failed to read preamble\n");
              return AVERROR_INVALIDDATA;
          }
  
          if ((ret = ff_alloc_extradata(st->codecpar, ALAC_HEADER)) < 0)
              return ret;
  
          /* For the old style cookie, we skip 12 bytes, then read 36 bytes.
           * The new style cookie only contains the last 24 bytes of what was
           * 36 bytes in the old style cookie, so we fabricate the first 12 bytes
           * in that case to maintain compatibility. */
          if (!memcmp(&preamble[4], "frmaalac", 8)) {
              if (size < ALAC_PREAMBLE + ALAC_HEADER) {
                  av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
                  av_freep(&st->codecpar->extradata);
                  return AVERROR_INVALIDDATA;
              }
              if (avio_read(pb, st->codecpar->extradata, ALAC_HEADER) != ALAC_HEADER) {
                  av_log(s, AV_LOG_ERROR, "failed to read kuki header\n");
                  av_freep(&st->codecpar->extradata);
                  return AVERROR_INVALIDDATA;
              }
              avio_skip(pb, size - ALAC_PREAMBLE - ALAC_HEADER);
          } else {
              AV_WB32(st->codecpar->extradata, 36);
              memcpy(&st->codecpar->extradata[4], "alac", 4);
              AV_WB32(&st->codecpar->extradata[8], 0);
              memcpy(&st->codecpar->extradata[12], preamble, 12);
              if (avio_read(pb, &st->codecpar->extradata[24], ALAC_NEW_KUKI - 12) != ALAC_NEW_KUKI - 12) {
                  av_log(s, AV_LOG_ERROR, "failed to read new kuki header\n");
                  av_freep(&st->codecpar->extradata);
                  return AVERROR_INVALIDDATA;
              }
              avio_skip(pb, size - ALAC_NEW_KUKI);
          }
      } else if (st->codecpar->codec_id == AV_CODEC_ID_OPUS) {
          // The data layout for Opus is currently unknown, so we do not export
          // extradata at all. Multichannel streams are not supported.
          if (st->codecpar->channels > 2) {
              avpriv_request_sample(s, "multichannel Opus in CAF");
              return AVERROR_PATCHWELCOME;
          }
          avio_skip(pb, size);
      } else if ((ret = ff_get_extradata(s, st->codecpar, pb, size)) < 0) {
          return ret;
      }
  
      return 0;
  }
  
  /** Read packet table chunk */
  static int read_pakt_chunk(AVFormatContext *s, int64_t size)
  {
      AVIOContext *pb = s->pb;
      AVStream *st      = s->streams[0];
      CafContext *caf   = s->priv_data;
      int64_t pos = 0, ccount, num_packets;
      int i;
      int ret;
  
      ccount = avio_tell(pb);
  
      num_packets = avio_rb64(pb);
      if (num_packets < 0 || INT32_MAX / sizeof(AVIndexEntry) < num_packets)
          return AVERROR_INVALIDDATA;
  
      st->nb_frames  = avio_rb64(pb); /* valid frames */
      st->nb_frames += avio_rb32(pb); /* priming frames */
      st->nb_frames += avio_rb32(pb); /* remainder frames */
  
      st->duration = 0;
      for (i = 0; i < num_packets; i++) {
          if (avio_feof(pb))
              return AVERROR_INVALIDDATA;
          ret = av_add_index_entry(s->streams[0], pos, st->duration, 0, 0, AVINDEX_KEYFRAME);
          if (ret < 0)
              return ret;
          pos += caf->bytes_per_packet ? caf->bytes_per_packet : ff_mp4_read_descr_len(pb);
          st->duration += caf->frames_per_packet ? caf->frames_per_packet : ff_mp4_read_descr_len(pb);
      }
  
      if (avio_tell(pb) - ccount > size) {
          av_log(s, AV_LOG_ERROR, "error reading packet table\n");
          return AVERROR_INVALIDDATA;
      }
      avio_skip(pb, ccount + size - avio_tell(pb));
  
      caf->num_bytes = pos;
      return 0;
  }
  
  /** Read information chunk */
  static void read_info_chunk(AVFormatContext *s, int64_t size)
  {
      AVIOContext *pb = s->pb;
      unsigned int i;
      unsigned int nb_entries = avio_rb32(pb);
      for (i = 0; i < nb_entries && !avio_feof(pb); i++) {
          char key[32];
          char value[1024];
          avio_get_str(pb, INT_MAX, key, sizeof(key));
          avio_get_str(pb, INT_MAX, value, sizeof(value));
          av_dict_set(&s->metadata, key, value, 0);
      }
  }
  
  static int read_header(AVFormatContext *s)
  {
      AVIOContext *pb = s->pb;
      CafContext *caf = s->priv_data;
      AVStream *st;
      uint32_t tag = 0;
      int found_data, ret;
      int64_t size, pos;
  
      avio_skip(pb, 8); /* magic, version, file flags */
  
      /* audio description chunk */
      if (avio_rb32(pb) != MKBETAG('d','e','s','c')) {
          av_log(s, AV_LOG_ERROR, "desc chunk not present\n");
          return AVERROR_INVALIDDATA;
      }
      size = avio_rb64(pb);
      if (size != 32)
          return AVERROR_INVALIDDATA;
  
      ret = read_desc_chunk(s);
      if (ret)
          return ret;
      st = s->streams[0];
  
      /* parse each chunk */
      found_data = 0;
      while (!avio_feof(pb)) {
  
          /* stop at data chunk if seeking is not supported or
             data chunk size is unknown */
          if (found_data && (caf->data_size < 0 || !(pb->seekable & AVIO_SEEKABLE_NORMAL)))
              break;
  
          tag  = avio_rb32(pb);
          size = avio_rb64(pb);
          pos  = avio_tell(pb);
          if (avio_feof(pb))
              break;
  
          switch (tag) {
          case MKBETAG('d','a','t','a'):
              avio_skip(pb, 4); /* edit count */
              caf->data_start = avio_tell(pb);
              caf->data_size  = size < 0 ? -1 : size - 4;
              if (caf->data_size > 0 && (pb->seekable & AVIO_SEEKABLE_NORMAL))
                  avio_skip(pb, caf->data_size);
              found_data = 1;
              break;
  
          case MKBETAG('c','h','a','n'):
              if ((ret = ff_mov_read_chan(s, s->pb, st, size)) < 0)
                  return ret;
              break;
  
          /* magic cookie chunk */
          case MKBETAG('k','u','k','i'):
              if (read_kuki_chunk(s, size))
                  return AVERROR_INVALIDDATA;
              break;
  
          /* packet table chunk */
          case MKBETAG('p','a','k','t'):
              if (read_pakt_chunk(s, size))
                  return AVERROR_INVALIDDATA;
              break;
  
          case MKBETAG('i','n','f','o'):
              read_info_chunk(s, size);
              break;
  
          default:
              av_log(s, AV_LOG_WARNING,
                     "skipping CAF chunk: %08"PRIX32" (%s), size %"PRId64"\n",
                     tag, av_fourcc2str(av_bswap32(tag)), size);
          case MKBETAG('f','r','e','e'):
              if (size < 0 && found_data)
                  goto found_data;
              if (size < 0)
                  return AVERROR_INVALIDDATA;
              break;
          }
  
          if (size > 0) {
              if (pos > INT64_MAX - size)
                  return AVERROR_INVALIDDATA;
              avio_skip(pb, FFMAX(0, pos + size - avio_tell(pb)));
          }
      }
  
      if (!found_data)
          return AVERROR_INVALIDDATA;
  
  found_data:
      if (caf->bytes_per_packet > 0 && caf->frames_per_packet > 0) {
          if (caf->data_size > 0)
              st->nb_frames = (caf->data_size / caf->bytes_per_packet) * caf->frames_per_packet;
      } else if (st->internal->nb_index_entries && st->duration > 0) {
          if (st->codecpar->sample_rate && caf->data_size / st->duration > INT64_MAX / st->codecpar->sample_rate / 8) {
              av_log(s, AV_LOG_ERROR, "Overflow during bit rate calculation %d * 8 * %"PRId64"\n",
                     st->codecpar->sample_rate, caf->data_size / st->duration);
              return AVERROR_INVALIDDATA;
          }
          st->codecpar->bit_rate = st->codecpar->sample_rate * 8LL *
                                   (caf->data_size / st->duration);
      } else {
          av_log(s, AV_LOG_ERROR, "Missing packet table. It is required when "
                                  "block size or frame size are variable.\n");
          return AVERROR_INVALIDDATA;
      }
  
      avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
      st->start_time = 0;
  
      /* position the stream at the start of data */
      if (caf->data_size >= 0)
          avio_seek(pb, caf->data_start, SEEK_SET);
  
      return 0;
  }
  
  #define CAF_MAX_PKT_SIZE 4096
  
  static int read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      AVIOContext *pb = s->pb;
      AVStream *st      = s->streams[0];
      CafContext *caf   = s->priv_data;
      int res, pkt_size = 0, pkt_frames = 0;
      int64_t left      = CAF_MAX_PKT_SIZE;
  
      if (avio_feof(pb))
          return AVERROR_EOF;
  
      /* don't read past end of data chunk */
      if (caf->data_size > 0) {
          left = (caf->data_start + caf->data_size) - avio_tell(pb);
          if (!left)
              return AVERROR_EOF;
          if (left < 0)
              return AVERROR(EIO);
      }
  
      pkt_frames = caf->frames_per_packet;
      pkt_size   = caf->bytes_per_packet;
  
      if (pkt_size > 0 && pkt_frames == 1) {
          pkt_size   = (CAF_MAX_PKT_SIZE / pkt_size) * pkt_size;
          pkt_size   = FFMIN(pkt_size, left);
          pkt_frames = pkt_size / caf->bytes_per_packet;
      } else if (st->internal->nb_index_entries) {
          if (caf->packet_cnt < st->internal->nb_index_entries - 1) {
              pkt_size   = st->internal->index_entries[caf->packet_cnt + 1].pos       - st->internal->index_entries[caf->packet_cnt].pos;
              pkt_frames = st->internal->index_entries[caf->packet_cnt + 1].timestamp - st->internal->index_entries[caf->packet_cnt].timestamp;
          } else if (caf->packet_cnt == st->internal->nb_index_entries - 1) {
              pkt_size   = caf->num_bytes - st->internal->index_entries[caf->packet_cnt].pos;
              pkt_frames = st->duration   - st->internal->index_entries[caf->packet_cnt].timestamp;
          } else {
              return AVERROR(EIO);
          }
      }
  
      if (pkt_size == 0 || pkt_frames == 0 || pkt_size > left)
          return AVERROR(EIO);
  
      res = av_get_packet(pb, pkt, pkt_size);
      if (res < 0)
          return res;
  
      pkt->size           = res;
      pkt->stream_index   = 0;
      pkt->dts = pkt->pts = caf->frame_cnt;
  
      caf->packet_cnt++;
      caf->frame_cnt += pkt_frames;
  
      return 0;
  }
  
  static int read_seek(AVFormatContext *s, int stream_index,
                       int64_t timestamp, int flags)
  {
      AVStream *st = s->streams[0];
      CafContext *caf = s->priv_data;
      int64_t pos, packet_cnt, frame_cnt;
  
      timestamp = FFMAX(timestamp, 0);
  
      if (caf->frames_per_packet > 0 && caf->bytes_per_packet > 0) {
          /* calculate new byte position based on target frame position */
          pos = caf->bytes_per_packet * (timestamp / caf->frames_per_packet);
          if (caf->data_size > 0)
              pos = FFMIN(pos, caf->data_size);
          packet_cnt = pos / caf->bytes_per_packet;
          frame_cnt  = caf->frames_per_packet * packet_cnt;
      } else if (st->internal->nb_index_entries) {
          packet_cnt = av_index_search_timestamp(st, timestamp, flags);
          frame_cnt  = st->internal->index_entries[packet_cnt].timestamp;
          pos        = st->internal->index_entries[packet_cnt].pos;
      } else {
          return -1;
      }
  
      if (avio_seek(s->pb, pos + caf->data_start, SEEK_SET) < 0)
          return -1;
  
      caf->packet_cnt = packet_cnt;
      caf->frame_cnt  = frame_cnt;
  
      return 0;
  }
  
  AVInputFormat ff_caf_demuxer = {
      .name           = "caf",
      .long_name      = NULL_IF_CONFIG_SMALL("Apple CAF (Core Audio Format)"),
      .priv_data_size = sizeof(CafContext),
      .read_probe     = probe,
      .read_header    = read_header,
      .read_packet    = read_packet,
      .read_seek      = read_seek,
      .codec_tag      = (const AVCodecTag* const []){ ff_codec_caf_tags, 0 },
  };
  