/*
  * xWMA demuxer
  * Copyright (c) 2011 Max Horn
  *

  * 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 <inttypes.h>
 

 #include "avformat.h"

 #include "internal.h"

 #include "riff.h"
 
 /*
  * Demuxer for xWMA, a Microsoft audio container used by XAudio 2.
  */
 
 typedef struct {
     int64_t data_end;
 } XWMAContext;
 
 static int xwma_probe(AVProbeData *p)
 {
     if (!memcmp(p->buf, "RIFF", 4) && !memcmp(p->buf + 8, "XWMA", 4))
         return AVPROBE_SCORE_MAX;
     return 0;
 }
 

 static int xwma_read_header(AVFormatContext *s)

 {

     int64_t size;

     int ret;

     uint32_t dpds_table_size = 0;
     uint32_t *dpds_table = 0;
     unsigned int tag;
     AVIOContext *pb = s->pb;
     AVStream *st;
     XWMAContext *xwma = s->priv_data;
     int i;
 
     /* The following code is mostly copied from wav.c, with some
      * minor alterations.
      */
 
     /* check RIFF header */
     tag = avio_rl32(pb);
     if (tag != MKTAG('R', 'I', 'F', 'F'))
         return -1;
     avio_rl32(pb); /* file size */
     tag = avio_rl32(pb);
     if (tag != MKTAG('X', 'W', 'M', 'A'))
         return -1;
 
     /* parse fmt header */
     tag = avio_rl32(pb);
     if (tag != MKTAG('f', 'm', 't', ' '))
         return -1;
     size = avio_rl32(pb);

     st = avformat_new_stream(s, NULL);

     if (!st)
         return AVERROR(ENOMEM);
 

     ret = ff_get_wav_header(pb, st->codec, size);
     if (ret < 0)
         return ret;

     st->need_parsing = AVSTREAM_PARSE_NONE;
 
     /* All xWMA files I have seen contained WMAv2 data. If there are files
      * using WMA Pro or some other codec, then we need to figure out the right
      * extradata for that. Thus, ask the user for feedback, but try to go on
      * anyway.
      */

     if (st->codec->codec_id != AV_CODEC_ID_WMAV2) {

         av_log(s, AV_LOG_WARNING, "unexpected codec (tag 0x04%x; id %d)\n",
                               st->codec->codec_tag, st->codec->codec_id);
         av_log_ask_for_sample(s, NULL);
     } else {
         /* In all xWMA files I have seen, there is no extradata. But the WMA
          * codecs require extradata, so we provide our own fake extradata.
          *
          * First, check that there really was no extradata in the header. If

          * there was, then try to use it, after asking the user to provide a

          * sample of this unusual file.
          */
         if (st->codec->extradata_size != 0) {
             /* Surprise, surprise: We *did* get some extradata. No idea
              * if it will work, but just go on and try it, after asking
              * the user for a sample.
              */
             av_log(s, AV_LOG_WARNING, "unexpected extradata (%d bytes)\n",
                                   st->codec->extradata_size);
             av_log_ask_for_sample(s, NULL);
         } else {
             st->codec->extradata_size = 6;
             st->codec->extradata      = av_mallocz(6 + FF_INPUT_BUFFER_PADDING_SIZE);
             if (!st->codec->extradata)
                 return AVERROR(ENOMEM);
 
             /* setup extradata with our experimentally obtained value */
             st->codec->extradata[4] = 31;
         }
     }
 

     if (!st->codec->channels) {
         av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n",
                st->codec->channels);
         return AVERROR_INVALIDDATA;
     }
     if (!st->codec->bits_per_coded_sample) {
         av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n",
                st->codec->bits_per_coded_sample);
         return AVERROR_INVALIDDATA;
     }
 

     /* set the sample rate */

     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);

 
     /* parse the remaining RIFF chunks */
     for (;;) {
         if (pb->eof_reached)
             return -1;
         /* read next chunk tag */
         tag = avio_rl32(pb);
         size = avio_rl32(pb);
         if (tag == MKTAG('d', 'a', 't', 'a')) {
             /* We assume that the data chunk comes last. */
             break;
         } else if (tag == MKTAG('d','p','d','s')) {
             /* Quoting the MSDN xWMA docs on the dpds chunk: "Contains the
              * decoded packet cumulative data size array, each element is the
              * number of bytes accumulated after the corresponding xWMA packet

              * is decoded in order."

              *
              * Each packet has size equal to st->codec->block_align, which in
              * all cases I saw so far was always 2230. Thus, we can use the
              * dpds data to compute a seeking index.
              */
 
             /* Error out if there is more than one dpds chunk. */
             if (dpds_table) {
                 av_log(s, AV_LOG_ERROR, "two dpds chunks present\n");
                 return -1;
             }
 
             /* Compute the number of entries in the dpds chunk. */
             if (size & 3) {  /* Size should be divisible by four */

                 av_log(s, AV_LOG_WARNING,
                        "dpds chunk size %"PRId64" not divisible by 4\n", size);

             }
             dpds_table_size = size / 4;
             if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) {

                 av_log(s, AV_LOG_ERROR,
                        "dpds chunk size %"PRId64" invalid\n", size);

                 return -1;
             }
 
             /* Allocate some temporary storage to keep the dpds data around.
              * for processing later on.
              */
             dpds_table = av_malloc(dpds_table_size * sizeof(uint32_t));
             if (!dpds_table) {
                 return AVERROR(ENOMEM);
             }
 
             for (i = 0; i < dpds_table_size; ++i) {
                 dpds_table[i] = avio_rl32(pb);
                 size -= 4;
             }
         }
         avio_skip(pb, size);
     }
 
     /* Determine overall data length */
     if (size < 0)
         return -1;
     if (!size) {
         xwma->data_end = INT64_MAX;
     } else
         xwma->data_end = avio_tell(pb) + size;
 
 
     if (dpds_table && dpds_table_size) {
         int64_t cur_pos;
         const uint32_t bytes_per_sample
                 = (st->codec->channels * st->codec->bits_per_coded_sample) >> 3;
 
         /* Estimate the duration from the total number of output bytes. */
         const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1];
         st->duration = total_decoded_bytes / bytes_per_sample;
 
         /* Use the dpds data to build a seek table.  We can only do this after
          * we know the offset to the data chunk, as we need that to determine
          * the actual offset to each input block.
          * Note: If we allowed ourselves to assume that the data chunk always
          * follows immediately after the dpds block, we could of course guess
          * the data block's start offset already while reading the dpds chunk.
          * I decided against that, just in case other chunks ever are
          * discovered.
          */
         cur_pos = avio_tell(pb);
         for (i = 0; i < dpds_table_size; ++i) {
             /* From the number of output bytes that would accumulate in the
              * output buffer after decoding the first (i+1) packets, we compute
              * an offset / timestamp pair.
              */
             av_add_index_entry(st,
                                cur_pos + (i+1) * st->codec->block_align, /* pos */
                                dpds_table[i] / bytes_per_sample,         /* timestamp */
                                st->codec->block_align,                   /* size */
                                0,                                        /* duration */
                                AVINDEX_KEYFRAME);
         }
     } else if (st->codec->bit_rate) {
         /* No dpds chunk was present (or only an empty one), so estimate
          * the total duration using the average bits per sample and the
          * total data length.
          */
         st->duration = (size<<3) * st->codec->sample_rate / st->codec->bit_rate;
     }
 
     av_free(dpds_table);
 
     return 0;
 }
 
 static int xwma_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int ret, size;
     int64_t left;
     AVStream *st;
     XWMAContext *xwma = s->priv_data;
 
     st = s->streams[0];
 
     left = xwma->data_end - avio_tell(s->pb);
     if (left <= 0) {
         return AVERROR_EOF;
     }
 
     /* read a single block; the default block size is 2230. */
     size = (st->codec->block_align > 1) ? st->codec->block_align : 2230;
     size = FFMIN(size, left);
 
     ret  = av_get_packet(s->pb, pkt, size);
     if (ret < 0)
         return ret;
 
     pkt->stream_index = 0;
     return ret;
 }
 
 AVInputFormat ff_xwma_demuxer = {

     .name           = "xwma",
     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft xWMA"),
     .priv_data_size = sizeof(XWMAContext),
     .read_probe     = xwma_probe,
     .read_header    = xwma_read_header,
     .read_packet    = xwma_read_packet,

 };