/*
  * raw FLAC muxer
  * Copyright (c) 2006-2009 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/opt.h"

 #include "libavcodec/flac.h"

 #include "avformat.h"

 #include "avio_internal.h"

 #include "flacenc.h"

 #include "vorbiscomment.h"
 #include "libavcodec/bytestream.h"

 typedef struct FlacMuxerContext {
     const AVClass *class;
     int write_header;

 
     /* updated streaminfo sent by the encoder at the end */
     uint8_t *streaminfo;

 } FlacMuxerContext;
 

 static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes,

                                     int last_block)
 {

     avio_w8(pb, last_block ? 0x81 : 0x01);
     avio_wb24(pb, n_padding_bytes);

     ffio_fill(pb, 0, n_padding_bytes);

     return 0;
 }
 

 static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m,

                                     int last_block, int bitexact)
 {
     const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;

     int64_t len;

     uint8_t *p, *p0;
 

     ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
 

     len = ff_vorbiscomment_length(*m, vendor);

     if (len >= ((1<<24) - 4))
         return AVERROR(EINVAL);

     p0 = av_malloc(len+4);
     if (!p0)
         return AVERROR(ENOMEM);
     p = p0;
 
     bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
     bytestream_put_be24(&p, len);

     ff_vorbiscomment_write(&p, m, vendor);

     avio_write(pb, p0, len+4);

     av_freep(&p0);
     p = NULL;
 
     return 0;
 }
 

 static int flac_write_header(struct AVFormatContext *s)
 {

     int ret;

     int padding = s->metadata_header_padding;

     AVCodecContext *codec = s->streams[0]->codec;

     FlacMuxerContext *c   = s->priv_data;
 
     if (!c->write_header)
         return 0;

     if (s->nb_streams > 1) {
         av_log(s, AV_LOG_ERROR, "only one stream is supported\n");
         return AVERROR(EINVAL);
     }
     if (codec->codec_id != AV_CODEC_ID_FLAC) {
         av_log(s, AV_LOG_ERROR, "unsupported codec\n");
         return AVERROR(EINVAL);
     }
 

     if (padding < 0)
         padding = 8192;
     /* The FLAC specification states that 24 bits are used to represent the
      * size of a metadata block so we must clip this value to 2^24-1. */

     padding = av_clip_uintp2(padding, 24);

     ret = ff_flac_write_header(s->pb, codec->extradata,
                                codec->extradata_size, 0);

     if (ret)
         return ret;
 

     /* add the channel layout tag */
     if (codec->channel_layout &&
         !(codec->channel_layout & ~0x3ffffULL) &&
         !ff_flac_is_native_layout(codec->channel_layout)) {
         AVDictionaryEntry *chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK",
                                                 NULL, 0);
 
         if (chmask) {
             av_log(s, AV_LOG_WARNING, "A WAVEFORMATEXTENSIBLE_CHANNEL_MASK is "
                    "already present, this muxer will not overwrite it.\n");
         } else {
             uint8_t buf[32];
             snprintf(buf, sizeof(buf), "0x%"PRIx64, codec->channel_layout);
             av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", buf, 0);
         }
     }
 

     ret = flac_write_block_comment(s->pb, &s->metadata, !padding,

                                    s->flags & AVFMT_FLAG_BITEXACT);

     if (ret)
         return ret;
 
     /* The command line flac encoder defaults to placing a seekpoint
      * every 10s.  So one might add padding to allow that later
      * but there seems to be no simple way to get the duration here.

      * So just add the amount requested by the user. */

     if (padding)
         flac_write_block_padding(s->pb, padding, 1);

 
     return ret;

 }
 

 static int flac_write_trailer(struct AVFormatContext *s)
 {

     AVIOContext *pb = s->pb;

     int64_t file_size;

     FlacMuxerContext *c = s->priv_data;

     uint8_t *streaminfo = c->streaminfo ? c->streaminfo :
                                           s->streams[0]->codec->extradata;

     if (!c->write_header || !streaminfo)

         return 0;

     if (pb->seekable) {

         /* rewrite the STREAMINFO header block data */

         file_size = avio_tell(pb);

         avio_seek(pb, 8, SEEK_SET);

         avio_write(pb, streaminfo, FLAC_STREAMINFO_SIZE);

         avio_seek(pb, file_size, SEEK_SET);

         avio_flush(pb);

     } else {
         av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");

     }

 
     av_freep(&c->streaminfo);
 

     return 0;
 }
 
 static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
 {

     FlacMuxerContext *c = s->priv_data;
     uint8_t *streaminfo;
     int streaminfo_size;
 
     /* check for updated streaminfo */
     streaminfo = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
                                          &streaminfo_size);
     if (streaminfo && streaminfo_size == FLAC_STREAMINFO_SIZE) {
         av_freep(&c->streaminfo);
 
         c->streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
         if (!c->streaminfo)
             return AVERROR(ENOMEM);
         memcpy(c->streaminfo, streaminfo, FLAC_STREAMINFO_SIZE);
     }
 
     if (pkt->size)
         avio_write(s->pb, pkt->data, pkt->size);

     return 0;
 }
 

 static const AVOption flacenc_options[] = {

     { "write_header", "Write the file header", offsetof(FlacMuxerContext, write_header), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },

     { NULL },
 };
 
 static const AVClass flac_muxer_class = {
     .class_name = "flac muxer",
     .item_name  = av_default_item_name,
     .option     = flacenc_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 AVOutputFormat ff_flac_muxer = {

     .name              = "flac",
     .long_name         = NULL_IF_CONFIG_SMALL("raw FLAC"),

     .priv_data_size    = sizeof(FlacMuxerContext),

     .mime_type         = "audio/x-flac",
     .extensions        = "flac",

     .audio_codec       = AV_CODEC_ID_FLAC,
     .video_codec       = AV_CODEC_ID_NONE,

     .write_header      = flac_write_header,
     .write_packet      = flac_write_packet,
     .write_trailer     = flac_write_trailer,

     .flags             = AVFMT_NOTIMESTAMPS,

     .priv_class        = &flac_muxer_class,

 };