/*
  * Metadata demuxer
  * Copyright (c) 2010 Anton Khirnov
  *
  * 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/mathematics.h"

 #include "avformat.h"

 #include "ffmeta.h"

 #include "internal.h"

 #include "libavutil/dict.h"

 
 static int probe(AVProbeData *p)
 {
     if(!memcmp(p->buf, ID_STRING, strlen(ID_STRING)))
         return AVPROBE_SCORE_MAX;
     return 0;
 }
 

 static void get_line(AVIOContext *s, uint8_t *buf, int size)

 {
     do {
         uint8_t c;
         int i = 0;
 

         while ((c = avio_r8(s))) {

             if (c == '\\') {
                 if (i < size - 1)
                     buf[i++] = c;

                 c = avio_r8(s);

             } else if (c == '\n')
                 break;
 
             if (i < size - 1)
                 buf[i++] = c;
         }
         buf[i] = 0;
     } while (!url_feof(s) && (buf[0] == ';' || buf[0] == '#' || buf[0] == 0));
 }
 
 static AVChapter *read_chapter(AVFormatContext *s)
 {
     uint8_t line[256];
     int64_t start, end;
     AVRational tb = {1, 1e9};
 
     get_line(s->pb, line, sizeof(line));
 
     if (sscanf(line, "TIMEBASE=%d/%d", &tb.num, &tb.den))
         get_line(s->pb, line, sizeof(line));

     if (!sscanf(line, "START=%"SCNd64, &start)) {

         av_log(s, AV_LOG_ERROR, "Expected chapter start timestamp, found %s.\n", line);
         start = (s->nb_chapters && s->chapters[s->nb_chapters - 1]->end != AV_NOPTS_VALUE) ?
                  s->chapters[s->nb_chapters - 1]->end : 0;
     } else
         get_line(s->pb, line, sizeof(line));
 

     if (!sscanf(line, "END=%"SCNd64, &end)) {

         av_log(s, AV_LOG_ERROR, "Expected chapter end timestamp, found %s.\n", line);
         end = AV_NOPTS_VALUE;
     }
 

     return avpriv_new_chapter(s, s->nb_chapters, tb, start, end, NULL);

 }
 
 static uint8_t *unescape(uint8_t *buf, int size)
 {
     uint8_t *ret = av_malloc(size + 1);
     uint8_t *p1  = ret, *p2 = buf;
 
     if (!ret)
         return NULL;
 
     while (p2 < buf + size) {
         if (*p2 == '\\')
             p2++;
         *p1++ = *p2++;
     }
     *p1 = 0;
     return ret;
 }
 

 static int read_tag(uint8_t *line, AVDictionary **m)

 {
     uint8_t *key, *value, *p = line;
 
     /* find first not escaped '=' */
     while (1) {
         if (*p == '=')
             break;
         else if (*p == '\\')
             p++;
 
         if (*p++)
             continue;
 
         return 0;
     }
 
     if (!(key = unescape(line, p - line)))
         return AVERROR(ENOMEM);
     if (!(value = unescape(p + 1, strlen(p + 1)))) {
         av_free(key);
         return AVERROR(ENOMEM);
     }
 

     av_dict_set(m, key, value, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);

     return 0;
 }
 

 static int read_header(AVFormatContext *s)

 {

     AVDictionary **m = &s->metadata;

     uint8_t line[1024];
 
     while(!url_feof(s->pb)) {
         get_line(s->pb, line, sizeof(line));
 
         if (!memcmp(line, ID_STREAM, strlen(ID_STREAM))) {

             AVStream *st = avformat_new_stream(s, NULL);

 
             if (!st)

                 return AVERROR(ENOMEM);

 
             st->codec->codec_type = AVMEDIA_TYPE_DATA;

             st->codec->codec_id   = AV_CODEC_ID_FFMETADATA;

 
             m = &st->metadata;
         } else if (!memcmp(line, ID_CHAPTER, strlen(ID_CHAPTER))) {
             AVChapter *ch = read_chapter(s);
 
             if (!ch)

                 return AVERROR(ENOMEM);

 
             m = &ch->metadata;
         } else
             read_tag(line, m);
     }
 
     s->start_time = 0;
     if (s->nb_chapters)
         s->duration = av_rescale_q(s->chapters[s->nb_chapters - 1]->end,
                                    s->chapters[s->nb_chapters - 1]->time_base,
                                    AV_TIME_BASE_Q);
 
     return 0;
 }
 
 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     return AVERROR_EOF;
 }
 

 AVInputFormat ff_ffmetadata_demuxer = {

     .name        = "ffmetadata",

     .long_name   = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text"),

     .read_probe  = probe,
     .read_header = read_header,
     .read_packet = read_packet,
 };