/*
  * Microsoft Windows ICO demuxer
  * Copyright (c) 2011 Peter Ross (pross@xvid.org)
  *
  * 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
  * Microsoft Windows ICO demuxer
  */
 
 #include "libavutil/intreadwrite.h"
 #include "libavcodec/bytestream.h"
 #include "libavcodec/bmp.h"

 #include "libavcodec/png.h"

 #include "avformat.h"
 #include "internal.h"
 
 typedef struct {
     int offset;
     int size;
     int nb_pal;
 } IcoImage;
 
 typedef struct {
     int current_image;
     int nb_images;
     IcoImage * images;
 } IcoDemuxContext;
 
 static int probe(AVProbeData *p)
 {

     unsigned i, frames, checked = 0;

     if (p->buf_size < 22 || AV_RL16(p->buf) || AV_RL16(p->buf + 2) != 1)

         return 0;

     frames = AV_RL16(p->buf + 4);
     if (!frames)
         return 0;
     for (i = 0; i < frames && i * 16 + 22 <= p->buf_size; i++) {

         unsigned offset;
         if (AV_RL16(p->buf + 10 + i * 16) & ~1)
             return FFMIN(i, AVPROBE_SCORE_MAX / 4);
         if (p->buf[13 + i * 16])
             return FFMIN(i, AVPROBE_SCORE_MAX / 4);
         if (AV_RL32(p->buf + 14 + i * 16) < 40)
             return FFMIN(i, AVPROBE_SCORE_MAX / 4);
         offset = AV_RL32(p->buf + 18 + i * 16);
         if (offset < 22)
             return FFMIN(i, AVPROBE_SCORE_MAX / 4);

         if (offset > p->buf_size - 8)

             continue;

         if (p->buf[offset] != 40 && AV_RB64(p->buf + offset) != PNGSIG)
             return FFMIN(i, AVPROBE_SCORE_MAX / 4);

         checked++;

     }
 

     if (checked < frames)
         return AVPROBE_SCORE_MAX / 4 + FFMIN(checked, 1);

     return AVPROBE_SCORE_MAX / 2 + 1;

 }
 

 static int read_header(AVFormatContext *s)

 {
     IcoDemuxContext *ico = s->priv_data;
     AVIOContext *pb = s->pb;

     int i, codec;

 
     avio_skip(pb, 4);
     ico->nb_images = avio_rl16(pb);
 

     ico->images = av_malloc_array(ico->nb_images, sizeof(IcoImage));

     if (!ico->images)
         return AVERROR(ENOMEM);
 
     for (i = 0; i < ico->nb_images; i++) {
         AVStream *st;

         int tmp;

 
         if (avio_seek(pb, 6 + i * 16, SEEK_SET) < 0)
             break;
 
         st = avformat_new_stream(s, NULL);
         if (!st)
             return AVERROR(ENOMEM);
 

         st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
         st->codecpar->width      = avio_r8(pb);
         st->codecpar->height     = avio_r8(pb);

         ico->images[i].nb_pal = avio_r8(pb);

         if (ico->images[i].nb_pal == 255)
             ico->images[i].nb_pal = 0;

         avio_skip(pb, 5);

 
         ico->images[i].size   = avio_rl32(pb);

         if (ico->images[i].size <= 0) {
             av_log(s, AV_LOG_ERROR, "Invalid image size %d\n", ico->images[i].size);
             return AVERROR_INVALIDDATA;
         }

         ico->images[i].offset = avio_rl32(pb);
 
         if (avio_seek(pb, ico->images[i].offset, SEEK_SET) < 0)
             break;
 

         codec = avio_rl32(pb);
         switch (codec) {

         case MKTAG(0x89, 'P', 'N', 'G'):

             st->codecpar->codec_id = AV_CODEC_ID_PNG;
             st->codecpar->width    = 0;
             st->codecpar->height   = 0;

             break;
         case 40:

             if (ico->images[i].size < 40)
                 return AVERROR_INVALIDDATA;

             st->codecpar->codec_id = AV_CODEC_ID_BMP;

             tmp = avio_rl32(pb);
             if (tmp)

                 st->codecpar->width = tmp;

             tmp = avio_rl32(pb);
             if (tmp)

                 st->codecpar->height = tmp / 2;

             break;
         default:

             avpriv_request_sample(s, "codec %d", codec);

             return AVERROR_INVALIDDATA;
         }
     }
 
     return 0;
 }
 
 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     IcoDemuxContext *ico = s->priv_data;
     IcoImage *image;
     AVIOContext *pb = s->pb;

     AVStream *st = s->streams[0];

     int ret;
 
     if (ico->current_image >= ico->nb_images)

         return AVERROR_EOF;

 
     image = &ico->images[ico->current_image];
 
     if ((ret = avio_seek(pb, image->offset, SEEK_SET)) < 0)
         return ret;
 

     if (s->streams[ico->current_image]->codecpar->codec_id == AV_CODEC_ID_PNG) {

         if ((ret = av_get_packet(pb, pkt, image->size)) < 0)
             return ret;
     } else {
         uint8_t *buf;
         if ((ret = av_new_packet(pkt, 14 + image->size)) < 0)
             return ret;
         buf = pkt->data;
 
         /* add BMP header */
         bytestream_put_byte(&buf, 'B');
         bytestream_put_byte(&buf, 'M');
         bytestream_put_le32(&buf, pkt->size);
         bytestream_put_le16(&buf, 0);
         bytestream_put_le16(&buf, 0);

         bytestream_put_le32(&buf, 0);

         if ((ret = avio_read(pb, buf, image->size)) != image->size) {

             av_packet_unref(pkt);

             return ret < 0 ? ret : AVERROR_INVALIDDATA;

         }

         st->codecpar->bits_per_coded_sample = AV_RL16(buf + 14);

 
         if (AV_RL32(buf + 32))
             image->nb_pal = AV_RL32(buf + 32);
 

         if (st->codecpar->bits_per_coded_sample <= 8 && !image->nb_pal) {
             image->nb_pal = 1 << st->codecpar->bits_per_coded_sample;

             AV_WL32(buf + 32, image->nb_pal);
         }
 
         AV_WL32(buf - 4, 14 + 40 + image->nb_pal * 4);

         AV_WL32(buf + 8, AV_RL32(buf + 8) / 2);
     }
 
     pkt->stream_index = ico->current_image++;
     pkt->flags |= AV_PKT_FLAG_KEY;
 
     return 0;
 }
 
 AVInputFormat ff_ico_demuxer = {
     .name           = "ico",
     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft Windows ICO"),
     .priv_data_size = sizeof(IcoDemuxContext),
     .read_probe     = probe,
     .read_header    = read_header,
     .read_packet    = read_packet,
     .flags          = AVFMT_NOTIMESTAMPS,
 };