/*
  * APE tag handling
  * Copyright (c) 2007 Benjamin Zores <ben@geexbox.org>
  *  based upon libdemac from Dave Chapman.
  *
  * 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/intreadwrite.h"

 #include "libavutil/dict.h"

 #include "avformat.h"

 #include "avio_internal.h"

 #include "apetag.h"

 #include "internal.h"

 
 #define APE_TAG_FLAG_CONTAINS_HEADER  (1 << 31)

 #define APE_TAG_FLAG_CONTAINS_FOOTER  (1 << 30)

 #define APE_TAG_FLAG_IS_HEADER        (1 << 29)

 #define APE_TAG_FLAG_IS_BINARY        (1 << 1)

 
 static int ape_tag_read_field(AVFormatContext *s)
 {

     AVIOContext *pb = s->pb;

     uint8_t key[1024], *value;

     uint32_t size, flags;

     int i, c;

     size = avio_rl32(pb);  /* field size */

     flags = avio_rl32(pb); /* field flags */

     for (i = 0; i < sizeof(key) - 1; i++) {

         c = avio_r8(pb);

         if (c < 0x20 || c > 0x7E)
             break;
         else
             key[i] = c;
     }
     key[i] = 0;
     if (c != 0) {
         av_log(s, AV_LOG_WARNING, "Invalid APE tag key '%s'.\n", key);
         return -1;
     }

     if (size > INT32_MAX - FF_INPUT_BUFFER_PADDING_SIZE) {
         av_log(s, AV_LOG_ERROR, "APE tag size too large.\n");
         return AVERROR_INVALIDDATA;
     }

     if (flags & APE_TAG_FLAG_IS_BINARY) {
         uint8_t filename[1024];

         enum AVCodecID id;

         AVStream *st = avformat_new_stream(s, NULL);
         if (!st)
             return AVERROR(ENOMEM);

 
         size -= avio_get_str(pb, size, filename, sizeof(filename));
         if (size <= 0) {
             av_log(s, AV_LOG_WARNING, "Skipping binary tag '%s'.\n", key);
             return 0;

         }

         av_dict_set(&st->metadata, key, filename, 0);

         if ((id = ff_guess_image2_codec(filename)) != AV_CODEC_ID_NONE) {

             AVPacket pkt;
             int ret;
 
             ret = av_get_packet(s->pb, &pkt, size);
             if (ret < 0) {
                 av_log(s, AV_LOG_ERROR, "Error reading cover art.\n");
                 return ret;
             }
 
             st->disposition      |= AV_DISPOSITION_ATTACHED_PIC;
             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
             st->codec->codec_id   = id;
 
             st->attached_pic              = pkt;
             st->attached_pic.stream_index = st->index;
             st->attached_pic.flags       |= AV_PKT_FLAG_KEY;
         } else {

             if (ff_get_extradata(st->codec, s->pb, size) < 0)

                 return AVERROR(ENOMEM);
             st->codec->codec_type = AVMEDIA_TYPE_ATTACHMENT;

         }

     } else {
         value = av_malloc(size+1);
         if (!value)
             return AVERROR(ENOMEM);
         c = avio_read(pb, value, size);

         if (c < 0) {
             av_free(value);

             return c;

         }

         value[c] = 0;
         av_dict_set(&s->metadata, key, value, AV_DICT_DONT_STRDUP_VAL);
     }

     return 0;
 }
 

 int64_t ff_ape_parse_tag(AVFormatContext *s)

 {

     AVIOContext *pb = s->pb;

     int64_t file_size = avio_size(pb);

     uint32_t val, fields, tag_bytes;
     uint8_t buf[8];

     int64_t tag_start;

     int i;
 
     if (file_size < APE_TAG_FOOTER_BYTES)

         return 0;

     avio_seek(pb, file_size - APE_TAG_FOOTER_BYTES, SEEK_SET);

     avio_read(pb, buf, 8);     /* APETAGEX */

     if (strncmp(buf, APE_TAG_PREAMBLE, 8)) {

         return 0;

     }
 

     val = avio_rl32(pb);       /* APE tag version */

     if (val > APE_TAG_VERSION) {
         av_log(s, AV_LOG_ERROR, "Unsupported tag version. (>=%d)\n", APE_TAG_VERSION);

         return 0;

     }
 

     tag_bytes = avio_rl32(pb); /* tag size */

     if (tag_bytes - APE_TAG_FOOTER_BYTES > (1024 * 1024 * 16)) {
         av_log(s, AV_LOG_ERROR, "Tag size is way too big\n");

         return 0;
     }
 

     if (tag_bytes > file_size - APE_TAG_FOOTER_BYTES) {

         av_log(s, AV_LOG_ERROR, "Invalid tag size %u.\n", tag_bytes);
         return 0;

     }

     tag_start = file_size - tag_bytes - APE_TAG_FOOTER_BYTES;

     fields = avio_rl32(pb);    /* number of fields */

     if (fields > 65536) {
         av_log(s, AV_LOG_ERROR, "Too many tag fields (%d)\n", fields);

         return 0;

     }
 

     val = avio_rl32(pb);       /* flags */

     if (val & APE_TAG_FLAG_IS_HEADER) {
         av_log(s, AV_LOG_ERROR, "APE Tag is a header\n");

         return 0;

     }
 

     avio_seek(pb, file_size - tag_bytes, SEEK_SET);

 
     for (i=0; i<fields; i++)
         if (ape_tag_read_field(s) < 0) break;

 
     return tag_start;

 }

 static int string_is_ascii(const uint8_t *str)
 {
     while (*str && *str >= 0x20 && *str <= 0x7e ) str++;
     return !*str;
 }
 

 int ff_ape_write_tag(AVFormatContext *s)
 {
     AVDictionaryEntry *e = NULL;

     int size, ret, count = 0;
     AVIOContext *dyn_bc = NULL;
     uint8_t *dyn_buf = NULL;

     if ((ret = avio_open_dyn_buf(&dyn_bc)) < 0)
         goto end;

 
     // flags

     avio_wl32(dyn_bc, APE_TAG_FLAG_CONTAINS_HEADER | APE_TAG_FLAG_CONTAINS_FOOTER |

                      APE_TAG_FLAG_IS_HEADER);

     ffio_fill(dyn_bc, 0, 8);             // reserved

 
     while ((e = av_dict_get(s->metadata, "", e, AV_DICT_IGNORE_SUFFIX))) {

         int val_len;
 
         if (!string_is_ascii(e->key)) {
             av_log(s, AV_LOG_WARNING, "Non ASCII keys are not allowed\n");
             continue;
         }

         val_len = strlen(e->value);

         avio_wl32(dyn_bc, val_len);            // value length
         avio_wl32(dyn_bc, 0);                  // item flags
         avio_put_str(dyn_bc, e->key);          // key
         avio_write(dyn_bc, e->value, val_len); // value

         count++;
     }

     if (!count)
         goto end;

     size = avio_close_dyn_buf(dyn_bc, &dyn_buf);
     if (size <= 0)
         goto end;
     size += 20;
 
     // header
     avio_write(s->pb, "APETAGEX", 8);   // id
     avio_wl32(s->pb, APE_TAG_VERSION);  // version
     avio_wl32(s->pb, size);
     avio_wl32(s->pb, count);
 
     avio_write(s->pb, dyn_buf, size - 20);

 
     // footer
     avio_write(s->pb, "APETAGEX", 8);   // id

     avio_wl32(s->pb, APE_TAG_VERSION);  // version

     avio_wl32(s->pb, size);             // size
     avio_wl32(s->pb, count);            // tag count
 
     // flags
     avio_wl32(s->pb, APE_TAG_FLAG_CONTAINS_HEADER | APE_TAG_FLAG_CONTAINS_FOOTER);
     ffio_fill(s->pb, 0, 8);             // reserved
 

 end:
     if (dyn_bc && !dyn_buf)
         avio_close_dyn_buf(dyn_bc, &dyn_buf);
     av_freep(&dyn_buf);

     return ret;

 }