FFmpeg/libavformat/apetag.c

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/*
* 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 "apetag.h"
#define APE_TAG_VERSION 2000
#define APE_TAG_FOOTER_BYTES 32
#define APE_TAG_FLAG_CONTAINS_HEADER (1 << 31)
#define APE_TAG_FLAG_IS_HEADER (1 << 29)
static int ape_tag_read_field(AVFormatContext *s)
{
AVIOContext *pb = s->pb;
uint8_t key[1024], *value;
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uint32_t size;
int i, c;
size = avio_rl32(pb); /* field size */
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avio_skip(pb, 4); /* 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 >= UINT_MAX)
return -1;
value = av_malloc(size+1);
if (!value)
return AVERROR(ENOMEM);
avio_read(pb, value, size);
value[size] = 0;
av_dict_set(&s->metadata, key, value, AV_DICT_DONT_STRDUP_VAL);
return 0;
}
void ff_ape_parse_tag(AVFormatContext *s)
{
AVIOContext *pb = s->pb;
int file_size = avio_size(pb);
uint32_t val, fields, tag_bytes;
uint8_t buf[8];
int i;
if (file_size < APE_TAG_FOOTER_BYTES)
return;
avio_seek(pb, file_size - APE_TAG_FOOTER_BYTES, SEEK_SET);
avio_read(pb, buf, 8); /* APETAGEX */
if (strncmp(buf, "APETAGEX", 8)) {
return;
}
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;
}
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;
}
fields = avio_rl32(pb); /* number of fields */
if (fields > 65536) {
av_log(s, AV_LOG_ERROR, "Too many tag fields (%d)\n", fields);
return;
}
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;
}
avio_seek(pb, file_size - tag_bytes, SEEK_SET);
for (i=0; i<fields; i++)
if (ape_tag_read_field(s) < 0) break;
}