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ffmpeg / libavformat / apetag.c @ f59d8ff8

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/*
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 * APE tag handling
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 * Copyright (c) 2007 Benjamin Zores <ben@geexbox.org>
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 *  based upon libdemac from Dave Chapman.
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "libavutil/intreadwrite.h"
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#include "avformat.h"
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#include "apetag.h"
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#define ENABLE_DEBUG 0
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#define APE_TAG_VERSION               2000
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#define APE_TAG_FOOTER_BYTES          32
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#define APE_TAG_FLAG_CONTAINS_HEADER  (1 << 31)
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#define APE_TAG_FLAG_IS_HEADER        (1 << 29)
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static int ape_tag_read_field(AVFormatContext *s)
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{
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    AVIOContext *pb = s->pb;
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    uint8_t key[1024], *value;
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    uint32_t size, flags;
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    int i, c;
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    size = avio_rl32(pb);  /* field size */
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    flags = avio_rl32(pb); /* field flags */
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    for (i = 0; i < sizeof(key) - 1; i++) {
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        c = avio_r8(pb);
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        if (c < 0x20 || c > 0x7E)
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            break;
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        else
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            key[i] = c;
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    }
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    key[i] = 0;
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    if (c != 0) {
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        av_log(s, AV_LOG_WARNING, "Invalid APE tag key '%s'.\n", key);
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        return -1;
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    }
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    if (size >= UINT_MAX)
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        return -1;
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    value = av_malloc(size+1);
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    if (!value)
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        return AVERROR(ENOMEM);
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    avio_read(pb, value, size);
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    value[size] = 0;
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    av_metadata_set2(&s->metadata, key, value, AV_METADATA_DONT_STRDUP_VAL);
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    return 0;
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}
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void ff_ape_parse_tag(AVFormatContext *s)
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{
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    AVIOContext *pb = s->pb;
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    int file_size = url_fsize(pb);
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    uint32_t val, fields, tag_bytes;
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    uint8_t buf[8];
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    int i;
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    if (file_size < APE_TAG_FOOTER_BYTES)
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        return;
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    avio_seek(pb, file_size - APE_TAG_FOOTER_BYTES, SEEK_SET);
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    avio_read(pb, buf, 8);     /* APETAGEX */
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    if (strncmp(buf, "APETAGEX", 8)) {
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        return;
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    }
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    val = avio_rl32(pb);       /* APE tag version */
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    if (val > APE_TAG_VERSION) {
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        av_log(s, AV_LOG_ERROR, "Unsupported tag version. (>=%d)\n", APE_TAG_VERSION);
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        return;
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    }
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    tag_bytes = avio_rl32(pb); /* tag size */
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    if (tag_bytes - APE_TAG_FOOTER_BYTES > (1024 * 1024 * 16)) {
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        av_log(s, AV_LOG_ERROR, "Tag size is way too big\n");
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        return;
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    }
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    fields = avio_rl32(pb);    /* number of fields */
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    if (fields > 65536) {
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        av_log(s, AV_LOG_ERROR, "Too many tag fields (%d)\n", fields);
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        return;
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    }
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    val = avio_rl32(pb);       /* flags */
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    if (val & APE_TAG_FLAG_IS_HEADER) {
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        av_log(s, AV_LOG_ERROR, "APE Tag is a header\n");
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        return;
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    }
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    avio_seek(pb, file_size - tag_bytes, SEEK_SET);
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    for (i=0; i<fields; i++)
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        if (ape_tag_read_field(s) < 0) break;
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}