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FFmpeg/libavformat/id3v2enc.c

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/*
* ID3v2 header writer
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include "libavutil/dict.h"
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "avio.h"
#include "id3v2.h"
static void id3v2_put_size(AVFormatContext *s, int size)
{
avio_w8(s->pb, size >> 21 & 0x7f);
avio_w8(s->pb, size >> 14 & 0x7f);
avio_w8(s->pb, size >> 7 & 0x7f);
avio_w8(s->pb, size & 0x7f);
}
static int string_is_ascii(const uint8_t *str)
{
while (*str && *str < 128) str++;
return !*str;
}
/**
* Write a text frame with one (normal frames) or two (TXXX frames) strings
* according to encoding (only UTF-8 or UTF-16+BOM supported).
* @return number of bytes written or a negative error code.
*/
static int id3v2_put_ttag(AVFormatContext *s, const char *str1, const char *str2,
uint32_t tag, enum ID3v2Encoding enc)
{
int len;
uint8_t *pb;
int (*put)(AVIOContext*, const char*);
AVIOContext *dyn_buf;
if (avio_open_dyn_buf(&dyn_buf) < 0)
return AVERROR(ENOMEM);
/* check if the strings are ASCII-only and use UTF16 only if
* they're not */
if (enc == ID3v2_ENCODING_UTF16BOM && string_is_ascii(str1) &&
(!str2 || string_is_ascii(str2)))
enc = ID3v2_ENCODING_ISO8859;
avio_w8(dyn_buf, enc);
if (enc == ID3v2_ENCODING_UTF16BOM) {
avio_wl16(dyn_buf, 0xFEFF); /* BOM */
put = avio_put_str16le;
} else
put = avio_put_str;
put(dyn_buf, str1);
if (str2)
put(dyn_buf, str2);
len = avio_close_dyn_buf(dyn_buf, &pb);
avio_wb32(s->pb, tag);
id3v2_put_size(s, len);
avio_wb16(s->pb, 0);
avio_write(s->pb, pb, len);
av_freep(&pb);
return len + ID3v2_HEADER_SIZE;
}
static int id3v2_check_write_tag(AVFormatContext *s, AVDictionaryEntry *t, const char table[][4],
enum ID3v2Encoding enc)
{
uint32_t tag;
int i;
if (t->key[0] != 'T' || strlen(t->key) != 4)
return -1;
tag = AV_RB32(t->key);
for (i = 0; *table[i]; i++)
if (tag == AV_RB32(table[i]))
return id3v2_put_ttag(s, t->value, NULL, tag, enc);
return -1;
}
int ff_id3v2_write(struct AVFormatContext *s, int id3v2_version,
const char *magic)
{
int64_t size_pos, cur_pos;
AVDictionaryEntry *t = NULL;
int totlen = 0, enc = id3v2_version == 3 ? ID3v2_ENCODING_UTF16BOM :
ID3v2_ENCODING_UTF8;
avio_wb32(s->pb, MKBETAG(magic[0], magic[1], magic[2], id3v2_version));
avio_w8(s->pb, 0);
avio_w8(s->pb, 0); /* flags */
/* reserve space for size */
size_pos = avio_tell(s->pb);
avio_wb32(s->pb, 0);
ff_metadata_conv(&s->metadata, ff_id3v2_34_metadata_conv, NULL);
if (id3v2_version == 4)
ff_metadata_conv(&s->metadata, ff_id3v2_4_metadata_conv, NULL);
while ((t = av_dict_get(s->metadata, "", t, AV_DICT_IGNORE_SUFFIX))) {
int ret;
if ((ret = id3v2_check_write_tag(s, t, ff_id3v2_tags, enc)) > 0) {
totlen += ret;
continue;
}
if ((ret = id3v2_check_write_tag(s, t, id3v2_version == 3 ?
ff_id3v2_3_tags : ff_id3v2_4_tags, enc)) > 0) {
totlen += ret;
continue;
}
/* unknown tag, write as TXXX frame */
if ((ret = id3v2_put_ttag(s, t->key, t->value, MKBETAG('T', 'X', 'X', 'X'), enc)) < 0)
return ret;
totlen += ret;
}
cur_pos = avio_tell(s->pb);
avio_seek(s->pb, size_pos, SEEK_SET);
id3v2_put_size(s, totlen);
avio_seek(s->pb, cur_pos, SEEK_SET);
return 0;
}