1/*
2 * ID3v2 header writer
3 *
4 * This file is part of Libav.
5 *
6 * Libav is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * Libav is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include <stdint.h>
22
23#include "libavutil/dict.h"
24#include "libavutil/intreadwrite.h"
25#include "avformat.h"
26#include "avio.h"
27#include "id3v2.h"
28
29static void id3v2_put_size(AVFormatContext *s, int size)
30{
31    avio_w8(s->pb, size >> 21 & 0x7f);
32    avio_w8(s->pb, size >> 14 & 0x7f);
33    avio_w8(s->pb, size >> 7  & 0x7f);
34    avio_w8(s->pb, size       & 0x7f);
35}
36
37static int string_is_ascii(const uint8_t *str)
38{
39    while (*str && *str < 128) str++;
40    return !*str;
41}
42
43/**
44 * Write a text frame with one (normal frames) or two (TXXX frames) strings
45 * according to encoding (only UTF-8 or UTF-16+BOM supported).
46 * @return number of bytes written or a negative error code.
47 */
48static int id3v2_put_ttag(AVFormatContext *s, const char *str1, const char *str2,
49                          uint32_t tag, enum ID3v2Encoding enc)
50{
51    int len;
52    uint8_t *pb;
53    int (*put)(AVIOContext*, const char*);
54    AVIOContext *dyn_buf;
55    if (avio_open_dyn_buf(&dyn_buf) < 0)
56        return AVERROR(ENOMEM);
57
58    /* check if the strings are ASCII-only and use UTF16 only if
59     * they're not */
60    if (enc == ID3v2_ENCODING_UTF16BOM && string_is_ascii(str1) &&
61        (!str2 || string_is_ascii(str2)))
62        enc = ID3v2_ENCODING_ISO8859;
63
64    avio_w8(dyn_buf, enc);
65    if (enc == ID3v2_ENCODING_UTF16BOM) {
66        avio_wl16(dyn_buf, 0xFEFF);      /* BOM */
67        put = avio_put_str16le;
68    } else
69        put = avio_put_str;
70
71    put(dyn_buf, str1);
72    if (str2)
73        put(dyn_buf, str2);
74    len = avio_close_dyn_buf(dyn_buf, &pb);
75
76    avio_wb32(s->pb, tag);
77    id3v2_put_size(s, len);
78    avio_wb16(s->pb, 0);
79    avio_write(s->pb, pb, len);
80
81    av_freep(&pb);
82    return len + ID3v2_HEADER_SIZE;
83}
84
85static int id3v2_check_write_tag(AVFormatContext *s, AVDictionaryEntry *t, const char table[][4],
86                                 enum ID3v2Encoding enc)
87{
88    uint32_t tag;
89    int i;
90
91    if (t->key[0] != 'T' || strlen(t->key) != 4)
92        return -1;
93    tag = AV_RB32(t->key);
94    for (i = 0; *table[i]; i++)
95        if (tag == AV_RB32(table[i]))
96            return id3v2_put_ttag(s, t->value, NULL, tag, enc);
97    return -1;
98}
99
100int ff_id3v2_write(struct AVFormatContext *s, int id3v2_version,
101                   const char *magic)
102{
103    int64_t size_pos, cur_pos;
104    AVDictionaryEntry *t = NULL;
105
106    int totlen = 0, enc = id3v2_version == 3 ? ID3v2_ENCODING_UTF16BOM :
107                                               ID3v2_ENCODING_UTF8;
108
109
110    avio_wb32(s->pb, MKBETAG(magic[0], magic[1], magic[2], id3v2_version));
111    avio_w8(s->pb, 0);
112    avio_w8(s->pb, 0); /* flags */
113
114    /* reserve space for size */
115    size_pos = avio_tell(s->pb);
116    avio_wb32(s->pb, 0);
117
118    ff_metadata_conv(&s->metadata, ff_id3v2_34_metadata_conv, NULL);
119    if (id3v2_version == 4)
120        ff_metadata_conv(&s->metadata, ff_id3v2_4_metadata_conv, NULL);
121
122    while ((t = av_dict_get(s->metadata, "", t, AV_DICT_IGNORE_SUFFIX))) {
123        int ret;
124
125        if ((ret = id3v2_check_write_tag(s, t, ff_id3v2_tags, enc)) > 0) {
126            totlen += ret;
127            continue;
128        }
129        if ((ret = id3v2_check_write_tag(s, t, id3v2_version == 3 ?
130                                               ff_id3v2_3_tags : ff_id3v2_4_tags, enc)) > 0) {
131            totlen += ret;
132            continue;
133        }
134
135        /* unknown tag, write as TXXX frame */
136        if ((ret = id3v2_put_ttag(s, t->key, t->value, MKBETAG('T', 'X', 'X', 'X'), enc)) < 0)
137            return ret;
138        totlen += ret;
139    }
140
141    cur_pos = avio_tell(s->pb);
142    avio_seek(s->pb, size_pos, SEEK_SET);
143    id3v2_put_size(s, totlen);
144    avio_seek(s->pb, cur_pos, SEEK_SET);
145    return 0;
146}
147