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