/* MP3 TAGS STUFF -- put together using public specs. * Copyright (C) 2018-2019 O. Sezer * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at * your option) any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "quakedef.h" #if defined(USE_CODEC_MP3) #include "snd_codec.h" #include "q_ctype.h" static inline qboolean is_id3v1(const unsigned char *data, long length) { /* http://id3.org/ID3v1 : 3 bytes "TAG" identifier and 125 bytes tag data */ if (length < 128 || memcmp(data,"TAG",3) != 0) { return false; } return true; } static qboolean is_id3v2(const unsigned char *data, size_t length) { /* ID3v2 header is 10 bytes: http://id3.org/id3v2.4.0-structure */ /* bytes 0-2: "ID3" identifier */ if (length < 10 || memcmp(data,"ID3",3) != 0) { return false; } /* bytes 3-4: version num (major,revision), each byte always less than 0xff. */ if (data[3] == 0xff || data[4] == 0xff) { return false; } /* bytes 6-9 are the ID3v2 tag size: a 32 bit 'synchsafe' integer, i.e. the * highest bit 7 in each byte zeroed. i.e.: 7 bit information in each byte -> * effectively a 28 bit value. */ if (data[6] >= 0x80 || data[7] >= 0x80 || data[8] >= 0x80 || data[9] >= 0x80) { return false; } return true; } static long get_id3v2_len(const unsigned char *data, long length) { /* size is a 'synchsafe' integer (see above) */ long size = (long)((data[6]<<21) + (data[7]<<14) + (data[8]<<7) + data[9]); size += 10; /* header size */ /* ID3v2 header[5] is flags (bits 4-7 only, 0-3 are zero). * bit 4 set: footer is present (a copy of the header but * with "3DI" as ident.) */ if (data[5] & 0x10) { size += 10; /* footer size */ } /* optional padding (always zeroes) */ while (size < length && data[size] == 0) { ++size; } return size; } static qboolean is_apetag(const unsigned char *data, size_t length) { /* http://wiki.hydrogenaud.io/index.php?title=APEv2_specification * Header/footer is 32 bytes: bytes 0-7 ident, bytes 8-11 version, * bytes 12-17 size. bytes 24-31 are reserved: must be all zeroes. */ unsigned int v; if (length < 32 || memcmp(data,"APETAGEX",8) != 0) { return false; } v = (unsigned)((data[11]<<24) | (data[10]<<16) | (data[9]<<8) | data[8]); /* version */ if (v != 2000U && v != 1000U) { return false; } v = 0; /* reserved bits : */ if (memcmp(&data[24],&v,4) != 0 || memcmp(&data[28],&v,4) != 0) { return false; } return true; } static long get_ape_len(const unsigned char *data) { unsigned int flags, version; long size = (long)((data[15]<<24) | (data[14]<<16) | (data[13]<<8) | data[12]); version = (unsigned)((data[11]<<24) | (data[10]<<16) | (data[9]<<8) | data[8]); flags = (unsigned)((data[23]<<24) | (data[22]<<16) | (data[21]<<8) | data[20]); if (version == 2000U && (flags & (1U<<31))) size += 32; /* header present. */ return size; } static inline int is_lyrics3tag(const unsigned char *data, long length) { /* http://id3.org/Lyrics3 * http://id3.org/Lyrics3v2 */ if (length < 15) return 0; if (memcmp(data+6,"LYRICS200",9) == 0) return 2; /* v2 */ if (memcmp(data+6,"LYRICSEND",9) == 0) return 1; /* v1 */ return 0; } static long get_lyrics3v1_len(snd_stream_t *stream) { const char *p; long i, len; char buf[5104]; /* needs manual search: http://id3.org/Lyrics3 */ if (stream->fh.length < 20) return -1; len = (stream->fh.length > 5109)? 5109 : stream->fh.length; FS_fseek(&stream->fh, -len, SEEK_END); FS_fread(buf, 1, (len -= 9), &stream->fh); /* exclude footer */ /* strstr() won't work here. */ for (i = len - 11, p = buf; i >= 0; --i, ++p) { if (memcmp(p, "LYRICSBEGIN", 11) == 0) break; } if (i < 0) return -1; return len - (long)(p - buf) + 9 /* footer */; } static inline long get_lyrics3v2_len(const unsigned char *data, long length) { /* 6 bytes before the end marker is size in decimal format - * does not include the 9 bytes end marker and size field. */ if (length != 6) return 0; return strtol((const char *)data, NULL, 10) + 15; } static inline qboolean verify_lyrics3v2(const unsigned char *data, long length) { if (length < 11) return false; if (memcmp(data,"LYRICSBEGIN",11) == 0) return true; return false; } #define MMTAG_PARANOID static qboolean is_musicmatch(const unsigned char *data, long length) { /* From docs/musicmatch.txt in id3lib: https://sourceforge.net/projects/id3lib/ Overall tag structure: +-----------------------------+ | Header | | (256 bytes, OPTIONAL) | +-----------------------------+ | Image extension (4 bytes) | +-----------------------------+ | Image binary | | (var. length >= 4 bytes) | +-----------------------------+ | Unused (4 bytes) | +-----------------------------+ | Version info (256 bytes) | +-----------------------------+ | Audio meta-data | | (var. length >= 7868 bytes) | +-----------------------------+ | Data offsets (20 bytes) | +-----------------------------+ | Footer (48 bytes) | +-----------------------------+ */ if (length < 48) return false; /* sig: 19 bytes company name + 13 bytes space */ if (memcmp(data,"Brava Software Inc. ",32) != 0) { return false; } /* 4 bytes version: x.xx */ if (!q_isdigit(data[32]) || data[33] != '.' || !q_isdigit(data[34]) ||!q_isdigit(data[35])) { return false; } #ifdef MMTAG_PARANOID /* [36..47]: 12 bytes trailing space */ for (length = 36; length < 48; ++length) { if (data[length] != ' ') return false; } #endif return true; } static long get_musicmatch_len(snd_stream_t *stream) { const int metasizes[4] = { 7868, 7936, 8004, 8132 }; const unsigned char syncstr[10] = {'1','8','2','7','3','6','4','5',0,0}; unsigned char buf[256]; int i, j, imgext_ofs, version_ofs; long len; FS_fseek(&stream->fh, -68, SEEK_END); FS_fread(buf, 1, 20, &stream->fh); imgext_ofs = (int)((buf[3] <<24) | (buf[2] <<16) | (buf[1] <<8) | buf[0] ); version_ofs = (int)((buf[15]<<24) | (buf[14]<<16) | (buf[13]<<8) | buf[12]); if (version_ofs <= imgext_ofs) return -1; if (version_ofs <= 0 || imgext_ofs <= 0) return -1; /* Try finding the version info section: * Because metadata section comes after it, and because metadata section * has different sizes across versions (format ver. <= 3.00: always 7868 * bytes), we can _not_ directly calculate using deltas from the offsets * section. */ for (i = 0; i < 4; ++i) { /* 48: footer, 20: offsets, 256: version info */ len = metasizes[i] + 48 + 20 + 256; if (stream->fh.length < len) return -1; FS_fseek(&stream->fh, -len, SEEK_END); FS_fread(buf, 1, 256, &stream->fh); /* [0..9]: sync string, [30..255]: 0x20 */ #ifdef MMTAG_PARANOID for (j = 30; j < 256; ++j) { if (buf[j] != ' ') break; } if (j < 256) continue; #endif if (memcmp(buf, syncstr, 10) == 0) { break; } } if (i == 4) return -1; /* no luck. */ #ifdef MMTAG_PARANOID /* unused section: (4 bytes of 0x00) */ FS_fseek(&stream->fh, -(len + 4), SEEK_END); FS_fread(buf, 1, 4, &stream->fh); j = 0; if (memcmp(buf, &j, 4) != 0) return -1; #endif len += (version_ofs - imgext_ofs); if (stream->fh.length < len) return -1; FS_fseek(&stream->fh, -len, SEEK_END); FS_fread(buf, 1, 8, &stream->fh); j = (int)((buf[7] <<24) | (buf[6] <<16) | (buf[5] <<8) | buf[4]); if (j < 0) return -1; /* verify image size: */ /* without this, we may land at a wrong place. */ if (j + 12 != version_ofs - imgext_ofs) return -1; /* try finding the optional header */ if (stream->fh.length < len + 256) return len; FS_fseek(&stream->fh, -(len + 256), SEEK_END); FS_fread(buf, 1, 256, &stream->fh); /* [0..9]: sync string, [30..255]: 0x20 */ if (memcmp(buf, syncstr, 10) != 0) { return len; } #ifdef MMTAG_PARANOID for (j = 30; j < 256; ++j) { if (buf[j] != ' ') return len; } #endif return len + 256; /* header is present. */ } static int probe_id3v1(snd_stream_t *stream, unsigned char *buf, int atend) { if (stream->fh.length >= 128) { FS_fseek(&stream->fh, -128, SEEK_END); if (FS_fread(buf, 1, 128, &stream->fh) != 128) return -1; if (is_id3v1(buf, 128)) { if (!atend) { /* possible false positive? */ if (is_musicmatch(buf + 128 - 48, 48) || is_apetag (buf + 128 - 32, 32) || is_lyrics3tag(buf + 128 - 15, 15)) { return 0; } } stream->fh.length -= 128; Con_DPrintf("MP3: skipped %ld bytes ID3v1 tag\n", 128L); return 1; /* FIXME: handle possible double-ID3v1 tags? */ } } return 0; } static int probe_mmtag(snd_stream_t *stream, unsigned char *buf) { long len; if (stream->fh.length >= 68) { FS_fseek(&stream->fh, -48, SEEK_END); if (FS_fread(buf, 1, 48, &stream->fh) != 48) return -1; if (is_musicmatch(buf, 48)) { len = get_musicmatch_len(stream); if (len < 0) return -1; if (len >= stream->fh.length) return -1; stream->fh.length -= len; Con_DPrintf("MP3: skipped %ld bytes MusicMatch tag\n", len); return 1; } } return 0; } static int probe_apetag(snd_stream_t *stream, unsigned char *buf) { long len; if (stream->fh.length >= 32) { FS_fseek(&stream->fh, -32, SEEK_END); if (FS_fread(buf, 1, 32, &stream->fh) != 32) return -1; if (is_apetag(buf, 32)) { len = get_ape_len(buf); if (len >= stream->fh.length) return -1; stream->fh.length -= len; Con_DPrintf("MP3: skipped %ld bytes APE tag\n", len); return 1; } } return 0; } static int probe_lyrics3(snd_stream_t *stream, unsigned char *buf) { long len; if (stream->fh.length >= 15) { FS_fseek(&stream->fh, -15, SEEK_END); if (FS_fread(buf, 1, 15, &stream->fh) != 15) return -1; len = is_lyrics3tag(buf, 15); if (len == 2) { len = get_lyrics3v2_len(buf, 6); if (len >= stream->fh.length) return -1; if (len < 15) return -1; FS_fseek(&stream->fh, -len, SEEK_END); if (FS_fread(buf, 1, 11, &stream->fh) != 11) return -1; if (!verify_lyrics3v2(buf, 11)) return -1; stream->fh.length -= len; Con_DPrintf("MP3: skipped %ld bytes Lyrics3 tag\n", len); return 1; } else if (len == 1) { len = get_lyrics3v1_len(stream); if (len < 0) return -1; stream->fh.length -= len; Con_DPrintf("MP3: skipped %ld bytes Lyrics3 tag\n", len); return 1; } } return 0; } int mp3_skiptags(snd_stream_t *stream) { unsigned char buf[128]; long len; size_t readsize; int c_id3, c_ape, c_lyr, c_mm; int rc = -1; /* failsafe */ long oldlength = stream->fh.length; long oldstart = stream->fh.start; /* MP3 standard has no metadata format, so everyone invented * their own thing, even with extensions, until ID3v2 became * dominant: Hence the impossible mess here. * * Note: I don't yet care about freaky broken mp3 files with * double tags. -- O.S. */ readsize = FS_fread(buf, 1, 128, &stream->fh); if (!readsize || FS_ferror(&stream->fh)) goto fail; /* ID3v2 tag is at the start */ if (is_id3v2(buf, readsize)) { len = get_id3v2_len(buf, (long)readsize); if (len >= stream->fh.length) goto fail; stream->fh.start += len; stream->fh.length -= len; Con_DPrintf("MP3: skipped %ld bytes ID3v2 tag\n", len); } /* APE tag _might_ be at the start (discouraged * but not forbidden, either.) read the header. */ else if (is_apetag(buf, readsize)) { len = get_ape_len(buf); if (len >= stream->fh.length) goto fail; stream->fh.start += len; stream->fh.length -= len; Con_DPrintf("MP3: skipped %ld bytes APE tag\n", len); } /* it's not impossible that _old_ MusicMatch tag * placing itself after ID3v1. */ if ((c_mm = probe_mmtag(stream, buf)) < 0) { goto fail; } /* ID3v1 tag is at the end */ if ((c_id3 = probe_id3v1(stream, buf, !c_mm)) < 0) { goto fail; } /* we do not know the order of ape or lyrics3 * or musicmatch tags, hence the loop here.. */ c_ape = 0; c_lyr = 0; for (;;) { if (!c_lyr) { /* care about mp3s with double Lyrics3 tags? */ if ((c_lyr = probe_lyrics3(stream, buf)) < 0) goto fail; if (c_lyr) continue; } if (!c_mm) { if ((c_mm = probe_mmtag(stream, buf)) < 0) goto fail; if (c_mm) continue; } if (!c_ape) { if ((c_ape = probe_apetag(stream, buf)) < 0) goto fail; if (c_ape) continue; } break; } /* for (;;) */ rc = (stream->fh.length > 0)? 0 : -1; fail: if (rc < 0) { stream->fh.start = oldstart; stream->fh.length = oldlength; } FS_rewind(&stream->fh); return rc; } #endif /* USE_CODEC_MP3 */