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Diffstat (limited to 'src/libapetag/is_tag.c')
| -rwxr-xr-x | src/libapetag/is_tag.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/src/libapetag/is_tag.c b/src/libapetag/is_tag.c new file mode 100755 index 0000000..dc56023 --- /dev/null +++ b/src/libapetag/is_tag.c @@ -0,0 +1,175 @@ +/******************************************************************** +* +* Copyright (c) 2002 Artur Polaczynski (Ar't) All rights reserved. +* <artii@o2.pl> LGPL-2.1 +* $ArtId: is_tag.c,v 1.10 2003/04/16 21:06:27 art Exp $ +********************************************************************/ +/* + * This program 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. + * + * 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 Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <string.h> +#include <stdio.h> +#include <stdlib.h> +#include <stddef.h> +#include <stdarg.h> +#include <string.h> +#include <limits.h> +#include <assert.h> +#include "is_tag.h" + +unsigned long +is_tag_ape2long (unsigned char *p); + +/* + PL: czy dany plik ma taga odpowiednio id3v1, id3v2 i ape ??? + PL: nie zmienia pozycji w pliku !!! +*/ + +/** + return size of all id3v1 tags (some bugy tagers add this again and + again tag) 0 no tag at all + + \param fp File pointer + \return Return size of id3v1 tag (in bytes) 0 no tag at all +*/ +int +is_id3v1 (FILE * fp) +{ + int n=0; + char buf[16]; + size_t savedFilePosition; + + savedFilePosition = ftell (fp); + fseek (fp, 0, SEEK_END); + do { + n++; + memset (buf, 0, sizeof (buf)); + fseek (fp, ((-128)*n) - 3 , SEEK_END); + fread (&buf, 1, sizeof (buf), fp); + if (memcmp (buf, "APETAGEX",8) == 0) /*APE.TAG.EX*/ + break; + } while (memcmp (buf+3, "TAG", 3) == 0); + + fseek (fp, savedFilePosition, SEEK_SET); + return (n-1)*128; +} + +/** + return size of tag id3v2 on begining of file. + check for buggy tagers (2 or more tags) + + \param fp File pointer + \return Return size of id3v2 tag (in bytes) + (some bugy tagers add this again and again ) 0 no tag at all +*/ +int +is_id3v2 (FILE * fp) +{ + char buf[16]; + size_t savedFilePosition; + long id3v2size=0; + + savedFilePosition = ftell (fp); + fseek (fp, 0, SEEK_SET); + do { + memset (buf, 0, sizeof (buf)); + fseek (fp, id3v2size, SEEK_SET); + fread (&buf, 1, sizeof (buf), fp); + if (memcmp (buf, "ID3", 3) != 0) { + break; + } + /* ID3v2 tag skipeer $49 44 33 yy yy xx zz zz zz zz [zz size + this 10 bytes] */ + id3v2size += 10 + (((long) (buf[9])) | ((long) (buf[8]) << 7) | + ((long) (buf[7]) << 14) | ((long) (buf[6]) << 21)); + } while(memcmp (buf, "ID3", 3) == 0); + + fseek (fp, savedFilePosition, SEEK_SET); + return (int) id3v2size; +} + + +/** + return 0 or 1000 or 2000 this is version of ape tag 0 no tag + + \param fp File pointer + \return Version of ape tag if any, else 0 +*/ +int +is_ape_ver (FILE * fp) +{ + char unsigned buf[32]; + size_t savedFilePosition; + + savedFilePosition = ftell (fp); + memset (buf, 0, sizeof (buf)); + + fseek (fp, (is_id3v1 (fp) ? -32 - 128 : -32), SEEK_END); + fread (&buf, 1, sizeof (buf), fp); + if (memcmp (buf, "APETAGEX", 8) != 0) { + fseek (fp, savedFilePosition, SEEK_SET); + return 0; + } + + fseek (fp, savedFilePosition, SEEK_SET); + return (int) is_tag_ape2long (buf + 8); +} + +#define IS_TAG_FOOTER_NOT 0x40000000 + +/** + return size of ape tag id3v1 is not counting + + \param fp File pointer + \return Size of ape tag if any, else 0 +*/ +int +is_ape (FILE * fp) +{ + char unsigned buf[32]; + size_t savedFilePosition; + + savedFilePosition = ftell (fp); + memset (buf, 0, sizeof (buf)); + + fseek (fp, (is_id3v1 (fp) ? -32 - 128 : -32), SEEK_END); + fread (&buf, 1, sizeof (buf), fp); + if (memcmp (buf, "APETAGEX", 8) != 0) { + fseek (fp, savedFilePosition, SEEK_SET); + return 0; + } + + fseek (fp, savedFilePosition, SEEK_SET); + /* WARNING! macabra code */ + return (int) (is_tag_ape2long (buf + 8 + 4) + + ( + ( (is_tag_ape2long (buf + 8) == 2000) && + !(is_tag_ape2long (buf + 8 + 4 + 8) & IS_TAG_FOOTER_NOT) + ) ? 32 : 0 + ) /* footer size = 32 */ + ); +} + + +unsigned long +is_tag_ape2long (unsigned char *p) +{ + + return (((unsigned long) p[0] << 0) | + ((unsigned long) p[1] << 8) | + ((unsigned long) p[2] << 16) | + ((unsigned long) p[3] << 24) ); + +} |