apps/metadata/metadata_common.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2005 Dave Chapman
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <stdlib.h>
  24 #include <ctype.h>
  25 #include <inttypes.h>
  26
  27 #include "system.h"
  28 #include "metadata.h"
  29 #include "metadata_common.h"
  30 #include "metadata_parsers.h"
  31 #include "replaygain.h"
  32 #include "misc.h"
  33
  34 /* Skip an ID3v2 tag if it can be found. We assume the tag is located at the
  35  * start of the file, which should be true in all cases where we need to skip it.
  36  * Returns true if successfully skipped or not skipped, and false if
  37  * something went wrong while skipping.
  38  */
  39 bool skip_id3v2(int fd, struct mp3entry *id3)
  40 {
  41     char buf[4];
  42
  43     read(fd, buf, 4);
  44     if (memcmp(buf, "ID3", 3) == 0)
  45     {
  46         /* We have found an ID3v2 tag at the start of the file - find its
  47            length and then skip it. */
  48         if ((id3->first_frame_offset = getid3v2len(fd)) == 0)
  49             return false;
  50
  51         if ((lseek(fd, id3->first_frame_offset, SEEK_SET) < 0))
  52             return false;
  53
  54         return true;
  55     } else {
  56         lseek(fd, 0, SEEK_SET);
  57         id3->first_frame_offset = 0;
  58         return true;
  59     }
  60 }
  61
  62
  63 /* Read a string from the file. Read up to size bytes, or, if eos != -1,
  64  * until the eos character is found (eos is not stored in buf, unless it is
  65  * nil). Writes up to buf_size chars to buf, always terminating with a nil.
  66  * Returns number of chars read or -1 on read error.
  67  */
  68 long read_string(int fd, char* buf, long buf_size, int eos, long size)
  69 {
  70     long read_bytes = 0;
  71     char c;
  72
  73     while (size != 0)
  74     {
  75         if (read(fd, &c, 1) != 1)
  76         {
  77             read_bytes = -1;
  78             break;
  79         }
  80
  81         read_bytes++;
  82         size--;
  83
  84         if ((eos != -1) && (eos == (unsigned char) c))
  85         {
  86             break;
  87         }
  88
  89         if (buf_size > 1)
  90         {
  91             *buf++ = c;
  92             buf_size--;
  93         }
  94     }
  95
  96     *buf = 0;
  97     return read_bytes;
  98 }
  99 /* Read an unsigned 8-bit integer from a file. */
 100 int read_uint8(int fd, uint8_t* buf)
 101 {
 102   size_t n;
 103
 104   n = read(fd, (char*) buf, 1);
 105   return n;
 106 }
 107
 108 #ifdef ROCKBOX_LITTLE_ENDIAN
 109 /* Read an unsigned 16-bit integer from a big-endian file. */
 110 int read_uint16be(int fd, uint16_t* buf)
 111 {
 112   size_t n;
 113
 114   n = read(fd, (char*) buf, 2);
 115   *buf = betoh16(*buf);
 116   return n;
 117 }
 118 /* Read an unsigned 32-bit integer from a big-endian file. */
 119 int read_uint32be(int fd, uint32_t* buf)
 120 {
 121   size_t n;
 122
 123   n = read(fd, (char*) buf, 4);
 124   *buf = betoh32(*buf);
 125   return n;
 126 }
 127 #else
 128 /* Read unsigned integers from a little-endian file. */
 129 int read_uint16le(int fd, uint16_t* buf)
 130 {
 131   size_t n;
 132
 133   n = read(fd, (char*) buf, 2);
 134   *buf = letoh16(*buf);
 135   return n;
 136 }
 137 int read_uint32le(int fd, uint32_t* buf)
 138 {
 139   size_t n;
 140
 141   n = read(fd, (char*) buf, 4);
 142   *buf = letoh32(*buf);
 143   return n;
 144 }
 145 int read_uint64le(int fd, uint64_t* buf)
 146 {
 147   size_t n;
 148   uint8_t data[8];
 149   int i;
 150
 151   n = read(fd, data, 8);
 152
 153   for (i=7, *buf=0; i>=0; i--) {
 154        *buf <<= 8;
 155        *buf |= data[i];
 156   }
 157
 158   return n;
 159 }
 160 #endif
 161
 162 /* Read an unaligned 32-bit little endian long from buffer. */
 163 unsigned long get_long_le(void* buf)
 164 {
 165     unsigned char* p = (unsigned char*) buf;
 166
 167     return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
 168 }
 169
 170 /* Read an unaligned 16-bit little endian short from buffer. */
 171 unsigned short get_short_le(void* buf)
 172 {
 173     unsigned char* p = (unsigned char*) buf;
 174
 175     return p[0] | (p[1] << 8);
 176 }
 177
 178 /* Read an unaligned 32-bit big endian long from buffer. */
 179 unsigned long get_long_be(void* buf)
 180 {
 181     unsigned char* p = (unsigned char*) buf;
 182
 183     return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
 184 }
 185
 186 /* Read an unaligned 32-bit little endian long from buffer. */
 187 long get_slong(void* buf)
 188 {
 189     unsigned char* p = (unsigned char*) buf;
 190
 191     return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
 192 }
 193
 194 unsigned long get_itunes_int32(char* value, int count)
 195 {
 196     static const char hexdigits[] = "0123456789ABCDEF";
 197     const char* c;
 198     int r = 0;
 199
 200     while (count-- > 0)
 201     {
 202         value = skip_whitespace(value);
 203
 204         while (*value && !isspace(*value))
 205         {
 206             value++;
 207         }
 208     }
 209
 210     value = skip_whitespace(value);
 211
 212     while (*value && ((c = strchr(hexdigits, toupper(*value))) != NULL))
 213     {
 214         r = (r << 4) | (c - hexdigits);
 215         value++;
 216     }
 217
 218     return r;
 219 }
 220
 221 /* Parse the tag (the name-value pair) and fill id3 and buffer accordingly.
 222  * String values to keep are written to buf. Returns number of bytes written
 223  * to buf (including end nil).
 224  */
 225 long parse_tag(const char* name, char* value, struct mp3entry* id3,
 226     char* buf, long buf_remaining, enum tagtype type)
 227 {
 228     long len = 0;
 229     char** p;
 230
 231     if ((((strcasecmp(name, "track") == 0) && (type == TAGTYPE_APE)))
 232         || ((strcasecmp(name, "tracknumber") == 0) && (type == TAGTYPE_VORBIS)))
 233     {
 234         id3->tracknum = atoi(value);
 235         p = &(id3->track_string);
 236     }
 237     else if (strcasecmp(name, "discnumber") == 0 || strcasecmp(name, "disc") == 0)
 238     {
 239         id3->discnum = atoi(value);
 240         p = &(id3->disc_string);
 241     }
 242     else if (((strcasecmp(name, "year") == 0) && (type == TAGTYPE_APE))
 243         || ((strcasecmp(name, "date") == 0) && (type == TAGTYPE_VORBIS)))
 244     {
 245         /* Date's can be in any format in Vorbis. However most of them
 246          * are in ISO8601 format so if we try and parse the first part
 247          * of the tag as a number, we should get the year. If we get crap,
 248          * then act like we never parsed it.
 249          */
 250         id3->year = atoi(value);
 251         if (id3->year < 1900)
 252         { /* yeah, not likely */
 253             id3->year = 0;
 254         }
 255         p = &(id3->year_string);
 256     }
 257     else if (strcasecmp(name, "title") == 0)
 258     {
 259         p = &(id3->title);
 260     }
 261     else if (strcasecmp(name, "artist") == 0)
 262     {
 263         p = &(id3->artist);
 264     }
 265     else if (strcasecmp(name, "album") == 0)
 266     {
 267         p = &(id3->album);
 268     }
 269     else if (strcasecmp(name, "genre") == 0)
 270     {
 271         p = &(id3->genre_string);
 272     }
 273     else if (strcasecmp(name, "composer") == 0)
 274     {
 275         p = &(id3->composer);
 276     }
 277     else if (strcasecmp(name, "comment") == 0)
 278     {
 279         p = &(id3->comment);
 280     }
 281     else if (strcasecmp(name, "albumartist") == 0)
 282     {
 283         p = &(id3->albumartist);
 284     }
 285     else if (strcasecmp(name, "album artist") == 0)
 286     {
 287         p = &(id3->albumartist);
 288     }
 289     else if (strcasecmp(name, "ensemble") == 0)
 290     {
 291         p = &(id3->albumartist);
 292     }
 293     else if (strcasecmp(name, "grouping") == 0)
 294     {
 295         p = &(id3->grouping);
 296     }
 297     else if (strcasecmp(name, "content group") == 0)
 298     {
 299         p = &(id3->grouping);
 300     }
 301     else if (strcasecmp(name, "contentgroup") == 0)
 302     {
 303         p = &(id3->grouping);
 304     }
 305     else if (strcasecmp(name, "musicbrainz_trackid") == 0
 306         || strcasecmp(name, "http://musicbrainz.org") == 0 )
 307     {
 308         p = &(id3->mb_track_id);
 309     }
 310     else
 311     {
 312         len = parse_replaygain(name, value, id3, buf, buf_remaining);
 313         p = NULL;
 314     }
 315
 316     if (p)
 317     {
 318         len = strlen(value);
 319         len = MIN(len, buf_remaining - 1);
 320
 321         if (len > 0)
 322         {
 323             len++;
 324             strlcpy(buf, value, len);
 325             *p = buf;
 326         }
 327         else
 328         {
 329             len = 0;
 330         }
 331     }
 332
 333     return len;
 334 }
 335