apps/mp3data.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2002 by Daniel Stenberg
  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
  22 /*
  23  * Parts of this code has been stolen from the Ample project and was written
  24  * by David Härdeman. It has since been extended and enhanced pretty much by
  25  * all sorts of friendly Rockbox people.
  26  *
  27  * A nice reference for MPEG header info:
  28  * http://rockbox.haxx.se/docs/mpeghdr.html
  29  *
  30  */
  31
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <stdbool.h>
  36 #include <limits.h>
  37 #include "debug.h"
  38 #include "logf.h"
  39 #include "mp3data.h"
  40 #include "file.h"
  41 #include "buffer.h"
  42 #include "metadata/metadata_common.h"
  43
  44 // #define DEBUG_VERBOSE
  45
  46 #ifdef DEBUG_VERBOSE
  47 #define VDEBUGF DEBUGF
  48 #else
  49 #define VDEBUGF(...) do { } while(0)
  50 #endif
  51
  52 #define SYNC_MASK (0x7ffL << 21)
  53 #define VERSION_MASK (3L << 19)
  54 #define LAYER_MASK (3L << 17)
  55 #define PROTECTION_MASK (1L << 16)
  56 #define BITRATE_MASK (0xfL << 12)
  57 #define SAMPLERATE_MASK (3L << 10)
  58 #define PADDING_MASK (1L << 9)
  59 #define PRIVATE_MASK (1L << 8)
  60 #define CHANNELMODE_MASK (3L << 6)
  61 #define MODE_EXT_MASK (3L << 4)
  62 #define COPYRIGHT_MASK (1L << 3)
  63 #define ORIGINAL_MASK (1L << 2)
  64 #define EMPHASIS_MASK 3L
  65
  66 /* MPEG Version table, sorted by version index */
  67 static const signed char version_table[4] = {
  68     MPEG_VERSION2_5, -1, MPEG_VERSION2, MPEG_VERSION1
  69 };
  70
  71 /* Bitrate table for mpeg audio, indexed by row index and birate index */
  72 static const short bitrates[5][16] = {
  73     {0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,0}, /* V1 L1 */
  74     {0,32,48,56, 64, 80, 96,112,128,160,192,224,256,320,384,0}, /* V1 L2 */
  75     {0,32,40,48, 56, 64, 80, 96,112,128,160,192,224,256,320,0}, /* V1 L3 */
  76     {0,32,48,56, 64, 80, 96,112,128,144,160,176,192,224,256,0}, /* V2 L1 */
  77     {0, 8,16,24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160,0}  /* V2 L2+L3 */
  78 };
  79
  80 /* Bitrate pointer table, indexed by version and layer */
  81 static const short *bitrate_table[3][3] =
  82 {
  83     {bitrates[0], bitrates[1], bitrates[2]},
  84     {bitrates[3], bitrates[4], bitrates[4]},
  85     {bitrates[3], bitrates[4], bitrates[4]}
  86 };
  87
  88 /* Sampling frequency table, indexed by version and frequency index */
  89 static const unsigned short freq_table[3][3] =
  90 {
  91     {44100, 48000, 32000}, /* MPEG Version 1 */
  92     {22050, 24000, 16000}, /* MPEG version 2 */
  93     {11025, 12000,  8000}, /* MPEG version 2.5 */
  94 };
  95
  96 unsigned long bytes2int(unsigned long b0, unsigned long b1,
  97                         unsigned long b2, unsigned long b3)
  98 {
  99    return (b0 & 0xFF) << (3*8) |
 100           (b1 & 0xFF) << (2*8) |
 101           (b2 & 0xFF) << (1*8) |
 102           (b3 & 0xFF) << (0*8);
 103 }
 104
 105 /* check if 'head' is a valid mp3 frame header */
 106 static bool is_mp3frameheader(unsigned long head)
 107 {
 108     if ((head & SYNC_MASK) != (unsigned long)SYNC_MASK) /* bad sync? */
 109         return false;
 110     if ((head & VERSION_MASK) == (1L << 19)) /* bad version? */
 111         return false;
 112     if (!(head & LAYER_MASK)) /* no layer? */
 113         return false;
 114 #if CONFIG_CODEC != SWCODEC
 115     /* The MAS can't decode layer 1, so treat layer 1 data as invalid */
 116     if ((head & LAYER_MASK) == LAYER_MASK)
 117         return false;
 118 #endif
 119     if ((head & BITRATE_MASK) == BITRATE_MASK) /* bad bitrate? */
 120         return false;
 121     if (!(head & BITRATE_MASK)) /* no bitrate? */
 122         return false;
 123     if ((head & SAMPLERATE_MASK) == SAMPLERATE_MASK) /* bad sample rate? */
 124         return false;
 125
 126     return true;
 127 }
 128
 129 static bool mp3headerinfo(struct mp3info *info, unsigned long header)
 130 {
 131     int bitindex, freqindex;
 132
 133     /* MPEG Audio Version */
 134     if ((header & VERSION_MASK) >> 19 >= sizeof(version_table))
 135         return false;
 136
 137     info->version = version_table[(header & VERSION_MASK) >> 19];
 138     if (info->version < 0)
 139         return false;
 140
 141     /* Layer */
 142     info->layer = 3 - ((header & LAYER_MASK) >> 17);
 143     if (info->layer == 3)
 144         return false;
 145
 146 /* Rockbox: not used
 147     info->protection = (header & PROTECTION_MASK) ? true : false;
 148 */
 149
 150     /* Bitrate */
 151     bitindex = (header & BITRATE_MASK) >> 12;
 152     info->bitrate = bitrate_table[info->version][info->layer][bitindex];
 153     if(info->bitrate == 0)
 154         return false;
 155
 156     /* Sampling frequency */
 157     freqindex = (header & SAMPLERATE_MASK) >> 10;
 158     if (freqindex == 3)
 159         return false;
 160     info->frequency = freq_table[info->version][freqindex];
 161
 162     info->padding = (header & PADDING_MASK) ? 1 : 0;
 163
 164     /* Calculate number of bytes, calculation depends on layer */
 165     if (info->layer == 0) {
 166         info->frame_samples = 384;
 167         info->frame_size = (12000 * info->bitrate / info->frequency
 168                             + info->padding) * 4;
 169     }
 170     else {
 171         if ((info->version > MPEG_VERSION1) && (info->layer == 2))
 172             info->frame_samples = 576;
 173         else
 174             info->frame_samples = 1152;
 175         info->frame_size = (1000/8) * info->frame_samples * info->bitrate
 176                            / info->frequency + info->padding;
 177     }
 178
 179     /* Frametime fraction denominator */
 180     if (freqindex != 0) {      /* 48/32/24/16/12/8 kHz */
 181         info->ft_den = 1;      /* integer number of milliseconds */
 182     }
 183     else {                     /* 44.1/22.05/11.025 kHz */
 184         if (info->layer == 0)     /* layer 1 */
 185             info->ft_den = 147;
 186         else                      /* layer 2+3 */
 187             info->ft_den = 49;
 188     }
 189     /* Frametime fraction numerator */
 190     info->ft_num = 1000 * info->ft_den * info->frame_samples / info->frequency;
 191
 192     info->channel_mode = (header & CHANNELMODE_MASK) >> 6;
 193 /* Rockbox: not used
 194     info->mode_extension = (header & MODE_EXT_MASK) >> 4;
 195     info->emphasis = header & EMPHASIS_MASK;
 196 */
 197     VDEBUGF( "Header: %08lx, Ver %d, lay %d, bitr %d, freq %ld, "
 198             "chmode %d, bytes: %d time: %d/%d\n",
 199             header, info->version, info->layer+1, info->bitrate,
 200             info->frequency, info->channel_mode,
 201             info->frame_size, info->ft_num, info->ft_den);
 202     return true;
 203 }
 204
 205 static bool headers_have_same_type(unsigned long header1,
 206                                    unsigned long header2)
 207 {
 208     /* Compare MPEG version, layer and sampling frequency. If header1 is zero
 209      * it is assumed the headers are of same type. */
 210     unsigned int mask = 0xfffe0c00;
 211     header1 &= mask;
 212     header2 &= mask;
 213     return header1 ? (header1 == header2) : true;
 214 }
 215
 216 /* Helper function to read 4-byte in big endian format. */
 217 static void read_uint32be_mp3data(int fd, unsigned long *data, long *pos)
 218 {
 219 #ifdef ROCKBOX_BIG_ENDIAN
 220     (void)read(fd, (char*)data, 4);
 221 #else
 222     char tmp[4];
 223     (void)read(fd, tmp, 4);
 224     *data = (tmp[0]<<24) | (tmp[1]<<16) | (tmp[2]<<8) | tmp[3];
 225 #endif
 226     *pos += 4;
 227 }
 228
 229 static unsigned long __find_next_frame(int fd, long *offset, long max_offset,
 230                                        unsigned long reference_header,
 231                                        int(*getfunc)(int fd, unsigned char *c),
 232                                        bool single_header)
 233 {
 234     unsigned long header=0;
 235     unsigned char tmp;
 236     long pos      = 0;
 237
 238     /* We will search until we find two consecutive MPEG frame headers with
 239      * the same MPEG version, layer and sampling frequency. The first header
 240      * of this pair is assumed to be the first valid MPEG frame header of the
 241      * whole stream. */
 242     do {
 243         /* Read 1 new byte. */
 244         header <<= 8;
 245         if (!getfunc(fd, &tmp))
 246             return 0;
 247         header |= tmp;
 248         pos++;
 249
 250         /* Abort if max_offset is reached. Stop parsing. */
 251         if (max_offset > 0 && pos > max_offset)
 252             return 0;
 253
 254         if (is_mp3frameheader(header)) {
 255             if (single_header) {
 256                 /* We search for one _single_ valid header that has the same
 257                  * type as the reference_header (if reference_header != 0).
 258                  * In this case we are finished. */
 259                 if (headers_have_same_type(reference_header, header))
 260                     break;
 261             } else {
 262                 /* The current header is valid. Now gather the frame size,
 263                  * seek to this byte position and check if there is another
 264                  * valid MPEG frame header of the same type. */
 265                 struct mp3info info;
 266
 267                 /* Gather frame size from given header and seek to next
 268                  * frame header. */
 269                 mp3headerinfo(&info, header);
 270                 lseek(fd, info.frame_size-4, SEEK_CUR);
 271
 272                 /* Read possible next frame header and seek back to last frame
 273                  * headers byte position. */
 274                 reference_header = 0;
 275                 read_uint32be_mp3data(fd, &reference_header, &pos);
 276                 //
 277                 lseek(fd, -info.frame_size, SEEK_CUR);
 278
 279                 /* If the current header is of the same type as the previous
 280                  * header we are finished. */
 281                 if (headers_have_same_type(header, reference_header))
 282                     break;
 283             }
 284         }
 285
 286     } while (true);
 287
 288     *offset = pos - 4;
 289
 290     if(*offset)
 291         VDEBUGF("Warning: skipping %ld bytes of garbage\n", *offset);
 292
 293     return header;
 294 }
 295
 296 static int fileread(int fd, unsigned char *c)
 297 {
 298     return read(fd, c, 1);
 299 }
 300
 301 unsigned long find_next_frame(int fd,
 302                               long *offset,
 303                               long max_offset,
 304                               unsigned long reference_header)
 305 {
 306     return __find_next_frame(fd, offset, max_offset, reference_header,
 307                              fileread, true);
 308 }
 309
 310 #ifndef __PCTOOL__
 311 static int fnf_read_index;
 312 static int fnf_buf_len;
 313
 314 static int buf_getbyte(int fd, unsigned char *c)
 315 {
 316     if(fnf_read_index < fnf_buf_len)
 317     {
 318         *c = audiobuf[fnf_read_index++];
 319         return 1;
 320     }
 321     else
 322     {
 323         fnf_buf_len = read(fd, audiobuf, audiobufend - audiobuf);
 324         if(fnf_buf_len < 0)
 325             return -1;
 326
 327         fnf_read_index = 0;
 328
 329         if(fnf_buf_len > 0)
 330         {
 331             *c = audiobuf[fnf_read_index++];
 332             return 1;
 333         }
 334         else
 335             return 0;
 336     }
 337     return 0;
 338 }
 339
 340 static int buf_seek(int fd, int len)
 341 {
 342     fnf_read_index += len;
 343     if(fnf_read_index > fnf_buf_len)
 344     {
 345         len = fnf_read_index - fnf_buf_len;
 346
 347         fnf_buf_len = read(fd, audiobuf, audiobufend - audiobuf);
 348         if(fnf_buf_len < 0)
 349             return -1;
 350
 351         fnf_read_index = 0;
 352         fnf_read_index += len;
 353     }
 354
 355     if(fnf_read_index > fnf_buf_len)
 356     {
 357         return -1;
 358     }
 359     else
 360         return 0;
 361 }
 362
 363 static void buf_init(void)
 364 {
 365     fnf_buf_len = 0;
 366     fnf_read_index = 0;
 367 }
 368
 369 static unsigned long buf_find_next_frame(int fd, long *offset, long max_offset)
 370 {
 371     return __find_next_frame(fd, offset, max_offset, 0, buf_getbyte, true);
 372 }
 373
 374 static int audiobuflen;
 375 static int mem_pos;
 376 static int mem_cnt;
 377 static int mem_maxlen;
 378
 379 static int mem_getbyte(int dummy, unsigned char *c)
 380 {
 381     dummy = dummy;
 382
 383     *c = audiobuf[mem_pos++];
 384     if(mem_pos >= audiobuflen)
 385         mem_pos = 0;
 386
 387     if(mem_cnt++ >= mem_maxlen)
 388         return 0;
 389     else
 390         return 1;
 391 }
 392
 393 unsigned long mem_find_next_frame(int startpos,
 394                                   long *offset,
 395                                   long max_offset,
 396                                   unsigned long reference_header)
 397 {
 398     audiobuflen = audiobufend - audiobuf;
 399     mem_pos = startpos;
 400     mem_cnt = 0;
 401     mem_maxlen = max_offset;
 402
 403     return __find_next_frame(0, offset, max_offset, reference_header,
 404                              mem_getbyte, true);
 405 }
 406 #endif
 407
 408 /* Extract information from a 'Xing' or 'Info' header. */
 409 static void get_xing_info(struct mp3info *info, unsigned char *buf)
 410 {
 411     int i = 8;
 412
 413     /* Is it a VBR file? */
 414     info->is_vbr = !memcmp(buf, "Xing", 4);
 415
 416     if (buf[7] & VBR_FRAMES_FLAG) /* Is the frame count there? */
 417     {
 418         info->frame_count = bytes2int(buf[i], buf[i+1], buf[i+2], buf[i+3]);
 419         if (info->frame_count <= ULONG_MAX / info->ft_num)
 420             info->file_time = info->frame_count * info->ft_num / info->ft_den;
 421         else
 422             info->file_time = info->frame_count / info->ft_den * info->ft_num;
 423         i += 4;
 424     }
 425
 426     if (buf[7] & VBR_BYTES_FLAG) /* Is byte count there? */
 427     {
 428         info->byte_count = bytes2int(buf[i], buf[i+1], buf[i+2], buf[i+3]);
 429         i += 4;
 430     }
 431
 432     if (info->file_time && info->byte_count)
 433     {
 434         if (info->byte_count <= (ULONG_MAX/8))
 435             info->bitrate = info->byte_count * 8 / info->file_time;
 436         else
 437             info->bitrate = info->byte_count / (info->file_time >> 3);
 438     }
 439
 440     if (buf[7] & VBR_TOC_FLAG) /* Is table-of-contents there? */
 441     {
 442         info->has_toc = true;
 443         memcpy( info->toc, buf+i, 100 );
 444         i += 100;
 445     }
 446     if (buf[7] & VBR_QUALITY_FLAG)
 447     {
 448         /* We don't care about this, but need to skip it */
 449         i += 4;
 450     }
 451 #if CONFIG_CODEC==SWCODEC
 452     i += 21;
 453     info->enc_delay   = ((int)buf[i  ] << 4) | (buf[i+1] >> 4);
 454     info->enc_padding = ((int)buf[i+1] << 8) |  buf[i+2];
 455     /* TODO: This sanity checking is rather silly, seeing as how the LAME
 456        header contains a CRC field that can be used to verify integrity. */
 457     if (!(info->enc_delay   >= 0 && info->enc_delay   <= 2880 &&
 458           info->enc_padding >= 0 && info->enc_padding <= 2*1152))
 459     {
 460        /* Invalid data */
 461        info->enc_delay   = -1;
 462        info->enc_padding = -1;
 463     }
 464 #endif
 465 }
 466
 467 /* Extract information from a 'VBRI' header. */
 468 static void get_vbri_info(struct mp3info *info, unsigned char *buf)
 469 {
 470     int i, num_offsets, offset = 0;
 471
 472     info->is_vbr  = true;  /* Yes, it is a FhG VBR file */
 473     info->has_toc = false; /* We don't parse the TOC (yet) */
 474
 475     info->byte_count  = bytes2int(buf[10], buf[11], buf[12], buf[13]);
 476     info->frame_count = bytes2int(buf[14], buf[15], buf[16], buf[17]);
 477     if (info->frame_count <= ULONG_MAX / info->ft_num)
 478         info->file_time = info->frame_count * info->ft_num / info->ft_den;
 479     else
 480         info->file_time = info->frame_count / info->ft_den * info->ft_num;
 481
 482     if (info->byte_count <= (ULONG_MAX/8))
 483         info->bitrate = info->byte_count * 8 / info->file_time;
 484     else
 485         info->bitrate = info->byte_count / (info->file_time >> 3);
 486
 487     /* We don't parse the TOC, since we don't yet know how to (FIXME) */
 488     num_offsets = bytes2int(0, 0, buf[18], buf[19]);
 489     VDEBUGF("Frame size (%dkpbs): %d bytes (0x%x)\n",
 490            info->bitrate, info->frame_size, info->frame_size);
 491     VDEBUGF("Frame count: %lx\n", info->frame_count);
 492     VDEBUGF("Byte count: %lx\n", info->byte_count);
 493     VDEBUGF("Offsets: %d\n", num_offsets);
 494     VDEBUGF("Frames/entry: %ld\n",
 495             bytes2int(0, 0, buf[24], buf[25]));
 496
 497     for(i = 0; i < num_offsets; i++)
 498     {
 499        offset += bytes2int(0, 0, buf[26+i*2], buf[27+i*2]);;
 500        VDEBUGF("%03d: %lx\n", i, offset - bytecount,);
 501     }
 502 }
 503
 504 /* Seek to next mpeg header and extract relevant information. */
 505 static int get_next_header_info(int fd, long *bytecount, struct mp3info *info,
 506                                 bool single_header)
 507 {
 508     long tmp;
 509     unsigned long header = 0;
 510
 511     header = __find_next_frame(fd, &tmp, 0x20000, 0, fileread, single_header);
 512     if(header == 0)
 513         return -1;
 514
 515     if(!mp3headerinfo(info, header))
 516         return -2;
 517
 518     /* Next frame header is tmp bytes away. */
 519     *bytecount += tmp;
 520
 521     return 0;
 522 }
 523
 524 int get_mp3file_info(int fd, struct mp3info *info)
 525 {
 526     unsigned char frame[1800], *vbrheader;
 527     long bytecount = 0;
 528     int result;
 529
 530     /* Initialize info and frame */
 531     memset(info,  0, sizeof(struct mp3info));
 532     memset(frame, 0, sizeof(frame));
 533
 534 #if CONFIG_CODEC==SWCODEC
 535     /* These two are needed for proper LAME gapless MP3 playback */
 536     info->enc_delay   = -1;
 537     info->enc_padding = -1;
 538 #endif
 539
 540     /* Get the very first single MPEG frame. */
 541     result = get_next_header_info(fd, &bytecount, info, true);
 542     if(result)
 543         return result;
 544
 545     /* OK, we have found a frame. Let's see if it has a Xing header */
 546     if (info->frame_size-4 >= (int)sizeof(frame))
 547     {
 548         DEBUGF("Error: Invalid id3 header, frame_size: %d\n", info->frame_size);
 549         return -8;
 550     }
 551
 552     if(read(fd, frame, info->frame_size-4) < 0)
 553         return -3;
 554
 555     /* Calculate position of a possible VBR header */
 556     if (info->version == MPEG_VERSION1) {
 557         if (info->channel_mode == 3) /* mono */
 558             vbrheader = frame + 17;
 559         else
 560             vbrheader = frame + 32;
 561     } else {
 562         if (info->channel_mode == 3) /* mono */
 563             vbrheader = frame + 9;
 564         else
 565             vbrheader = frame + 17;
 566     }
 567
 568     if (!memcmp(vbrheader, "Xing", 4) || !memcmp(vbrheader, "Info", 4))
 569     {
 570         VDEBUGF("-- XING header --\n");
 571
 572         /* We want to skip the Xing frame when playing the stream */
 573         bytecount += info->frame_size;
 574
 575         /* Now get the next frame to read the real info about the mp3 stream */
 576         result = get_next_header_info(fd, &bytecount, info, false);
 577         if(result)
 578             return result;
 579
 580         get_xing_info(info, vbrheader);
 581     }
 582     else if (!memcmp(vbrheader, "VBRI", 4))
 583     {
 584         VDEBUGF("-- VBRI header --\n");
 585
 586         /* We want to skip the VBRI frame when playing the stream */
 587         bytecount += info->frame_size;
 588
 589         /* Now get the next frame to read the real info about the mp3 stream */
 590         result = get_next_header_info(fd, &bytecount, info, false);
 591         if(result)
 592             return result;
 593
 594         get_vbri_info(info, vbrheader);
 595     }
 596     else
 597     {
 598         VDEBUGF("-- No VBR header --\n");
 599
 600         /* There was no VBR header found. So, we seek back to beginning and
 601          * search for the first MPEG frame header of the mp3 stream. */
 602         lseek(fd, -info->frame_size, SEEK_CUR);
 603         result = get_next_header_info(fd, &bytecount, info, false);
 604         if(result)
 605             return result;
 606     }
 607
 608     return bytecount;
 609 }
 610
 611 #ifndef __PCTOOL__
 612 static void long2bytes(unsigned char *buf, long val)
 613 {
 614     buf[0] = (val >> 24) & 0xff;
 615     buf[1] = (val >> 16) & 0xff;
 616     buf[2] = (val >> 8) & 0xff;
 617     buf[3] = val & 0xff;
 618 }
 619
 620 int count_mp3_frames(int fd, int startpos, int filesize,
 621                      void (*progressfunc)(int))
 622 {
 623     unsigned long header = 0;
 624     struct mp3info info;
 625     int num_frames;
 626     long bytes;
 627     int cnt;
 628     long progress_chunk = filesize / 50; /* Max is 50%, in 1% increments */
 629     int progress_cnt = 0;
 630     bool is_vbr = false;
 631     int last_bitrate = 0;
 632     int header_template = 0;
 633
 634     if(lseek(fd, startpos, SEEK_SET) < 0)
 635         return -1;
 636
 637     buf_init();
 638
 639     /* Find out the total number of frames */
 640     num_frames = 0;
 641     cnt = 0;
 642
 643     while((header = buf_find_next_frame(fd, &bytes, header_template))) {
 644         mp3headerinfo(&info, header);
 645
 646         if(!header_template)
 647             header_template = header;
 648
 649         /* See if this really is a VBR file */
 650         if(last_bitrate && info.bitrate != last_bitrate)
 651         {
 652             is_vbr = true;
 653         }
 654         last_bitrate = info.bitrate;
 655
 656         buf_seek(fd, info.frame_size-4);
 657         num_frames++;
 658         if(progressfunc)
 659         {
 660             cnt += bytes + info.frame_size;
 661             if(cnt > progress_chunk)
 662             {
 663                 progress_cnt++;
 664                 progressfunc(progress_cnt);
 665                 cnt = 0;
 666             }
 667         }
 668     }
 669     VDEBUGF("Total number of frames: %d\n", num_frames);
 670
 671     if(is_vbr)
 672         return num_frames;
 673     else
 674     {
 675         DEBUGF("Not a VBR file\n");
 676         return 0;
 677     }
 678 }
 679
 680 static const char cooltext[] = "Rockbox - rocks your box";
 681
 682 /* buf needs to be the audio buffer with TOC generation enabled,
 683    and at least MAX_XING_HEADER_SIZE bytes otherwise */
 684 int create_xing_header(int fd, long startpos, long filesize,
 685                        unsigned char *buf, unsigned long num_frames,
 686                        unsigned long rec_time, unsigned long header_template,
 687                        void (*progressfunc)(int), bool generate_toc)
 688 {
 689     struct mp3info info;
 690     unsigned char toc[100];
 691     unsigned long header = 0;
 692     unsigned long xing_header_template = header_template;
 693     unsigned long filepos;
 694     long pos, last_pos;
 695     long j;
 696     long bytes;
 697     int i;
 698     int index;
 699
 700     DEBUGF("create_xing_header()\n");
 701
 702     if(generate_toc)
 703     {
 704         lseek(fd, startpos, SEEK_SET);
 705         buf_init();
 706
 707         /* Generate filepos table */
 708         last_pos = 0;
 709         filepos = 0;
 710         header = 0;
 711         for(i = 0;i < 100;i++) {
 712             /* Calculate the absolute frame number for this seek point */
 713             pos = i * num_frames / 100;
 714
 715             /* Advance from the last seek point to this one */
 716             for(j = 0;j < pos - last_pos;j++)
 717             {
 718                 header = buf_find_next_frame(fd, &bytes, header_template);
 719                 filepos += bytes;
 720                 mp3headerinfo(&info, header);
 721                 buf_seek(fd, info.frame_size-4);
 722                 filepos += info.frame_size;
 723
 724                 if(!header_template)
 725                     header_template = header;
 726             }
 727
 728             /* Save a header for later use if header_template is empty.
 729                We only save one header, and we want to save one in the
 730                middle of the stream, just in case the first and the last
 731                headers are corrupt. */
 732             if(!xing_header_template && i == 1)
 733                 xing_header_template = header;
 734
 735             if(progressfunc)
 736             {
 737                 progressfunc(50 + i/2);
 738             }
 739
 740             /* Fill in the TOC entry */
 741             /* each toc is a single byte indicating how many 256ths of the
 742              * way through the file, is that percent of the way through the
 743              * song. the easy method, filepos*256/filesize, chokes when
 744              * the upper 8 bits of the file position are nonzero
 745              * (i.e. files over 16mb in size).
 746              */
 747             if (filepos > (ULONG_MAX/256))
 748             {
 749                 /* instead of multiplying filepos by 256, we divide
 750                  * filesize by 256.
 751                  */
 752                 toc[i] = filepos / (filesize >> 8);
 753             }
 754             else
 755             {
 756                 toc[i] = filepos * 256 / filesize;
 757             }
 758
 759             VDEBUGF("Pos %d: %ld  relpos: %ld  filepos: %lx tocentry: %x\n",
 760                    i, pos, pos-last_pos, filepos, toc[i]);
 761
 762             last_pos = pos;
 763         }
 764     }
 765
 766     /* Use the template header and create a new one.
 767        We ignore the Protection bit even if the rest of the stream is
 768        protected. */
 769     header = xing_header_template & ~(BITRATE_MASK|PROTECTION_MASK|PADDING_MASK);
 770     header |= 8 << 12; /* This gives us plenty of space, 192..576 bytes */
 771
 772     if (!mp3headerinfo(&info, header))
 773         return 0;  /* invalid header */
 774
 775     if (num_frames == 0 && rec_time) {
 776         /* estimate the number of frames based on the recording time */
 777         if (rec_time <= ULONG_MAX / info.ft_den)
 778             num_frames = rec_time * info.ft_den / info.ft_num;
 779         else
 780             num_frames = rec_time / info.ft_num * info.ft_den;
 781     }
 782
 783     /* Clear the frame */
 784     memset(buf, 0, MAX_XING_HEADER_SIZE);
 785
 786     /* Write the header to the buffer */
 787     long2bytes(buf, header);
 788
 789     /* Calculate position of VBR header */
 790     if (info.version == MPEG_VERSION1) {
 791         if (info.channel_mode == 3) /* mono */
 792             index = 21;
 793         else
 794             index = 36;
 795     }
 796     else {
 797         if (info.channel_mode == 3) /* mono */
 798             index = 13;
 799         else
 800             index = 21;
 801     }
 802
 803     /* Create the Xing data */
 804     memcpy(&buf[index], "Xing", 4);
 805     long2bytes(&buf[index+4], (num_frames ? VBR_FRAMES_FLAG : 0)
 806                               | (filesize ? VBR_BYTES_FLAG : 0)
 807                               | (generate_toc ? VBR_TOC_FLAG : 0));
 808     index += 8;
 809     if(num_frames)
 810     {
 811         long2bytes(&buf[index], num_frames);
 812         index += 4;
 813     }
 814
 815     if(filesize)
 816     {
 817         long2bytes(&buf[index], filesize - startpos);
 818         index += 4;
 819     }
 820
 821     /* Copy the TOC */
 822     memcpy(buf + index, toc, 100);
 823
 824     /* And some extra cool info */
 825     memcpy(buf + index + 100, cooltext, sizeof(cooltext));
 826
 827 #ifdef DEBUG
 828     for(i = 0;i < info.frame_size;i++)
 829     {
 830         if(i && !(i % 16))
 831             DEBUGF("\n");
 832
 833         DEBUGF("%02x ", buf[i]);
 834     }
 835 #endif
 836
 837     return info.frame_size;
 838 }
 839
 840 #endif