142ac27212276beb69457281204c69d31c3db24f
[reactos.git] / reactos / lib / 3rdparty / libmpg123 / parse.c
1 /*
2 parse: spawned from common; clustering around stream/frame parsing
3
4 copyright ?-2014 by the mpg123 project - free software under the terms of the LGPL 2.1
5 see COPYING and AUTHORS files in distribution or http://mpg123.org
6 initially written by Michael Hipp & Thomas Orgis
7 */
8
9 #include "mpg123lib_intern.h"
10
11 #include <sys/stat.h>
12 #include <fcntl.h>
13
14 #include "getbits.h"
15
16 #if defined (WANT_WIN32_SOCKETS)
17 #include <winsock2.h>
18 #include <ws2tcpip.h>
19 #endif
20
21 /* a limit for number of frames in a track; beyond that unsigned long may not be enough to hold byte addresses */
22 #ifdef HAVE_LIMITS_H
23 #include <limits.h>
24 #endif
25 #ifndef ULONG_MAX
26 /* hm, is this portable across preprocessors? */
27 #define ULONG_MAX ((unsigned long)-1)
28 #endif
29 #define TRACK_MAX_FRAMES ULONG_MAX/4/1152
30
31 #include "mpeghead.h"
32
33 #include "debug.h"
34
35 #define bsbufid(fr) (fr)->bsbuf==(fr)->bsspace[0] ? 0 : ((fr)->bsbuf==fr->bsspace[1] ? 1 : ( (fr)->bsbuf==(fr)->bsspace[0]+512 ? 2 : ((fr)->bsbuf==fr->bsspace[1]+512 ? 3 : -1) ) )
36
37 /* PARSE_GOOD and PARSE_BAD have to be 1 and 0 (TRUE and FALSE), others can vary. */
38 enum parse_codes
39 {
40 PARSE_MORE = MPG123_NEED_MORE
41 ,PARSE_ERR = MPG123_ERR
42 ,PARSE_END = 10 /* No more audio data to find. */
43 ,PARSE_GOOD = 1 /* Everything's fine. */
44 ,PARSE_BAD = 0 /* Not fine (invalid data). */
45 ,PARSE_RESYNC = 2 /* Header not good, go into resync. */
46 ,PARSE_AGAIN = 3 /* Really start over, throw away and read a new header, again. */
47 };
48
49 /* bitrates for [mpeg1/2][layer] */
50 static const int tabsel_123[2][3][16] =
51 {
52 {
53 {0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,},
54 {0,32,48,56, 64, 80, 96,112,128,160,192,224,256,320,384,},
55 {0,32,40,48, 56, 64, 80, 96,112,128,160,192,224,256,320,}
56 },
57 {
58 {0,32,48,56,64,80,96,112,128,144,160,176,192,224,256,},
59 {0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,},
60 {0,8,16,24,32,40,48,56,64,80,96,112,128,144,160,}
61 }
62 };
63
64 static const long freqs[9] = { 44100, 48000, 32000, 22050, 24000, 16000 , 11025 , 12000 , 8000 };
65
66 static int decode_header(mpg123_handle *fr,unsigned long newhead, int *freeformat_count);
67 static int skip_junk(mpg123_handle *fr, unsigned long *newheadp, long *headcount);
68 static int do_readahead(mpg123_handle *fr, unsigned long newhead);
69 static int wetwork(mpg123_handle *fr, unsigned long *newheadp);
70
71 /* These two are to be replaced by one function that gives all the frame parameters (for outsiders).*/
72 /* Those functions are unsafe regarding bad arguments (inside the mpg123_handle), but just returning anything would also be unsafe, the caller code has to be trusted. */
73
74 int frame_bitrate(mpg123_handle *fr)
75 {
76 return tabsel_123[fr->lsf][fr->lay-1][fr->bitrate_index];
77 }
78
79 long frame_freq(mpg123_handle *fr)
80 {
81 return freqs[fr->sampling_frequency];
82 }
83
84 /* compiler is smart enought to inline this one or should I really do it as macro...? */
85 static int head_check(unsigned long head)
86 {
87 if
88 (
89 ((head & HDR_SYNC) != HDR_SYNC)
90 ||
91 /* layer: 01,10,11 is 1,2,3; 00 is reserved */
92 (!(HDR_LAYER_VAL(head)))
93 ||
94 /* 1111 means bad bitrate */
95 (HDR_BITRATE_VAL(head) == 0xf)
96 ||
97 /* sampling freq: 11 is reserved */
98 (HDR_SAMPLERATE_VAL(head) == 0x3)
99 /* here used to be a mpeg 2.5 check... re-enabled 2.5 decoding due to lack of evidence that it is really not good */
100 )
101 {
102 return FALSE;
103 }
104 /* if no check failed, the header is valid (hopefully)*/
105 else
106 {
107 return TRUE;
108 }
109 }
110
111 /* This is moderately sized buffers. Int offset is enough. */
112 static unsigned long bit_read_long(unsigned char *buf, int *offset)
113 {
114 unsigned long val = /* 32 bit value */
115 (((unsigned long) buf[*offset]) << 24)
116 | (((unsigned long) buf[*offset+1]) << 16)
117 | (((unsigned long) buf[*offset+2]) << 8)
118 | ((unsigned long) buf[*offset+3]);
119 *offset += 4;
120 return val;
121 }
122
123 static unsigned short bit_read_short(unsigned char *buf, int *offset)
124 {
125 unsigned short val = /* 16 bit value */
126 (((unsigned short) buf[*offset] ) << 8)
127 | ((unsigned short) buf[*offset+1]);
128 *offset += 2;
129 return val;
130 }
131
132 static int check_lame_tag(mpg123_handle *fr)
133 {
134 int i;
135 unsigned long xing_flags;
136 unsigned long long_tmp;
137 /*
138 going to look for Xing or Info at some position after the header
139 MPEG 1 MPEG 2/2.5 (LSF)
140 Stereo, Joint Stereo, Dual Channel 32 17
141 Mono 17 9
142 */
143 int lame_offset = (fr->stereo == 2)
144 ? (fr->lsf ? 17 : 32)
145 : (fr->lsf ? 9 : 17);
146
147 if(fr->p.flags & MPG123_IGNORE_INFOFRAME) goto check_lame_tag_no;
148
149 debug("do we have lame tag?");
150 /*
151 Note: CRC or not, that does not matter here.
152 But, there is any combination of Xing flags in the wild. There are headers
153 without the search index table! I cannot assume a reasonable minimal size
154 for the actual data, have to check if each byte of information is present.
155 But: 4 B Info/Xing + 4 B flags is bare minimum.
156 */
157 if(fr->framesize < lame_offset+8) goto check_lame_tag_no;
158
159 /* only search for tag when all zero before it (apart from checksum) */
160 for(i=2; i < lame_offset; ++i) if(fr->bsbuf[i] != 0) goto check_lame_tag_no;
161
162 debug("possibly...");
163 if
164 (
165 (fr->bsbuf[lame_offset] == 'I')
166 && (fr->bsbuf[lame_offset+1] == 'n')
167 && (fr->bsbuf[lame_offset+2] == 'f')
168 && (fr->bsbuf[lame_offset+3] == 'o')
169 )
170 {
171 /* We still have to see what there is */
172 }
173 else if
174 (
175 (fr->bsbuf[lame_offset] == 'X')
176 && (fr->bsbuf[lame_offset+1] == 'i')
177 && (fr->bsbuf[lame_offset+2] == 'n')
178 && (fr->bsbuf[lame_offset+3] == 'g')
179 )
180 {
181 fr->vbr = MPG123_VBR; /* Xing header means always VBR */
182 }
183 else goto check_lame_tag_no;
184
185 /* we have one of these headers... */
186 if(VERBOSE2) fprintf(stderr, "Note: Xing/Lame/Info header detected\n");
187 lame_offset += 4;
188 xing_flags = bit_read_long(fr->bsbuf, &lame_offset);
189 debug1("Xing: flags 0x%08lx", xing_flags);
190
191 /* From now on, I have to carefully check if the announced data is actually
192 there! I'm always returning 'yes', though. */
193 #define check_bytes_left(n) if(fr->framesize < lame_offset+n) \
194 goto check_lame_tag_yes
195 if(xing_flags & 1) /* total bitstream frames */
196 {
197 check_bytes_left(4); long_tmp = bit_read_long(fr->bsbuf, &lame_offset);
198 if(fr->p.flags & MPG123_IGNORE_STREAMLENGTH)
199 {
200 if(VERBOSE3) fprintf(stderr
201 , "Note: Ignoring Xing frames because of MPG123_IGNORE_STREAMLENGTH\n");
202 }
203 else
204 {
205 /* Check for endless stream, but: TRACK_MAX_FRAMES sensible at all? */
206 fr->track_frames = long_tmp > TRACK_MAX_FRAMES ? 0 : (off_t) long_tmp;
207 #ifdef GAPLESS
208 /* All or nothing: Only if encoder delay/padding is known, we'll cut
209 samples for gapless. */
210 if(fr->p.flags & MPG123_GAPLESS)
211 frame_gapless_init(fr, fr->track_frames, 0, 0);
212 #endif
213 if(VERBOSE3) fprintf(stderr, "Note: Xing: %lu frames\n", long_tmp);
214 }
215 }
216 if(xing_flags & 0x2) /* total bitstream bytes */
217 {
218 check_bytes_left(4); long_tmp = bit_read_long(fr->bsbuf, &lame_offset);
219 if(fr->p.flags & MPG123_IGNORE_STREAMLENGTH)
220 {
221 if(VERBOSE3) fprintf(stderr
222 , "Note: Ignoring Xing bytes because of MPG123_IGNORE_STREAMLENGTH\n");
223 }
224 else
225 {
226 /* The Xing bitstream length, at least as interpreted by the Lame
227 encoder, encompasses all data from the Xing header frame on,
228 ignoring leading ID3v2 data. Trailing tags (ID3v1) seem to be
229 included, though. */
230 if(fr->rdat.filelen < 1)
231 fr->rdat.filelen = (off_t) long_tmp + fr->audio_start; /* Overflow? */
232 else
233 {
234 if((off_t)long_tmp != fr->rdat.filelen - fr->audio_start && NOQUIET)
235 { /* 1/filelen instead of 1/(filelen-start), my decision */
236 double diff = 100.0/fr->rdat.filelen
237 * ( fr->rdat.filelen - fr->audio_start
238 - (off_t)long_tmp );
239 if(diff < 0.) diff = -diff;
240
241 if(VERBOSE3) fprintf(stderr
242 , "Note: Xing stream size %lu differs by %f%% from determined/given file size!\n"
243 , long_tmp, diff);
244
245 if(diff > 1. && NOQUIET) fprintf(stderr
246 , "Warning: Xing stream size off by more than 1%%, fuzzy seeking may be even more fuzzy than by design!\n");
247 }
248 }
249
250 if(VERBOSE3) fprintf(stderr, "Note: Xing: %lu bytes\n", long_tmp);
251 }
252 }
253 if(xing_flags & 0x4) /* TOC */
254 {
255 check_bytes_left(100);
256 frame_fill_toc(fr, fr->bsbuf+lame_offset);
257 lame_offset += 100;
258 }
259 if(xing_flags & 0x8) /* VBR quality */
260 {
261 check_bytes_left(4); long_tmp = bit_read_long(fr->bsbuf, &lame_offset);
262 if(VERBOSE3) fprintf(stderr, "Note: Xing: quality = %lu\n", long_tmp);
263 }
264 /*
265 Either zeros/nothing, or:
266 0-8: LAME3.90a
267 9: revision/VBR method
268 10: lowpass
269 11-18: ReplayGain
270 19: encoder flags
271 20: ABR
272 21-23: encoder delays
273 */
274 check_bytes_left(24); /* I'm interested in 24 B of extra info. */
275 if(fr->bsbuf[lame_offset] != 0)
276 {
277 unsigned char lame_vbr;
278 float replay_gain[2] = {0,0};
279 float peak = 0;
280 float gain_offset = 0; /* going to be +6 for old lame that used 83dB */
281 char nb[10];
282 off_t pad_in;
283 off_t pad_out;
284 memcpy(nb, fr->bsbuf+lame_offset, 9);
285 nb[9] = 0;
286 if(VERBOSE3) fprintf(stderr, "Note: Info: Encoder: %s\n", nb);
287 if(!strncmp("LAME", nb, 4))
288 {
289 /* Lame versions before 3.95.1 used 83 dB reference level, later
290 versions 89 dB. We stick with 89 dB as being "normal", adding
291 6 dB. */
292 unsigned int major, minor;
293 char rest[6];
294 rest[0] = 0;
295 if(sscanf(nb+4, "%u.%u%s", &major, &minor, rest) >= 2)
296 {
297 debug3("LAME: %u/%u/%s", major, minor, rest);
298 /* We cannot detect LAME 3.95 reliably (same version string as
299 3.95.1), so this is a blind spot. Everything < 3.95 is safe,
300 though. */
301 if(major < 3 || (major == 3 && minor < 95))
302 {
303 gain_offset = 6;
304 if(VERBOSE3) fprintf(stderr
305 , "Note: Info: Old LAME detected, using ReplayGain preamp of %f dB.\n"
306 , gain_offset);
307 }
308 }
309 else if(VERBOSE3) fprintf(stderr
310 , "Note: Info: Cannot determine LAME version.\n");
311 }
312 lame_offset += 9; /* 9 in */
313
314 /* The 4 big bits are tag revision, the small bits vbr method. */
315 lame_vbr = fr->bsbuf[lame_offset] & 15;
316 lame_offset += 1; /* 10 in */
317 if(VERBOSE3)
318 {
319 fprintf(stderr, "Note: Info: rev %u\n", fr->bsbuf[lame_offset] >> 4);
320 fprintf(stderr, "Note: Info: vbr mode %u\n", lame_vbr);
321 }
322 switch(lame_vbr)
323 {
324 /* from rev1 proposal... not sure if all good in practice */
325 case 1:
326 case 8: fr->vbr = MPG123_CBR; break;
327 case 2:
328 case 9: fr->vbr = MPG123_ABR; break;
329 default: fr->vbr = MPG123_VBR; /* 00==unknown is taken as VBR */
330 }
331 lame_offset += 1; /* 11 in, skipping lowpass filter value */
332
333 /* ReplayGain peak ampitude, 32 bit float -- why did I parse it as int
334 before?? Ah, yes, Lame seems to store it as int since some day in 2003;
335 I've only seen zeros anyway until now, bah! */
336 if
337 (
338 (fr->bsbuf[lame_offset] != 0)
339 || (fr->bsbuf[lame_offset+1] != 0)
340 || (fr->bsbuf[lame_offset+2] != 0)
341 || (fr->bsbuf[lame_offset+3] != 0)
342 )
343 {
344 debug("Wow! Is there _really_ a non-zero peak value? Now is it stored as float or int - how should I know?");
345 /* byte*peak_bytes = (byte*) &peak;
346 ... endianess ... just copy bytes to avoid floating point operation on unaligned memory?
347 peak_bytes[0] = ...
348 peak = *(float*) (fr->bsbuf+lame_offset); */
349 }
350 if(VERBOSE3) fprintf(stderr
351 , "Note: Info: peak = %f (I won't use this)\n", peak);
352 peak = 0; /* until better times arrived */
353 lame_offset += 4; /* 15 in */
354
355 /* ReplayGain values - lame only writes radio mode gain...
356 16bit gain, 3 bits name, 3 bits originator, sign (1=-, 0=+),
357 dB value*10 in 9 bits (fixed point) ignore the setting if name or
358 originator == 000!
359 radio 0 0 1 0 1 1 1 0 0 1 1 1 1 1 0 1
360 audiophile 0 1 0 0 1 0 0 0 0 0 0 1 0 1 0 0 */
361 for(i =0; i < 2; ++i)
362 {
363 unsigned char gt = fr->bsbuf[lame_offset] >> 5;
364 unsigned char origin = (fr->bsbuf[lame_offset] >> 2) & 0x7;
365 float factor = (fr->bsbuf[lame_offset] & 0x2) ? -0.1 : 0.1;
366 unsigned short gain = bit_read_short(fr->bsbuf, &lame_offset) & 0x1ff; /* 19 in (2 cycles) */
367 if(origin == 0 || gt < 1 || gt > 2) continue;
368
369 --gt;
370 replay_gain[gt] = factor * (float) gain;
371 /* Apply gain offset for automatic origin. */
372 if(origin == 3) replay_gain[gt] += gain_offset;
373 }
374 if(VERBOSE3)
375 {
376 fprintf(stderr, "Note: Info: Radio Gain = %03.1fdB\n"
377 , replay_gain[0]);
378 fprintf(stderr, "Note: Info: Audiophile Gain = %03.1fdB\n"
379 , replay_gain[1]);
380 }
381 for(i=0; i < 2; ++i)
382 {
383 if(fr->rva.level[i] <= 0)
384 {
385 fr->rva.peak[i] = 0; /* TODO: use parsed peak? */
386 fr->rva.gain[i] = replay_gain[i];
387 fr->rva.level[i] = 0;
388 }
389 }
390
391 lame_offset += 1; /* 20 in, skipping encoding flags byte */
392
393 /* ABR rate */
394 if(fr->vbr == MPG123_ABR)
395 {
396 fr->abr_rate = fr->bsbuf[lame_offset];
397 if(VERBOSE3) fprintf(stderr, "Note: Info: ABR rate = %u\n"
398 , fr->abr_rate);
399 }
400 lame_offset += 1; /* 21 in */
401
402 /* Encoder delay and padding, two 12 bit values
403 ... lame does write them from int. */
404 pad_in = ( (((int) fr->bsbuf[lame_offset]) << 4)
405 | (((int) fr->bsbuf[lame_offset+1]) >> 4) );
406 pad_out = ( (((int) fr->bsbuf[lame_offset+1]) << 8)
407 | ((int) fr->bsbuf[lame_offset+2]) ) & 0xfff;
408 lame_offset += 3; /* 24 in */
409 if(VERBOSE3) fprintf(stderr, "Note: Encoder delay = %i; padding = %i\n"
410 , (int)pad_in, (int)pad_out);
411 #ifdef GAPLESS
412 if(fr->p.flags & MPG123_GAPLESS)
413 frame_gapless_init(fr, fr->track_frames, pad_in, pad_out);
414 #endif
415 /* final: 24 B LAME data */
416 }
417
418 check_lame_tag_yes:
419 /* switch buffer back ... */
420 fr->bsbuf = fr->bsspace[fr->bsnum]+512;
421 fr->bsnum = (fr->bsnum + 1) & 1;
422 return 1;
423 check_lame_tag_no:
424 return 0;
425 }
426
427 /* Just tell if the header is some mono. */
428 static int header_mono(unsigned long newhead)
429 {
430 return HDR_CHANNEL_VAL(newhead) == MPG_MD_MONO ? TRUE : FALSE;
431 }
432
433 /* true if the two headers will work with the same decoding routines */
434 static int head_compatible(unsigned long fred, unsigned long bret)
435 {
436 return ( (fred & HDR_CMPMASK) == (bret & HDR_CMPMASK)
437 && header_mono(fred) == header_mono(bret) );
438 }
439
440 static void halfspeed_prepare(mpg123_handle *fr)
441 {
442 /* save for repetition */
443 if(fr->p.halfspeed && fr->lay == 3)
444 {
445 debug("halfspeed - reusing old bsbuf ");
446 memcpy (fr->ssave, fr->bsbuf, fr->ssize);
447 }
448 }
449
450 /* If this returns 1, the next frame is the repetition. */
451 static int halfspeed_do(mpg123_handle *fr)
452 {
453 /* Speed-down hack: Play it again, Sam (the frame, I mean). */
454 if (fr->p.halfspeed)
455 {
456 if(fr->halfphase) /* repeat last frame */
457 {
458 debug("repeat!");
459 fr->to_decode = fr->to_ignore = TRUE;
460 --fr->halfphase;
461 fr->bitindex = 0;
462 fr->wordpointer = (unsigned char *) fr->bsbuf;
463 if(fr->lay == 3) memcpy (fr->bsbuf, fr->ssave, fr->ssize);
464 if(fr->error_protection) fr->crc = getbits(fr, 16); /* skip crc */
465 return 1;
466 }
467 else
468 {
469 fr->halfphase = fr->p.halfspeed - 1;
470 }
471 }
472 return 0;
473 }
474
475 /*
476 Temporary macro until we got this worked out.
477 Idea is to filter out special return values that shall trigger direct jumps to end / resync / read again.
478 Particularily, the generic ret==PARSE_BAD==0 and ret==PARSE_GOOD==1 are not affected.
479 */
480 #define JUMP_CONCLUSION(ret) \
481 { \
482 if(ret < 0){ debug1("%s", ret == MPG123_NEED_MORE ? "need more" : "read error"); goto read_frame_bad; } \
483 else if(ret == PARSE_AGAIN) goto read_again; \
484 else if(ret == PARSE_RESYNC) goto init_resync; \
485 else if(ret == PARSE_END){ ret=0; goto read_frame_bad; } \
486 }
487
488 /*
489 That's a big one: read the next frame. 1 is success, <= 0 is some error
490 Special error READER_MORE means: Please feed more data and try again.
491 */
492 int read_frame(mpg123_handle *fr)
493 {
494 /* TODO: rework this thing */
495 int freeformat_count = 0;
496 unsigned long newhead;
497 off_t framepos;
498 int ret;
499 /* stuff that needs resetting if complete frame reading fails */
500 int oldsize = fr->framesize;
501 int oldphase = fr->halfphase;
502
503 /* The counter for the search-first-header loop.
504 It is persistent outside the loop to prevent seemingly endless loops
505 when repeatedly headers are found that do not have valid followup headers. */
506 long headcount = 0;
507
508 fr->fsizeold=fr->framesize; /* for Layer3 */
509
510 if(halfspeed_do(fr) == 1) return 1;
511
512 read_again:
513 /* In case we are looping to find a valid frame, discard any buffered data before the current position.
514 This is essential to prevent endless looping, always going back to the beginning when feeder buffer is exhausted. */
515 if(fr->rd->forget != NULL) fr->rd->forget(fr);
516
517 debug2("trying to get frame %"OFF_P" at %"OFF_P, (off_p)fr->num+1, (off_p)fr->rd->tell(fr));
518 if((ret = fr->rd->head_read(fr,&newhead)) <= 0){ debug1("need more? (%i)", ret); goto read_frame_bad;}
519
520 init_resync:
521
522 #ifdef SKIP_JUNK
523 if(!fr->firsthead && !head_check(newhead))
524 {
525 ret = skip_junk(fr, &newhead, &headcount);
526 JUMP_CONCLUSION(ret);
527 }
528 #endif
529
530 ret = head_check(newhead);
531 if(ret) ret = decode_header(fr, newhead, &freeformat_count);
532
533 JUMP_CONCLUSION(ret); /* That only continues for ret == PARSE_BAD or PARSE_GOOD. */
534 if(ret == PARSE_BAD)
535 { /* Header was not good. */
536 ret = wetwork(fr, &newhead); /* Messy stuff, handle junk, resync ... */
537 JUMP_CONCLUSION(ret);
538 /* Normally, we jumped already. If for some reason everything's fine to continue, do continue. */
539 if(ret != PARSE_GOOD) goto read_frame_bad;
540 }
541
542 if(!fr->firsthead)
543 {
544 ret = do_readahead(fr, newhead);
545 /* readahead can fail mit NEED_MORE, in which case we must also make the just read header available again for next go */
546 if(ret < 0) fr->rd->back_bytes(fr, 4);
547 JUMP_CONCLUSION(ret);
548 }
549
550 /* Now we should have our valid header and proceed to reading the frame. */
551
552 /* if filepos is invalid, so is framepos */
553 framepos = fr->rd->tell(fr) - 4;
554 /* flip/init buffer for Layer 3 */
555 {
556 unsigned char *newbuf = fr->bsspace[fr->bsnum]+512;
557 /* read main data into memory */
558 if((ret=fr->rd->read_frame_body(fr,newbuf,fr->framesize))<0)
559 {
560 /* if failed: flip back */
561 debug("need more?");
562 goto read_frame_bad;
563 }
564 fr->bsbufold = fr->bsbuf;
565 fr->bsbuf = newbuf;
566 }
567 fr->bsnum = (fr->bsnum + 1) & 1;
568
569 if(!fr->firsthead)
570 {
571 fr->firsthead = newhead; /* _now_ it's time to store it... the first real header */
572 /* This is the first header of our current stream segment.
573 It is only the actual first header of the whole stream when fr->num is still below zero!
574 Think of resyncs where firsthead has been reset for format flexibility. */
575 if(fr->num < 0)
576 {
577 fr->audio_start = framepos;
578 /* Only check for LAME tag at beginning of whole stream
579 ... when there indeed is one in between, it's the user's problem. */
580 if(fr->lay == 3 && check_lame_tag(fr) == 1)
581 { /* ...in practice, Xing/LAME tags are layer 3 only. */
582 if(fr->rd->forget != NULL) fr->rd->forget(fr);
583
584 fr->oldhead = 0;
585 goto read_again;
586 }
587 /* now adjust volume */
588 do_rva(fr);
589 }
590
591 debug2("fr->firsthead: %08lx, audio_start: %li", fr->firsthead, (long int)fr->audio_start);
592 }
593
594 fr->bitindex = 0;
595 fr->wordpointer = (unsigned char *) fr->bsbuf;
596 /* Question: How bad does the floating point value get with repeated recomputation?
597 Also, considering that we can play the file or parts of many times. */
598 if(++fr->mean_frames != 0)
599 {
600 fr->mean_framesize = ((fr->mean_frames-1)*fr->mean_framesize+compute_bpf(fr)) / fr->mean_frames ;
601 }
602 ++fr->num; /* 0 for first frame! */
603 debug4("Frame %"OFF_P" %08lx %i, next filepos=%"OFF_P,
604 (off_p)fr->num, newhead, fr->framesize, (off_p)fr->rd->tell(fr));
605 if(!(fr->state_flags & FRAME_FRANKENSTEIN) && (
606 (fr->track_frames > 0 && fr->num >= fr->track_frames)
607 #ifdef GAPLESS
608 || (fr->gapless_frames > 0 && fr->num >= fr->gapless_frames)
609 #endif
610 ))
611 {
612 fr->state_flags |= FRAME_FRANKENSTEIN;
613 if(NOQUIET) fprintf(stderr, "\nWarning: Encountered more data after announced end of track (frame %"OFF_P"/%"OFF_P"). Frankenstein!\n", (off_p)fr->num,
614 #ifdef GAPLESS
615 fr->gapless_frames > 0 ? (off_p)fr->gapless_frames :
616 #endif
617 (off_p)fr->track_frames);
618 }
619
620 halfspeed_prepare(fr);
621
622 /* index the position */
623 fr->input_offset = framepos;
624 #ifdef FRAME_INDEX
625 /* Keep track of true frame positions in our frame index.
626 but only do so when we are sure that the frame number is accurate... */
627 if((fr->state_flags & FRAME_ACCURATE) && FI_NEXT(fr->index, fr->num))
628 fi_add(&fr->index, framepos);
629 #endif
630
631 if(fr->silent_resync > 0) --fr->silent_resync;
632
633 if(fr->rd->forget != NULL) fr->rd->forget(fr);
634
635 fr->to_decode = fr->to_ignore = TRUE;
636 if(fr->error_protection) fr->crc = getbits(fr, 16); /* skip crc */
637
638 /*
639 Let's check for header change after deciding that the new one is good
640 and actually having read a frame.
641
642 header_change > 1: decoder structure has to be updated
643 Preserve header_change value from previous runs if it is serious.
644 If we still have a big change pending, it should be dealt with outside,
645 fr->header_change set to zero afterwards.
646 */
647 if(fr->header_change < 2)
648 {
649 fr->header_change = 2; /* output format change is possible... */
650 if(fr->oldhead) /* check a following header for change */
651 {
652 if(fr->oldhead == newhead) fr->header_change = 0;
653 else
654 /* Headers that match in this test behave the same for the outside world.
655 namely: same decoding routines, same amount of decoded data. */
656 if(head_compatible(fr->oldhead, newhead))
657 fr->header_change = 1;
658 else
659 {
660 fr->state_flags |= FRAME_FRANKENSTEIN;
661 if(NOQUIET)
662 fprintf(stderr, "\nWarning: Big change (MPEG version, layer, rate). Frankenstein stream?\n");
663 }
664 }
665 else if(fr->firsthead && !head_compatible(fr->firsthead, newhead))
666 {
667 fr->state_flags |= FRAME_FRANKENSTEIN;
668 if(NOQUIET)
669 fprintf(stderr, "\nWarning: Big change from first (MPEG version, layer, rate). Frankenstein stream?\n");
670 }
671 }
672
673 fr->oldhead = newhead;
674
675 return 1;
676 read_frame_bad:
677 /* Also if we searched for valid data in vein, we can forget skipped data.
678 Otherwise, the feeder would hold every dead old byte in memory until the first valid frame! */
679 if(fr->rd->forget != NULL) fr->rd->forget(fr);
680
681 fr->silent_resync = 0;
682 if(fr->err == MPG123_OK) fr->err = MPG123_ERR_READER;
683 fr->framesize = oldsize;
684 fr->halfphase = oldphase;
685 /* That return code might be inherited from some feeder action, or reader error. */
686 return ret;
687 }
688
689
690 /*
691 * read ahead and find the next MPEG header, to guess framesize
692 * return value: success code
693 * PARSE_GOOD: found a valid frame size (stored in the handle).
694 * <0: error codes, possibly from feeder buffer (NEED_MORE)
695 * PARSE_BAD: cannot get the framesize for some reason and shall silentry try the next possible header (if this is no free format stream after all...)
696 */
697 static int guess_freeformat_framesize(mpg123_handle *fr)
698 {
699 long i;
700 int ret;
701 unsigned long head;
702 if(!(fr->rdat.flags & (READER_SEEKABLE|READER_BUFFERED)))
703 {
704 if(NOQUIET) error("Cannot look for freeformat frame size with non-seekable and non-buffered stream!");
705
706 return PARSE_BAD;
707 }
708 if((ret=fr->rd->head_read(fr,&head))<=0)
709 return ret;
710
711 /* We are already 4 bytes into it */
712 for(i=4;i<MAXFRAMESIZE+4;i++)
713 {
714 if((ret=fr->rd->head_shift(fr,&head))<=0) return ret;
715
716 /* No head_check needed, the mask contains all relevant bits. */
717 if((head & HDR_SAMEMASK) == (fr->oldhead & HDR_SAMEMASK))
718 {
719 fr->rd->back_bytes(fr,i+1);
720 fr->framesize = i-3;
721 return PARSE_GOOD; /* Success! */
722 }
723 }
724 fr->rd->back_bytes(fr,i);
725 return PARSE_BAD;
726 }
727
728
729 /*
730 * decode a header and write the information
731 * into the frame structure
732 * Return values are compatible with those of read_frame, namely:
733 * 1: success
734 * 0: no valid header
735 * <0: some error
736 * You are required to do a head_check() before calling!
737 */
738 static int decode_header(mpg123_handle *fr,unsigned long newhead, int *freeformat_count)
739 {
740 #ifdef DEBUG /* Do not waste cycles checking the header twice all the time. */
741 if(!head_check(newhead))
742 {
743 error1("trying to decode obviously invalid header 0x%08lx", newhead);
744 }
745 #endif
746 /* For some reason, the layer and sampling freq settings used to be wrapped
747 in a weird conditional including MPG123_NO_RESYNC. What was I thinking?
748 This information has to be consistent. */
749 fr->lay = 4 - HDR_LAYER_VAL(newhead);
750
751 if(HDR_VERSION_VAL(newhead) & 0x2)
752 {
753 fr->lsf = (HDR_VERSION_VAL(newhead) & 0x1) ? 0 : 1;
754 fr->mpeg25 = 0;
755 fr->sampling_frequency = HDR_SAMPLERATE_VAL(newhead) + (fr->lsf*3);
756 }
757 else
758 {
759 fr->lsf = 1;
760 fr->mpeg25 = 1;
761 fr->sampling_frequency = 6 + HDR_SAMPLERATE_VAL(newhead);
762 }
763
764 #ifdef DEBUG
765 /* seen a file where this varies (old lame tag without crc, track with crc) */
766 if((HDR_CRC_VAL(newhead)^0x1) != fr->error_protection) debug("changed crc bit!");
767 #endif
768 fr->error_protection = HDR_CRC_VAL(newhead)^0x1;
769 fr->bitrate_index = HDR_BITRATE_VAL(newhead);
770 fr->padding = HDR_PADDING_VAL(newhead);
771 fr->extension = HDR_PRIVATE_VAL(newhead);
772 fr->mode = HDR_CHANNEL_VAL(newhead);
773 fr->mode_ext = HDR_CHANEX_VAL(newhead);
774 fr->copyright = HDR_COPYRIGHT_VAL(newhead);
775 fr->original = HDR_ORIGINAL_VAL(newhead);
776 fr->emphasis = HDR_EMPHASIS_VAL(newhead);
777 fr->freeformat = !(newhead & HDR_BITRATE);
778
779 fr->stereo = (fr->mode == MPG_MD_MONO) ? 1 : 2;
780
781 /* we can't use tabsel_123 for freeformat, so trying to guess framesize... */
782 if(fr->freeformat)
783 {
784 /* when we first encounter the frame with freeformat, guess framesize */
785 if(fr->freeformat_framesize < 0)
786 {
787 int ret;
788 *freeformat_count += 1;
789 if(*freeformat_count > 5)
790 {
791 if(VERBOSE3) error("You fooled me too often. Refusing to guess free format frame size _again_.");
792 return PARSE_BAD;
793 }
794 ret = guess_freeformat_framesize(fr);
795 if(ret == PARSE_GOOD)
796 {
797 fr->freeformat_framesize = fr->framesize - fr->padding;
798 if(VERBOSE2)
799 fprintf(stderr, "Note: free format frame size %li\n", fr->freeformat_framesize);
800 }
801 else
802 {
803 if(ret == MPG123_NEED_MORE)
804 debug("Need more data to guess free format frame size.");
805 else if(VERBOSE3)
806 error("Encountered free format header, but failed to guess frame size.");
807
808 return ret;
809 }
810 }
811 /* freeformat should be CBR, so the same framesize can be used at the 2nd reading or later */
812 else
813 {
814 fr->framesize = fr->freeformat_framesize + fr->padding;
815 }
816 }
817
818 switch(fr->lay)
819 {
820 #ifndef NO_LAYER1
821 case 1:
822 fr->spf = 384;
823 fr->do_layer = do_layer1;
824 if(!fr->freeformat)
825 {
826 fr->framesize = (long) tabsel_123[fr->lsf][0][fr->bitrate_index] * 12000;
827 fr->framesize /= freqs[fr->sampling_frequency];
828 fr->framesize = ((fr->framesize+fr->padding)<<2)-4;
829 }
830 break;
831 #endif
832 #ifndef NO_LAYER2
833 case 2:
834 fr->spf = 1152;
835 fr->do_layer = do_layer2;
836 if(!fr->freeformat)
837 {
838 debug2("bitrate index: %i (%i)", fr->bitrate_index, tabsel_123[fr->lsf][1][fr->bitrate_index] );
839 fr->framesize = (long) tabsel_123[fr->lsf][1][fr->bitrate_index] * 144000;
840 fr->framesize /= freqs[fr->sampling_frequency];
841 fr->framesize += fr->padding - 4;
842 }
843 break;
844 #endif
845 #ifndef NO_LAYER3
846 case 3:
847 fr->spf = fr->lsf ? 576 : 1152; /* MPEG 2.5 implies LSF.*/
848 fr->do_layer = do_layer3;
849 if(fr->lsf)
850 fr->ssize = (fr->stereo == 1) ? 9 : 17;
851 else
852 fr->ssize = (fr->stereo == 1) ? 17 : 32;
853
854 if(fr->error_protection)
855 fr->ssize += 2;
856
857 if(!fr->freeformat)
858 {
859 fr->framesize = (long) tabsel_123[fr->lsf][2][fr->bitrate_index] * 144000;
860 fr->framesize /= freqs[fr->sampling_frequency]<<(fr->lsf);
861 fr->framesize = fr->framesize + fr->padding - 4;
862 }
863 break;
864 #endif
865 default:
866 if(NOQUIET) error1("Layer type %i not supported in this build!", fr->lay);
867
868 return PARSE_BAD;
869 }
870 if (fr->framesize > MAXFRAMESIZE)
871 {
872 if(NOQUIET) error1("Frame size too big: %d", fr->framesize+4-fr->padding);
873
874 return PARSE_BAD;
875 }
876 return PARSE_GOOD;
877 }
878
879 void set_pointer(mpg123_handle *fr, long backstep)
880 {
881 fr->wordpointer = fr->bsbuf + fr->ssize - backstep;
882 if (backstep)
883 memcpy(fr->wordpointer,fr->bsbufold+fr->fsizeold-backstep,backstep);
884
885 fr->bitindex = 0;
886 }
887
888 /********************************/
889
890 double compute_bpf(mpg123_handle *fr)
891 {
892 double bpf;
893
894 switch(fr->lay)
895 {
896 case 1:
897 bpf = tabsel_123[fr->lsf][0][fr->bitrate_index];
898 bpf *= 12000.0 * 4.0;
899 bpf /= freqs[fr->sampling_frequency] <<(fr->lsf);
900 break;
901 case 2:
902 case 3:
903 bpf = tabsel_123[fr->lsf][fr->lay-1][fr->bitrate_index];
904 bpf *= 144000;
905 bpf /= freqs[fr->sampling_frequency] << (fr->lsf);
906 break;
907 default:
908 bpf = 1.0;
909 }
910
911 return bpf;
912 }
913
914 int attribute_align_arg mpg123_spf(mpg123_handle *mh)
915 {
916 if(mh == NULL) return MPG123_ERR;
917
918 return mh->firsthead ? mh->spf : MPG123_ERR;
919 }
920
921 double attribute_align_arg mpg123_tpf(mpg123_handle *fr)
922 {
923 static int bs[4] = { 0,384,1152,1152 };
924 double tpf;
925 if(fr == NULL || !fr->firsthead) return MPG123_ERR;
926
927 tpf = (double) bs[fr->lay];
928 tpf /= freqs[fr->sampling_frequency] << (fr->lsf);
929 return tpf;
930 }
931
932 int attribute_align_arg mpg123_position(mpg123_handle *fr, off_t no, off_t buffsize,
933 off_t *current_frame, off_t *frames_left,
934 double *current_seconds, double *seconds_left)
935 {
936 double tpf;
937 double dt = 0.0;
938 off_t cur, left;
939 double curs, lefts;
940
941 if(!fr || !fr->rd) return MPG123_ERR;
942
943 no += fr->num; /* no starts out as offset */
944 cur = no;
945 tpf = mpg123_tpf(fr);
946 if(buffsize > 0 && fr->af.rate > 0 && fr->af.channels > 0)
947 {
948 dt = (double) buffsize / fr->af.rate / fr->af.channels;
949 if(fr->af.encoding & MPG123_ENC_16) dt *= 0.5;
950 }
951
952 left = 0;
953
954 if((fr->track_frames != 0) && (fr->track_frames >= fr->num)) left = no < fr->track_frames ? fr->track_frames - no : 0;
955 else
956 if(fr->rdat.filelen >= 0)
957 {
958 double bpf;
959 off_t t = fr->rd->tell(fr);
960 bpf = fr->mean_framesize ? fr->mean_framesize : compute_bpf(fr);
961 left = (off_t)((double)(fr->rdat.filelen-t)/bpf);
962 /* no can be different for prophetic purposes, file pointer is always associated with fr->num! */
963 if(fr->num != no)
964 {
965 if(fr->num > no) left += fr->num - no;
966 else
967 {
968 if(left >= (no - fr->num)) left -= no - fr->num;
969 else left = 0; /* uh, oh! */
970 }
971 }
972 /* I totally don't understand why we should re-estimate the given correct(?) value */
973 /* fr->num = (unsigned long)((double)t/bpf); */
974 }
975
976 /* beginning with 0 or 1?*/
977 curs = (double) no*tpf-dt;
978 lefts = (double)left*tpf+dt;
979 #if 0
980 curs = curs < 0 ? 0.0 : curs;
981 #endif
982 if(left < 0 || lefts < 0)
983 { /* That is the case for non-seekable streams. */
984 left = 0;
985 lefts = 0.0;
986 }
987 if(current_frame != NULL) *current_frame = cur;
988 if(frames_left != NULL) *frames_left = left;
989 if(current_seconds != NULL) *current_seconds = curs;
990 if(seconds_left != NULL) *seconds_left = lefts;
991 return MPG123_OK;
992 }
993
994 int get_songlen(mpg123_handle *fr,int no)
995 {
996 double tpf;
997
998 if(!fr)
999 return 0;
1000
1001 if(no < 0) {
1002 if(!fr->rd || fr->rdat.filelen < 0)
1003 return 0;
1004 no = (int) ((double) fr->rdat.filelen / compute_bpf(fr));
1005 }
1006
1007 tpf = mpg123_tpf(fr);
1008 return (int) (no*tpf);
1009 }
1010
1011 /* first attempt of read ahead check to find the real first header; cannot believe what junk is out there! */
1012 static int do_readahead(mpg123_handle *fr, unsigned long newhead)
1013 {
1014 unsigned long nexthead = 0;
1015 int hd = 0;
1016 off_t start, oret;
1017 int ret;
1018
1019 if( ! (!fr->firsthead && fr->rdat.flags & (READER_SEEKABLE|READER_BUFFERED)) )
1020 return PARSE_GOOD;
1021
1022 start = fr->rd->tell(fr);
1023
1024 debug2("doing ahead check with BPF %d at %"OFF_P, fr->framesize+4, (off_p)start);
1025 /* step framesize bytes forward and read next possible header*/
1026 if((oret=fr->rd->skip_bytes(fr, fr->framesize))<0)
1027 {
1028 if(oret==READER_ERROR && NOQUIET) error("cannot seek!");
1029
1030 return oret == MPG123_NEED_MORE ? PARSE_MORE : PARSE_ERR;
1031 }
1032
1033 /* Read header, seek back. */
1034 hd = fr->rd->head_read(fr,&nexthead);
1035 if( fr->rd->back_bytes(fr, fr->rd->tell(fr)-start) < 0 )
1036 {
1037 if(NOQUIET) error("Cannot seek back!");
1038
1039 return PARSE_ERR;
1040 }
1041 if(hd == MPG123_NEED_MORE) return PARSE_MORE;
1042
1043 debug1("After fetching next header, at %"OFF_P, (off_p)fr->rd->tell(fr));
1044 if(!hd)
1045 {
1046 if(NOQUIET) warning("Cannot read next header, a one-frame stream? Duh...");
1047 return PARSE_END;
1048 }
1049
1050 debug2("does next header 0x%08lx match first 0x%08lx?", nexthead, newhead);
1051 if(!head_check(nexthead) || !head_compatible(newhead, nexthead))
1052 {
1053 debug("No, the header was not valid, start from beginning...");
1054 fr->oldhead = 0; /* start over */
1055 /* try next byte for valid header */
1056 if((ret=fr->rd->back_bytes(fr, 3))<0)
1057 {
1058 if(NOQUIET) error("Cannot seek 3 bytes back!");
1059
1060 return PARSE_ERR;
1061 }
1062 return PARSE_AGAIN;
1063 }
1064 else return PARSE_GOOD;
1065 }
1066
1067 static int handle_id3v2(mpg123_handle *fr, unsigned long newhead)
1068 {
1069 int ret;
1070 fr->oldhead = 0; /* Think about that. Used to be present only for skipping of junk, not resync-style wetwork. */
1071 ret = parse_new_id3(fr, newhead);
1072 if (ret < 0) return ret;
1073 #ifndef NO_ID3V2
1074 else if(ret > 0){ debug("got ID3v2"); fr->metaflags |= MPG123_NEW_ID3|MPG123_ID3; }
1075 else debug("no useful ID3v2");
1076 #endif
1077 return PARSE_AGAIN;
1078 }
1079
1080 /* Advance a byte in stream to get next possible header and forget
1081 buffered data if possible (for feed reader). */
1082 #define FORGET_INTERVAL 1024 /* Used by callers to set forget flag each <n> bytes. */
1083 static int forget_head_shift(mpg123_handle *fr, unsigned long *newheadp, int forget)
1084 {
1085 int ret;
1086 if((ret=fr->rd->head_shift(fr,newheadp))<=0) return ret;
1087 /* Try to forget buffered data as early as possible to speed up parsing where
1088 new data needs to be added for resync (and things would be re-parsed again
1089 and again because of the start from beginning after hitting end). */
1090 if(forget && fr->rd->forget != NULL)
1091 {
1092 /* Ensure that the last 4 bytes stay in buffers for reading the header
1093 anew. */
1094 if(!fr->rd->back_bytes(fr, 4))
1095 {
1096 fr->rd->forget(fr);
1097 fr->rd->back_bytes(fr, -4);
1098 }
1099 }
1100 return ret; /* No surprise here, error already triggered early return. */
1101 }
1102
1103 /* watch out for junk/tags on beginning of stream by invalid header */
1104 static int skip_junk(mpg123_handle *fr, unsigned long *newheadp, long *headcount)
1105 {
1106 int ret;
1107 int freeformat_count = 0;
1108 long limit = 65536;
1109 unsigned long newhead = *newheadp;
1110 unsigned int forgetcount = 0;
1111 /* check for id3v2; first three bytes (of 4) are "ID3" */
1112 if((newhead & (unsigned long) 0xffffff00) == (unsigned long) 0x49443300)
1113 {
1114 return handle_id3v2(fr, newhead);
1115 }
1116 else if(VERBOSE2 && fr->silent_resync == 0) fprintf(stderr,"Note: Junk at the beginning (0x%08lx)\n",newhead);
1117
1118 /* I even saw RIFF headers at the beginning of MPEG streams ;( */
1119 if(newhead == ('R'<<24)+('I'<<16)+('F'<<8)+'F')
1120 {
1121 if(VERBOSE2 && fr->silent_resync == 0) fprintf(stderr, "Note: Looks like a RIFF header.\n");
1122
1123 if((ret=fr->rd->head_read(fr,&newhead))<=0) return ret;
1124
1125 while(newhead != ('d'<<24)+('a'<<16)+('t'<<8)+'a')
1126 {
1127 if(++forgetcount > FORGET_INTERVAL) forgetcount = 0;
1128 if((ret=forget_head_shift(fr,&newhead,!forgetcount))<=0) return ret;
1129 }
1130 if((ret=fr->rd->head_read(fr,&newhead))<=0) return ret;
1131
1132 if(VERBOSE2 && fr->silent_resync == 0) fprintf(stderr,"Note: Skipped RIFF header!\n");
1133
1134 fr->oldhead = 0;
1135 *newheadp = newhead;
1136 return PARSE_AGAIN;
1137 }
1138
1139 /*
1140 Unhandled junk... just continue search for a header, stepping in single bytes through next 64K.
1141 This is rather identical to the resync loop.
1142 */
1143 debug("searching for header...");
1144 *newheadp = 0; /* Invalidate the external value. */
1145 ret = 0; /* We will check the value after the loop. */
1146
1147 /* We prepare for at least the 64K bytes as usual, unless
1148 user explicitly wanted more (even infinity). Never less. */
1149 if(fr->p.resync_limit < 0 || fr->p.resync_limit > limit)
1150 limit = fr->p.resync_limit;
1151
1152 do
1153 {
1154 ++(*headcount);
1155 if(limit >= 0 && *headcount >= limit) break;
1156
1157 if(++forgetcount > FORGET_INTERVAL) forgetcount = 0;
1158 if((ret=forget_head_shift(fr, &newhead, !forgetcount))<=0) return ret;
1159
1160 if(head_check(newhead) && (ret=decode_header(fr, newhead, &freeformat_count))) break;
1161 } while(1);
1162 if(ret<0) return ret;
1163
1164 if(limit >= 0 && *headcount >= limit)
1165 {
1166 if(NOQUIET) error1("Giving up searching valid MPEG header after %li bytes of junk.", *headcount);
1167 return PARSE_END;
1168 }
1169 else debug1("hopefully found one at %"OFF_P, (off_p)fr->rd->tell(fr));
1170
1171 /* If the new header ist good, it is already decoded. */
1172 *newheadp = newhead;
1173 return PARSE_GOOD;
1174 }
1175
1176 /* The newhead is bad, so let's check if it is something special, otherwise just resync. */
1177 static int wetwork(mpg123_handle *fr, unsigned long *newheadp)
1178 {
1179 int ret = PARSE_ERR;
1180 unsigned long newhead = *newheadp;
1181 *newheadp = 0;
1182
1183 /* Classic ID3 tags. Read, then start parsing again. */
1184 if((newhead & 0xffffff00) == ('T'<<24)+('A'<<16)+('G'<<8))
1185 {
1186 fr->id3buf[0] = (unsigned char) ((newhead >> 24) & 0xff);
1187 fr->id3buf[1] = (unsigned char) ((newhead >> 16) & 0xff);
1188 fr->id3buf[2] = (unsigned char) ((newhead >> 8) & 0xff);
1189 fr->id3buf[3] = (unsigned char) ( newhead & 0xff);
1190
1191 if((ret=fr->rd->fullread(fr,fr->id3buf+4,124)) < 0) return ret;
1192
1193 fr->metaflags |= MPG123_NEW_ID3|MPG123_ID3;
1194 fr->rdat.flags |= READER_ID3TAG; /* that marks id3v1 */
1195 if(VERBOSE3) fprintf(stderr,"Note: Skipped ID3v1 tag.\n");
1196
1197 return PARSE_AGAIN;
1198 }
1199 /* This is similar to initial junk skipping code... */
1200 /* Check for id3v2; first three bytes (of 4) are "ID3" */
1201 if((newhead & (unsigned long) 0xffffff00) == (unsigned long) 0x49443300)
1202 {
1203 return handle_id3v2(fr, newhead);
1204 }
1205 else if(NOQUIET && fr->silent_resync == 0)
1206 {
1207 fprintf(stderr,"Note: Illegal Audio-MPEG-Header 0x%08lx at offset %"OFF_P".\n",
1208 newhead, (off_p)fr->rd->tell(fr)-4);
1209 }
1210
1211 /* Now we got something bad at hand, try to recover. */
1212
1213 if(NOQUIET && (newhead & 0xffffff00) == ('b'<<24)+('m'<<16)+('p'<<8)) fprintf(stderr,"Note: Could be a BMP album art.\n");
1214
1215 if( !(fr->p.flags & MPG123_NO_RESYNC) )
1216 {
1217 long try = 0;
1218 long limit = fr->p.resync_limit;
1219 unsigned int forgetcount = 0;
1220
1221 /* If a resync is needed the bitreservoir of previous frames is no longer valid */
1222 fr->bitreservoir = 0;
1223
1224 if(NOQUIET && fr->silent_resync == 0) fprintf(stderr, "Note: Trying to resync...\n");
1225
1226 do /* ... shift the header with additional single bytes until be found something that could be a header. */
1227 {
1228 ++try;
1229 if(limit >= 0 && try >= limit) break;
1230
1231 if(++forgetcount > FORGET_INTERVAL) forgetcount = 0;
1232 if((ret=forget_head_shift(fr,&newhead,!forgetcount)) <= 0)
1233 {
1234 *newheadp = newhead;
1235 if(NOQUIET) fprintf (stderr, "Note: Hit end of (available) data during resync.\n");
1236
1237 return ret ? ret : PARSE_END;
1238 }
1239 if(VERBOSE3) debug3("resync try %li at %"OFF_P", got newhead 0x%08lx", try, (off_p)fr->rd->tell(fr), newhead);
1240 } while(!head_check(newhead));
1241
1242 *newheadp = newhead;
1243 if(NOQUIET && fr->silent_resync == 0) fprintf (stderr, "Note: Skipped %li bytes in input.\n", try);
1244
1245 /* Now we either got something that could be a header, or we gave up. */
1246 if(limit >= 0 && try >= limit)
1247 {
1248 if(NOQUIET)
1249 error1("Giving up resync after %li bytes - your stream is not nice... (maybe increasing resync limit could help).", try);
1250
1251 fr->err = MPG123_RESYNC_FAIL;
1252 return PARSE_ERR;
1253 }
1254 else
1255 {
1256 debug1("Found possibly valid header 0x%lx... unsetting oldhead to reinit stream.", newhead);
1257 fr->oldhead = 0;
1258 return PARSE_RESYNC;
1259 }
1260 }
1261 else
1262 {
1263 if(NOQUIET) error("not attempting to resync...");
1264
1265 fr->err = MPG123_OUT_OF_SYNC;
1266 return PARSE_ERR;
1267 }
1268 /* Control never goes here... we return before that. */
1269 }