[LIBMPG123] Update to version 1.25.13. CORE-16550
[reactos.git] / sdk / 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) ? -0.1f : 0.1f;
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 /* From now on, old frame data is tainted by parsing attempts. */
513 fr->to_decode = fr->to_ignore = FALSE;
514 read_again:
515 /* In case we are looping to find a valid frame, discard any buffered data before the current position.
516 This is essential to prevent endless looping, always going back to the beginning when feeder buffer is exhausted. */
517 if(fr->rd->forget != NULL) fr->rd->forget(fr);
518
519 debug2("trying to get frame %"OFF_P" at %"OFF_P, (off_p)fr->num+1, (off_p)fr->rd->tell(fr));
520 if((ret = fr->rd->head_read(fr,&newhead)) <= 0){ debug1("need more? (%i)", ret); goto read_frame_bad;}
521
522 init_resync:
523
524 #ifdef SKIP_JUNK
525 if(!fr->firsthead && !head_check(newhead))
526 {
527 ret = skip_junk(fr, &newhead, &headcount);
528 JUMP_CONCLUSION(ret);
529 }
530 #endif
531
532 ret = head_check(newhead);
533 if(ret) ret = decode_header(fr, newhead, &freeformat_count);
534
535 JUMP_CONCLUSION(ret); /* That only continues for ret == PARSE_BAD or PARSE_GOOD. */
536 if(ret == PARSE_BAD)
537 { /* Header was not good. */
538 ret = wetwork(fr, &newhead); /* Messy stuff, handle junk, resync ... */
539 JUMP_CONCLUSION(ret);
540 /* Normally, we jumped already. If for some reason everything's fine to continue, do continue. */
541 if(ret != PARSE_GOOD) goto read_frame_bad;
542 }
543
544 if(!fr->firsthead)
545 {
546 ret = do_readahead(fr, newhead);
547 /* readahead can fail mit NEED_MORE, in which case we must also make the just read header available again for next go */
548 if(ret < 0) fr->rd->back_bytes(fr, 4);
549 JUMP_CONCLUSION(ret);
550 }
551
552 /* Now we should have our valid header and proceed to reading the frame. */
553
554 /* if filepos is invalid, so is framepos */
555 framepos = fr->rd->tell(fr) - 4;
556 /* flip/init buffer for Layer 3 */
557 {
558 unsigned char *newbuf = fr->bsspace[fr->bsnum]+512;
559 /* read main data into memory */
560 if((ret=fr->rd->read_frame_body(fr,newbuf,fr->framesize))<0)
561 {
562 /* if failed: flip back */
563 debug("need more?");
564 goto read_frame_bad;
565 }
566 fr->bsbufold = fr->bsbuf;
567 fr->bsbuf = newbuf;
568 }
569 fr->bsnum = (fr->bsnum + 1) & 1;
570
571 if(!fr->firsthead)
572 {
573 fr->firsthead = newhead; /* _now_ it's time to store it... the first real header */
574 /* This is the first header of our current stream segment.
575 It is only the actual first header of the whole stream when fr->num is still below zero!
576 Think of resyncs where firsthead has been reset for format flexibility. */
577 if(fr->num < 0)
578 {
579 fr->audio_start = framepos;
580 /* Only check for LAME tag at beginning of whole stream
581 ... when there indeed is one in between, it's the user's problem. */
582 if(fr->lay == 3 && check_lame_tag(fr) == 1)
583 { /* ...in practice, Xing/LAME tags are layer 3 only. */
584 if(fr->rd->forget != NULL) fr->rd->forget(fr);
585
586 fr->oldhead = 0;
587 goto read_again;
588 }
589 /* now adjust volume */
590 do_rva(fr);
591 }
592
593 debug2("fr->firsthead: %08lx, audio_start: %li", fr->firsthead, (long int)fr->audio_start);
594 }
595
596 fr->bitindex = 0;
597 fr->wordpointer = (unsigned char *) fr->bsbuf;
598 /* Question: How bad does the floating point value get with repeated recomputation?
599 Also, considering that we can play the file or parts of many times. */
600 if(++fr->mean_frames != 0)
601 {
602 fr->mean_framesize = ((fr->mean_frames-1)*fr->mean_framesize+compute_bpf(fr)) / fr->mean_frames ;
603 }
604 ++fr->num; /* 0 for first frame! */
605 debug4("Frame %"OFF_P" %08lx %i, next filepos=%"OFF_P,
606 (off_p)fr->num, newhead, fr->framesize, (off_p)fr->rd->tell(fr));
607 if(!(fr->state_flags & FRAME_FRANKENSTEIN) && (
608 (fr->track_frames > 0 && fr->num >= fr->track_frames)
609 #ifdef GAPLESS
610 || (fr->gapless_frames > 0 && fr->num >= fr->gapless_frames)
611 #endif
612 ))
613 {
614 fr->state_flags |= FRAME_FRANKENSTEIN;
615 if(NOQUIET) fprintf(stderr, "\nWarning: Encountered more data after announced end of track (frame %"OFF_P"/%"OFF_P"). Frankenstein!\n", (off_p)fr->num,
616 #ifdef GAPLESS
617 fr->gapless_frames > 0 ? (off_p)fr->gapless_frames :
618 #endif
619 (off_p)fr->track_frames);
620 }
621
622 halfspeed_prepare(fr);
623
624 /* index the position */
625 fr->input_offset = framepos;
626 #ifdef FRAME_INDEX
627 /* Keep track of true frame positions in our frame index.
628 but only do so when we are sure that the frame number is accurate... */
629 if((fr->state_flags & FRAME_ACCURATE) && FI_NEXT(fr->index, fr->num))
630 fi_add(&fr->index, framepos);
631 #endif
632
633 if(fr->silent_resync > 0) --fr->silent_resync;
634
635 if(fr->rd->forget != NULL) fr->rd->forget(fr);
636
637 fr->to_decode = fr->to_ignore = TRUE;
638 if(fr->error_protection) fr->crc = getbits(fr, 16); /* skip crc */
639
640 /*
641 Let's check for header change after deciding that the new one is good
642 and actually having read a frame.
643
644 header_change > 1: decoder structure has to be updated
645 Preserve header_change value from previous runs if it is serious.
646 If we still have a big change pending, it should be dealt with outside,
647 fr->header_change set to zero afterwards.
648 */
649 if(fr->header_change < 2)
650 {
651 fr->header_change = 2; /* output format change is possible... */
652 if(fr->oldhead) /* check a following header for change */
653 {
654 if(fr->oldhead == newhead) fr->header_change = 0;
655 else
656 /* Headers that match in this test behave the same for the outside world.
657 namely: same decoding routines, same amount of decoded data. */
658 if(head_compatible(fr->oldhead, newhead))
659 fr->header_change = 1;
660 else
661 {
662 fr->state_flags |= FRAME_FRANKENSTEIN;
663 if(NOQUIET)
664 fprintf(stderr, "\nWarning: Big change (MPEG version, layer, rate). Frankenstein stream?\n");
665 }
666 }
667 else if(fr->firsthead && !head_compatible(fr->firsthead, newhead))
668 {
669 fr->state_flags |= FRAME_FRANKENSTEIN;
670 if(NOQUIET)
671 fprintf(stderr, "\nWarning: Big change from first (MPEG version, layer, rate). Frankenstein stream?\n");
672 }
673 }
674
675 fr->oldhead = newhead;
676
677 return 1;
678 read_frame_bad:
679 /* Also if we searched for valid data in vein, we can forget skipped data.
680 Otherwise, the feeder would hold every dead old byte in memory until the first valid frame! */
681 if(fr->rd->forget != NULL) fr->rd->forget(fr);
682
683 fr->silent_resync = 0;
684 if(fr->err == MPG123_OK) fr->err = MPG123_ERR_READER;
685 fr->framesize = oldsize;
686 fr->halfphase = oldphase;
687 /* That return code might be inherited from some feeder action, or reader error. */
688 return ret;
689 }
690
691
692 /*
693 * read ahead and find the next MPEG header, to guess framesize
694 * return value: success code
695 * PARSE_GOOD: found a valid frame size (stored in the handle).
696 * <0: error codes, possibly from feeder buffer (NEED_MORE)
697 * 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...)
698 */
699 static int guess_freeformat_framesize(mpg123_handle *fr, unsigned long oldhead)
700 {
701 long i;
702 int ret;
703 unsigned long head;
704 if(!(fr->rdat.flags & (READER_SEEKABLE|READER_BUFFERED)))
705 {
706 if(NOQUIET) error("Cannot look for freeformat frame size with non-seekable and non-buffered stream!");
707
708 return PARSE_BAD;
709 }
710 if((ret=fr->rd->head_read(fr,&head))<=0)
711 return ret;
712
713 /* We are already 4 bytes into it */
714 for(i=4;i<MAXFRAMESIZE+4;i++)
715 {
716 if((ret=fr->rd->head_shift(fr,&head))<=0) return ret;
717
718 /* No head_check needed, the mask contains all relevant bits. */
719 if((head & HDR_SAMEMASK) == (oldhead & HDR_SAMEMASK))
720 {
721 fr->rd->back_bytes(fr,i+1);
722 fr->framesize = i-3;
723 return PARSE_GOOD; /* Success! */
724 }
725 }
726 fr->rd->back_bytes(fr,i);
727 return PARSE_BAD;
728 }
729
730
731 /*
732 * decode a header and write the information
733 * into the frame structure
734 * Return values are compatible with those of read_frame, namely:
735 * 1: success
736 * 0: no valid header
737 * <0: some error
738 * You are required to do a head_check() before calling!
739 */
740 static int decode_header(mpg123_handle *fr,unsigned long newhead, int *freeformat_count)
741 {
742 #ifdef DEBUG /* Do not waste cycles checking the header twice all the time. */
743 if(!head_check(newhead))
744 {
745 error1("trying to decode obviously invalid header 0x%08lx", newhead);
746 }
747 #endif
748 /* For some reason, the layer and sampling freq settings used to be wrapped
749 in a weird conditional including MPG123_NO_RESYNC. What was I thinking?
750 This information has to be consistent. */
751 fr->lay = 4 - HDR_LAYER_VAL(newhead);
752
753 if(HDR_VERSION_VAL(newhead) & 0x2)
754 {
755 fr->lsf = (HDR_VERSION_VAL(newhead) & 0x1) ? 0 : 1;
756 fr->mpeg25 = 0;
757 fr->sampling_frequency = HDR_SAMPLERATE_VAL(newhead) + (fr->lsf*3);
758 }
759 else
760 {
761 fr->lsf = 1;
762 fr->mpeg25 = 1;
763 fr->sampling_frequency = 6 + HDR_SAMPLERATE_VAL(newhead);
764 }
765
766 #ifdef DEBUG
767 /* seen a file where this varies (old lame tag without crc, track with crc) */
768 if((HDR_CRC_VAL(newhead)^0x1) != fr->error_protection) debug("changed crc bit!");
769 #endif
770 fr->error_protection = HDR_CRC_VAL(newhead)^0x1;
771 fr->bitrate_index = HDR_BITRATE_VAL(newhead);
772 fr->padding = HDR_PADDING_VAL(newhead);
773 fr->extension = HDR_PRIVATE_VAL(newhead);
774 fr->mode = HDR_CHANNEL_VAL(newhead);
775 fr->mode_ext = HDR_CHANEX_VAL(newhead);
776 fr->copyright = HDR_COPYRIGHT_VAL(newhead);
777 fr->original = HDR_ORIGINAL_VAL(newhead);
778 fr->emphasis = HDR_EMPHASIS_VAL(newhead);
779 fr->freeformat = !(newhead & HDR_BITRATE);
780
781 fr->stereo = (fr->mode == MPG_MD_MONO) ? 1 : 2;
782
783 /* we can't use tabsel_123 for freeformat, so trying to guess framesize... */
784 if(fr->freeformat)
785 {
786 /* when we first encounter the frame with freeformat, guess framesize */
787 if(fr->freeformat_framesize < 0)
788 {
789 int ret;
790 *freeformat_count += 1;
791 if(*freeformat_count > 5)
792 {
793 if(VERBOSE3) error("You fooled me too often. Refusing to guess free format frame size _again_.");
794 return PARSE_BAD;
795 }
796 ret = guess_freeformat_framesize(fr, newhead);
797 if(ret == PARSE_GOOD)
798 {
799 fr->freeformat_framesize = fr->framesize - fr->padding;
800 if(VERBOSE2)
801 fprintf(stderr, "Note: free format frame size %li\n", fr->freeformat_framesize);
802 }
803 else
804 {
805 if(ret == MPG123_NEED_MORE)
806 debug("Need more data to guess free format frame size.");
807 else if(VERBOSE3)
808 error("Encountered free format header, but failed to guess frame size.");
809
810 return ret;
811 }
812 }
813 /* freeformat should be CBR, so the same framesize can be used at the 2nd reading or later */
814 else
815 {
816 fr->framesize = fr->freeformat_framesize + fr->padding;
817 }
818 }
819
820 switch(fr->lay)
821 {
822 #ifndef NO_LAYER1
823 case 1:
824 fr->spf = 384;
825 fr->do_layer = do_layer1;
826 if(!fr->freeformat)
827 {
828 fr->framesize = (long) tabsel_123[fr->lsf][0][fr->bitrate_index] * 12000;
829 fr->framesize /= freqs[fr->sampling_frequency];
830 fr->framesize = ((fr->framesize+fr->padding)<<2)-4;
831 }
832 break;
833 #endif
834 #ifndef NO_LAYER2
835 case 2:
836 fr->spf = 1152;
837 fr->do_layer = do_layer2;
838 if(!fr->freeformat)
839 {
840 debug2("bitrate index: %i (%i)", fr->bitrate_index, tabsel_123[fr->lsf][1][fr->bitrate_index] );
841 fr->framesize = (long) tabsel_123[fr->lsf][1][fr->bitrate_index] * 144000;
842 fr->framesize /= freqs[fr->sampling_frequency];
843 fr->framesize += fr->padding - 4;
844 }
845 break;
846 #endif
847 #ifndef NO_LAYER3
848 case 3:
849 fr->spf = fr->lsf ? 576 : 1152; /* MPEG 2.5 implies LSF.*/
850 fr->do_layer = do_layer3;
851 if(fr->lsf)
852 fr->ssize = (fr->stereo == 1) ? 9 : 17;
853 else
854 fr->ssize = (fr->stereo == 1) ? 17 : 32;
855
856 if(fr->error_protection)
857 fr->ssize += 2;
858
859 if(!fr->freeformat)
860 {
861 fr->framesize = (long) tabsel_123[fr->lsf][2][fr->bitrate_index] * 144000;
862 fr->framesize /= freqs[fr->sampling_frequency]<<(fr->lsf);
863 fr->framesize = fr->framesize + fr->padding - 4;
864 }
865 break;
866 #endif
867 default:
868 if(NOQUIET) error1("Layer type %i not supported in this build!", fr->lay);
869
870 return PARSE_BAD;
871 }
872 if (fr->framesize > MAXFRAMESIZE)
873 {
874 if(NOQUIET) error1("Frame size too big: %d", fr->framesize+4-fr->padding);
875
876 return PARSE_BAD;
877 }
878 return PARSE_GOOD;
879 }
880
881 void set_pointer(mpg123_handle *fr, long backstep)
882 {
883 fr->wordpointer = fr->bsbuf + fr->ssize - backstep;
884 if (backstep)
885 memcpy(fr->wordpointer,fr->bsbufold+fr->fsizeold-backstep,backstep);
886
887 fr->bitindex = 0;
888 }
889
890 /********************************/
891
892 double compute_bpf(mpg123_handle *fr)
893 {
894 return (fr->framesize > 0) ? fr->framesize + 4.0 : 1.0;
895 }
896
897 int attribute_align_arg mpg123_spf(mpg123_handle *mh)
898 {
899 if(mh == NULL) return MPG123_ERR;
900
901 return mh->firsthead ? mh->spf : MPG123_ERR;
902 }
903
904 double attribute_align_arg mpg123_tpf(mpg123_handle *fr)
905 {
906 static int bs[4] = { 0,384,1152,1152 };
907 double tpf;
908 if(fr == NULL || !fr->firsthead) return MPG123_ERR;
909
910 tpf = (double) bs[fr->lay];
911 tpf /= freqs[fr->sampling_frequency] << (fr->lsf);
912 return tpf;
913 }
914
915 int attribute_align_arg mpg123_position(mpg123_handle *fr, off_t no, off_t buffsize,
916 off_t *current_frame, off_t *frames_left,
917 double *current_seconds, double *seconds_left)
918 {
919 double tpf;
920 double dt = 0.0;
921 off_t cur, left;
922 double curs, lefts;
923
924 if(!fr || !fr->rd) return MPG123_ERR;
925
926 no += fr->num; /* no starts out as offset */
927 cur = no;
928 tpf = mpg123_tpf(fr);
929 if(buffsize > 0 && fr->af.rate > 0 && fr->af.channels > 0)
930 {
931 dt = (double) buffsize / fr->af.rate / fr->af.channels;
932 if(fr->af.encoding & MPG123_ENC_16) dt *= 0.5;
933 }
934
935 left = 0;
936
937 if((fr->track_frames != 0) && (fr->track_frames >= fr->num)) left = no < fr->track_frames ? fr->track_frames - no : 0;
938 else
939 if(fr->rdat.filelen >= 0)
940 {
941 double bpf;
942 off_t t = fr->rd->tell(fr);
943 bpf = fr->mean_framesize ? fr->mean_framesize : compute_bpf(fr);
944 left = (off_t)((double)(fr->rdat.filelen-t)/bpf);
945 /* no can be different for prophetic purposes, file pointer is always associated with fr->num! */
946 if(fr->num != no)
947 {
948 if(fr->num > no) left += fr->num - no;
949 else
950 {
951 if(left >= (no - fr->num)) left -= no - fr->num;
952 else left = 0; /* uh, oh! */
953 }
954 }
955 /* I totally don't understand why we should re-estimate the given correct(?) value */
956 /* fr->num = (unsigned long)((double)t/bpf); */
957 }
958
959 /* beginning with 0 or 1?*/
960 curs = (double) no*tpf-dt;
961 lefts = (double)left*tpf+dt;
962 #if 0
963 curs = curs < 0 ? 0.0 : curs;
964 #endif
965 if(left < 0 || lefts < 0)
966 { /* That is the case for non-seekable streams. */
967 left = 0;
968 lefts = 0.0;
969 }
970 if(current_frame != NULL) *current_frame = cur;
971 if(frames_left != NULL) *frames_left = left;
972 if(current_seconds != NULL) *current_seconds = curs;
973 if(seconds_left != NULL) *seconds_left = lefts;
974 return MPG123_OK;
975 }
976
977 int get_songlen(mpg123_handle *fr,int no)
978 {
979 double tpf;
980
981 if(!fr)
982 return 0;
983
984 if(no < 0) {
985 if(!fr->rd || fr->rdat.filelen < 0)
986 return 0;
987 no = (int) ((double) fr->rdat.filelen / compute_bpf(fr));
988 }
989
990 tpf = mpg123_tpf(fr);
991 return (int) (no*tpf);
992 }
993
994 /* first attempt of read ahead check to find the real first header; cannot believe what junk is out there! */
995 static int do_readahead(mpg123_handle *fr, unsigned long newhead)
996 {
997 unsigned long nexthead = 0;
998 int hd = 0;
999 off_t start, oret;
1000 int ret;
1001
1002 if( ! (!fr->firsthead && fr->rdat.flags & (READER_SEEKABLE|READER_BUFFERED)) )
1003 return PARSE_GOOD;
1004
1005 start = fr->rd->tell(fr);
1006
1007 debug2("doing ahead check with BPF %d at %"OFF_P, fr->framesize+4, (off_p)start);
1008 /* step framesize bytes forward and read next possible header*/
1009 if((oret=fr->rd->skip_bytes(fr, fr->framesize))<0)
1010 {
1011 if(oret==READER_ERROR && NOQUIET) error("cannot seek!");
1012
1013 return oret == MPG123_NEED_MORE ? PARSE_MORE : PARSE_ERR;
1014 }
1015
1016 /* Read header, seek back. */
1017 hd = fr->rd->head_read(fr,&nexthead);
1018 if( fr->rd->back_bytes(fr, fr->rd->tell(fr)-start) < 0 )
1019 {
1020 if(NOQUIET) error("Cannot seek back!");
1021
1022 return PARSE_ERR;
1023 }
1024 if(hd == MPG123_NEED_MORE) return PARSE_MORE;
1025
1026 debug1("After fetching next header, at %"OFF_P, (off_p)fr->rd->tell(fr));
1027 if(!hd)
1028 {
1029 if(NOQUIET) warning("Cannot read next header, a one-frame stream? Duh...");
1030 return PARSE_END;
1031 }
1032
1033 debug2("does next header 0x%08lx match first 0x%08lx?", nexthead, newhead);
1034 if(!head_check(nexthead) || !head_compatible(newhead, nexthead))
1035 {
1036 debug("No, the header was not valid, start from beginning...");
1037 fr->oldhead = 0; /* start over */
1038 /* try next byte for valid header */
1039 if((ret=fr->rd->back_bytes(fr, 3))<0)
1040 {
1041 if(NOQUIET) error("Cannot seek 3 bytes back!");
1042
1043 return PARSE_ERR;
1044 }
1045 return PARSE_AGAIN;
1046 }
1047 else return PARSE_GOOD;
1048 }
1049
1050 static int handle_id3v2(mpg123_handle *fr, unsigned long newhead)
1051 {
1052 int ret;
1053 fr->oldhead = 0; /* Think about that. Used to be present only for skipping of junk, not resync-style wetwork. */
1054 ret = parse_new_id3(fr, newhead);
1055 if (ret < 0) return ret;
1056 #ifndef NO_ID3V2
1057 else if(ret > 0){ debug("got ID3v2"); fr->metaflags |= MPG123_NEW_ID3|MPG123_ID3; }
1058 else debug("no useful ID3v2");
1059 #endif
1060 return PARSE_AGAIN;
1061 }
1062
1063 static int handle_apetag(mpg123_handle *fr, unsigned long newhead)
1064 {
1065 unsigned char apebuf[28];
1066 unsigned long val;
1067 int i, ret;
1068 /* How many bytes to backpedal to get back to just after the first byte of */
1069 /* the supposed header. */
1070 int back_bytes = 3;
1071 fr->oldhead = 0;
1072
1073 debug1("trying to read remaining APE header at %"OFF_P, (off_p)fr->rd->tell(fr));
1074 /* Apetag headers are 32 bytes, newhead contains 4, read the rest */
1075 if((ret=fr->rd->fullread(fr,apebuf,28)) < 0)
1076 return ret;
1077 back_bytes += ret;
1078 if(ret < 28)
1079 goto apetag_bad;
1080
1081 debug1("trying to parse APE header at %"OFF_P, (off_p)fr->rd->tell(fr));
1082 /* Apetags start with "APETAGEX", "APET" is already tested. */
1083 if(strncmp((char *)apebuf,"AGEX",4) != 0)
1084 goto apetag_bad;
1085
1086 /* Version must be 2.000 / 2000 */
1087 val = ((unsigned long)apebuf[7]<<24)
1088 | ((unsigned long)apebuf[6]<<16)
1089 | ((unsigned long)apebuf[5]<<8)
1090 | apebuf[4];
1091 if(val != 2000)
1092 goto apetag_bad;
1093
1094 /* Last 8 bytes must be 0 */
1095 for(i=20; i<28; i++)
1096 if(apebuf[i])
1097 goto apetag_bad;
1098
1099 /* Looks good, skip the rest. */
1100 val = ((unsigned long)apebuf[11]<<24)
1101 | ((unsigned long)apebuf[10]<<16)
1102 | ((unsigned long)apebuf[9]<<8)
1103 | apebuf[8];
1104 debug2( "skipping %lu bytes of APE data at %"OFF_P
1105 , val, (off_p)fr->rd->tell(fr) );
1106 /* If encountering EOF here, things are just at an end. */
1107 if((ret=fr->rd->skip_bytes(fr,val)) < 0)
1108 return ret;
1109
1110 return PARSE_AGAIN;
1111
1112 apetag_bad:
1113 debug("no proper APE tag found, seeking back");
1114 if(fr->rd->back_bytes(fr,back_bytes) < 0 && NOQUIET)
1115 error1("Cannot seek %d bytes back!", back_bytes);
1116
1117 return PARSE_AGAIN; /* Give the resync code a chance to fix things */
1118 }
1119
1120 /* Advance a byte in stream to get next possible header and forget
1121 buffered data if possible (for feed reader). */
1122 #define FORGET_INTERVAL 1024 /* Used by callers to set forget flag each <n> bytes. */
1123 static int forget_head_shift(mpg123_handle *fr, unsigned long *newheadp, int forget)
1124 {
1125 int ret;
1126 if((ret=fr->rd->head_shift(fr,newheadp))<=0) return ret;
1127 /* Try to forget buffered data as early as possible to speed up parsing where
1128 new data needs to be added for resync (and things would be re-parsed again
1129 and again because of the start from beginning after hitting end). */
1130 if(forget && fr->rd->forget != NULL)
1131 {
1132 /* Ensure that the last 4 bytes stay in buffers for reading the header
1133 anew. */
1134 if(!fr->rd->back_bytes(fr, 4))
1135 {
1136 fr->rd->forget(fr);
1137 fr->rd->back_bytes(fr, -4);
1138 }
1139 }
1140 return ret; /* No surprise here, error already triggered early return. */
1141 }
1142
1143 /* watch out for junk/tags on beginning of stream by invalid header */
1144 static int skip_junk(mpg123_handle *fr, unsigned long *newheadp, long *headcount)
1145 {
1146 int ret;
1147 int freeformat_count = 0;
1148 long limit = 65536;
1149 unsigned long newhead = *newheadp;
1150 unsigned int forgetcount = 0;
1151 /* check for id3v2; first three bytes (of 4) are "ID3" */
1152 if((newhead & (unsigned long) 0xffffff00) == (unsigned long) 0x49443300)
1153 {
1154 return handle_id3v2(fr, newhead);
1155 }
1156 else if(VERBOSE2 && fr->silent_resync == 0) fprintf(stderr,"Note: Junk at the beginning (0x%08lx)\n",newhead);
1157
1158 /* I even saw RIFF headers at the beginning of MPEG streams ;( */
1159 if(newhead == ('R'<<24)+('I'<<16)+('F'<<8)+'F')
1160 {
1161 if(VERBOSE2 && fr->silent_resync == 0) fprintf(stderr, "Note: Looks like a RIFF header.\n");
1162
1163 if((ret=fr->rd->head_read(fr,&newhead))<=0) return ret;
1164
1165 while(newhead != ('d'<<24)+('a'<<16)+('t'<<8)+'a')
1166 {
1167 if(++forgetcount > FORGET_INTERVAL) forgetcount = 0;
1168 if((ret=forget_head_shift(fr,&newhead,!forgetcount))<=0) return ret;
1169 }
1170 if((ret=fr->rd->head_read(fr,&newhead))<=0) return ret;
1171
1172 if(VERBOSE2 && fr->silent_resync == 0) fprintf(stderr,"Note: Skipped RIFF header!\n");
1173
1174 fr->oldhead = 0;
1175 *newheadp = newhead;
1176 return PARSE_AGAIN;
1177 }
1178
1179 /*
1180 Unhandled junk... just continue search for a header, stepping in single bytes through next 64K.
1181 This is rather identical to the resync loop.
1182 */
1183 debug("searching for header...");
1184 *newheadp = 0; /* Invalidate the external value. */
1185 ret = 0; /* We will check the value after the loop. */
1186
1187 /* We prepare for at least the 64K bytes as usual, unless
1188 user explicitly wanted more (even infinity). Never less. */
1189 if(fr->p.resync_limit < 0 || fr->p.resync_limit > limit)
1190 limit = fr->p.resync_limit;
1191
1192 do
1193 {
1194 ++(*headcount);
1195 if(limit >= 0 && *headcount >= limit) break;
1196
1197 if(++forgetcount > FORGET_INTERVAL) forgetcount = 0;
1198 if((ret=forget_head_shift(fr, &newhead, !forgetcount))<=0) return ret;
1199
1200 if(head_check(newhead) && (ret=decode_header(fr, newhead, &freeformat_count))) break;
1201 } while(1);
1202 if(ret<0) return ret;
1203
1204 if(limit >= 0 && *headcount >= limit)
1205 {
1206 if(NOQUIET) error1("Giving up searching valid MPEG header after %li bytes of junk.", *headcount);
1207 return PARSE_END;
1208 }
1209 else debug1("hopefully found one at %"OFF_P, (off_p)fr->rd->tell(fr));
1210
1211 /* If the new header ist good, it is already decoded. */
1212 *newheadp = newhead;
1213 return PARSE_GOOD;
1214 }
1215
1216 /* The newhead is bad, so let's check if it is something special, otherwise just resync. */
1217 static int wetwork(mpg123_handle *fr, unsigned long *newheadp)
1218 {
1219 int ret = PARSE_ERR;
1220 unsigned long newhead = *newheadp;
1221 *newheadp = 0;
1222
1223 /* Classic ID3 tags. Read, then start parsing again. */
1224 if((newhead & 0xffffff00) == ('T'<<24)+('A'<<16)+('G'<<8))
1225 {
1226 fr->id3buf[0] = (unsigned char) ((newhead >> 24) & 0xff);
1227 fr->id3buf[1] = (unsigned char) ((newhead >> 16) & 0xff);
1228 fr->id3buf[2] = (unsigned char) ((newhead >> 8) & 0xff);
1229 fr->id3buf[3] = (unsigned char) ( newhead & 0xff);
1230
1231 if((ret=fr->rd->fullread(fr,fr->id3buf+4,124)) < 0) return ret;
1232
1233 fr->metaflags |= MPG123_NEW_ID3|MPG123_ID3;
1234 fr->rdat.flags |= READER_ID3TAG; /* that marks id3v1 */
1235 if(VERBOSE3) fprintf(stderr,"Note: Skipped ID3v1 tag.\n");
1236
1237 return PARSE_AGAIN;
1238 }
1239 /* This is similar to initial junk skipping code... */
1240 /* Check for id3v2; first three bytes (of 4) are "ID3" */
1241 if((newhead & (unsigned long) 0xffffff00) == (unsigned long) 0x49443300)
1242 {
1243 return handle_id3v2(fr, newhead);
1244 }
1245 /* Check for an apetag header */
1246 if(newhead == ('A'<<24)+('P'<<16)+('E'<<8)+'T')
1247 {
1248 return handle_apetag(fr, newhead);
1249 }
1250 else if(NOQUIET && fr->silent_resync == 0)
1251 {
1252 fprintf(stderr,"Note: Illegal Audio-MPEG-Header 0x%08lx at offset %"OFF_P".\n",
1253 newhead, (off_p)fr->rd->tell(fr)-4);
1254 }
1255
1256 /* Now we got something bad at hand, try to recover. */
1257
1258 if(NOQUIET && (newhead & 0xffffff00) == ('b'<<24)+('m'<<16)+('p'<<8)) fprintf(stderr,"Note: Could be a BMP album art.\n");
1259
1260 if( !(fr->p.flags & MPG123_NO_RESYNC) )
1261 {
1262 long try = 0;
1263 long limit = fr->p.resync_limit;
1264 unsigned int forgetcount = 0;
1265
1266 /* If a resync is needed the bitreservoir of previous frames is no longer valid */
1267 fr->bitreservoir = 0;
1268
1269 if(NOQUIET && fr->silent_resync == 0) fprintf(stderr, "Note: Trying to resync...\n");
1270
1271 do /* ... shift the header with additional single bytes until be found something that could be a header. */
1272 {
1273 ++try;
1274 if(limit >= 0 && try >= limit) break;
1275
1276 if(++forgetcount > FORGET_INTERVAL) forgetcount = 0;
1277 if((ret=forget_head_shift(fr,&newhead,!forgetcount)) <= 0)
1278 {
1279 *newheadp = newhead;
1280 if(NOQUIET) fprintf (stderr, "Note: Hit end of (available) data during resync.\n");
1281
1282 return ret ? ret : PARSE_END;
1283 }
1284 if(VERBOSE3) debug3("resync try %li at %"OFF_P", got newhead 0x%08lx", try, (off_p)fr->rd->tell(fr), newhead);
1285 } while(!head_check(newhead));
1286
1287 *newheadp = newhead;
1288 if(NOQUIET && fr->silent_resync == 0) fprintf (stderr, "Note: Skipped %li bytes in input.\n", try);
1289
1290 /* Now we either got something that could be a header, or we gave up. */
1291 if(limit >= 0 && try >= limit)
1292 {
1293 if(NOQUIET)
1294 error1("Giving up resync after %li bytes - your stream is not nice... (maybe increasing resync limit could help).", try);
1295
1296 fr->err = MPG123_RESYNC_FAIL;
1297 return PARSE_ERR;
1298 }
1299 else
1300 {
1301 debug1("Found possibly valid header 0x%lx... unsetting oldhead to reinit stream.", newhead);
1302 fr->oldhead = 0;
1303 return PARSE_RESYNC;
1304 }
1305 }
1306 else
1307 {
1308 if(NOQUIET) error("not attempting to resync...");
1309
1310 fr->err = MPG123_OUT_OF_SYNC;
1311 return PARSE_ERR;
1312 }
1313 /* Control never goes here... we return before that. */
1314 }