1 /* libFLAC - Free Lossless Audio Codec library
2 * Copyright (C) 2000,2001,2002 Josh Coalson
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
21 #include <stdlib.h> /* for malloc() */
22 #include <string.h> /* for memcpy()/memcmp() */
23 #include "FLAC/assert.h"
24 #include "protected/seekable_stream_decoder.h"
25 #include "protected/stream_decoder.h"
26 #include "private/md5.h"
28 /***********************************************************************
30 * Private class method prototypes
32 ***********************************************************************/
34 static void seekable_stream_decoder_set_defaults_(FLAC__SeekableStreamDecoder *decoder);
35 static FLAC__StreamDecoderReadStatus read_callback_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], unsigned *bytes, void *client_data);
36 static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data);
37 static void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data);
38 static void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
39 static FLAC__bool seek_to_absolute_sample_(FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample);
41 /***********************************************************************
45 ***********************************************************************/
47 typedef struct FLAC__SeekableStreamDecoderPrivate {
48 FLAC__SeekableStreamDecoderReadStatus (*read_callback)(const FLAC__SeekableStreamDecoder *decoder, FLAC__byte buffer[], unsigned *bytes, void *client_data);
49 FLAC__SeekableStreamDecoderSeekStatus (*seek_callback)(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 absolute_byte_offset, void *client_data);
50 FLAC__SeekableStreamDecoderTellStatus (*tell_callback)(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 *absolute_byte_offset, void *client_data);
51 FLAC__SeekableStreamDecoderLengthStatus (*length_callback)(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 *stream_length, void *client_data);
52 FLAC__bool (*eof_callback)(const FLAC__SeekableStreamDecoder *decoder, void *client_data);
53 FLAC__StreamDecoderWriteStatus (*write_callback)(const FLAC__SeekableStreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data);
54 void (*metadata_callback)(const FLAC__SeekableStreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data);
55 void (*error_callback)(const FLAC__SeekableStreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
57 FLAC__StreamDecoder *stream_decoder;
58 FLAC__bool do_md5_checking; /* initially gets protected_->md5_checking but is turned off after a seek */
59 struct MD5Context md5context;
60 FLAC__byte stored_md5sum[16]; /* this is what is stored in the metadata */
61 FLAC__byte computed_md5sum[16]; /* this is the sum we computed from the decoded data */
62 /* the rest of these are only used for seeking: */
63 FLAC__StreamMetadata_StreamInfo stream_info; /* we keep this around so we can figure out how to seek quickly */
64 const FLAC__StreamMetadata_SeekTable *seek_table; /* we hold a pointer to the stream decoder's seek table for the same reason */
65 /* Since we always want to see the STREAMINFO and SEEK_TABLE blocks at this level, we need some extra flags to keep track of whether they should be passed on up through the metadata_callback */
66 FLAC__bool ignore_stream_info_block;
67 FLAC__bool ignore_seek_table_block;
68 FLAC__Frame last_frame; /* holds the info of the last frame we seeked to */
69 FLAC__uint64 target_sample;
70 } FLAC__SeekableStreamDecoderPrivate;
72 /***********************************************************************
74 * Public static class data
76 ***********************************************************************/
78 const char * const FLAC__SeekableStreamDecoderStateString[] = {
79 "FLAC__SEEKABLE_STREAM_DECODER_OK",
80 "FLAC__SEEKABLE_STREAM_DECODER_SEEKING",
81 "FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM",
82 "FLAC__SEEKABLE_STREAM_DECODER_MEMORY_ALLOCATION_ERROR",
83 "FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR",
84 "FLAC__SEEKABLE_STREAM_DECODER_READ_ERROR",
85 "FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR",
86 "FLAC__SEEKABLE_STREAM_DECODER_ALREADY_INITIALIZED",
87 "FLAC__SEEKABLE_STREAM_DECODER_INVALID_CALLBACK",
88 "FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED"
91 const char * const FLAC__SeekableStreamDecoderReadStatusString[] = {
92 "FLAC__SEEKABLE_STREAM_DECODER_READ_STATUS_OK",
93 "FLAC__SEEKABLE_STREAM_DECODER_READ_STATUS_ERROR"
96 const char * const FLAC__SeekableStreamDecoderSeekStatusString[] = {
97 "FLAC__SEEKABLE_STREAM_DECODER_SEEK_STATUS_OK",
98 "FLAC__SEEKABLE_STREAM_DECODER_SEEK_STATUS_ERROR"
101 const char * const FLAC__SeekableStreamDecoderTellStatusString[] = {
102 "FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_OK",
103 "FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_ERROR"
106 const char * const FLAC__SeekableStreamDecoderLengthStatusString[] = {
107 "FLAC__SEEKABLE_STREAM_DECODER_LENGTH_STATUS_OK",
108 "FLAC__SEEKABLE_STREAM_DECODER_LENGTH_STATUS_ERROR"
111 /***********************************************************************
113 * Class constructor/destructor
115 ***********************************************************************/
117 FLAC__SeekableStreamDecoder *FLAC__seekable_stream_decoder_new()
119 FLAC__SeekableStreamDecoder *decoder;
121 FLAC__ASSERT(sizeof(int) >= 4); /* we want to die right away if this is not true */
123 decoder = (FLAC__SeekableStreamDecoder*)malloc(sizeof(FLAC__SeekableStreamDecoder));
127 decoder->protected_ = (FLAC__SeekableStreamDecoderProtected*)malloc(sizeof(FLAC__SeekableStreamDecoderProtected));
128 if(decoder->protected_ == 0) {
132 decoder->private_ = (FLAC__SeekableStreamDecoderPrivate*)malloc(sizeof(FLAC__SeekableStreamDecoderPrivate));
133 if(decoder->private_ == 0) {
134 free(decoder->protected_);
139 decoder->private_->stream_decoder = FLAC__stream_decoder_new();
141 if(0 == decoder->private_->stream_decoder) {
142 free(decoder->private_);
143 free(decoder->protected_);
148 seekable_stream_decoder_set_defaults_(decoder);
150 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED;
155 void FLAC__seekable_stream_decoder_delete(FLAC__SeekableStreamDecoder *decoder)
157 FLAC__ASSERT(decoder != 0);
158 FLAC__ASSERT(decoder->protected_ != 0);
159 FLAC__ASSERT(decoder->private_ != 0);
160 FLAC__ASSERT(decoder->private_->stream_decoder != 0);
162 (void)FLAC__seekable_stream_decoder_finish(decoder);
164 FLAC__stream_decoder_delete(decoder->private_->stream_decoder);
166 free(decoder->private_);
167 free(decoder->protected_);
171 /***********************************************************************
173 * Public class methods
175 ***********************************************************************/
177 FLAC__SeekableStreamDecoderState FLAC__seekable_stream_decoder_init(FLAC__SeekableStreamDecoder *decoder)
179 FLAC__ASSERT(decoder != 0);
181 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
182 return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_ALREADY_INITIALIZED;
184 if(0 == decoder->private_->read_callback || 0 == decoder->private_->seek_callback || 0 == decoder->private_->tell_callback || 0 == decoder->private_->length_callback || 0 == decoder->private_->eof_callback)
185 return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_INVALID_CALLBACK;
187 if(0 == decoder->private_->write_callback || 0 == decoder->private_->metadata_callback || 0 == decoder->private_->error_callback)
188 return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_INVALID_CALLBACK;
190 decoder->private_->seek_table = 0;
192 decoder->private_->do_md5_checking = decoder->protected_->md5_checking;
194 /* We initialize the MD5Context even though we may never use it. This is
195 * because md5 checking may be turned on to start and then turned off if a
196 * seek occurs. So we always init the context here and finalize it in
197 * FLAC__seekable_stream_decoder_finish() to make sure things are always
198 * cleaned up properly.
200 MD5Init(&decoder->private_->md5context);
202 FLAC__stream_decoder_set_read_callback(decoder->private_->stream_decoder, read_callback_);
203 FLAC__stream_decoder_set_write_callback(decoder->private_->stream_decoder, write_callback_);
204 FLAC__stream_decoder_set_metadata_callback(decoder->private_->stream_decoder, metadata_callback_);
205 FLAC__stream_decoder_set_error_callback(decoder->private_->stream_decoder, error_callback_);
206 FLAC__stream_decoder_set_client_data(decoder->private_->stream_decoder, decoder);
208 /* We always want to see these blocks. Whether or not we pass them up
209 * through the metadata callback will be determined by flags set in our
210 * implementation of ..._set_metadata_respond/ignore...()
212 FLAC__stream_decoder_set_metadata_respond(decoder->private_->stream_decoder, FLAC__METADATA_TYPE_STREAMINFO);
213 FLAC__stream_decoder_set_metadata_respond(decoder->private_->stream_decoder, FLAC__METADATA_TYPE_SEEKTABLE);
215 if(FLAC__stream_decoder_init(decoder->private_->stream_decoder) != FLAC__STREAM_DECODER_SEARCH_FOR_METADATA)
216 return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
218 return decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_OK;
221 FLAC__bool FLAC__seekable_stream_decoder_finish(FLAC__SeekableStreamDecoder *decoder)
223 FLAC__bool md5_failed = false;
225 FLAC__ASSERT(decoder != 0);
226 FLAC__ASSERT(decoder->private_ != 0);
227 FLAC__ASSERT(decoder->protected_ != 0);
229 if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
232 FLAC__ASSERT(decoder->private_->stream_decoder != 0);
234 /* see the comment in FLAC__seekable_stream_decoder_init() as to why we
235 * always call MD5Final()
237 MD5Final(decoder->private_->computed_md5sum, &decoder->private_->md5context);
239 FLAC__stream_decoder_finish(decoder->private_->stream_decoder);
241 if(decoder->private_->do_md5_checking) {
242 if(memcmp(decoder->private_->stored_md5sum, decoder->private_->computed_md5sum, 16))
246 seekable_stream_decoder_set_defaults_(decoder);
248 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED;
253 FLAC__bool FLAC__seekable_stream_decoder_set_md5_checking(FLAC__SeekableStreamDecoder *decoder, FLAC__bool value)
255 FLAC__ASSERT(decoder != 0);
256 FLAC__ASSERT(decoder->protected_ != 0);
257 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
259 decoder->protected_->md5_checking = value;
263 FLAC__bool FLAC__seekable_stream_decoder_set_read_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderReadStatus (*value)(const FLAC__SeekableStreamDecoder *decoder, FLAC__byte buffer[], unsigned *bytes, void *client_data))
265 FLAC__ASSERT(decoder != 0);
266 FLAC__ASSERT(decoder->private_ != 0);
267 FLAC__ASSERT(decoder->protected_ != 0);
268 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
270 decoder->private_->read_callback = value;
274 FLAC__bool FLAC__seekable_stream_decoder_set_seek_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderSeekStatus (*value)(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 absolute_byte_offset, void *client_data))
276 FLAC__ASSERT(decoder != 0);
277 FLAC__ASSERT(decoder->private_ != 0);
278 FLAC__ASSERT(decoder->protected_ != 0);
279 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
281 decoder->private_->seek_callback = value;
285 FLAC__bool FLAC__seekable_stream_decoder_set_tell_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderTellStatus (*value)(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 *absolute_byte_offset, void *client_data))
287 FLAC__ASSERT(decoder != 0);
288 FLAC__ASSERT(decoder->private_ != 0);
289 FLAC__ASSERT(decoder->protected_ != 0);
290 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
292 decoder->private_->tell_callback = value;
296 FLAC__bool FLAC__seekable_stream_decoder_set_length_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__SeekableStreamDecoderLengthStatus (*value)(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 *stream_length, void *client_data))
298 FLAC__ASSERT(decoder != 0);
299 FLAC__ASSERT(decoder->private_ != 0);
300 FLAC__ASSERT(decoder->protected_ != 0);
301 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
303 decoder->private_->length_callback = value;
307 FLAC__bool FLAC__seekable_stream_decoder_set_eof_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__bool (*value)(const FLAC__SeekableStreamDecoder *decoder, void *client_data))
309 FLAC__ASSERT(decoder != 0);
310 FLAC__ASSERT(decoder->private_ != 0);
311 FLAC__ASSERT(decoder->protected_ != 0);
312 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
314 decoder->private_->eof_callback = value;
318 FLAC__bool FLAC__seekable_stream_decoder_set_write_callback(FLAC__SeekableStreamDecoder *decoder, FLAC__StreamDecoderWriteStatus (*value)(const FLAC__SeekableStreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data))
320 FLAC__ASSERT(decoder != 0);
321 FLAC__ASSERT(decoder->private_ != 0);
322 FLAC__ASSERT(decoder->protected_ != 0);
323 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
325 decoder->private_->write_callback = value;
329 FLAC__bool FLAC__seekable_stream_decoder_set_metadata_callback(FLAC__SeekableStreamDecoder *decoder, void (*value)(const FLAC__SeekableStreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data))
331 FLAC__ASSERT(decoder != 0);
332 FLAC__ASSERT(decoder->private_ != 0);
333 FLAC__ASSERT(decoder->protected_ != 0);
334 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
336 decoder->private_->metadata_callback = value;
340 FLAC__bool FLAC__seekable_stream_decoder_set_error_callback(FLAC__SeekableStreamDecoder *decoder, void (*value)(const FLAC__SeekableStreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data))
342 FLAC__ASSERT(decoder != 0);
343 FLAC__ASSERT(decoder->private_ != 0);
344 FLAC__ASSERT(decoder->protected_ != 0);
345 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
347 decoder->private_->error_callback = value;
351 FLAC__bool FLAC__seekable_stream_decoder_set_client_data(FLAC__SeekableStreamDecoder *decoder, void *value)
353 FLAC__ASSERT(decoder != 0);
354 FLAC__ASSERT(decoder->private_ != 0);
355 FLAC__ASSERT(decoder->protected_ != 0);
356 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
358 decoder->private_->client_data = value;
362 FLAC__bool FLAC__seekable_stream_decoder_set_metadata_respond(FLAC__SeekableStreamDecoder *decoder, FLAC__MetadataType type)
364 FLAC__ASSERT(decoder != 0);
365 FLAC__ASSERT(decoder->private_ != 0);
366 FLAC__ASSERT(decoder->protected_ != 0);
367 FLAC__ASSERT(decoder->private_->stream_decoder != 0);
368 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
370 if(type == FLAC__METADATA_TYPE_STREAMINFO)
371 decoder->private_->ignore_stream_info_block = false;
372 else if(type == FLAC__METADATA_TYPE_SEEKTABLE)
373 decoder->private_->ignore_seek_table_block = false;
374 return FLAC__stream_decoder_set_metadata_respond(decoder->private_->stream_decoder, type);
377 FLAC__bool FLAC__seekable_stream_decoder_set_metadata_respond_application(FLAC__SeekableStreamDecoder *decoder, const FLAC__byte id[4])
379 FLAC__ASSERT(decoder != 0);
380 FLAC__ASSERT(decoder->private_ != 0);
381 FLAC__ASSERT(decoder->protected_ != 0);
382 FLAC__ASSERT(decoder->private_->stream_decoder != 0);
383 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
385 return FLAC__stream_decoder_set_metadata_respond_application(decoder->private_->stream_decoder, id);
388 FLAC__bool FLAC__seekable_stream_decoder_set_metadata_respond_all(FLAC__SeekableStreamDecoder *decoder)
390 FLAC__ASSERT(decoder != 0);
391 FLAC__ASSERT(decoder->private_ != 0);
392 FLAC__ASSERT(decoder->protected_ != 0);
393 FLAC__ASSERT(decoder->private_->stream_decoder != 0);
394 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
396 decoder->private_->ignore_stream_info_block = false;
397 decoder->private_->ignore_seek_table_block = false;
398 return FLAC__stream_decoder_set_metadata_respond_all(decoder->private_->stream_decoder);
401 FLAC__bool FLAC__seekable_stream_decoder_set_metadata_ignore(FLAC__SeekableStreamDecoder *decoder, FLAC__MetadataType type)
403 FLAC__ASSERT(decoder != 0);
404 FLAC__ASSERT(decoder->private_ != 0);
405 FLAC__ASSERT(decoder->protected_ != 0);
406 FLAC__ASSERT(decoder->private_->stream_decoder != 0);
407 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
409 if(type == FLAC__METADATA_TYPE_STREAMINFO)
410 decoder->private_->ignore_stream_info_block = true;
411 else if(type == FLAC__METADATA_TYPE_SEEKTABLE)
412 decoder->private_->ignore_seek_table_block = true;
413 return FLAC__stream_decoder_set_metadata_ignore(decoder->private_->stream_decoder, type);
416 FLAC__bool FLAC__seekable_stream_decoder_set_metadata_ignore_application(FLAC__SeekableStreamDecoder *decoder, const FLAC__byte id[4])
418 FLAC__ASSERT(decoder != 0);
419 FLAC__ASSERT(decoder->private_ != 0);
420 FLAC__ASSERT(decoder->protected_ != 0);
421 FLAC__ASSERT(decoder->private_->stream_decoder != 0);
422 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
424 return FLAC__stream_decoder_set_metadata_ignore_application(decoder->private_->stream_decoder, id);
427 FLAC__bool FLAC__seekable_stream_decoder_set_metadata_ignore_all(FLAC__SeekableStreamDecoder *decoder)
429 FLAC__ASSERT(decoder != 0);
430 FLAC__ASSERT(decoder->private_ != 0);
431 FLAC__ASSERT(decoder->protected_ != 0);
432 FLAC__ASSERT(decoder->private_->stream_decoder != 0);
433 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_UNINITIALIZED)
435 decoder->private_->ignore_stream_info_block = true;
436 decoder->private_->ignore_seek_table_block = true;
437 return FLAC__stream_decoder_set_metadata_ignore_all(decoder->private_->stream_decoder);
440 FLAC__SeekableStreamDecoderState FLAC__seekable_stream_decoder_get_state(const FLAC__SeekableStreamDecoder *decoder)
442 FLAC__ASSERT(decoder != 0);
443 FLAC__ASSERT(decoder->protected_ != 0);
444 return decoder->protected_->state;
447 FLAC__bool FLAC__seekable_stream_decoder_get_md5_checking(const FLAC__SeekableStreamDecoder *decoder)
449 FLAC__ASSERT(decoder != 0);
450 FLAC__ASSERT(decoder->protected_ != 0);
451 return decoder->protected_->md5_checking;
454 unsigned FLAC__seekable_stream_decoder_get_channels(const FLAC__SeekableStreamDecoder *decoder)
456 FLAC__ASSERT(decoder != 0);
457 FLAC__ASSERT(decoder->private_ != 0);
458 return FLAC__stream_decoder_get_channels(decoder->private_->stream_decoder);
461 FLAC__ChannelAssignment FLAC__seekable_stream_decoder_get_channel_assignment(const FLAC__SeekableStreamDecoder *decoder)
463 FLAC__ASSERT(decoder != 0);
464 FLAC__ASSERT(decoder->private_ != 0);
465 return FLAC__stream_decoder_get_channel_assignment(decoder->private_->stream_decoder);
468 unsigned FLAC__seekable_stream_decoder_get_bits_per_sample(const FLAC__SeekableStreamDecoder *decoder)
470 FLAC__ASSERT(decoder != 0);
471 FLAC__ASSERT(decoder->private_ != 0);
472 return FLAC__stream_decoder_get_bits_per_sample(decoder->private_->stream_decoder);
475 unsigned FLAC__seekable_stream_decoder_get_sample_rate(const FLAC__SeekableStreamDecoder *decoder)
477 FLAC__ASSERT(decoder != 0);
478 FLAC__ASSERT(decoder->private_ != 0);
479 return FLAC__stream_decoder_get_sample_rate(decoder->private_->stream_decoder);
482 unsigned FLAC__seekable_stream_decoder_get_blocksize(const FLAC__SeekableStreamDecoder *decoder)
484 FLAC__ASSERT(decoder != 0);
485 FLAC__ASSERT(decoder->private_ != 0);
486 return FLAC__stream_decoder_get_blocksize(decoder->private_->stream_decoder);
489 FLAC__bool FLAC__seekable_stream_decoder_flush(FLAC__SeekableStreamDecoder *decoder)
491 FLAC__ASSERT(decoder != 0);
492 FLAC__ASSERT(decoder->private_ != 0);
493 FLAC__ASSERT(decoder->protected_ != 0);
495 decoder->private_->do_md5_checking = false;
497 if(!FLAC__stream_decoder_flush(decoder->private_->stream_decoder)) {
498 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
502 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_OK;
507 FLAC__bool FLAC__seekable_stream_decoder_reset(FLAC__SeekableStreamDecoder *decoder)
509 FLAC__ASSERT(decoder != 0);
510 FLAC__ASSERT(decoder->private_ != 0);
511 FLAC__ASSERT(decoder->protected_ != 0);
513 if(!FLAC__seekable_stream_decoder_flush(decoder)) {
514 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
518 if(!FLAC__stream_decoder_reset(decoder->private_->stream_decoder)) {
519 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
523 decoder->private_->seek_table = 0;
525 decoder->private_->do_md5_checking = decoder->protected_->md5_checking;
527 /* We initialize the MD5Context even though we may never use it. This is
528 * because md5 checking may be turned on to start and then turned off if a
529 * seek occurs. So we always init the context here and finalize it in
530 * FLAC__seekable_stream_decoder_finish() to make sure things are always
531 * cleaned up properly.
533 MD5Init(&decoder->private_->md5context);
535 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_OK;
540 FLAC__bool FLAC__seekable_stream_decoder_process_whole_stream(FLAC__SeekableStreamDecoder *decoder)
543 FLAC__ASSERT(decoder != 0);
545 if(decoder->private_->stream_decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM)
546 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
548 if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM)
551 FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK);
553 ret = FLAC__stream_decoder_process_whole_stream(decoder->private_->stream_decoder);
555 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
560 FLAC__bool FLAC__seekable_stream_decoder_process_metadata(FLAC__SeekableStreamDecoder *decoder)
563 FLAC__ASSERT(decoder != 0);
565 if(decoder->private_->stream_decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM)
566 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
568 if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM)
571 FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK);
573 ret = FLAC__stream_decoder_process_metadata(decoder->private_->stream_decoder);
575 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
580 FLAC__bool FLAC__seekable_stream_decoder_process_one_frame(FLAC__SeekableStreamDecoder *decoder)
583 FLAC__ASSERT(decoder != 0);
585 if(decoder->private_->stream_decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM)
586 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
588 if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM)
591 FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK);
593 ret = FLAC__stream_decoder_process_one_frame(decoder->private_->stream_decoder);
595 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
600 FLAC__bool FLAC__seekable_stream_decoder_process_remaining_frames(FLAC__SeekableStreamDecoder *decoder)
603 FLAC__ASSERT(decoder != 0);
605 if(decoder->private_->stream_decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM)
606 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
608 if(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM)
611 FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK);
613 ret = FLAC__stream_decoder_process_remaining_frames(decoder->private_->stream_decoder);
615 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
620 FLAC__bool FLAC__seekable_stream_decoder_seek_absolute(FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 sample)
624 FLAC__ASSERT(decoder != 0);
625 FLAC__ASSERT(decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_OK || decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM);
627 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEKING;
629 /* turn off md5 checking if a seek is attempted */
630 decoder->private_->do_md5_checking = false;
632 if(!FLAC__stream_decoder_reset(decoder->private_->stream_decoder)) {
633 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
636 /* get the file length */
637 if(decoder->private_->length_callback(decoder, &length, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_LENGTH_STATUS_OK) {
638 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
642 if(decoder->private_->seek_callback(decoder, 0, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_SEEK_STATUS_OK) {
643 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
646 if(!FLAC__stream_decoder_process_metadata(decoder->private_->stream_decoder)) {
647 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
650 if(decoder->private_->stream_info.total_samples > 0 && sample > decoder->private_->stream_info.total_samples) {
651 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
655 return seek_to_absolute_sample_(decoder, length, sample);
658 /***********************************************************************
660 * Private class methods
662 ***********************************************************************/
664 void seekable_stream_decoder_set_defaults_(FLAC__SeekableStreamDecoder *decoder)
666 decoder->private_->read_callback = 0;
667 decoder->private_->seek_callback = 0;
668 decoder->private_->tell_callback = 0;
669 decoder->private_->length_callback = 0;
670 decoder->private_->eof_callback = 0;
671 decoder->private_->write_callback = 0;
672 decoder->private_->metadata_callback = 0;
673 decoder->private_->error_callback = 0;
674 decoder->private_->client_data = 0;
675 /* WATCHOUT: these should match the default behavior of FLAC__StreamDecoder */
676 decoder->private_->ignore_stream_info_block = false;
677 decoder->private_->ignore_seek_table_block = true;
679 decoder->protected_->md5_checking = false;
682 FLAC__StreamDecoderReadStatus read_callback_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], unsigned *bytes, void *client_data)
684 FLAC__SeekableStreamDecoder *seekable_stream_decoder = (FLAC__SeekableStreamDecoder *)client_data;
686 if(seekable_stream_decoder->private_->eof_callback(seekable_stream_decoder, seekable_stream_decoder->private_->client_data)) {
687 seekable_stream_decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
688 return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
690 else if(*bytes > 0) {
691 unsigned bytes_read = *bytes;
692 if(seekable_stream_decoder->private_->read_callback(seekable_stream_decoder, buffer, &bytes_read, seekable_stream_decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_READ_STATUS_OK) {
693 seekable_stream_decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_READ_ERROR;
694 return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
696 if(bytes_read == 0) {
697 if(seekable_stream_decoder->private_->eof_callback(seekable_stream_decoder, seekable_stream_decoder->private_->client_data)) {
698 seekable_stream_decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_END_OF_STREAM;
699 return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
702 return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
706 return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
710 return FLAC__STREAM_DECODER_READ_STATUS_ABORT; /* abort to avoid a deadlock */
713 FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
715 FLAC__SeekableStreamDecoder *seekable_stream_decoder = (FLAC__SeekableStreamDecoder *)client_data;
718 if(seekable_stream_decoder->protected_->state == FLAC__SEEKABLE_STREAM_DECODER_SEEKING) {
719 FLAC__uint64 this_frame_sample = frame->header.number.sample_number;
720 FLAC__uint64 next_frame_sample = this_frame_sample + (FLAC__uint64)frame->header.blocksize;
721 FLAC__uint64 target_sample = seekable_stream_decoder->private_->target_sample;
723 FLAC__ASSERT(frame->header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
725 seekable_stream_decoder->private_->last_frame = *frame; /* save the frame */
726 if(this_frame_sample <= target_sample && target_sample < next_frame_sample) { /* we hit our target frame */
727 unsigned delta = (unsigned)(target_sample - this_frame_sample);
728 /* kick out of seek mode */
729 seekable_stream_decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_OK;
730 /* shift out the samples before target_sample */
733 const FLAC__int32 *newbuffer[FLAC__MAX_CHANNELS];
734 for(channel = 0; channel < frame->header.channels; channel++)
735 newbuffer[channel] = buffer[channel] + delta;
736 seekable_stream_decoder->private_->last_frame.header.blocksize -= delta;
737 seekable_stream_decoder->private_->last_frame.header.number.sample_number += (FLAC__uint64)delta;
738 /* write the relevant samples */
739 return seekable_stream_decoder->private_->write_callback(seekable_stream_decoder, &seekable_stream_decoder->private_->last_frame, newbuffer, seekable_stream_decoder->private_->client_data);
742 /* write the relevant samples */
743 return seekable_stream_decoder->private_->write_callback(seekable_stream_decoder, frame, buffer, seekable_stream_decoder->private_->client_data);
747 return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
751 if(seekable_stream_decoder->private_->do_md5_checking) {
752 if(!FLAC__MD5Accumulate(&seekable_stream_decoder->private_->md5context, buffer, frame->header.channels, frame->header.blocksize, (frame->header.bits_per_sample+7) / 8))
753 return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
755 return seekable_stream_decoder->private_->write_callback(seekable_stream_decoder, frame, buffer, seekable_stream_decoder->private_->client_data);
759 void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
761 FLAC__SeekableStreamDecoder *seekable_stream_decoder = (FLAC__SeekableStreamDecoder *)client_data;
764 if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO) {
765 seekable_stream_decoder->private_->stream_info = metadata->data.stream_info;
766 /* save the MD5 signature for comparison later */
767 memcpy(seekable_stream_decoder->private_->stored_md5sum, metadata->data.stream_info.md5sum, 16);
768 if(0 == memcmp(seekable_stream_decoder->private_->stored_md5sum, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 16))
769 seekable_stream_decoder->private_->do_md5_checking = false;
771 else if(metadata->type == FLAC__METADATA_TYPE_SEEKTABLE) {
772 seekable_stream_decoder->private_->seek_table = &metadata->data.seek_table;
775 if(seekable_stream_decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_SEEKING) {
776 FLAC__bool ignore_block = false;
777 if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO && seekable_stream_decoder->private_->ignore_stream_info_block)
779 else if(metadata->type == FLAC__METADATA_TYPE_SEEKTABLE && seekable_stream_decoder->private_->ignore_seek_table_block)
782 seekable_stream_decoder->private_->metadata_callback(seekable_stream_decoder, metadata, seekable_stream_decoder->private_->client_data);
786 void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
788 FLAC__SeekableStreamDecoder *seekable_stream_decoder = (FLAC__SeekableStreamDecoder *)client_data;
791 if(seekable_stream_decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_SEEKING)
792 seekable_stream_decoder->private_->error_callback(seekable_stream_decoder, status, seekable_stream_decoder->private_->client_data);
795 FLAC__bool seek_to_absolute_sample_(FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample)
797 FLAC__uint64 first_frame_offset, lower_bound, upper_bound;
798 FLAC__int64 pos = -1, last_pos = -1;
799 int i, lower_seek_point = -1, upper_seek_point = -1;
800 unsigned approx_bytes_per_frame;
801 FLAC__uint64 last_frame_sample = 0xffffffffffffffff;
802 FLAC__bool needs_seek;
803 const FLAC__uint64 total_samples = decoder->private_->stream_info.total_samples;
804 const unsigned min_blocksize = decoder->private_->stream_info.min_blocksize;
805 const unsigned max_blocksize = decoder->private_->stream_info.max_blocksize;
806 const unsigned max_framesize = decoder->private_->stream_info.max_framesize;
807 const unsigned channels = FLAC__seekable_stream_decoder_get_channels(decoder);
808 const unsigned bps = FLAC__seekable_stream_decoder_get_bits_per_sample(decoder);
810 /* we are just guessing here, but we want to guess high, not low */
811 if(max_framesize > 0) {
812 approx_bytes_per_frame = max_framesize;
815 * Check if it's a known fixed-blocksize stream. Note that though
816 * the spec doesn't allow zeroes in the STREAMINFO block, we may
817 * never get a STREAMINFO block when decoding so the value of
818 * min_blocksize might be zero.
820 else if(min_blocksize == max_blocksize && min_blocksize > 0) {
821 /* note there are no () around 'bps/8' to keep precision up since it's an integer calulation */
822 approx_bytes_per_frame = min_blocksize * channels * bps/8 + 64;
825 approx_bytes_per_frame = 4608 * channels * bps/8 + 64;
828 * The stream position is currently at the first frame plus any read
829 * ahead data, so first we get the stream position, then subtract
830 * uncomsumed bytes to get the position of the first frame in the
833 if(decoder->private_->tell_callback(decoder, &first_frame_offset, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_OK) {
834 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
837 FLAC__ASSERT(first_frame_offset >= FLAC__stream_decoder_get_input_bytes_unconsumed(decoder->private_->stream_decoder));
838 first_frame_offset -= FLAC__stream_decoder_get_input_bytes_unconsumed(decoder->private_->stream_decoder);
841 * First, we set an upper and lower bound on where in the
842 * stream we will search. For now we assume the worst case
843 * scenario, which is our best guess at the beginning of
844 * the first and last frames.
846 lower_bound = first_frame_offset;
848 /* calc the upper_bound, beyond which we never want to seek */
849 if(max_framesize > 0)
850 upper_bound = stream_length - (max_framesize + 128 + 2); /* 128 for a possible ID3V1 tag, 2 for indexing differences */
852 upper_bound = stream_length - ((channels * bps * FLAC__MAX_BLOCK_SIZE) / 8 + 128 + 2);
855 * Now we refine the bounds if we have a seektable with
856 * suitable points. Note that according to the spec they
857 * must be ordered by ascending sample number.
859 if(0 != decoder->private_->seek_table) {
860 /* find the closest seek point <= target_sample, if it exists */
861 for(i = (int)decoder->private_->seek_table->num_points - 1; i >= 0; i--) {
862 if(decoder->private_->seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER && decoder->private_->seek_table->points[i].sample_number <= target_sample)
865 if(i >= 0) { /* i.e. we found a suitable seek point... */
866 lower_bound = first_frame_offset + decoder->private_->seek_table->points[i].stream_offset;
867 lower_seek_point = i;
870 /* find the closest seek point > target_sample, if it exists */
871 for(i = 0; i < (int)decoder->private_->seek_table->num_points; i++) {
872 if(decoder->private_->seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER && decoder->private_->seek_table->points[i].sample_number > target_sample)
875 if(i < (int)decoder->private_->seek_table->num_points) { /* i.e. we found a suitable seek point... */
876 upper_bound = first_frame_offset + decoder->private_->seek_table->points[i].stream_offset;
877 upper_seek_point = i;
882 * Now guess at where within those bounds our target
885 if(lower_seek_point >= 0) {
886 /* first see if our sample is within a few frames of the lower seekpoint */
887 if(decoder->private_->seek_table->points[lower_seek_point].sample_number <= target_sample && target_sample < decoder->private_->seek_table->points[lower_seek_point].sample_number + (decoder->private_->seek_table->points[lower_seek_point].frame_samples * 4)) {
888 pos = (FLAC__int64)lower_bound;
890 else if(upper_seek_point >= 0) {
891 const FLAC__uint64 target_offset = target_sample - decoder->private_->seek_table->points[lower_seek_point].sample_number;
892 const FLAC__uint64 range_samples = decoder->private_->seek_table->points[upper_seek_point].sample_number - decoder->private_->seek_table->points[lower_seek_point].sample_number;
893 const FLAC__uint64 range_bytes = upper_bound - lower_bound;
894 #if defined _MSC_VER || defined __MINGW32__
895 /* with VC++ you have to spoon feed it the casting */
896 pos = (FLAC__int64)lower_bound + (FLAC__int64)((double)(FLAC__int64)target_offset / (double)(FLAC__int64)range_samples * (double)(FLAC__int64)(range_bytes-1)) - approx_bytes_per_frame;
898 pos = (FLAC__int64)lower_bound + (FLAC__int64)((double)target_offset / (double)range_samples * (double)(range_bytes-1)) - approx_bytes_per_frame;
904 * If there's no seek table, we need to use the metadata (if we
905 * have it) and the filelength to estimate the position of the
906 * frame with the correct sample.
908 if(pos < 0 && total_samples > 0) {
909 #if defined _MSC_VER || defined __MINGW32__
910 /* with VC++ you have to spoon feed it the casting */
911 pos = (FLAC__int64)first_frame_offset + (FLAC__int64)((double)(FLAC__int64)target_sample / (double)(FLAC__int64)total_samples * (double)(FLAC__int64)(stream_length-first_frame_offset-1)) - approx_bytes_per_frame;
913 pos = (FLAC__int64)first_frame_offset + (FLAC__int64)((double)target_sample / (double)total_samples * (double)(stream_length-first_frame_offset-1)) - approx_bytes_per_frame;
918 * If there's no seek table and total_samples is unknown, we
919 * don't even bother trying to figure out a target, we just use
920 * our current position.
924 if(decoder->private_->tell_callback(decoder, &upos, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_OK) {
925 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
928 pos = (FLAC__int32)upos;
934 /* clip the position to the bounds, lower bound takes precedence */
935 if(pos >= (FLAC__int64)upper_bound) {
936 pos = (FLAC__int64)upper_bound-1;
939 if(pos < (FLAC__int64)lower_bound) {
940 pos = (FLAC__int64)lower_bound;
944 decoder->private_->target_sample = target_sample;
947 if(decoder->private_->seek_callback(decoder, (FLAC__uint64)pos, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_SEEK_STATUS_OK) {
948 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
951 if(!FLAC__stream_decoder_flush(decoder->private_->stream_decoder)) {
952 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR;
956 if(!FLAC__stream_decoder_process_one_frame(decoder->private_->stream_decoder)) {
957 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
960 /* our write callback will change the state when it gets to the target frame */
961 if(decoder->protected_->state != FLAC__SEEKABLE_STREAM_DECODER_SEEKING) {
964 else { /* we need to narrow the search */
965 FLAC__uint64 this_frame_sample = decoder->private_->last_frame.header.number.sample_number;
966 FLAC__ASSERT(decoder->private_->last_frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
967 if(this_frame_sample == last_frame_sample) {
968 /* our last move backwards wasn't big enough */
969 pos -= (last_pos - pos);
973 if(target_sample < this_frame_sample) {
975 approx_bytes_per_frame = decoder->private_->last_frame.header.blocksize * channels * bps/8 + 64;
976 pos -= approx_bytes_per_frame;
979 else { /* target_sample >= this_frame_sample + this frame's blocksize */
981 if(decoder->private_->tell_callback(decoder, &upos, decoder->private_->client_data) != FLAC__SEEKABLE_STREAM_DECODER_TELL_STATUS_OK) {
982 decoder->protected_->state = FLAC__SEEKABLE_STREAM_DECODER_SEEK_ERROR;
986 pos = (FLAC__int32)upos;
987 pos -= FLAC__stream_decoder_get_input_bytes_unconsumed(decoder->private_->stream_decoder);
991 if(pos < (FLAC__int64)lower_bound)
992 pos = (FLAC__int64)lower_bound;
993 last_frame_sample = this_frame_sample;