src/libFLAC/stream_decoder.c

   1 /* libFLAC - Free Lossless Audio Codec library
   2  * Copyright (C) 2000,2001  Josh Coalson
   3  *
   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.
   8  *
   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.
  13  *
  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.
  18  */
  19
  20 #include <assert.h>
  21 #include <stdio.h>
  22 #include <stdlib.h> /* for malloc() */
  23 #include "FLAC/stream_decoder.h"
  24 #include "private/bitbuffer.h"
  25 #include "private/crc.h"
  26 #include "private/fixed.h"
  27 #include "private/lpc.h"
  28
  29 typedef struct FLAC__StreamDecoderPrivate {
  30         FLAC__StreamDecoderReadStatus (*read_callback)(const FLAC__StreamDecoder *decoder, byte buffer[], unsigned *bytes, void *client_data);
  31         FLAC__StreamDecoderWriteStatus (*write_callback)(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const int32 *buffer[], void *client_data);
  32         void (*metadata_callback)(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetaData *metadata, void *client_data);
  33         void (*error_callback)(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
  34         void *client_data;
  35         FLAC__BitBuffer input;
  36         int32 *output[FLAC__MAX_CHANNELS];
  37         int32 *residual[FLAC__MAX_CHANNELS];
  38         unsigned output_capacity, output_channels;
  39         uint32 last_frame_number;
  40         uint64 samples_decoded;
  41         bool has_stream_header;
  42         FLAC__StreamMetaData stream_header;
  43         FLAC__Frame frame;
  44         byte header_warmup[2]; /* contains the sync code and reserved bits */
  45         byte lookahead; /* temp storage when we need to look ahead one byte in the stream */
  46         bool cached; /* true if there is a byte in lookahead */
  47 } FLAC__StreamDecoderPrivate;
  48
  49 static byte ID3V2_TAG_[3] = { 'I', 'D', '3' };
  50
  51 static bool stream_decoder_allocate_output_(FLAC__StreamDecoder *decoder, unsigned size, unsigned channels);
  52 static bool stream_decoder_find_metadata_(FLAC__StreamDecoder *decoder);
  53 static bool stream_decoder_read_metadata_(FLAC__StreamDecoder *decoder);
  54 static bool stream_decoder_skip_id3v2_tag_(FLAC__StreamDecoder *decoder);
  55 static bool stream_decoder_frame_sync_(FLAC__StreamDecoder *decoder);
  56 static bool stream_decoder_read_frame_(FLAC__StreamDecoder *decoder, bool *got_a_frame);
  57 static bool stream_decoder_read_frame_header_(FLAC__StreamDecoder *decoder);
  58 static bool stream_decoder_read_subframe_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
  59 static bool stream_decoder_read_subframe_constant_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
  60 static bool stream_decoder_read_subframe_fixed_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order);
  61 static bool stream_decoder_read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order);
  62 static bool stream_decoder_read_subframe_verbatim_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
  63 static bool stream_decoder_read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, unsigned predictor_order, unsigned partition_order, int32 *residual);
  64 static bool stream_decoder_read_zero_padding_(FLAC__StreamDecoder *decoder);
  65 static bool read_callback_(byte buffer[], unsigned *bytes, void *client_data);
  66
  67 const char *FLAC__StreamDecoderStateString[] = {
  68         "FLAC__STREAM_DECODER_SEARCH_FOR_METADATA",
  69         "FLAC__STREAM_DECODER_READ_METADATA",
  70         "FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC",
  71         "FLAC__STREAM_DECODER_READ_FRAME",
  72         "FLAC__STREAM_DECODER_END_OF_STREAM",
  73         "FLAC__STREAM_DECODER_ABORTED",
  74         "FLAC__STREAM_DECODER_UNPARSEABLE_STREAM",
  75         "FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR",
  76         "FLAC__STREAM_DECODER_UNINITIALIZED"
  77 };
  78
  79 const char *FLAC__StreamDecoderReadStatusString[] = {
  80         "FLAC__STREAM_DECODER_READ_CONTINUE",
  81         "FLAC__STREAM_DECODER_READ_END_OF_STREAM",
  82         "FLAC__STREAM_DECODER_READ_ABORT"
  83 };
  84
  85 const char *FLAC__StreamDecoderWriteStatusString[] = {
  86         "FLAC__STREAM_DECODER_WRITE_CONTINUE",
  87         "FLAC__STREAM_DECODER_WRITE_ABORT"
  88 };
  89
  90 const char *FLAC__StreamDecoderErrorStatusString[] = {
  91         "FLAC__STREAM_DECODER_ERROR_LOST_SYNC",
  92         "FLAC__STREAM_DECODER_ERROR_BAD_HEADER",
  93         "FLAC__STREAM_DECODER_ERROR_FRAME_CRC_MISMATCH"
  94 };
  95
  96 FLAC__StreamDecoder *FLAC__stream_decoder_get_new_instance()
  97 {
  98         FLAC__StreamDecoder *decoder = (FLAC__StreamDecoder*)malloc(sizeof(FLAC__StreamDecoder));
  99         if(decoder != 0) {
 100                 decoder->state = FLAC__STREAM_DECODER_UNINITIALIZED;
 101                 decoder->guts = 0;
 102         }
 103         return decoder;
 104 }
 105
 106 void FLAC__stream_decoder_free_instance(FLAC__StreamDecoder *decoder)
 107 {
 108         free(decoder);
 109 }
 110
 111 FLAC__StreamDecoderState FLAC__stream_decoder_init(
 112         FLAC__StreamDecoder *decoder,
 113         FLAC__StreamDecoderReadStatus (*read_callback)(const FLAC__StreamDecoder *decoder, byte buffer[], unsigned *bytes, void *client_data),
 114         FLAC__StreamDecoderWriteStatus (*write_callback)(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const int32 *buffer[], void *client_data),
 115         void (*metadata_callback)(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetaData *metadata, void *client_data),
 116         void (*error_callback)(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data),
 117         void *client_data
 118 )
 119 {
 120         unsigned i;
 121
 122         assert(sizeof(int) >= 4); /* we want to die right away if this is not true */
 123         assert(decoder != 0);
 124         assert(read_callback != 0);
 125         assert(write_callback != 0);
 126         assert(metadata_callback != 0);
 127         assert(error_callback != 0);
 128         assert(decoder->state == FLAC__STREAM_DECODER_UNINITIALIZED);
 129         assert(decoder->guts == 0);
 130
 131         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;
 132
 133         decoder->guts = (FLAC__StreamDecoderPrivate*)malloc(sizeof(FLAC__StreamDecoderPrivate));
 134         if(decoder->guts == 0)
 135                 return decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 136
 137         decoder->guts->read_callback = read_callback;
 138         decoder->guts->write_callback = write_callback;
 139         decoder->guts->metadata_callback = metadata_callback;
 140         decoder->guts->error_callback = error_callback;
 141         decoder->guts->client_data = client_data;
 142
 143         FLAC__bitbuffer_init(&decoder->guts->input);
 144
 145         for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 146                 decoder->guts->output[i] = 0;
 147                 decoder->guts->residual[i] = 0;
 148         }
 149
 150         decoder->guts->output_capacity = 0;
 151         decoder->guts->output_channels = 0;
 152         decoder->guts->last_frame_number = 0;
 153         decoder->guts->samples_decoded = 0;
 154         decoder->guts->has_stream_header = false;
 155         decoder->guts->cached = false;
 156
 157         return decoder->state;
 158 }
 159
 160 void FLAC__stream_decoder_finish(FLAC__StreamDecoder *decoder)
 161 {
 162         unsigned i;
 163         assert(decoder != 0);
 164         if(decoder->state == FLAC__STREAM_DECODER_UNINITIALIZED)
 165                 return;
 166         if(decoder->guts != 0) {
 167                 FLAC__bitbuffer_free(&decoder->guts->input);
 168                 for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 169                         if(decoder->guts->output[i] != 0) {
 170                                 free(decoder->guts->output[i]);
 171                                 decoder->guts->output[i] = 0;
 172                         }
 173                         if(decoder->guts->residual[i] != 0) {
 174                                 free(decoder->guts->residual[i]);
 175                                 decoder->guts->residual[i] = 0;
 176                         }
 177                 }
 178                 free(decoder->guts);
 179                 decoder->guts = 0;
 180         }
 181         decoder->state = FLAC__STREAM_DECODER_UNINITIALIZED;
 182 }
 183
 184 bool FLAC__stream_decoder_flush(FLAC__StreamDecoder *decoder)
 185 {
 186         assert(decoder != 0);
 187
 188         if(!FLAC__bitbuffer_clear(&decoder->guts->input)) {
 189                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 190                 return false;
 191         }
 192
 193         return true;
 194 }
 195
 196 bool FLAC__stream_decoder_reset(FLAC__StreamDecoder *decoder)
 197 {
 198         assert(decoder != 0);
 199
 200         if(!FLAC__stream_decoder_flush(decoder)) {
 201                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 202                 return false;
 203         }
 204         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;
 205
 206         return true;
 207 }
 208
 209 bool FLAC__stream_decoder_process_whole_stream(FLAC__StreamDecoder *decoder)
 210 {
 211         bool dummy;
 212         assert(decoder != 0);
 213
 214         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 215                 return true;
 216
 217         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_METADATA);
 218
 219         if(!FLAC__stream_decoder_reset(decoder)) {
 220                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 221                 return false;
 222         }
 223
 224         while(1) {
 225                 switch(decoder->state) {
 226                         case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
 227                                 if(!stream_decoder_find_metadata_(decoder))
 228                                         return false; /* above function sets the status for us */
 229                                 break;
 230                         case FLAC__STREAM_DECODER_READ_METADATA:
 231                                 if(!stream_decoder_read_metadata_(decoder))
 232                                         return false; /* above function sets the status for us */
 233                                 break;
 234                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 235                                 if(!stream_decoder_frame_sync_(decoder))
 236                                         return true; /* above function sets the status for us */
 237                                 break;
 238                         case FLAC__STREAM_DECODER_READ_FRAME:
 239                                 if(!stream_decoder_read_frame_(decoder, &dummy))
 240                                         return false; /* above function sets the status for us */
 241                                 break;
 242                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 243                                 return true;
 244                         default:
 245                                 assert(0);
 246                 }
 247         }
 248 }
 249
 250 bool FLAC__stream_decoder_process_metadata(FLAC__StreamDecoder *decoder)
 251 {
 252         assert(decoder != 0);
 253
 254         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 255                 return true;
 256
 257         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_METADATA);
 258
 259         if(!FLAC__stream_decoder_reset(decoder)) {
 260                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 261                 return false;
 262         }
 263
 264         while(1) {
 265                 switch(decoder->state) {
 266                         case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
 267                                 if(!stream_decoder_find_metadata_(decoder))
 268                                         return false; /* above function sets the status for us */
 269                                 break;
 270                         case FLAC__STREAM_DECODER_READ_METADATA:
 271                                 if(!stream_decoder_read_metadata_(decoder))
 272                                         return false; /* above function sets the status for us */
 273                                 break;
 274                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 275                                 return true;
 276                                 break;
 277                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 278                                 return true;
 279                         default:
 280                                 assert(0);
 281                 }
 282         }
 283 }
 284
 285 bool FLAC__stream_decoder_process_one_frame(FLAC__StreamDecoder *decoder)
 286 {
 287         bool got_a_frame;
 288         assert(decoder != 0);
 289
 290         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 291                 return true;
 292
 293         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC);
 294
 295         while(1) {
 296                 switch(decoder->state) {
 297                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 298                                 if(!stream_decoder_frame_sync_(decoder))
 299                                         return true; /* above function sets the status for us */
 300                                 break;
 301                         case FLAC__STREAM_DECODER_READ_FRAME:
 302                                 if(!stream_decoder_read_frame_(decoder, &got_a_frame))
 303                                         return false; /* above function sets the status for us */
 304                                 if(got_a_frame)
 305                                         return true; /* above function sets the status for us */
 306                                 break;
 307                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 308                                 return true;
 309                         default:
 310                                 assert(0);
 311                 }
 312         }
 313 }
 314
 315 bool FLAC__stream_decoder_process_remaining_frames(FLAC__StreamDecoder *decoder)
 316 {
 317         bool dummy;
 318         assert(decoder != 0);
 319
 320         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 321                 return true;
 322
 323         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC);
 324
 325         while(1) {
 326                 switch(decoder->state) {
 327                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 328                                 if(!stream_decoder_frame_sync_(decoder))
 329                                         return true; /* above function sets the status for us */
 330                                 break;
 331                         case FLAC__STREAM_DECODER_READ_FRAME:
 332                                 if(!stream_decoder_read_frame_(decoder, &dummy))
 333                                         return false; /* above function sets the status for us */
 334                                 break;
 335                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 336                                 return true;
 337                         default:
 338                                 assert(0);
 339                 }
 340         }
 341 }
 342
 343 unsigned FLAC__stream_decoder_input_bytes_unconsumed(FLAC__StreamDecoder *decoder)
 344 {
 345         assert(decoder != 0);
 346         return decoder->guts->input.bytes - decoder->guts->input.consumed_bytes;
 347 }
 348
 349 bool stream_decoder_allocate_output_(FLAC__StreamDecoder *decoder, unsigned size, unsigned channels)
 350 {
 351         unsigned i;
 352         int32 *tmp;
 353
 354         if(size <= decoder->guts->output_capacity && channels <= decoder->guts->output_channels)
 355                 return true;
 356
 357         /* @@@ should change to use realloc() */
 358
 359         for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 360                 if(decoder->guts->output[i] != 0) {
 361                         free(decoder->guts->output[i]);
 362                         decoder->guts->output[i] = 0;
 363                 }
 364                 if(decoder->guts->residual[i] != 0) {
 365                         free(decoder->guts->residual[i]);
 366                         decoder->guts->residual[i] = 0;
 367                 }
 368         }
 369
 370         for(i = 0; i < channels; i++) {
 371                 tmp = (int32*)malloc(sizeof(int32)*size);
 372                 if(tmp == 0) {
 373                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 374                         return false;
 375                 }
 376                 decoder->guts->output[i] = tmp;
 377
 378                 tmp = (int32*)malloc(sizeof(int32)*size);
 379                 if(tmp == 0) {
 380                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 381                         return false;
 382                 }
 383                 decoder->guts->residual[i] = tmp;
 384         }
 385
 386         decoder->guts->output_capacity = size;
 387         decoder->guts->output_channels = channels;
 388
 389         return true;
 390 }
 391
 392 bool stream_decoder_find_metadata_(FLAC__StreamDecoder *decoder)
 393 {
 394         uint32 x;
 395         unsigned i, id;
 396         bool first = true;
 397
 398         assert(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 399
 400         for(i = id = 0; i < 4; ) {
 401                 if(decoder->guts->cached) {
 402                         x = (uint32)decoder->guts->lookahead;
 403                         decoder->guts->cached = false;
 404                 }
 405                 else {
 406                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 407                                 return false; /* the read_callback_ sets the state for us */
 408                 }
 409                 if(x == FLAC__STREAM_SYNC_STRING[i]) {
 410                         first = true;
 411                         i++;
 412                         id = 0;
 413                         continue;
 414                 }
 415                 if(x == ID3V2_TAG_[id]) {
 416                         id++;
 417                         i = 0;
 418                         if(id == 3) {
 419                                 if(!stream_decoder_skip_id3v2_tag_(decoder))
 420                                         return false; /* the read_callback_ sets the state for us */
 421                         }
 422                         continue;
 423                 }
 424                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 425                         decoder->guts->header_warmup[0] = (byte)x;
 426                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 427                                 return false; /* the read_callback_ sets the state for us */
 428
 429                         /* we have to check if we just read two 0xff's in a row; the second may actually be the beginning of the sync code */
 430                         /* else we have to check if the second byte is the end of a sync code */
 431                         if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 432                                 decoder->guts->lookahead = (byte)x;
 433                                 decoder->guts->cached = true;
 434                         }
 435                         else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
 436                                 decoder->guts->header_warmup[1] = (byte)x;
 437                                 decoder->state = FLAC__STREAM_DECODER_READ_FRAME;
 438                                 return true;
 439                         }
 440                 }
 441                 i = 0;
 442                 if(first) {
 443                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
 444                         first = false;
 445                 }
 446         }
 447
 448         decoder->state = FLAC__STREAM_DECODER_READ_METADATA;
 449         return true;
 450 }
 451
 452 bool stream_decoder_read_metadata_(FLAC__StreamDecoder *decoder)
 453 {
 454         uint32 i, x, last_block, type, length;
 455
 456         assert(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 457
 458         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &last_block, FLAC__STREAM_METADATA_IS_LAST_LEN, read_callback_, decoder))
 459                 return false; /* the read_callback_ sets the state for us */
 460         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &type, FLAC__STREAM_METADATA_TYPE_LEN, read_callback_, decoder))
 461                 return false; /* the read_callback_ sets the state for us */
 462         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &length, FLAC__STREAM_METADATA_LENGTH_LEN, read_callback_, decoder))
 463                 return false; /* the read_callback_ sets the state for us */
 464         if(type == FLAC__METADATA_TYPE_STREAMINFO) {
 465                 unsigned used_bits = 0;
 466                 decoder->guts->stream_header.type = type;
 467                 decoder->guts->stream_header.is_last = last_block;
 468                 decoder->guts->stream_header.length = length;
 469
 470                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN, read_callback_, decoder))
 471                         return false; /* the read_callback_ sets the state for us */
 472                 decoder->guts->stream_header.data.stream_info.min_blocksize = x;
 473                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN;
 474
 475                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN, read_callback_, decoder))
 476                         return false; /* the read_callback_ sets the state for us */
 477                 decoder->guts->stream_header.data.stream_info.max_blocksize = x;
 478                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN;
 479
 480                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN, read_callback_, decoder))
 481                         return false; /* the read_callback_ sets the state for us */
 482                 decoder->guts->stream_header.data.stream_info.min_framesize = x;
 483                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN;
 484
 485                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN, read_callback_, decoder))
 486                         return false; /* the read_callback_ sets the state for us */
 487                 decoder->guts->stream_header.data.stream_info.max_framesize = x;
 488                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN;
 489
 490                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN, read_callback_, decoder))
 491                         return false; /* the read_callback_ sets the state for us */
 492                 decoder->guts->stream_header.data.stream_info.sample_rate = x;
 493                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN;
 494
 495                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN, read_callback_, decoder))
 496                         return false; /* the read_callback_ sets the state for us */
 497                 decoder->guts->stream_header.data.stream_info.channels = x+1;
 498                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN;
 499
 500                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN, read_callback_, decoder))
 501                         return false; /* the read_callback_ sets the state for us */
 502                 decoder->guts->stream_header.data.stream_info.bits_per_sample = x+1;
 503                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN;
 504
 505                 if(!FLAC__bitbuffer_read_raw_uint64(&decoder->guts->input, &decoder->guts->stream_header.data.stream_info.total_samples, FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN, read_callback_, decoder))
 506                         return false; /* the read_callback_ sets the state for us */
 507                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN;
 508
 509                 for(i = 0; i < 16; i++) {
 510                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 511                                 return false; /* the read_callback_ sets the state for us */
 512                         decoder->guts->stream_header.data.stream_info.md5sum[i] = (byte)x;
 513                 }
 514                 used_bits += i*8;
 515
 516                 /* skip the rest of the block */
 517                 assert(used_bits % 8 == 0);
 518                 length -= (used_bits / 8);
 519                 for(i = 0; i < length; i++) {
 520                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 521                                 return false; /* the read_callback_ sets the state for us */
 522                 }
 523
 524                 decoder->guts->has_stream_header = true;
 525                 decoder->guts->metadata_callback(decoder, &decoder->guts->stream_header, decoder->guts->client_data);
 526         }
 527         else {
 528                 /* skip other metadata blocks */
 529                 for(i = 0; i < length; i++) {
 530                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 531                                 return false; /* the read_callback_ sets the state for us */
 532                 }
 533         }
 534
 535         if(last_block)
 536                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 537
 538         return true;
 539 }
 540
 541 bool stream_decoder_skip_id3v2_tag_(FLAC__StreamDecoder *decoder)
 542 {
 543         uint32 x;
 544         unsigned i, skip;
 545
 546         /* skip the version and flags bytes */
 547         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 24, read_callback_, decoder))
 548                 return false; /* the read_callback_ sets the state for us */
 549         /* get the size (in bytes) to skip */
 550         skip = 0;
 551         for(i = 0; i < 4; i++) {
 552                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 553                         return false; /* the read_callback_ sets the state for us */
 554                 skip <<= 7;
 555                 skip |= (x & 0x7f);
 556         }
 557         /* skip the rest of the tag */
 558         for(i = 0; i < skip; i++) {
 559                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 560                         return false; /* the read_callback_ sets the state for us */
 561         }
 562         return true;
 563 }
 564
 565 bool stream_decoder_frame_sync_(FLAC__StreamDecoder *decoder)
 566 {
 567         uint32 x;
 568         bool first = true;
 569
 570         /* If we know the total number of samples in the stream, stop if we've read that many. */
 571         /* This will stop us, for example, from wasting time trying to sync on an ID3V1 tag. */
 572         if(decoder->guts->has_stream_header && decoder->guts->stream_header.data.stream_info.total_samples) {
 573                 if(decoder->guts->samples_decoded >= decoder->guts->stream_header.data.stream_info.total_samples) {
 574                         decoder->state = FLAC__STREAM_DECODER_END_OF_STREAM;
 575                         return true;
 576                 }
 577         }
 578
 579         /* make sure we're byte aligned */
 580         if(decoder->guts->input.consumed_bits != 0) {
 581                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8-decoder->guts->input.consumed_bits, read_callback_, decoder))
 582                         return false; /* the read_callback_ sets the state for us */
 583         }
 584
 585         while(1) {
 586                 if(decoder->guts->cached) {
 587                         x = (uint32)decoder->guts->lookahead;
 588                         decoder->guts->cached = false;
 589                 }
 590                 else {
 591                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 592                                 return false; /* the read_callback_ sets the state for us */
 593                 }
 594                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 595                         decoder->guts->header_warmup[0] = (byte)x;
 596                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 597                                 return false; /* the read_callback_ sets the state for us */
 598
 599                         /* we have to check if we just read two 0xff's in a row; the second may actually be the beginning of the sync code */
 600                         /* else we have to check if the second byte is the end of a sync code */
 601                         if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 602                                 decoder->guts->lookahead = (byte)x;
 603                                 decoder->guts->cached = true;
 604                         }
 605                         else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
 606                                 decoder->guts->header_warmup[1] = (byte)x;
 607                                 decoder->state = FLAC__STREAM_DECODER_READ_FRAME;
 608                                 return true;
 609                         }
 610                 }
 611                 if(first) {
 612                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
 613                         first = 0;
 614                 }
 615         }
 616
 617         return true;
 618 }
 619
 620 bool stream_decoder_read_frame_(FLAC__StreamDecoder *decoder, bool *got_a_frame)
 621 {
 622         unsigned channel;
 623         unsigned i;
 624         int32 mid, side, left, right;
 625         uint16 frame_crc; /* the one we calculate from the input stream */
 626         uint32 x;
 627
 628         *got_a_frame = false;
 629
 630         /* init the CRC */
 631         frame_crc = 0;
 632         FLAC__CRC16_UPDATE(decoder->guts->header_warmup[0], frame_crc);
 633         FLAC__CRC16_UPDATE(decoder->guts->header_warmup[1], frame_crc);
 634         FLAC__bitbuffer_init_read_crc16(&decoder->guts->input, frame_crc);
 635
 636         if(!stream_decoder_read_frame_header_(decoder))
 637                 return false;
 638         if(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC)
 639                 return true;
 640         if(!stream_decoder_allocate_output_(decoder, decoder->guts->frame.header.blocksize, decoder->guts->frame.header.channels))
 641                 return false;
 642         for(channel = 0; channel < decoder->guts->frame.header.channels; channel++) {
 643                 /*
 644                  * first figure the correct bits-per-sample of the subframe
 645                  */
 646                 unsigned bps = decoder->guts->frame.header.bits_per_sample;
 647                 switch(decoder->guts->frame.header.channel_assignment) {
 648                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 649                                 /* no adjustment needed */
 650                                 break;
 651                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 652                                 assert(decoder->guts->frame.header.channels == 2);
 653                                 if(channel == 1)
 654                                         bps++;
 655                                 break;
 656                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 657                                 assert(decoder->guts->frame.header.channels == 2);
 658                                 if(channel == 0)
 659                                         bps++;
 660                                 break;
 661                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 662                                 assert(decoder->guts->frame.header.channels == 2);
 663                                 if(channel == 1)
 664                                         bps++;
 665                                 break;
 666                         default:
 667                                 assert(0);
 668                 }
 669                 /*
 670                  * now read it
 671                  */
 672                 if(!stream_decoder_read_subframe_(decoder, channel, bps))
 673                         return false;
 674                 if(decoder->state != FLAC__STREAM_DECODER_READ_FRAME) {
 675                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 676                         return true;
 677                 }
 678         }
 679         if(!stream_decoder_read_zero_padding_(decoder))
 680                 return false;
 681
 682         /*
 683          * Read the frame CRC-16 from the footer and check
 684          */
 685         frame_crc = decoder->guts->input.read_crc16;
 686         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__FRAME_FOOTER_CRC_LEN, read_callback_, decoder))
 687                 return false; /* the read_callback_ sets the state for us */
 688         if(frame_crc == (uint16)x) {
 689                 /* Undo any special channel coding */
 690                 switch(decoder->guts->frame.header.channel_assignment) {
 691                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 692                                 /* do nothing */
 693                                 break;
 694                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 695                                 assert(decoder->guts->frame.header.channels == 2);
 696                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
 697                                         decoder->guts->output[1][i] = decoder->guts->output[0][i] - decoder->guts->output[1][i];
 698                                 break;
 699                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 700                                 assert(decoder->guts->frame.header.channels == 2);
 701                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
 702                                         decoder->guts->output[0][i] += decoder->guts->output[1][i];
 703                                 break;
 704                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 705                                 assert(decoder->guts->frame.header.channels == 2);
 706                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++) {
 707                                         mid = decoder->guts->output[0][i];
 708                                         side = decoder->guts->output[1][i];
 709                                         mid <<= 1;
 710                                         if(side & 1) /* i.e. if 'side' is odd... */
 711                                                 mid++;
 712                                         left = mid + side;
 713                                         right = mid - side;
 714                                         decoder->guts->output[0][i] = left >> 1;
 715                                         decoder->guts->output[1][i] = right >> 1;
 716                                 }
 717                                 break;
 718                         default:
 719                                 assert(0);
 720                                 break;
 721                 }
 722         }
 723         else {
 724                 /* Bad frame, emit error and zero the output signal */
 725                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_FRAME_CRC_MISMATCH, decoder->guts->client_data);
 726                 for(channel = 0; channel < decoder->guts->frame.header.channels; channel++) {
 727                         memset(decoder->guts->output[channel], 0, sizeof(int32) * decoder->guts->frame.header.blocksize);
 728                 }
 729         }
 730
 731         *got_a_frame = true;
 732
 733         /* put the latest values into the public section of the decoder instance */
 734         decoder->channels = decoder->guts->frame.header.channels;
 735         decoder->channel_assignment = decoder->guts->frame.header.channel_assignment;
 736         decoder->bits_per_sample = decoder->guts->frame.header.bits_per_sample;
 737         decoder->sample_rate = decoder->guts->frame.header.sample_rate;
 738         decoder->blocksize = decoder->guts->frame.header.blocksize;
 739
 740         decoder->guts->samples_decoded += decoder->guts->frame.header.blocksize;
 741
 742         /* write it */
 743         if(decoder->guts->write_callback(decoder, &decoder->guts->frame, decoder->guts->output, decoder->guts->client_data) != FLAC__STREAM_DECODER_WRITE_CONTINUE)
 744                 return false;
 745
 746         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 747         return true;
 748 }
 749
 750 bool stream_decoder_read_frame_header_(FLAC__StreamDecoder *decoder)
 751 {
 752         uint32 x;
 753         uint64 xx;
 754         unsigned i, blocksize_hint = 0, sample_rate_hint = 0;
 755         byte crc8, raw_header[16]; /* MAGIC NUMBER based on the maximum frame header size, including CRC */
 756         unsigned raw_header_len;
 757         bool is_unparseable = false;
 758
 759         assert(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 760
 761         /* init the raw header with the saved bits from synchronization */
 762         raw_header[0] = decoder->guts->header_warmup[0];
 763         raw_header[1] = decoder->guts->header_warmup[1];
 764         raw_header_len = 2;
 765
 766         /*
 767          * check to make sure that the reserved bits are 0
 768          */
 769         if(raw_header[1] & 0x03) { /* MAGIC NUMBER */
 770                 is_unparseable = true;
 771         }
 772
 773         /*
 774          * Note that along the way as we read the header, we look for a sync
 775          * code inside.  If we find one it would indicate that our original
 776          * sync was bad since there cannot be a sync code in a valid header.
 777          */
 778
 779         /*
 780          * read in the raw header as bytes so we can CRC it, and parse it on the way
 781          */
 782         for(i = 0; i < 2; i++) {
 783                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 784                         return false; /* the read_callback_ sets the state for us */
 785                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 786                         /* if we get here it means our original sync was erroneous since the sync code cannot appear in the header */
 787                         decoder->guts->lookahead = (byte)x;
 788                         decoder->guts->cached = true;
 789                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 790                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 791                         return true;
 792                 }
 793                 raw_header[raw_header_len++] = (byte)x;
 794         }
 795
 796         switch(x = raw_header[2] >> 4) {
 797                 case 0:
 798                         if(decoder->guts->has_stream_header && decoder->guts->stream_header.data.stream_info.min_blocksize == decoder->guts->stream_header.data.stream_info.max_blocksize) /* i.e. it's a fixed-blocksize stream */
 799                                 decoder->guts->frame.header.blocksize = decoder->guts->stream_header.data.stream_info.min_blocksize;
 800                         else
 801                                 is_unparseable = true;
 802                         break;
 803                 case 1:
 804                         decoder->guts->frame.header.blocksize = 192;
 805                         break;
 806                 case 2:
 807                 case 3:
 808                 case 4:
 809                 case 5:
 810                         decoder->guts->frame.header.blocksize = 576 << (x-2);
 811                         break;
 812                 case 6:
 813                 case 7:
 814                         blocksize_hint = x;
 815                         break;
 816                 case 8:
 817                 case 9:
 818                 case 10:
 819                 case 11:
 820                 case 12:
 821                 case 13:
 822                 case 14:
 823                 case 15:
 824                         decoder->guts->frame.header.blocksize = 256 << (x-8);
 825                         break;
 826                 default:
 827                         assert(0);
 828                         break;
 829         }
 830
 831         switch(x = raw_header[2] & 0x0f) {
 832                 case 0:
 833                         if(decoder->guts->has_stream_header)
 834                                 decoder->guts->frame.header.sample_rate = decoder->guts->stream_header.data.stream_info.sample_rate;
 835                         else
 836                                 is_unparseable = true;
 837                         break;
 838                 case 1:
 839                 case 2:
 840                 case 3:
 841                         is_unparseable = true;
 842                         break;
 843                 case 4:
 844                         decoder->guts->frame.header.sample_rate = 8000;
 845                         break;
 846                 case 5:
 847                         decoder->guts->frame.header.sample_rate = 16000;
 848                         break;
 849                 case 6:
 850                         decoder->guts->frame.header.sample_rate = 22050;
 851                         break;
 852                 case 7:
 853                         decoder->guts->frame.header.sample_rate = 24000;
 854                         break;
 855                 case 8:
 856                         decoder->guts->frame.header.sample_rate = 32000;
 857                         break;
 858                 case 9:
 859                         decoder->guts->frame.header.sample_rate = 44100;
 860                         break;
 861                 case 10:
 862                         decoder->guts->frame.header.sample_rate = 48000;
 863                         break;
 864                 case 11:
 865                         decoder->guts->frame.header.sample_rate = 96000;
 866                         break;
 867                 case 12:
 868                 case 13:
 869                 case 14:
 870                         sample_rate_hint = x;
 871                         break;
 872                 case 15:
 873                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 874                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 875                         return true;
 876                 default:
 877                         assert(0);
 878         }
 879
 880         x = (unsigned)(raw_header[3] >> 4);
 881         if(x & 8) {
 882                 decoder->guts->frame.header.channels = 2;
 883                 switch(x & 7) {
 884                         case 0:
 885                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE;
 886                                 break;
 887                         case 1:
 888                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE;
 889                                 break;
 890                         case 2:
 891                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_MID_SIDE;
 892                                 break;
 893                         default:
 894                                 is_unparseable = true;
 895                                 break;
 896                 }
 897         }
 898         else {
 899                 decoder->guts->frame.header.channels = (unsigned)x + 1;
 900                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT;
 901         }
 902
 903         switch(x = (unsigned)(raw_header[3] & 0x0e) >> 1) {
 904                 case 0:
 905                         if(decoder->guts->has_stream_header)
 906                                 decoder->guts->frame.header.bits_per_sample = decoder->guts->stream_header.data.stream_info.bits_per_sample;
 907                         else
 908                                 is_unparseable = true;
 909                         break;
 910                 case 1:
 911                         decoder->guts->frame.header.bits_per_sample = 8;
 912                         break;
 913                 case 2:
 914                         decoder->guts->frame.header.bits_per_sample = 12;
 915                         break;
 916                 case 4:
 917                         decoder->guts->frame.header.bits_per_sample = 16;
 918                         break;
 919                 case 5:
 920                         decoder->guts->frame.header.bits_per_sample = 20;
 921                         break;
 922                 case 6:
 923                         decoder->guts->frame.header.bits_per_sample = 24;
 924                         break;
 925                 case 3:
 926                 case 7:
 927                         is_unparseable = true;
 928                         break;
 929                 default:
 930                         assert(0);
 931                         break;
 932         }
 933
 934         if(raw_header[3] & 0x01) { /* this should be a zero padding bit */
 935                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 936                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 937                 return true;
 938         }
 939
 940         if(blocksize_hint) {
 941                 if(!FLAC__bitbuffer_read_utf8_uint64(&decoder->guts->input, &xx, read_callback_, decoder, raw_header, &raw_header_len))
 942                         return false; /* the read_callback_ sets the state for us */
 943                 if(xx == 0xffffffffffffffff) { /* i.e. non-UTF8 code... */
 944                         decoder->guts->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
 945                         decoder->guts->cached = true;
 946                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 947                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 948                         return true;
 949                 }
 950                 if(decoder->guts->has_stream_header && decoder->guts->stream_header.data.stream_info.min_blocksize == decoder->guts->stream_header.data.stream_info.max_blocksize) /* i.e. it's a fixed-blocksize stream */
 951                         decoder->guts->frame.header.number.sample_number = (uint64)decoder->guts->last_frame_number * (int64)decoder->guts->stream_header.data.stream_info.min_blocksize + xx;
 952                 else
 953                         decoder->guts->frame.header.number.sample_number = xx;
 954         }
 955         else {
 956                 if(!FLAC__bitbuffer_read_utf8_uint32(&decoder->guts->input, &x, read_callback_, decoder, raw_header, &raw_header_len))
 957                         return false; /* the read_callback_ sets the state for us */
 958                 if(x == 0xffffffff) { /* i.e. non-UTF8 code... */
 959                         decoder->guts->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
 960                         decoder->guts->cached = true;
 961                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 962                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 963                         return true;
 964                 }
 965                 decoder->guts->last_frame_number = x;
 966                 if(decoder->guts->has_stream_header) {
 967                         decoder->guts->frame.header.number.sample_number = (int64)decoder->guts->stream_header.data.stream_info.min_blocksize * (int64)x;
 968                 }
 969                 else {
 970                         is_unparseable = true;
 971                 }
 972         }
 973
 974         if(blocksize_hint) {
 975                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 976                         return false; /* the read_callback_ sets the state for us */
 977                 raw_header[raw_header_len++] = (byte)x;
 978                 if(blocksize_hint == 7) {
 979                         uint32 _x;
 980                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &_x, 8, read_callback_, decoder))
 981                                 return false; /* the read_callback_ sets the state for us */
 982                         raw_header[raw_header_len++] = (byte)_x;
 983                         x = (x << 8) | _x;
 984                 }
 985                 decoder->guts->frame.header.blocksize = x+1;
 986         }
 987
 988         if(sample_rate_hint) {
 989                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 990                         return false; /* the read_callback_ sets the state for us */
 991                 raw_header[raw_header_len++] = (byte)x;
 992                 if(sample_rate_hint != 12) {
 993                         uint32 _x;
 994                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &_x, 8, read_callback_, decoder))
 995                                 return false; /* the read_callback_ sets the state for us */
 996                         raw_header[raw_header_len++] = (byte)_x;
 997                         x = (x << 8) | _x;
 998                 }
 999                 if(sample_rate_hint == 12)
1000                         decoder->guts->frame.header.sample_rate = x*1000;
1001                 else if(sample_rate_hint == 13)
1002                         decoder->guts->frame.header.sample_rate = x;
1003                 else
1004                         decoder->guts->frame.header.sample_rate = x*10;
1005         }
1006
1007         /* read the CRC-8 byte */
1008         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1009                 return false; /* the read_callback_ sets the state for us */
1010         crc8 = (byte)x;
1011
1012         if(FLAC__crc8(raw_header, raw_header_len) != crc8) {
1013                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1014                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1015                 return true;
1016         }
1017
1018         if(is_unparseable) {
1019                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1020                 return false;
1021         }
1022
1023         return true;
1024 }
1025
1026 bool stream_decoder_read_subframe_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1027 {
1028         uint32 x;
1029         bool wasted_bits;
1030
1031         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder)) /* MAGIC NUMBER */
1032                 return false; /* the read_callback_ sets the state for us */
1033
1034         wasted_bits = (x & 1);
1035         x &= 0xfe;
1036
1037         if(wasted_bits) {
1038                 unsigned u;
1039                 if(!FLAC__bitbuffer_read_unary_unsigned(&decoder->guts->input, &u, read_callback_, decoder))
1040                         return false; /* the read_callback_ sets the state for us */
1041                 decoder->guts->frame.subframes[channel].wasted_bits = u+1;
1042                 bps -= decoder->guts->frame.subframes[channel].wasted_bits;
1043         }
1044         else
1045                 decoder->guts->frame.subframes[channel].wasted_bits = 0;
1046
1047         /*
1048          * Lots of magic numbers here
1049          */
1050         if(x & 0x80) {
1051                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1052                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1053                 return true;
1054         }
1055         else if(x == 0) {
1056                 if(!stream_decoder_read_subframe_constant_(decoder, channel, bps))
1057                         return false;
1058         }
1059         else if(x == 2) {
1060                 if(!stream_decoder_read_subframe_verbatim_(decoder, channel, bps))
1061                         return false;
1062         }
1063         else if(x < 16) {
1064                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1065                 return false;
1066         }
1067         else if(x <= 24) {
1068                 if(!stream_decoder_read_subframe_fixed_(decoder, channel, bps, (x>>1)&7))
1069                         return false;
1070         }
1071         else if(x < 64) {
1072                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1073                 return false;
1074         }
1075         else {
1076                 if(!stream_decoder_read_subframe_lpc_(decoder, channel, bps, ((x>>1)&31)+1))
1077                         return false;
1078         }
1079
1080         if(wasted_bits) {
1081                 unsigned i;
1082                 x = decoder->guts->frame.subframes[channel].wasted_bits;
1083                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
1084                         decoder->guts->output[channel][i] <<= x;
1085         }
1086
1087         return true;
1088 }
1089
1090 bool stream_decoder_read_subframe_constant_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1091 {
1092         FLAC__Subframe_Constant *subframe = &decoder->guts->frame.subframes[channel].data.constant;
1093         int32 x;
1094         unsigned i;
1095         int32 *output = decoder->guts->output[channel];
1096
1097         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_CONSTANT;
1098
1099         if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &x, bps, read_callback_, decoder))
1100                 return false; /* the read_callback_ sets the state for us */
1101
1102         subframe->value = x;
1103
1104         /* decode the subframe */
1105         for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
1106                 output[i] = x;
1107
1108         return true;
1109 }
1110
1111 bool stream_decoder_read_subframe_fixed_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order)
1112 {
1113         FLAC__Subframe_Fixed *subframe = &decoder->guts->frame.subframes[channel].data.fixed;
1114         int32 i32;
1115         uint32 u32;
1116         unsigned u;
1117
1118         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_FIXED;
1119
1120         subframe->residual = decoder->guts->residual[channel];
1121         subframe->order = order;
1122
1123         /* read warm-up samples */
1124         for(u = 0; u < order; u++) {
1125                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, bps - decoder->guts->frame.subframes[channel].wasted_bits, read_callback_, decoder))
1126                         return false; /* the read_callback_ sets the state for us */
1127                 subframe->warmup[u] = i32;
1128         }
1129
1130         /* read entropy coding method info */
1131         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN, read_callback_, decoder))
1132                 return false; /* the read_callback_ sets the state for us */
1133         subframe->entropy_coding_method.type = u32;
1134         switch(subframe->entropy_coding_method.type) {
1135                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1136                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN, read_callback_, decoder))
1137                                 return false; /* the read_callback_ sets the state for us */
1138                         subframe->entropy_coding_method.data.partitioned_rice.order = u32;
1139                         break;
1140                 default:
1141                         decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1142                         return false;
1143         }
1144
1145         /* read residual */
1146         switch(subframe->entropy_coding_method.type) {
1147                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1148                         if(!stream_decoder_read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, decoder->guts->residual[channel]))
1149                                 return false;
1150                         break;
1151                 default:
1152                         assert(0);
1153         }
1154
1155         /* decode the subframe */
1156         memcpy(decoder->guts->output[channel], subframe->warmup, sizeof(int32) * order);
1157         FLAC__fixed_restore_signal(decoder->guts->residual[channel], decoder->guts->frame.header.blocksize-order, order, decoder->guts->output[channel]+order);
1158
1159         return true;
1160 }
1161
1162 bool stream_decoder_read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order)
1163 {
1164         FLAC__Subframe_LPC *subframe = &decoder->guts->frame.subframes[channel].data.lpc;
1165         int32 i32;
1166         uint32 u32;
1167         unsigned u;
1168
1169         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_LPC;
1170
1171         subframe->residual = decoder->guts->residual[channel];
1172         subframe->order = order;
1173
1174         /* read warm-up samples */
1175         for(u = 0; u < order; u++) {
1176                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, bps - decoder->guts->frame.subframes[channel].wasted_bits, read_callback_, decoder))
1177                         return false; /* the read_callback_ sets the state for us */
1178                 subframe->warmup[u] = i32;
1179         }
1180
1181         /* read qlp coeff precision */
1182         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN, read_callback_, decoder))
1183                 return false; /* the read_callback_ sets the state for us */
1184         if(u32 == 15) {
1185                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1186                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1187                 return true;
1188         }
1189         subframe->qlp_coeff_precision = u32+1;
1190
1191         /* read qlp shift */
1192         if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN, read_callback_, decoder))
1193                 return false; /* the read_callback_ sets the state for us */
1194         subframe->quantization_level = i32;
1195
1196         /* read quantized lp coefficiencts */
1197         for(u = 0; u < order; u++) {
1198                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, subframe->qlp_coeff_precision, read_callback_, decoder))
1199                         return false; /* the read_callback_ sets the state for us */
1200                 subframe->qlp_coeff[u] = i32;
1201         }
1202
1203         /* read entropy coding method info */
1204         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN, read_callback_, decoder))
1205                 return false; /* the read_callback_ sets the state for us */
1206         subframe->entropy_coding_method.type = u32;
1207         switch(subframe->entropy_coding_method.type) {
1208                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1209                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN, read_callback_, decoder))
1210                                 return false; /* the read_callback_ sets the state for us */
1211                         subframe->entropy_coding_method.data.partitioned_rice.order = u32;
1212                         break;
1213                 default:
1214                         decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1215                         return false;
1216         }
1217
1218         /* read residual */
1219         switch(subframe->entropy_coding_method.type) {
1220                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1221                         if(!stream_decoder_read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, decoder->guts->residual[channel]))
1222                                 return false;
1223                         break;
1224                 default:
1225                         assert(0);
1226         }
1227
1228         /* decode the subframe */
1229         memcpy(decoder->guts->output[channel], subframe->warmup, sizeof(int32) * order);
1230         FLAC__lpc_restore_signal(decoder->guts->residual[channel], decoder->guts->frame.header.blocksize-order, subframe->qlp_coeff, order, subframe->quantization_level, decoder->guts->output[channel]+order);
1231
1232         return true;
1233 }
1234
1235 bool stream_decoder_read_subframe_verbatim_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1236 {
1237         FLAC__Subframe_Verbatim *subframe = &decoder->guts->frame.subframes[channel].data.verbatim;
1238         int32 x, *residual = decoder->guts->residual[channel];
1239         unsigned i;
1240
1241         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_VERBATIM;
1242
1243         subframe->data = residual;
1244
1245         for(i = 0; i < decoder->guts->frame.header.blocksize; i++) {
1246                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &x, bps, read_callback_, decoder))
1247                         return false; /* the read_callback_ sets the state for us */
1248                 residual[i] = x;
1249         }
1250
1251         /* decode the subframe */
1252         memcpy(decoder->guts->output[channel], subframe->data, sizeof(int32) * decoder->guts->frame.header.blocksize);
1253
1254         return true;
1255 }
1256
1257 bool stream_decoder_read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, unsigned predictor_order, unsigned partition_order, int32 *residual)
1258 {
1259         uint32 rice_parameter;
1260         int i;
1261         unsigned partition, sample, u;
1262         const unsigned partitions = 1u << partition_order;
1263         const unsigned partition_samples = partition_order > 0? decoder->guts->frame.header.blocksize >> partition_order : decoder->guts->frame.header.blocksize - predictor_order;
1264
1265         sample = 0;
1266         for(partition = 0; partition < partitions; partition++) {
1267                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &rice_parameter, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN, read_callback_, decoder))
1268                         return false; /* the read_callback_ sets the state for us */
1269                 for(u = (partition_order == 0 || partition > 0)? 0 : predictor_order; u < partition_samples; u++, sample++) {
1270 #ifdef SYMMETRIC_RICE
1271                         if(!FLAC__bitbuffer_read_symmetric_rice_signed(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1272                                 return false; /* the read_callback_ sets the state for us */
1273 #else
1274                         if(!FLAC__bitbuffer_read_rice_signed(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1275                                 return false; /* the read_callback_ sets the state for us */
1276 #endif
1277                         residual[sample] = i;
1278                 }
1279         }
1280
1281         return true;
1282 }
1283
1284 bool stream_decoder_read_zero_padding_(FLAC__StreamDecoder *decoder)
1285 {
1286         if(decoder->guts->input.consumed_bits != 0) {
1287                 uint32 zero = 0;
1288                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &zero, 8-decoder->guts->input.consumed_bits, read_callback_, decoder))
1289                         return false; /* the read_callback_ sets the state for us */
1290                 if(zero != 0) {
1291                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1292                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1293                 }
1294         }
1295         return true;
1296 }
1297
1298 bool read_callback_(byte buffer[], unsigned *bytes, void *client_data)
1299 {
1300         FLAC__StreamDecoder *decoder = (FLAC__StreamDecoder *)client_data;
1301         FLAC__StreamDecoderReadStatus status;
1302         status = decoder->guts->read_callback(decoder, buffer, bytes, decoder->guts->client_data);
1303         if(status == FLAC__STREAM_DECODER_READ_END_OF_STREAM)
1304                 decoder->state = FLAC__STREAM_DECODER_END_OF_STREAM;
1305         else if(status == FLAC__STREAM_DECODER_READ_ABORT)
1306                 decoder->state = FLAC__STREAM_DECODER_ABORTED;
1307         return status == FLAC__STREAM_DECODER_READ_CONTINUE;
1308 }