src/libFLAC/stream_decoder.c

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