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