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 <stdio.h>
  21 #include <stdlib.h> /* for malloc() */
  22 #include <string.h> /* for memset/memcpy() */
  23 #include "FLAC/assert.h"
  24 #include "FLAC/stream_decoder.h"
  25 #include "private/bitbuffer.h"
  26 #include "private/cpu.h"
  27 #include "private/crc.h"
  28 #include "private/fixed.h"
  29 #include "private/lpc.h"
  30
  31 typedef struct FLAC__StreamDecoderPrivate {
  32         FLAC__StreamDecoderReadStatus (*read_callback)(const FLAC__StreamDecoder *decoder, byte buffer[], unsigned *bytes, void *client_data);
  33         FLAC__StreamDecoderWriteStatus (*write_callback)(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const int32 *buffer[], void *client_data);
  34         void (*metadata_callback)(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetaData *metadata, void *client_data);
  35         void (*error_callback)(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data);
  36         void (*local_lpc_restore_signal)(const int32 residual[], unsigned data_len, const int32 qlp_coeff[], unsigned order, int lp_quantization, int32 data[]);
  37         void (*local_lpc_restore_signal_16bit)(const int32 residual[], unsigned data_len, const int32 qlp_coeff[], unsigned order, int lp_quantization, int32 data[]);
  38         void *client_data;
  39         FLAC__BitBuffer input;
  40         int32 *output[FLAC__MAX_CHANNELS];
  41         int32 *residual[FLAC__MAX_CHANNELS];
  42         unsigned output_capacity, output_channels;
  43         uint32 last_frame_number;
  44         uint64 samples_decoded;
  45         bool has_stream_info, has_seek_table;
  46         FLAC__StreamMetaData stream_info;
  47         FLAC__StreamMetaData seek_table;
  48         FLAC__Frame frame;
  49         bool cached; /* true if there is a byte in lookahead */
  50         FLAC__CPUInfo cpuinfo;
  51         byte header_warmup[2]; /* contains the sync code and reserved bits */
  52         byte lookahead; /* temp storage when we need to look ahead one byte in the stream */
  53 } FLAC__StreamDecoderPrivate;
  54
  55 static byte ID3V2_TAG_[3] = { 'I', 'D', '3' };
  56
  57 static bool stream_decoder_allocate_output_(FLAC__StreamDecoder *decoder, unsigned size, unsigned channels);
  58 static bool stream_decoder_find_metadata_(FLAC__StreamDecoder *decoder);
  59 static bool stream_decoder_read_metadata_(FLAC__StreamDecoder *decoder);
  60 static bool stream_decoder_skip_id3v2_tag_(FLAC__StreamDecoder *decoder);
  61 static bool stream_decoder_frame_sync_(FLAC__StreamDecoder *decoder);
  62 static bool stream_decoder_read_frame_(FLAC__StreamDecoder *decoder, bool *got_a_frame);
  63 static bool stream_decoder_read_frame_header_(FLAC__StreamDecoder *decoder);
  64 static bool stream_decoder_read_subframe_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
  65 static bool stream_decoder_read_subframe_constant_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
  66 static bool stream_decoder_read_subframe_fixed_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order);
  67 static bool stream_decoder_read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order);
  68 static bool stream_decoder_read_subframe_verbatim_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
  69 static bool stream_decoder_read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, unsigned predictor_order, unsigned partition_order, int32 *residual);
  70 static bool stream_decoder_read_zero_padding_(FLAC__StreamDecoder *decoder);
  71 static bool read_callback_(byte buffer[], unsigned *bytes, void *client_data);
  72
  73 const char *FLAC__StreamDecoderStateString[] = {
  74         "FLAC__STREAM_DECODER_SEARCH_FOR_METADATA",
  75         "FLAC__STREAM_DECODER_READ_METADATA",
  76         "FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC",
  77         "FLAC__STREAM_DECODER_READ_FRAME",
  78         "FLAC__STREAM_DECODER_END_OF_STREAM",
  79         "FLAC__STREAM_DECODER_ABORTED",
  80         "FLAC__STREAM_DECODER_UNPARSEABLE_STREAM",
  81         "FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR",
  82         "FLAC__STREAM_DECODER_UNINITIALIZED"
  83 };
  84
  85 const char *FLAC__StreamDecoderReadStatusString[] = {
  86         "FLAC__STREAM_DECODER_READ_CONTINUE",
  87         "FLAC__STREAM_DECODER_READ_END_OF_STREAM",
  88         "FLAC__STREAM_DECODER_READ_ABORT"
  89 };
  90
  91 const char *FLAC__StreamDecoderWriteStatusString[] = {
  92         "FLAC__STREAM_DECODER_WRITE_CONTINUE",
  93         "FLAC__STREAM_DECODER_WRITE_ABORT"
  94 };
  95
  96 const char *FLAC__StreamDecoderErrorStatusString[] = {
  97         "FLAC__STREAM_DECODER_ERROR_LOST_SYNC",
  98         "FLAC__STREAM_DECODER_ERROR_BAD_HEADER",
  99         "FLAC__STREAM_DECODER_ERROR_FRAME_CRC_MISMATCH"
 100 };
 101
 102 FLAC__StreamDecoder *FLAC__stream_decoder_get_new_instance()
 103 {
 104         FLAC__StreamDecoder *decoder = (FLAC__StreamDecoder*)malloc(sizeof(FLAC__StreamDecoder));
 105         if(decoder != 0) {
 106                 decoder->state = FLAC__STREAM_DECODER_UNINITIALIZED;
 107                 decoder->guts = 0;
 108         }
 109         return decoder;
 110 }
 111
 112 void FLAC__stream_decoder_free_instance(FLAC__StreamDecoder *decoder)
 113 {
 114         free(decoder);
 115 }
 116
 117 FLAC__StreamDecoderState FLAC__stream_decoder_init(
 118         FLAC__StreamDecoder *decoder,
 119         FLAC__StreamDecoderReadStatus (*read_callback)(const FLAC__StreamDecoder *decoder, byte buffer[], unsigned *bytes, void *client_data),
 120         FLAC__StreamDecoderWriteStatus (*write_callback)(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const int32 *buffer[], void *client_data),
 121         void (*metadata_callback)(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetaData *metadata, void *client_data),
 122         void (*error_callback)(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data),
 123         void *client_data
 124 )
 125 {
 126         unsigned i;
 127
 128         FLAC__ASSERT(sizeof(int) >= 4); /* we want to die right away if this is not true */
 129         FLAC__ASSERT(decoder != 0);
 130         FLAC__ASSERT(read_callback != 0);
 131         FLAC__ASSERT(write_callback != 0);
 132         FLAC__ASSERT(metadata_callback != 0);
 133         FLAC__ASSERT(error_callback != 0);
 134         FLAC__ASSERT(decoder->state == FLAC__STREAM_DECODER_UNINITIALIZED);
 135         FLAC__ASSERT(decoder->guts == 0);
 136
 137         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;
 138
 139         decoder->guts = (FLAC__StreamDecoderPrivate*)malloc(sizeof(FLAC__StreamDecoderPrivate));
 140         if(decoder->guts == 0)
 141                 return decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 142
 143         decoder->guts->read_callback = read_callback;
 144         decoder->guts->write_callback = write_callback;
 145         decoder->guts->metadata_callback = metadata_callback;
 146         decoder->guts->error_callback = error_callback;
 147         decoder->guts->client_data = client_data;
 148
 149         FLAC__bitbuffer_init(&decoder->guts->input);
 150
 151         for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 152                 decoder->guts->output[i] = 0;
 153                 decoder->guts->residual[i] = 0;
 154         }
 155
 156         decoder->guts->output_capacity = 0;
 157         decoder->guts->output_channels = 0;
 158         decoder->guts->last_frame_number = 0;
 159         decoder->guts->samples_decoded = 0;
 160         decoder->guts->has_stream_info = false;
 161         decoder->guts->has_seek_table = false;
 162         decoder->guts->cached = false;
 163
 164         /*
 165          * get the CPU info and set the function pointers
 166          */
 167         FLAC__cpu_info(&decoder->guts->cpuinfo);
 168         /* first default to the non-asm routines */
 169         decoder->guts->local_lpc_restore_signal = FLAC__lpc_restore_signal;
 170         decoder->guts->local_lpc_restore_signal_16bit = FLAC__lpc_restore_signal;
 171         /* now override with asm where appropriate */
 172 #ifndef FLAC__NO_ASM
 173         FLAC__ASSERT(decoder->guts->cpuinfo.use_asm);
 174 #ifdef FLAC__CPU_IA32
 175         FLAC__ASSERT(decoder->guts->cpuinfo.type == FLAC__CPUINFO_TYPE_IA32);
 176 #ifdef FLAC__HAS_NASM
 177         if(decoder->guts->cpuinfo.data.ia32.mmx) {
 178                 decoder->guts->local_lpc_restore_signal = FLAC__lpc_restore_signal_asm_i386;
 179                 decoder->guts->local_lpc_restore_signal_16bit = FLAC__lpc_restore_signal_asm_i386_mmx;
 180         }
 181         else {
 182                 decoder->guts->local_lpc_restore_signal = FLAC__lpc_restore_signal_asm_i386;
 183                 decoder->guts->local_lpc_restore_signal_16bit = FLAC__lpc_restore_signal_asm_i386;
 184         }
 185 #endif
 186 #endif
 187 #endif
 188
 189         return decoder->state;
 190 }
 191
 192 void FLAC__stream_decoder_finish(FLAC__StreamDecoder *decoder)
 193 {
 194         unsigned i;
 195         FLAC__ASSERT(decoder != 0);
 196         if(decoder->state == FLAC__STREAM_DECODER_UNINITIALIZED)
 197                 return;
 198         if(decoder->guts != 0) {
 199                 if(decoder->guts->has_seek_table) {
 200                         free(decoder->guts->seek_table.data.seek_table.points);
 201                         decoder->guts->seek_table.data.seek_table.points = 0;
 202                 }
 203                 FLAC__bitbuffer_free(&decoder->guts->input);
 204                 for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 205                         if(decoder->guts->output[i] != 0) {
 206                                 free(decoder->guts->output[i]);
 207                                 decoder->guts->output[i] = 0;
 208                         }
 209                         if(decoder->guts->residual[i] != 0) {
 210                                 free(decoder->guts->residual[i]);
 211                                 decoder->guts->residual[i] = 0;
 212                         }
 213                 }
 214                 free(decoder->guts);
 215                 decoder->guts = 0;
 216         }
 217         decoder->state = FLAC__STREAM_DECODER_UNINITIALIZED;
 218 }
 219
 220 bool FLAC__stream_decoder_flush(FLAC__StreamDecoder *decoder)
 221 {
 222         FLAC__ASSERT(decoder != 0);
 223
 224         if(!FLAC__bitbuffer_clear(&decoder->guts->input)) {
 225                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 226                 return false;
 227         }
 228
 229         return true;
 230 }
 231
 232 bool FLAC__stream_decoder_reset(FLAC__StreamDecoder *decoder)
 233 {
 234         FLAC__ASSERT(decoder != 0);
 235
 236         if(!FLAC__stream_decoder_flush(decoder)) {
 237                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 238                 return false;
 239         }
 240         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;
 241
 242         decoder->guts->samples_decoded = 0;
 243
 244         return true;
 245 }
 246
 247 bool FLAC__stream_decoder_process_whole_stream(FLAC__StreamDecoder *decoder)
 248 {
 249         bool dummy;
 250         FLAC__ASSERT(decoder != 0);
 251
 252         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 253                 return true;
 254
 255         FLAC__ASSERT(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_METADATA);
 256
 257         if(!FLAC__stream_decoder_reset(decoder)) {
 258                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 259                 return false;
 260         }
 261
 262         while(1) {
 263                 switch(decoder->state) {
 264                         case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
 265                                 if(!stream_decoder_find_metadata_(decoder))
 266                                         return false; /* above function sets the status for us */
 267                                 break;
 268                         case FLAC__STREAM_DECODER_READ_METADATA:
 269                                 if(!stream_decoder_read_metadata_(decoder))
 270                                         return false; /* above function sets the status for us */
 271                                 break;
 272                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 273                                 if(!stream_decoder_frame_sync_(decoder))
 274                                         return true; /* above function sets the status for us */
 275                                 break;
 276                         case FLAC__STREAM_DECODER_READ_FRAME:
 277                                 if(!stream_decoder_read_frame_(decoder, &dummy))
 278                                         return false; /* above function sets the status for us */
 279                                 break;
 280                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 281                                 return true;
 282                         default:
 283                                 FLAC__ASSERT(0);
 284                 }
 285         }
 286 }
 287
 288 bool FLAC__stream_decoder_process_metadata(FLAC__StreamDecoder *decoder)
 289 {
 290         FLAC__ASSERT(decoder != 0);
 291
 292         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 293                 return true;
 294
 295         FLAC__ASSERT(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_METADATA);
 296
 297         if(!FLAC__stream_decoder_reset(decoder)) {
 298                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 299                 return false;
 300         }
 301
 302         while(1) {
 303                 switch(decoder->state) {
 304                         case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
 305                                 if(!stream_decoder_find_metadata_(decoder))
 306                                         return false; /* above function sets the status for us */
 307                                 break;
 308                         case FLAC__STREAM_DECODER_READ_METADATA:
 309                                 if(!stream_decoder_read_metadata_(decoder))
 310                                         return false; /* above function sets the status for us */
 311                                 break;
 312                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 313                                 return true;
 314                                 break;
 315                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 316                                 return true;
 317                         default:
 318                                 FLAC__ASSERT(0);
 319                 }
 320         }
 321 }
 322
 323 bool FLAC__stream_decoder_process_one_frame(FLAC__StreamDecoder *decoder)
 324 {
 325         bool got_a_frame;
 326         FLAC__ASSERT(decoder != 0);
 327
 328         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 329                 return true;
 330
 331         FLAC__ASSERT(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC);
 332
 333         while(1) {
 334                 switch(decoder->state) {
 335                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 336                                 if(!stream_decoder_frame_sync_(decoder))
 337                                         return true; /* above function sets the status for us */
 338                                 break;
 339                         case FLAC__STREAM_DECODER_READ_FRAME:
 340                                 if(!stream_decoder_read_frame_(decoder, &got_a_frame))
 341                                         return false; /* above function sets the status for us */
 342                                 if(got_a_frame)
 343                                         return true; /* above function sets the status for us */
 344                                 break;
 345                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 346                                 return true;
 347                         default:
 348                                 FLAC__ASSERT(0);
 349                 }
 350         }
 351 }
 352
 353 bool FLAC__stream_decoder_process_remaining_frames(FLAC__StreamDecoder *decoder)
 354 {
 355         bool dummy;
 356         FLAC__ASSERT(decoder != 0);
 357
 358         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 359                 return true;
 360
 361         FLAC__ASSERT(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC);
 362
 363         while(1) {
 364                 switch(decoder->state) {
 365                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 366                                 if(!stream_decoder_frame_sync_(decoder))
 367                                         return true; /* above function sets the status for us */
 368                                 break;
 369                         case FLAC__STREAM_DECODER_READ_FRAME:
 370                                 if(!stream_decoder_read_frame_(decoder, &dummy))
 371                                         return false; /* above function sets the status for us */
 372                                 break;
 373                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 374                                 return true;
 375                         default:
 376                                 FLAC__ASSERT(0);
 377                 }
 378         }
 379 }
 380
 381 unsigned FLAC__stream_decoder_input_bytes_unconsumed(FLAC__StreamDecoder *decoder)
 382 {
 383         FLAC__ASSERT(decoder != 0);
 384         return decoder->guts->input.bytes - decoder->guts->input.consumed_bytes;
 385 }
 386
 387 bool stream_decoder_allocate_output_(FLAC__StreamDecoder *decoder, unsigned size, unsigned channels)
 388 {
 389         unsigned i;
 390         int32 *tmp;
 391
 392         if(size <= decoder->guts->output_capacity && channels <= decoder->guts->output_channels)
 393                 return true;
 394
 395         /* @@@ should change to use realloc() */
 396
 397         for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 398                 if(decoder->guts->output[i] != 0) {
 399                         free(decoder->guts->output[i]);
 400                         decoder->guts->output[i] = 0;
 401                 }
 402                 if(decoder->guts->residual[i] != 0) {
 403                         free(decoder->guts->residual[i]);
 404                         decoder->guts->residual[i] = 0;
 405                 }
 406         }
 407
 408         for(i = 0; i < channels; i++) {
 409                 tmp = (int32*)malloc(sizeof(int32)*size);
 410                 if(tmp == 0) {
 411                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 412                         return false;
 413                 }
 414                 decoder->guts->output[i] = tmp;
 415
 416                 tmp = (int32*)malloc(sizeof(int32)*size);
 417                 if(tmp == 0) {
 418                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 419                         return false;
 420                 }
 421                 decoder->guts->residual[i] = tmp;
 422         }
 423
 424         decoder->guts->output_capacity = size;
 425         decoder->guts->output_channels = channels;
 426
 427         return true;
 428 }
 429
 430 bool stream_decoder_find_metadata_(FLAC__StreamDecoder *decoder)
 431 {
 432         uint32 x;
 433         unsigned i, id;
 434         bool first = true;
 435
 436         FLAC__ASSERT(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 437
 438         for(i = id = 0; i < 4; ) {
 439                 if(decoder->guts->cached) {
 440                         x = (uint32)decoder->guts->lookahead;
 441                         decoder->guts->cached = false;
 442                 }
 443                 else {
 444                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 445                                 return false; /* the read_callback_ sets the state for us */
 446                 }
 447                 if(x == FLAC__STREAM_SYNC_STRING[i]) {
 448                         first = true;
 449                         i++;
 450                         id = 0;
 451                         continue;
 452                 }
 453                 if(x == ID3V2_TAG_[id]) {
 454                         id++;
 455                         i = 0;
 456                         if(id == 3) {
 457                                 if(!stream_decoder_skip_id3v2_tag_(decoder))
 458                                         return false; /* the read_callback_ sets the state for us */
 459                         }
 460                         continue;
 461                 }
 462                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 463                         decoder->guts->header_warmup[0] = (byte)x;
 464                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 465                                 return false; /* the read_callback_ sets the state for us */
 466
 467                         /* we have to check if we just read two 0xff's in a row; the second may actually be the beginning of the sync code */
 468                         /* else we have to check if the second byte is the end of a sync code */
 469                         if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 470                                 decoder->guts->lookahead = (byte)x;
 471                                 decoder->guts->cached = true;
 472                         }
 473                         else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
 474                                 decoder->guts->header_warmup[1] = (byte)x;
 475                                 decoder->state = FLAC__STREAM_DECODER_READ_FRAME;
 476                                 return true;
 477                         }
 478                 }
 479                 i = 0;
 480                 if(first) {
 481                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
 482                         first = false;
 483                 }
 484         }
 485
 486         decoder->state = FLAC__STREAM_DECODER_READ_METADATA;
 487         return true;
 488 }
 489
 490 bool stream_decoder_read_metadata_(FLAC__StreamDecoder *decoder)
 491 {
 492         uint32 i, x, last_block, type, length;
 493         uint64 xx;
 494
 495         FLAC__ASSERT(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 496
 497         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &last_block, FLAC__STREAM_METADATA_IS_LAST_LEN, read_callback_, decoder))
 498                 return false; /* the read_callback_ sets the state for us */
 499         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &type, FLAC__STREAM_METADATA_TYPE_LEN, read_callback_, decoder))
 500                 return false; /* the read_callback_ sets the state for us */
 501         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &length, FLAC__STREAM_METADATA_LENGTH_LEN, read_callback_, decoder))
 502                 return false; /* the read_callback_ sets the state for us */
 503         if(type == FLAC__METADATA_TYPE_STREAMINFO) {
 504                 unsigned used_bits = 0;
 505                 decoder->guts->stream_info.type = type;
 506                 decoder->guts->stream_info.is_last = last_block;
 507                 decoder->guts->stream_info.length = length;
 508
 509                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN, read_callback_, decoder))
 510                         return false; /* the read_callback_ sets the state for us */
 511                 decoder->guts->stream_info.data.stream_info.min_blocksize = x;
 512                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN;
 513
 514                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN, read_callback_, decoder))
 515                         return false; /* the read_callback_ sets the state for us */
 516                 decoder->guts->stream_info.data.stream_info.max_blocksize = x;
 517                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN;
 518
 519                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN, read_callback_, decoder))
 520                         return false; /* the read_callback_ sets the state for us */
 521                 decoder->guts->stream_info.data.stream_info.min_framesize = x;
 522                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN;
 523
 524                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN, read_callback_, decoder))
 525                         return false; /* the read_callback_ sets the state for us */
 526                 decoder->guts->stream_info.data.stream_info.max_framesize = x;
 527                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN;
 528
 529                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN, read_callback_, decoder))
 530                         return false; /* the read_callback_ sets the state for us */
 531                 decoder->guts->stream_info.data.stream_info.sample_rate = x;
 532                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN;
 533
 534                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN, read_callback_, decoder))
 535                         return false; /* the read_callback_ sets the state for us */
 536                 decoder->guts->stream_info.data.stream_info.channels = x+1;
 537                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN;
 538
 539                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN, read_callback_, decoder))
 540                         return false; /* the read_callback_ sets the state for us */
 541                 decoder->guts->stream_info.data.stream_info.bits_per_sample = x+1;
 542                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN;
 543
 544                 if(!FLAC__bitbuffer_read_raw_uint64(&decoder->guts->input, &decoder->guts->stream_info.data.stream_info.total_samples, FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN, read_callback_, decoder))
 545                         return false; /* the read_callback_ sets the state for us */
 546                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN;
 547
 548                 for(i = 0; i < 16; i++) {
 549                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 550                                 return false; /* the read_callback_ sets the state for us */
 551                         decoder->guts->stream_info.data.stream_info.md5sum[i] = (byte)x;
 552                 }
 553                 used_bits += i*8;
 554
 555                 /* skip the rest of the block */
 556                 FLAC__ASSERT(used_bits % 8 == 0);
 557                 length -= (used_bits / 8);
 558                 for(i = 0; i < length; i++) {
 559                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 560                                 return false; /* the read_callback_ sets the state for us */
 561                 }
 562
 563                 decoder->guts->has_stream_info = true;
 564                 decoder->guts->metadata_callback(decoder, &decoder->guts->stream_info, decoder->guts->client_data);
 565         }
 566         else if(type == FLAC__METADATA_TYPE_SEEKTABLE) {
 567                 unsigned real_points;
 568
 569                 decoder->guts->seek_table.type = type;
 570                 decoder->guts->seek_table.is_last = last_block;
 571                 decoder->guts->seek_table.length = length;
 572
 573                 decoder->guts->seek_table.data.seek_table.num_points = length / FLAC__STREAM_METADATA_SEEKPOINT_LEN;
 574
 575                 if(0 == (decoder->guts->seek_table.data.seek_table.points = (FLAC__StreamMetaData_SeekPoint*)malloc(decoder->guts->seek_table.data.seek_table.num_points * sizeof(FLAC__StreamMetaData_SeekPoint)))) {
 576                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 577                         return false;
 578                 }
 579                 for(i = real_points = 0; i < decoder->guts->seek_table.data.seek_table.num_points; i++) {
 580                         if(!FLAC__bitbuffer_read_raw_uint64(&decoder->guts->input, &xx, FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN, read_callback_, decoder))
 581                                 return false; /* the read_callback_ sets the state for us */
 582                         decoder->guts->seek_table.data.seek_table.points[real_points].sample_number = xx;
 583
 584                         if(!FLAC__bitbuffer_read_raw_uint64(&decoder->guts->input, &xx, FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN, read_callback_, decoder))
 585                                 return false; /* the read_callback_ sets the state for us */
 586                         decoder->guts->seek_table.data.seek_table.points[real_points].stream_offset = xx;
 587
 588                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_SEEKPOINT_FRAME_SAMPLES_LEN, read_callback_, decoder))
 589                                 return false; /* the read_callback_ sets the state for us */
 590                         decoder->guts->seek_table.data.seek_table.points[real_points].frame_samples = x;
 591
 592                         if(decoder->guts->seek_table.data.seek_table.points[real_points].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER)
 593                                 real_points++;
 594                 }
 595                 decoder->guts->seek_table.data.seek_table.num_points = real_points;
 596
 597                 decoder->guts->has_seek_table = true;
 598                 decoder->guts->metadata_callback(decoder, &decoder->guts->seek_table, decoder->guts->client_data);
 599         }
 600         else {
 601                 /* skip other metadata blocks */
 602                 for(i = 0; i < length; i++) {
 603                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 604                                 return false; /* the read_callback_ sets the state for us */
 605                 }
 606         }
 607
 608         if(last_block)
 609                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 610
 611         return true;
 612 }
 613
 614 bool stream_decoder_skip_id3v2_tag_(FLAC__StreamDecoder *decoder)
 615 {
 616         uint32 x;
 617         unsigned i, skip;
 618
 619         /* skip the version and flags bytes */
 620         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 24, read_callback_, decoder))
 621                 return false; /* the read_callback_ sets the state for us */
 622         /* get the size (in bytes) to skip */
 623         skip = 0;
 624         for(i = 0; i < 4; i++) {
 625                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 626                         return false; /* the read_callback_ sets the state for us */
 627                 skip <<= 7;
 628                 skip |= (x & 0x7f);
 629         }
 630         /* skip the rest of the tag */
 631         for(i = 0; i < skip; i++) {
 632                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 633                         return false; /* the read_callback_ sets the state for us */
 634         }
 635         return true;
 636 }
 637
 638 bool stream_decoder_frame_sync_(FLAC__StreamDecoder *decoder)
 639 {
 640         uint32 x;
 641         bool first = true;
 642
 643         /* If we know the total number of samples in the stream, stop if we've read that many. */
 644         /* This will stop us, for example, from wasting time trying to sync on an ID3V1 tag. */
 645         if(decoder->guts->has_stream_info && decoder->guts->stream_info.data.stream_info.total_samples) {
 646                 if(decoder->guts->samples_decoded >= decoder->guts->stream_info.data.stream_info.total_samples) {
 647                         decoder->state = FLAC__STREAM_DECODER_END_OF_STREAM;
 648                         return true;
 649                 }
 650         }
 651
 652         /* make sure we're byte aligned */
 653         if(decoder->guts->input.consumed_bits != 0) {
 654                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8-decoder->guts->input.consumed_bits, read_callback_, decoder))
 655                         return false; /* the read_callback_ sets the state for us */
 656         }
 657
 658         while(1) {
 659                 if(decoder->guts->cached) {
 660                         x = (uint32)decoder->guts->lookahead;
 661                         decoder->guts->cached = false;
 662                 }
 663                 else {
 664                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 665                                 return false; /* the read_callback_ sets the state for us */
 666                 }
 667                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 668                         decoder->guts->header_warmup[0] = (byte)x;
 669                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 670                                 return false; /* the read_callback_ sets the state for us */
 671
 672                         /* we have to check if we just read two 0xff's in a row; the second may actually be the beginning of the sync code */
 673                         /* else we have to check if the second byte is the end of a sync code */
 674                         if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 675                                 decoder->guts->lookahead = (byte)x;
 676                                 decoder->guts->cached = true;
 677                         }
 678                         else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
 679                                 decoder->guts->header_warmup[1] = (byte)x;
 680                                 decoder->state = FLAC__STREAM_DECODER_READ_FRAME;
 681                                 return true;
 682                         }
 683                 }
 684                 if(first) {
 685                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
 686                         first = 0;
 687                 }
 688         }
 689
 690         return true;
 691 }
 692
 693 bool stream_decoder_read_frame_(FLAC__StreamDecoder *decoder, bool *got_a_frame)
 694 {
 695         unsigned channel;
 696         unsigned i;
 697         int32 mid, side, left, right;
 698         uint16 frame_crc; /* the one we calculate from the input stream */
 699         uint32 x;
 700
 701         *got_a_frame = false;
 702
 703         /* init the CRC */
 704         frame_crc = 0;
 705         FLAC__CRC16_UPDATE(decoder->guts->header_warmup[0], frame_crc);
 706         FLAC__CRC16_UPDATE(decoder->guts->header_warmup[1], frame_crc);
 707         FLAC__bitbuffer_init_read_crc16(&decoder->guts->input, frame_crc);
 708
 709         if(!stream_decoder_read_frame_header_(decoder))
 710                 return false;
 711         if(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC)
 712                 return true;
 713         if(!stream_decoder_allocate_output_(decoder, decoder->guts->frame.header.blocksize, decoder->guts->frame.header.channels))
 714                 return false;
 715         for(channel = 0; channel < decoder->guts->frame.header.channels; channel++) {
 716                 /*
 717                  * first figure the correct bits-per-sample of the subframe
 718                  */
 719                 unsigned bps = decoder->guts->frame.header.bits_per_sample;
 720                 switch(decoder->guts->frame.header.channel_assignment) {
 721                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 722                                 /* no adjustment needed */
 723                                 break;
 724                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 725                                 FLAC__ASSERT(decoder->guts->frame.header.channels == 2);
 726                                 if(channel == 1)
 727                                         bps++;
 728                                 break;
 729                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 730                                 FLAC__ASSERT(decoder->guts->frame.header.channels == 2);
 731                                 if(channel == 0)
 732                                         bps++;
 733                                 break;
 734                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 735                                 FLAC__ASSERT(decoder->guts->frame.header.channels == 2);
 736                                 if(channel == 1)
 737                                         bps++;
 738                                 break;
 739                         default:
 740                                 FLAC__ASSERT(0);
 741                 }
 742                 /*
 743                  * now read it
 744                  */
 745                 if(!stream_decoder_read_subframe_(decoder, channel, bps))
 746                         return false;
 747                 if(decoder->state != FLAC__STREAM_DECODER_READ_FRAME) {
 748                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 749                         return true;
 750                 }
 751         }
 752         if(!stream_decoder_read_zero_padding_(decoder))
 753                 return false;
 754
 755         /*
 756          * Read the frame CRC-16 from the footer and check
 757          */
 758         frame_crc = decoder->guts->input.read_crc16;
 759         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__FRAME_FOOTER_CRC_LEN, read_callback_, decoder))
 760                 return false; /* the read_callback_ sets the state for us */
 761         if(frame_crc == (uint16)x) {
 762                 /* Undo any special channel coding */
 763                 switch(decoder->guts->frame.header.channel_assignment) {
 764                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 765                                 /* do nothing */
 766                                 break;
 767                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 768                                 FLAC__ASSERT(decoder->guts->frame.header.channels == 2);
 769                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
 770                                         decoder->guts->output[1][i] = decoder->guts->output[0][i] - decoder->guts->output[1][i];
 771                                 break;
 772                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 773                                 FLAC__ASSERT(decoder->guts->frame.header.channels == 2);
 774                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
 775                                         decoder->guts->output[0][i] += decoder->guts->output[1][i];
 776                                 break;
 777                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 778                                 FLAC__ASSERT(decoder->guts->frame.header.channels == 2);
 779                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++) {
 780                                         mid = decoder->guts->output[0][i];
 781                                         side = decoder->guts->output[1][i];
 782                                         mid <<= 1;
 783                                         if(side & 1) /* i.e. if 'side' is odd... */
 784                                                 mid++;
 785                                         left = mid + side;
 786                                         right = mid - side;
 787                                         decoder->guts->output[0][i] = left >> 1;
 788                                         decoder->guts->output[1][i] = right >> 1;
 789                                 }
 790                                 break;
 791                         default:
 792                                 FLAC__ASSERT(0);
 793                                 break;
 794                 }
 795         }
 796         else {
 797                 /* Bad frame, emit error and zero the output signal */
 798                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_FRAME_CRC_MISMATCH, decoder->guts->client_data);
 799                 for(channel = 0; channel < decoder->guts->frame.header.channels; channel++) {
 800                         memset(decoder->guts->output[channel], 0, sizeof(int32) * decoder->guts->frame.header.blocksize);
 801                 }
 802         }
 803
 804         *got_a_frame = true;
 805
 806         /* put the latest values into the public section of the decoder instance */
 807         decoder->channels = decoder->guts->frame.header.channels;
 808         decoder->channel_assignment = decoder->guts->frame.header.channel_assignment;
 809         decoder->bits_per_sample = decoder->guts->frame.header.bits_per_sample;
 810         decoder->sample_rate = decoder->guts->frame.header.sample_rate;
 811         decoder->blocksize = decoder->guts->frame.header.blocksize;
 812
 813         decoder->guts->samples_decoded = decoder->guts->frame.header.number.sample_number + decoder->guts->frame.header.blocksize;
 814
 815         /* write it */
 816         /* NOTE: some versions of GCC can't figure out const-ness right and will give you an 'incompatible pointer type' warning on arg 3 here: */
 817         if(decoder->guts->write_callback(decoder, &decoder->guts->frame, decoder->guts->output, decoder->guts->client_data) != FLAC__STREAM_DECODER_WRITE_CONTINUE)
 818                 return false;
 819
 820         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 821         return true;
 822 }
 823
 824 bool stream_decoder_read_frame_header_(FLAC__StreamDecoder *decoder)
 825 {
 826         uint32 x;
 827         uint64 xx;
 828         unsigned i, blocksize_hint = 0, sample_rate_hint = 0;
 829         byte crc8, raw_header[16]; /* MAGIC NUMBER based on the maximum frame header size, including CRC */
 830         unsigned raw_header_len;
 831         bool is_unparseable = false;
 832         const bool is_known_variable_blocksize_stream = (decoder->guts->has_stream_info && decoder->guts->stream_info.data.stream_info.min_blocksize != decoder->guts->stream_info.data.stream_info.max_blocksize);
 833         const bool is_known_fixed_blocksize_stream = (decoder->guts->has_stream_info && decoder->guts->stream_info.data.stream_info.min_blocksize == decoder->guts->stream_info.data.stream_info.max_blocksize);
 834
 835         FLAC__ASSERT(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 836
 837         /* init the raw header with the saved bits from synchronization */
 838         raw_header[0] = decoder->guts->header_warmup[0];
 839         raw_header[1] = decoder->guts->header_warmup[1];
 840         raw_header_len = 2;
 841
 842         /*
 843          * check to make sure that the reserved bits are 0
 844          */
 845         if(raw_header[1] & 0x03) { /* MAGIC NUMBER */
 846                 is_unparseable = true;
 847         }
 848
 849         /*
 850          * Note that along the way as we read the header, we look for a sync
 851          * code inside.  If we find one it would indicate that our original
 852          * sync was bad since there cannot be a sync code in a valid header.
 853          */
 854
 855         /*
 856          * read in the raw header as bytes so we can CRC it, and parse it on the way
 857          */
 858         for(i = 0; i < 2; i++) {
 859                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 860                         return false; /* the read_callback_ sets the state for us */
 861                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 862                         /* if we get here it means our original sync was erroneous since the sync code cannot appear in the header */
 863                         decoder->guts->lookahead = (byte)x;
 864                         decoder->guts->cached = true;
 865                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 866                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 867                         return true;
 868                 }
 869                 raw_header[raw_header_len++] = (byte)x;
 870         }
 871
 872         switch(x = raw_header[2] >> 4) {
 873                 case 0:
 874                         if(is_known_fixed_blocksize_stream)
 875                                 decoder->guts->frame.header.blocksize = decoder->guts->stream_info.data.stream_info.min_blocksize;
 876                         else
 877                                 is_unparseable = true;
 878                         break;
 879                 case 1:
 880                         decoder->guts->frame.header.blocksize = 192;
 881                         break;
 882                 case 2:
 883                 case 3:
 884                 case 4:
 885                 case 5:
 886                         decoder->guts->frame.header.blocksize = 576 << (x-2);
 887                         break;
 888                 case 6:
 889                 case 7:
 890                         blocksize_hint = x;
 891                         break;
 892                 case 8:
 893                 case 9:
 894                 case 10:
 895                 case 11:
 896                 case 12:
 897                 case 13:
 898                 case 14:
 899                 case 15:
 900                         decoder->guts->frame.header.blocksize = 256 << (x-8);
 901                         break;
 902                 default:
 903                         FLAC__ASSERT(0);
 904                         break;
 905         }
 906
 907         switch(x = raw_header[2] & 0x0f) {
 908                 case 0:
 909                         if(decoder->guts->has_stream_info)
 910                                 decoder->guts->frame.header.sample_rate = decoder->guts->stream_info.data.stream_info.sample_rate;
 911                         else
 912                                 is_unparseable = true;
 913                         break;
 914                 case 1:
 915                 case 2:
 916                 case 3:
 917                         is_unparseable = true;
 918                         break;
 919                 case 4:
 920                         decoder->guts->frame.header.sample_rate = 8000;
 921                         break;
 922                 case 5:
 923                         decoder->guts->frame.header.sample_rate = 16000;
 924                         break;
 925                 case 6:
 926                         decoder->guts->frame.header.sample_rate = 22050;
 927                         break;
 928                 case 7:
 929                         decoder->guts->frame.header.sample_rate = 24000;
 930                         break;
 931                 case 8:
 932                         decoder->guts->frame.header.sample_rate = 32000;
 933                         break;
 934                 case 9:
 935                         decoder->guts->frame.header.sample_rate = 44100;
 936                         break;
 937                 case 10:
 938                         decoder->guts->frame.header.sample_rate = 48000;
 939                         break;
 940                 case 11:
 941                         decoder->guts->frame.header.sample_rate = 96000;
 942                         break;
 943                 case 12:
 944                 case 13:
 945                 case 14:
 946                         sample_rate_hint = x;
 947                         break;
 948                 case 15:
 949                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 950                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 951                         return true;
 952                 default:
 953                         FLAC__ASSERT(0);
 954         }
 955
 956         x = (unsigned)(raw_header[3] >> 4);
 957         if(x & 8) {
 958                 decoder->guts->frame.header.channels = 2;
 959                 switch(x & 7) {
 960                         case 0:
 961                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE;
 962                                 break;
 963                         case 1:
 964                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE;
 965                                 break;
 966                         case 2:
 967                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_MID_SIDE;
 968                                 break;
 969                         default:
 970                                 is_unparseable = true;
 971                                 break;
 972                 }
 973         }
 974         else {
 975                 decoder->guts->frame.header.channels = (unsigned)x + 1;
 976                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT;
 977         }
 978
 979         switch(x = (unsigned)(raw_header[3] & 0x0e) >> 1) {
 980                 case 0:
 981                         if(decoder->guts->has_stream_info)
 982                                 decoder->guts->frame.header.bits_per_sample = decoder->guts->stream_info.data.stream_info.bits_per_sample;
 983                         else
 984                                 is_unparseable = true;
 985                         break;
 986                 case 1:
 987                         decoder->guts->frame.header.bits_per_sample = 8;
 988                         break;
 989                 case 2:
 990                         decoder->guts->frame.header.bits_per_sample = 12;
 991                         break;
 992                 case 4:
 993                         decoder->guts->frame.header.bits_per_sample = 16;
 994                         break;
 995                 case 5:
 996                         decoder->guts->frame.header.bits_per_sample = 20;
 997                         break;
 998                 case 6:
 999                         decoder->guts->frame.header.bits_per_sample = 24;
1000                         break;
1001                 case 3:
1002                 case 7:
1003                         is_unparseable = true;
1004                         break;
1005                 default:
1006                         FLAC__ASSERT(0);
1007                         break;
1008         }
1009
1010         if(raw_header[3] & 0x01) { /* this should be a zero padding bit */
1011                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1012                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1013                 return true;
1014         }
1015
1016         if(blocksize_hint && is_known_variable_blocksize_stream) {
1017                 if(!FLAC__bitbuffer_read_utf8_uint64(&decoder->guts->input, &xx, read_callback_, decoder, raw_header, &raw_header_len))
1018                         return false; /* the read_callback_ sets the state for us */
1019                 if(xx == 0xffffffffffffffff) { /* i.e. non-UTF8 code... */
1020                         decoder->guts->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
1021                         decoder->guts->cached = true;
1022                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1023                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1024                         return true;
1025                 }
1026                 decoder->guts->frame.header.number.sample_number = xx;
1027         }
1028         else {
1029                 if(!FLAC__bitbuffer_read_utf8_uint32(&decoder->guts->input, &x, read_callback_, decoder, raw_header, &raw_header_len))
1030                         return false; /* the read_callback_ sets the state for us */
1031                 if(x == 0xffffffff) { /* i.e. non-UTF8 code... */
1032                         decoder->guts->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
1033                         decoder->guts->cached = true;
1034                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1035                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1036                         return true;
1037                 }
1038                 decoder->guts->last_frame_number = x;
1039                 if(decoder->guts->has_stream_info) {
1040                         decoder->guts->frame.header.number.sample_number = (int64)decoder->guts->stream_info.data.stream_info.min_blocksize * (int64)x;
1041                 }
1042                 else {
1043                         is_unparseable = true;
1044                 }
1045         }
1046
1047         if(blocksize_hint) {
1048                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1049                         return false; /* the read_callback_ sets the state for us */
1050                 raw_header[raw_header_len++] = (byte)x;
1051                 if(blocksize_hint == 7) {
1052                         uint32 _x;
1053                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &_x, 8, read_callback_, decoder))
1054                                 return false; /* the read_callback_ sets the state for us */
1055                         raw_header[raw_header_len++] = (byte)_x;
1056                         x = (x << 8) | _x;
1057                 }
1058                 decoder->guts->frame.header.blocksize = x+1;
1059         }
1060
1061         if(sample_rate_hint) {
1062                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1063                         return false; /* the read_callback_ sets the state for us */
1064                 raw_header[raw_header_len++] = (byte)x;
1065                 if(sample_rate_hint != 12) {
1066                         uint32 _x;
1067                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &_x, 8, read_callback_, decoder))
1068                                 return false; /* the read_callback_ sets the state for us */
1069                         raw_header[raw_header_len++] = (byte)_x;
1070                         x = (x << 8) | _x;
1071                 }
1072                 if(sample_rate_hint == 12)
1073                         decoder->guts->frame.header.sample_rate = x*1000;
1074                 else if(sample_rate_hint == 13)
1075                         decoder->guts->frame.header.sample_rate = x;
1076                 else
1077                         decoder->guts->frame.header.sample_rate = x*10;
1078         }
1079
1080         /* read the CRC-8 byte */
1081         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1082                 return false; /* the read_callback_ sets the state for us */
1083         crc8 = (byte)x;
1084
1085         if(FLAC__crc8(raw_header, raw_header_len) != crc8) {
1086                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1087                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1088                 return true;
1089         }
1090
1091         if(is_unparseable) {
1092                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1093                 return false;
1094         }
1095
1096         return true;
1097 }
1098
1099 bool stream_decoder_read_subframe_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1100 {
1101         uint32 x;
1102         bool wasted_bits;
1103
1104         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder)) /* MAGIC NUMBER */
1105                 return false; /* the read_callback_ sets the state for us */
1106
1107         wasted_bits = (x & 1);
1108         x &= 0xfe;
1109
1110         if(wasted_bits) {
1111                 unsigned u;
1112                 if(!FLAC__bitbuffer_read_unary_unsigned(&decoder->guts->input, &u, read_callback_, decoder))
1113                         return false; /* the read_callback_ sets the state for us */
1114                 decoder->guts->frame.subframes[channel].wasted_bits = u+1;
1115                 bps -= decoder->guts->frame.subframes[channel].wasted_bits;
1116         }
1117         else
1118                 decoder->guts->frame.subframes[channel].wasted_bits = 0;
1119
1120         /*
1121          * Lots of magic numbers here
1122          */
1123         if(x & 0x80) {
1124                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1125                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1126                 return true;
1127         }
1128         else if(x == 0) {
1129                 if(!stream_decoder_read_subframe_constant_(decoder, channel, bps))
1130                         return false;
1131         }
1132         else if(x == 2) {
1133                 if(!stream_decoder_read_subframe_verbatim_(decoder, channel, bps))
1134                         return false;
1135         }
1136         else if(x < 16) {
1137                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1138                 return false;
1139         }
1140         else if(x <= 24) {
1141                 if(!stream_decoder_read_subframe_fixed_(decoder, channel, bps, (x>>1)&7))
1142                         return false;
1143         }
1144         else if(x < 64) {
1145                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1146                 return false;
1147         }
1148         else {
1149                 if(!stream_decoder_read_subframe_lpc_(decoder, channel, bps, ((x>>1)&31)+1))
1150                         return false;
1151         }
1152
1153         if(wasted_bits) {
1154                 unsigned i;
1155                 x = decoder->guts->frame.subframes[channel].wasted_bits;
1156                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
1157                         decoder->guts->output[channel][i] <<= x;
1158         }
1159
1160         return true;
1161 }
1162
1163 bool stream_decoder_read_subframe_constant_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1164 {
1165         FLAC__Subframe_Constant *subframe = &decoder->guts->frame.subframes[channel].data.constant;
1166         int32 x;
1167         unsigned i;
1168         int32 *output = decoder->guts->output[channel];
1169
1170         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_CONSTANT;
1171
1172         if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &x, bps, read_callback_, decoder))
1173                 return false; /* the read_callback_ sets the state for us */
1174
1175         subframe->value = x;
1176
1177         /* decode the subframe */
1178         for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
1179                 output[i] = x;
1180
1181         return true;
1182 }
1183
1184 bool stream_decoder_read_subframe_fixed_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order)
1185 {
1186         FLAC__Subframe_Fixed *subframe = &decoder->guts->frame.subframes[channel].data.fixed;
1187         int32 i32;
1188         uint32 u32;
1189         unsigned u;
1190
1191         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_FIXED;
1192
1193         subframe->residual = decoder->guts->residual[channel];
1194         subframe->order = order;
1195
1196         /* read warm-up samples */
1197         for(u = 0; u < order; u++) {
1198                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, bps, read_callback_, decoder))
1199                         return false; /* the read_callback_ sets the state for us */
1200                 subframe->warmup[u] = i32;
1201         }
1202
1203         /* read entropy coding method info */
1204         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN, read_callback_, decoder))
1205                 return false; /* the read_callback_ sets the state for us */
1206         subframe->entropy_coding_method.type = u32;
1207         switch(subframe->entropy_coding_method.type) {
1208                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1209                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN, read_callback_, decoder))
1210                                 return false; /* the read_callback_ sets the state for us */
1211                         subframe->entropy_coding_method.data.partitioned_rice.order = u32;
1212                         break;
1213                 default:
1214                         decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1215                         return false;
1216         }
1217
1218         /* read residual */
1219         switch(subframe->entropy_coding_method.type) {
1220                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1221                         if(!stream_decoder_read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, decoder->guts->residual[channel]))
1222                                 return false;
1223                         break;
1224                 default:
1225                         FLAC__ASSERT(0);
1226         }
1227
1228         /* decode the subframe */
1229         memcpy(decoder->guts->output[channel], subframe->warmup, sizeof(int32) * order);
1230         FLAC__fixed_restore_signal(decoder->guts->residual[channel], decoder->guts->frame.header.blocksize-order, order, decoder->guts->output[channel]+order);
1231
1232         return true;
1233 }
1234
1235 bool stream_decoder_read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order)
1236 {
1237         FLAC__Subframe_LPC *subframe = &decoder->guts->frame.subframes[channel].data.lpc;
1238         int32 i32;
1239         uint32 u32;
1240         unsigned u;
1241
1242         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_LPC;
1243
1244         subframe->residual = decoder->guts->residual[channel];
1245         subframe->order = order;
1246
1247         /* read warm-up samples */
1248         for(u = 0; u < order; u++) {
1249                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, bps, read_callback_, decoder))
1250                         return false; /* the read_callback_ sets the state for us */
1251                 subframe->warmup[u] = i32;
1252         }
1253
1254         /* read qlp coeff precision */
1255         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN, read_callback_, decoder))
1256                 return false; /* the read_callback_ sets the state for us */
1257         if(u32 == (1u << FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN) - 1) {
1258                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1259                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1260                 return true;
1261         }
1262         subframe->qlp_coeff_precision = u32+1;
1263
1264         /* read qlp shift */
1265         if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN, read_callback_, decoder))
1266                 return false; /* the read_callback_ sets the state for us */
1267         subframe->quantization_level = i32;
1268
1269         /* read quantized lp coefficiencts */
1270         for(u = 0; u < order; u++) {
1271                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, subframe->qlp_coeff_precision, read_callback_, decoder))
1272                         return false; /* the read_callback_ sets the state for us */
1273                 subframe->qlp_coeff[u] = i32;
1274         }
1275
1276         /* read entropy coding method info */
1277         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN, read_callback_, decoder))
1278                 return false; /* the read_callback_ sets the state for us */
1279         subframe->entropy_coding_method.type = u32;
1280         switch(subframe->entropy_coding_method.type) {
1281                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1282                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN, read_callback_, decoder))
1283                                 return false; /* the read_callback_ sets the state for us */
1284                         subframe->entropy_coding_method.data.partitioned_rice.order = u32;
1285                         break;
1286                 default:
1287                         decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1288                         return false;
1289         }
1290
1291         /* read residual */
1292         switch(subframe->entropy_coding_method.type) {
1293                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1294                         if(!stream_decoder_read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, decoder->guts->residual[channel]))
1295                                 return false;
1296                         break;
1297                 default:
1298                         FLAC__ASSERT(0);
1299         }
1300
1301         /* decode the subframe */
1302         memcpy(decoder->guts->output[channel], subframe->warmup, sizeof(int32) * order);
1303         if(bps <= 16 && subframe->qlp_coeff_precision <= 16)
1304                 decoder->guts->local_lpc_restore_signal_16bit(decoder->guts->residual[channel], decoder->guts->frame.header.blocksize-order, subframe->qlp_coeff, order, subframe->quantization_level, decoder->guts->output[channel]+order);
1305         else
1306                 decoder->guts->local_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);
1307
1308         return true;
1309 }
1310
1311 bool stream_decoder_read_subframe_verbatim_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1312 {
1313         FLAC__Subframe_Verbatim *subframe = &decoder->guts->frame.subframes[channel].data.verbatim;
1314         int32 x, *residual = decoder->guts->residual[channel];
1315         unsigned i;
1316
1317         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_VERBATIM;
1318
1319         subframe->data = residual;
1320
1321         for(i = 0; i < decoder->guts->frame.header.blocksize; i++) {
1322                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &x, bps, read_callback_, decoder))
1323                         return false; /* the read_callback_ sets the state for us */
1324                 residual[i] = x;
1325         }
1326
1327         /* decode the subframe */
1328         memcpy(decoder->guts->output[channel], subframe->data, sizeof(int32) * decoder->guts->frame.header.blocksize);
1329
1330         return true;
1331 }
1332
1333 bool stream_decoder_read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, unsigned predictor_order, unsigned partition_order, int32 *residual)
1334 {
1335         uint32 rice_parameter;
1336         int i;
1337         unsigned partition, sample, u;
1338         const unsigned partitions = 1u << partition_order;
1339         const unsigned partition_samples = partition_order > 0? decoder->guts->frame.header.blocksize >> partition_order : decoder->guts->frame.header.blocksize - predictor_order;
1340
1341         sample = 0;
1342         for(partition = 0; partition < partitions; partition++) {
1343                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &rice_parameter, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN, read_callback_, decoder))
1344                         return false; /* the read_callback_ sets the state for us */
1345                 if(rice_parameter < FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER) {
1346                         for(u = (partition_order == 0 || partition > 0)? 0 : predictor_order; u < partition_samples; u++, sample++) {
1347 #ifdef FLAC__SYMMETRIC_RICE
1348                                 if(!FLAC__bitbuffer_read_symmetric_rice_signed(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1349                                         return false; /* the read_callback_ sets the state for us */
1350 #else
1351                                 if(!FLAC__bitbuffer_read_rice_signed(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1352                                         return false; /* the read_callback_ sets the state for us */
1353 #endif
1354                                 residual[sample] = i;
1355                         }
1356                 }
1357                 else {
1358                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &rice_parameter, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN, read_callback_, decoder))
1359                                 return false; /* the read_callback_ sets the state for us */
1360                         for(u = (partition_order == 0 || partition > 0)? 0 : predictor_order; u < partition_samples; u++, sample++) {
1361                                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1362                                         return false; /* the read_callback_ sets the state for us */
1363                                 residual[sample] = i;
1364                         }
1365                 }
1366         }
1367
1368         return true;
1369 }
1370
1371 bool stream_decoder_read_zero_padding_(FLAC__StreamDecoder *decoder)
1372 {
1373         if(decoder->guts->input.consumed_bits != 0) {
1374                 uint32 zero = 0;
1375                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &zero, 8-decoder->guts->input.consumed_bits, read_callback_, decoder))
1376                         return false; /* the read_callback_ sets the state for us */
1377                 if(zero != 0) {
1378                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1379                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1380                 }
1381         }
1382         return true;
1383 }
1384
1385 bool read_callback_(byte buffer[], unsigned *bytes, void *client_data)
1386 {
1387         FLAC__StreamDecoder *decoder = (FLAC__StreamDecoder *)client_data;
1388         FLAC__StreamDecoderReadStatus status;
1389         status = decoder->guts->read_callback(decoder, buffer, bytes, decoder->guts->client_data);
1390         if(status == FLAC__STREAM_DECODER_READ_END_OF_STREAM)
1391                 decoder->state = FLAC__STREAM_DECODER_END_OF_STREAM;
1392         else if(status == FLAC__STREAM_DECODER_READ_ABORT)
1393                 decoder->state = FLAC__STREAM_DECODER_ABORTED;
1394         return status == FLAC__STREAM_DECODER_READ_CONTINUE;
1395 }