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 <string.h> /* for memset/memcpy() */
  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 *client_data;
  38         FLAC__BitBuffer input;
  39         int32 *output[FLAC__MAX_CHANNELS];
  40         int32 *residual[FLAC__MAX_CHANNELS];
  41         unsigned output_capacity, output_channels;
  42         uint32 last_frame_number;
  43         uint64 samples_decoded;
  44         bool has_stream_info, has_seek_table;
  45         FLAC__StreamMetaData stream_info;
  46         FLAC__StreamMetaData seek_table;
  47         FLAC__Frame frame;
  48         bool cached; /* true if there is a byte in lookahead */
  49         FLAC__CPUInfo cpuinfo;
  50         byte header_warmup[2]; /* contains the sync code and reserved bits */
  51         byte lookahead; /* temp storage when we need to look ahead one byte in the stream */
  52 } FLAC__StreamDecoderPrivate;
  53
  54 static byte ID3V2_TAG_[3] = { 'I', 'D', '3' };
  55
  56 static bool stream_decoder_allocate_output_(FLAC__StreamDecoder *decoder, unsigned size, unsigned channels);
  57 static bool stream_decoder_find_metadata_(FLAC__StreamDecoder *decoder);
  58 static bool stream_decoder_read_metadata_(FLAC__StreamDecoder *decoder);
  59 static bool stream_decoder_skip_id3v2_tag_(FLAC__StreamDecoder *decoder);
  60 static bool stream_decoder_frame_sync_(FLAC__StreamDecoder *decoder);
  61 static bool stream_decoder_read_frame_(FLAC__StreamDecoder *decoder, bool *got_a_frame);
  62 static bool stream_decoder_read_frame_header_(FLAC__StreamDecoder *decoder);
  63 static bool stream_decoder_read_subframe_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
  64 static bool stream_decoder_read_subframe_constant_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
  65 static bool stream_decoder_read_subframe_fixed_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order);
  66 static bool stream_decoder_read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order);
  67 static bool stream_decoder_read_subframe_verbatim_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
  68 static bool stream_decoder_read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, unsigned predictor_order, unsigned partition_order, int32 *residual);
  69 static bool stream_decoder_read_zero_padding_(FLAC__StreamDecoder *decoder);
  70 static bool read_callback_(byte buffer[], unsigned *bytes, void *client_data);
  71
  72 const char *FLAC__StreamDecoderStateString[] = {
  73         "FLAC__STREAM_DECODER_SEARCH_FOR_METADATA",
  74         "FLAC__STREAM_DECODER_READ_METADATA",
  75         "FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC",
  76         "FLAC__STREAM_DECODER_READ_FRAME",
  77         "FLAC__STREAM_DECODER_END_OF_STREAM",
  78         "FLAC__STREAM_DECODER_ABORTED",
  79         "FLAC__STREAM_DECODER_UNPARSEABLE_STREAM",
  80         "FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR",
  81         "FLAC__STREAM_DECODER_UNINITIALIZED"
  82 };
  83
  84 const char *FLAC__StreamDecoderReadStatusString[] = {
  85         "FLAC__STREAM_DECODER_READ_CONTINUE",
  86         "FLAC__STREAM_DECODER_READ_END_OF_STREAM",
  87         "FLAC__STREAM_DECODER_READ_ABORT"
  88 };
  89
  90 const char *FLAC__StreamDecoderWriteStatusString[] = {
  91         "FLAC__STREAM_DECODER_WRITE_CONTINUE",
  92         "FLAC__STREAM_DECODER_WRITE_ABORT"
  93 };
  94
  95 const char *FLAC__StreamDecoderErrorStatusString[] = {
  96         "FLAC__STREAM_DECODER_ERROR_LOST_SYNC",
  97         "FLAC__STREAM_DECODER_ERROR_BAD_HEADER",
  98         "FLAC__STREAM_DECODER_ERROR_FRAME_CRC_MISMATCH"
  99 };
 100
 101 FLAC__StreamDecoder *FLAC__stream_decoder_get_new_instance()
 102 {
 103         FLAC__StreamDecoder *decoder = (FLAC__StreamDecoder*)malloc(sizeof(FLAC__StreamDecoder));
 104         if(decoder != 0) {
 105                 decoder->state = FLAC__STREAM_DECODER_UNINITIALIZED;
 106                 decoder->guts = 0;
 107         }
 108         return decoder;
 109 }
 110
 111 void FLAC__stream_decoder_free_instance(FLAC__StreamDecoder *decoder)
 112 {
 113         free(decoder);
 114 }
 115
 116 FLAC__StreamDecoderState FLAC__stream_decoder_init(
 117         FLAC__StreamDecoder *decoder,
 118         FLAC__StreamDecoderReadStatus (*read_callback)(const FLAC__StreamDecoder *decoder, byte buffer[], unsigned *bytes, void *client_data),
 119         FLAC__StreamDecoderWriteStatus (*write_callback)(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const int32 *buffer[], void *client_data),
 120         void (*metadata_callback)(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetaData *metadata, void *client_data),
 121         void (*error_callback)(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data),
 122         void *client_data
 123 )
 124 {
 125         unsigned i;
 126
 127         assert(sizeof(int) >= 4); /* we want to die right away if this is not true */
 128         assert(decoder != 0);
 129         assert(read_callback != 0);
 130         assert(write_callback != 0);
 131         assert(metadata_callback != 0);
 132         assert(error_callback != 0);
 133         assert(decoder->state == FLAC__STREAM_DECODER_UNINITIALIZED);
 134         assert(decoder->guts == 0);
 135
 136         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;
 137
 138         decoder->guts = (FLAC__StreamDecoderPrivate*)malloc(sizeof(FLAC__StreamDecoderPrivate));
 139         if(decoder->guts == 0)
 140                 return decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 141
 142         decoder->guts->read_callback = read_callback;
 143         decoder->guts->write_callback = write_callback;
 144         decoder->guts->metadata_callback = metadata_callback;
 145         decoder->guts->error_callback = error_callback;
 146         decoder->guts->client_data = client_data;
 147
 148         FLAC__bitbuffer_init(&decoder->guts->input);
 149
 150         for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 151                 decoder->guts->output[i] = 0;
 152                 decoder->guts->residual[i] = 0;
 153         }
 154
 155         decoder->guts->output_capacity = 0;
 156         decoder->guts->output_channels = 0;
 157         decoder->guts->last_frame_number = 0;
 158         decoder->guts->samples_decoded = 0;
 159         decoder->guts->has_stream_info = false;
 160         decoder->guts->has_seek_table = false;
 161         decoder->guts->cached = false;
 162
 163         /*
 164          * get the CPU info and set the function pointers
 165          */
 166         FLAC__cpu_info(&decoder->guts->cpuinfo);
 167         /* first default to the non-asm routines */
 168         decoder->guts->local_lpc_restore_signal = FLAC__lpc_restore_signal;
 169         /* now override with asm where appropriate */
 170         if(decoder->guts->cpuinfo.use_asm) {
 171 #ifdef FLAC__CPU_IA32
 172                 assert(decoder->guts->cpuinfo.type == FLAC__CPUINFO_TYPE_IA32);
 173 #ifdef FLAC__HAS_NASM
 174 #if 0
 175                 /* @@@ MMX version needs bps check */
 176                 if(decoder->guts->cpuinfo.data.ia32.mmx && @@@bps check here@@@)
 177                         decoder->guts->local_lpc_restore_signal = FLAC__lpc_restore_signal_asm_i386_mmx;
 178                 else
 179 #endif
 180 fprintf(stderr,"@@@ got _asm_i386 of lpc_restore_signal()\n");
 181                         decoder->guts->local_lpc_restore_signal = FLAC__lpc_restore_signal_asm_i386;
 182 #endif
 183 #endif
 184         }
 185
 186         return decoder->state;
 187 }
 188
 189 void FLAC__stream_decoder_finish(FLAC__StreamDecoder *decoder)
 190 {
 191         unsigned i;
 192         assert(decoder != 0);
 193         if(decoder->state == FLAC__STREAM_DECODER_UNINITIALIZED)
 194                 return;
 195         if(decoder->guts != 0) {
 196                 if(decoder->guts->has_seek_table) {
 197                         free(decoder->guts->seek_table.data.seek_table.points);
 198                         decoder->guts->seek_table.data.seek_table.points = 0;
 199                 }
 200                 FLAC__bitbuffer_free(&decoder->guts->input);
 201                 for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 202                         if(decoder->guts->output[i] != 0) {
 203                                 free(decoder->guts->output[i]);
 204                                 decoder->guts->output[i] = 0;
 205                         }
 206                         if(decoder->guts->residual[i] != 0) {
 207                                 free(decoder->guts->residual[i]);
 208                                 decoder->guts->residual[i] = 0;
 209                         }
 210                 }
 211                 free(decoder->guts);
 212                 decoder->guts = 0;
 213         }
 214         decoder->state = FLAC__STREAM_DECODER_UNINITIALIZED;
 215 }
 216
 217 bool FLAC__stream_decoder_flush(FLAC__StreamDecoder *decoder)
 218 {
 219         assert(decoder != 0);
 220
 221         if(!FLAC__bitbuffer_clear(&decoder->guts->input)) {
 222                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 223                 return false;
 224         }
 225
 226         return true;
 227 }
 228
 229 bool FLAC__stream_decoder_reset(FLAC__StreamDecoder *decoder)
 230 {
 231         assert(decoder != 0);
 232
 233         if(!FLAC__stream_decoder_flush(decoder)) {
 234                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 235                 return false;
 236         }
 237         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;
 238
 239         decoder->guts->samples_decoded = 0;
 240
 241         return true;
 242 }
 243
 244 bool FLAC__stream_decoder_process_whole_stream(FLAC__StreamDecoder *decoder)
 245 {
 246         bool dummy;
 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                                 if(!stream_decoder_frame_sync_(decoder))
 271                                         return true; /* above function sets the status for us */
 272                                 break;
 273                         case FLAC__STREAM_DECODER_READ_FRAME:
 274                                 if(!stream_decoder_read_frame_(decoder, &dummy))
 275                                         return false; /* above function sets the status for us */
 276                                 break;
 277                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 278                                 return true;
 279                         default:
 280                                 assert(0);
 281                 }
 282         }
 283 }
 284
 285 bool FLAC__stream_decoder_process_metadata(FLAC__StreamDecoder *decoder)
 286 {
 287         assert(decoder != 0);
 288
 289         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 290                 return true;
 291
 292         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_METADATA);
 293
 294         if(!FLAC__stream_decoder_reset(decoder)) {
 295                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 296                 return false;
 297         }
 298
 299         while(1) {
 300                 switch(decoder->state) {
 301                         case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
 302                                 if(!stream_decoder_find_metadata_(decoder))
 303                                         return false; /* above function sets the status for us */
 304                                 break;
 305                         case FLAC__STREAM_DECODER_READ_METADATA:
 306                                 if(!stream_decoder_read_metadata_(decoder))
 307                                         return false; /* above function sets the status for us */
 308                                 break;
 309                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 310                                 return true;
 311                                 break;
 312                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 313                                 return true;
 314                         default:
 315                                 assert(0);
 316                 }
 317         }
 318 }
 319
 320 bool FLAC__stream_decoder_process_one_frame(FLAC__StreamDecoder *decoder)
 321 {
 322         bool got_a_frame;
 323         assert(decoder != 0);
 324
 325         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 326                 return true;
 327
 328         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC);
 329
 330         while(1) {
 331                 switch(decoder->state) {
 332                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 333                                 if(!stream_decoder_frame_sync_(decoder))
 334                                         return true; /* above function sets the status for us */
 335                                 break;
 336                         case FLAC__STREAM_DECODER_READ_FRAME:
 337                                 if(!stream_decoder_read_frame_(decoder, &got_a_frame))
 338                                         return false; /* above function sets the status for us */
 339                                 if(got_a_frame)
 340                                         return true; /* above function sets the status for us */
 341                                 break;
 342                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 343                                 return true;
 344                         default:
 345                                 assert(0);
 346                 }
 347         }
 348 }
 349
 350 bool FLAC__stream_decoder_process_remaining_frames(FLAC__StreamDecoder *decoder)
 351 {
 352         bool dummy;
 353         assert(decoder != 0);
 354
 355         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 356                 return true;
 357
 358         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC);
 359
 360         while(1) {
 361                 switch(decoder->state) {
 362                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 363                                 if(!stream_decoder_frame_sync_(decoder))
 364                                         return true; /* above function sets the status for us */
 365                                 break;
 366                         case FLAC__STREAM_DECODER_READ_FRAME:
 367                                 if(!stream_decoder_read_frame_(decoder, &dummy))
 368                                         return false; /* above function sets the status for us */
 369                                 break;
 370                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 371                                 return true;
 372                         default:
 373                                 assert(0);
 374                 }
 375         }
 376 }
 377
 378 unsigned FLAC__stream_decoder_input_bytes_unconsumed(FLAC__StreamDecoder *decoder)
 379 {
 380         assert(decoder != 0);
 381         return decoder->guts->input.bytes - decoder->guts->input.consumed_bytes;
 382 }
 383
 384 bool stream_decoder_allocate_output_(FLAC__StreamDecoder *decoder, unsigned size, unsigned channels)
 385 {
 386         unsigned i;
 387         int32 *tmp;
 388
 389         if(size <= decoder->guts->output_capacity && channels <= decoder->guts->output_channels)
 390                 return true;
 391
 392         /* @@@ should change to use realloc() */
 393
 394         for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 395                 if(decoder->guts->output[i] != 0) {
 396                         free(decoder->guts->output[i]);
 397                         decoder->guts->output[i] = 0;
 398                 }
 399                 if(decoder->guts->residual[i] != 0) {
 400                         free(decoder->guts->residual[i]);
 401                         decoder->guts->residual[i] = 0;
 402                 }
 403         }
 404
 405         for(i = 0; i < channels; i++) {
 406                 tmp = (int32*)malloc(sizeof(int32)*size);
 407                 if(tmp == 0) {
 408                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 409                         return false;
 410                 }
 411                 decoder->guts->output[i] = tmp;
 412
 413                 tmp = (int32*)malloc(sizeof(int32)*size);
 414                 if(tmp == 0) {
 415                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 416                         return false;
 417                 }
 418                 decoder->guts->residual[i] = tmp;
 419         }
 420
 421         decoder->guts->output_capacity = size;
 422         decoder->guts->output_channels = channels;
 423
 424         return true;
 425 }
 426
 427 bool stream_decoder_find_metadata_(FLAC__StreamDecoder *decoder)
 428 {
 429         uint32 x;
 430         unsigned i, id;
 431         bool first = true;
 432
 433         assert(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 434
 435         for(i = id = 0; i < 4; ) {
 436                 if(decoder->guts->cached) {
 437                         x = (uint32)decoder->guts->lookahead;
 438                         decoder->guts->cached = false;
 439                 }
 440                 else {
 441                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 442                                 return false; /* the read_callback_ sets the state for us */
 443                 }
 444                 if(x == FLAC__STREAM_SYNC_STRING[i]) {
 445                         first = true;
 446                         i++;
 447                         id = 0;
 448                         continue;
 449                 }
 450                 if(x == ID3V2_TAG_[id]) {
 451                         id++;
 452                         i = 0;
 453                         if(id == 3) {
 454                                 if(!stream_decoder_skip_id3v2_tag_(decoder))
 455                                         return false; /* the read_callback_ sets the state for us */
 456                         }
 457                         continue;
 458                 }
 459                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 460                         decoder->guts->header_warmup[0] = (byte)x;
 461                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 462                                 return false; /* the read_callback_ sets the state for us */
 463
 464                         /* 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 */
 465                         /* else we have to check if the second byte is the end of a sync code */
 466                         if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 467                                 decoder->guts->lookahead = (byte)x;
 468                                 decoder->guts->cached = true;
 469                         }
 470                         else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
 471                                 decoder->guts->header_warmup[1] = (byte)x;
 472                                 decoder->state = FLAC__STREAM_DECODER_READ_FRAME;
 473                                 return true;
 474                         }
 475                 }
 476                 i = 0;
 477                 if(first) {
 478                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
 479                         first = false;
 480                 }
 481         }
 482
 483         decoder->state = FLAC__STREAM_DECODER_READ_METADATA;
 484         return true;
 485 }
 486
 487 bool stream_decoder_read_metadata_(FLAC__StreamDecoder *decoder)
 488 {
 489         uint32 i, x, last_block, type, length;
 490         uint64 xx;
 491
 492         assert(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 493
 494         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &last_block, FLAC__STREAM_METADATA_IS_LAST_LEN, read_callback_, decoder))
 495                 return false; /* the read_callback_ sets the state for us */
 496         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &type, FLAC__STREAM_METADATA_TYPE_LEN, read_callback_, decoder))
 497                 return false; /* the read_callback_ sets the state for us */
 498         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &length, FLAC__STREAM_METADATA_LENGTH_LEN, read_callback_, decoder))
 499                 return false; /* the read_callback_ sets the state for us */
 500         if(type == FLAC__METADATA_TYPE_STREAMINFO) {
 501                 unsigned used_bits = 0;
 502                 decoder->guts->stream_info.type = type;
 503                 decoder->guts->stream_info.is_last = last_block;
 504                 decoder->guts->stream_info.length = length;
 505
 506                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN, read_callback_, decoder))
 507                         return false; /* the read_callback_ sets the state for us */
 508                 decoder->guts->stream_info.data.stream_info.min_blocksize = x;
 509                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN;
 510
 511                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN, read_callback_, decoder))
 512                         return false; /* the read_callback_ sets the state for us */
 513                 decoder->guts->stream_info.data.stream_info.max_blocksize = x;
 514                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN;
 515
 516                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN, read_callback_, decoder))
 517                         return false; /* the read_callback_ sets the state for us */
 518                 decoder->guts->stream_info.data.stream_info.min_framesize = x;
 519                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN;
 520
 521                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN, read_callback_, decoder))
 522                         return false; /* the read_callback_ sets the state for us */
 523                 decoder->guts->stream_info.data.stream_info.max_framesize = x;
 524                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN;
 525
 526                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN, read_callback_, decoder))
 527                         return false; /* the read_callback_ sets the state for us */
 528                 decoder->guts->stream_info.data.stream_info.sample_rate = x;
 529                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN;
 530
 531                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN, read_callback_, decoder))
 532                         return false; /* the read_callback_ sets the state for us */
 533                 decoder->guts->stream_info.data.stream_info.channels = x+1;
 534                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN;
 535
 536                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN, read_callback_, decoder))
 537                         return false; /* the read_callback_ sets the state for us */
 538                 decoder->guts->stream_info.data.stream_info.bits_per_sample = x+1;
 539                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN;
 540
 541                 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))
 542                         return false; /* the read_callback_ sets the state for us */
 543                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN;
 544
 545                 for(i = 0; i < 16; i++) {
 546                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 547                                 return false; /* the read_callback_ sets the state for us */
 548                         decoder->guts->stream_info.data.stream_info.md5sum[i] = (byte)x;
 549                 }
 550                 used_bits += i*8;
 551
 552                 /* skip the rest of the block */
 553                 assert(used_bits % 8 == 0);
 554                 length -= (used_bits / 8);
 555                 for(i = 0; i < length; i++) {
 556                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 557                                 return false; /* the read_callback_ sets the state for us */
 558                 }
 559
 560                 decoder->guts->has_stream_info = true;
 561                 decoder->guts->metadata_callback(decoder, &decoder->guts->stream_info, decoder->guts->client_data);
 562         }
 563         else if(type == FLAC__METADATA_TYPE_SEEKTABLE) {
 564                 unsigned real_points;
 565
 566                 decoder->guts->seek_table.type = type;
 567                 decoder->guts->seek_table.is_last = last_block;
 568                 decoder->guts->seek_table.length = length;
 569
 570                 decoder->guts->seek_table.data.seek_table.num_points = length / FLAC__STREAM_METADATA_SEEKPOINT_LEN;
 571
 572                 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)))) {
 573                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 574                         return false;
 575                 }
 576                 for(i = real_points = 0; i < decoder->guts->seek_table.data.seek_table.num_points; i++) {
 577                         if(!FLAC__bitbuffer_read_raw_uint64(&decoder->guts->input, &xx, FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN, read_callback_, decoder))
 578                                 return false; /* the read_callback_ sets the state for us */
 579                         decoder->guts->seek_table.data.seek_table.points[real_points].sample_number = xx;
 580
 581                         if(!FLAC__bitbuffer_read_raw_uint64(&decoder->guts->input, &xx, FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN, read_callback_, decoder))
 582                                 return false; /* the read_callback_ sets the state for us */
 583                         decoder->guts->seek_table.data.seek_table.points[real_points].stream_offset = xx;
 584
 585                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_SEEKPOINT_FRAME_SAMPLES_LEN, read_callback_, decoder))
 586                                 return false; /* the read_callback_ sets the state for us */
 587                         decoder->guts->seek_table.data.seek_table.points[real_points].frame_samples = x;
 588
 589                         if(decoder->guts->seek_table.data.seek_table.points[real_points].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER)
 590                                 real_points++;
 591                 }
 592                 decoder->guts->seek_table.data.seek_table.num_points = real_points;
 593
 594                 decoder->guts->has_seek_table = true;
 595                 decoder->guts->metadata_callback(decoder, &decoder->guts->seek_table, decoder->guts->client_data);
 596         }
 597         else {
 598                 /* skip other metadata blocks */
 599                 for(i = 0; i < length; i++) {
 600                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 601                                 return false; /* the read_callback_ sets the state for us */
 602                 }
 603         }
 604
 605         if(last_block)
 606                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 607
 608         return true;
 609 }
 610
 611 bool stream_decoder_skip_id3v2_tag_(FLAC__StreamDecoder *decoder)
 612 {
 613         uint32 x;
 614         unsigned i, skip;
 615
 616         /* skip the version and flags bytes */
 617         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 24, read_callback_, decoder))
 618                 return false; /* the read_callback_ sets the state for us */
 619         /* get the size (in bytes) to skip */
 620         skip = 0;
 621         for(i = 0; i < 4; i++) {
 622                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 623                         return false; /* the read_callback_ sets the state for us */
 624                 skip <<= 7;
 625                 skip |= (x & 0x7f);
 626         }
 627         /* skip the rest of the tag */
 628         for(i = 0; i < skip; i++) {
 629                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 630                         return false; /* the read_callback_ sets the state for us */
 631         }
 632         return true;
 633 }
 634
 635 bool stream_decoder_frame_sync_(FLAC__StreamDecoder *decoder)
 636 {
 637         uint32 x;
 638         bool first = true;
 639
 640         /* If we know the total number of samples in the stream, stop if we've read that many. */
 641         /* This will stop us, for example, from wasting time trying to sync on an ID3V1 tag. */
 642         if(decoder->guts->has_stream_info && decoder->guts->stream_info.data.stream_info.total_samples) {
 643                 if(decoder->guts->samples_decoded >= decoder->guts->stream_info.data.stream_info.total_samples) {
 644                         decoder->state = FLAC__STREAM_DECODER_END_OF_STREAM;
 645                         return true;
 646                 }
 647         }
 648
 649         /* make sure we're byte aligned */
 650         if(decoder->guts->input.consumed_bits != 0) {
 651                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8-decoder->guts->input.consumed_bits, read_callback_, decoder))
 652                         return false; /* the read_callback_ sets the state for us */
 653         }
 654
 655         while(1) {
 656                 if(decoder->guts->cached) {
 657                         x = (uint32)decoder->guts->lookahead;
 658                         decoder->guts->cached = false;
 659                 }
 660                 else {
 661                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 662                                 return false; /* the read_callback_ sets the state for us */
 663                 }
 664                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 665                         decoder->guts->header_warmup[0] = (byte)x;
 666                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 667                                 return false; /* the read_callback_ sets the state for us */
 668
 669                         /* 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 */
 670                         /* else we have to check if the second byte is the end of a sync code */
 671                         if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 672                                 decoder->guts->lookahead = (byte)x;
 673                                 decoder->guts->cached = true;
 674                         }
 675                         else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
 676                                 decoder->guts->header_warmup[1] = (byte)x;
 677                                 decoder->state = FLAC__STREAM_DECODER_READ_FRAME;
 678                                 return true;
 679                         }
 680                 }
 681                 if(first) {
 682                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
 683                         first = 0;
 684                 }
 685         }
 686
 687         return true;
 688 }
 689
 690 bool stream_decoder_read_frame_(FLAC__StreamDecoder *decoder, bool *got_a_frame)
 691 {
 692         unsigned channel;
 693         unsigned i;
 694         int32 mid, side, left, right;
 695         uint16 frame_crc; /* the one we calculate from the input stream */
 696         uint32 x;
 697
 698         *got_a_frame = false;
 699
 700         /* init the CRC */
 701         frame_crc = 0;
 702         FLAC__CRC16_UPDATE(decoder->guts->header_warmup[0], frame_crc);
 703         FLAC__CRC16_UPDATE(decoder->guts->header_warmup[1], frame_crc);
 704         FLAC__bitbuffer_init_read_crc16(&decoder->guts->input, frame_crc);
 705
 706         if(!stream_decoder_read_frame_header_(decoder))
 707                 return false;
 708         if(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC)
 709                 return true;
 710         if(!stream_decoder_allocate_output_(decoder, decoder->guts->frame.header.blocksize, decoder->guts->frame.header.channels))
 711                 return false;
 712         for(channel = 0; channel < decoder->guts->frame.header.channels; channel++) {
 713                 /*
 714                  * first figure the correct bits-per-sample of the subframe
 715                  */
 716                 unsigned bps = decoder->guts->frame.header.bits_per_sample;
 717                 switch(decoder->guts->frame.header.channel_assignment) {
 718                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 719                                 /* no adjustment needed */
 720                                 break;
 721                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 722                                 assert(decoder->guts->frame.header.channels == 2);
 723                                 if(channel == 1)
 724                                         bps++;
 725                                 break;
 726                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 727                                 assert(decoder->guts->frame.header.channels == 2);
 728                                 if(channel == 0)
 729                                         bps++;
 730                                 break;
 731                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 732                                 assert(decoder->guts->frame.header.channels == 2);
 733                                 if(channel == 1)
 734                                         bps++;
 735                                 break;
 736                         default:
 737                                 assert(0);
 738                 }
 739                 /*
 740                  * now read it
 741                  */
 742                 if(!stream_decoder_read_subframe_(decoder, channel, bps))
 743                         return false;
 744                 if(decoder->state != FLAC__STREAM_DECODER_READ_FRAME) {
 745                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 746                         return true;
 747                 }
 748         }
 749         if(!stream_decoder_read_zero_padding_(decoder))
 750                 return false;
 751
 752         /*
 753          * Read the frame CRC-16 from the footer and check
 754          */
 755         frame_crc = decoder->guts->input.read_crc16;
 756         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__FRAME_FOOTER_CRC_LEN, read_callback_, decoder))
 757                 return false; /* the read_callback_ sets the state for us */
 758         if(frame_crc == (uint16)x) {
 759                 /* Undo any special channel coding */
 760                 switch(decoder->guts->frame.header.channel_assignment) {
 761                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 762                                 /* do nothing */
 763                                 break;
 764                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 765                                 assert(decoder->guts->frame.header.channels == 2);
 766                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
 767                                         decoder->guts->output[1][i] = decoder->guts->output[0][i] - decoder->guts->output[1][i];
 768                                 break;
 769                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 770                                 assert(decoder->guts->frame.header.channels == 2);
 771                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
 772                                         decoder->guts->output[0][i] += decoder->guts->output[1][i];
 773                                 break;
 774                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 775                                 assert(decoder->guts->frame.header.channels == 2);
 776                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++) {
 777                                         mid = decoder->guts->output[0][i];
 778                                         side = decoder->guts->output[1][i];
 779                                         mid <<= 1;
 780                                         if(side & 1) /* i.e. if 'side' is odd... */
 781                                                 mid++;
 782                                         left = mid + side;
 783                                         right = mid - side;
 784                                         decoder->guts->output[0][i] = left >> 1;
 785                                         decoder->guts->output[1][i] = right >> 1;
 786                                 }
 787                                 break;
 788                         default:
 789                                 assert(0);
 790                                 break;
 791                 }
 792         }
 793         else {
 794                 /* Bad frame, emit error and zero the output signal */
 795                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_FRAME_CRC_MISMATCH, decoder->guts->client_data);
 796                 for(channel = 0; channel < decoder->guts->frame.header.channels; channel++) {
 797                         memset(decoder->guts->output[channel], 0, sizeof(int32) * decoder->guts->frame.header.blocksize);
 798                 }
 799         }
 800
 801         *got_a_frame = true;
 802
 803         /* put the latest values into the public section of the decoder instance */
 804         decoder->channels = decoder->guts->frame.header.channels;
 805         decoder->channel_assignment = decoder->guts->frame.header.channel_assignment;
 806         decoder->bits_per_sample = decoder->guts->frame.header.bits_per_sample;
 807         decoder->sample_rate = decoder->guts->frame.header.sample_rate;
 808         decoder->blocksize = decoder->guts->frame.header.blocksize;
 809
 810         decoder->guts->samples_decoded = decoder->guts->frame.header.number.sample_number + decoder->guts->frame.header.blocksize;
 811
 812         /* write it */
 813         /* 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: */
 814         if(decoder->guts->write_callback(decoder, &decoder->guts->frame, decoder->guts->output, decoder->guts->client_data) != FLAC__STREAM_DECODER_WRITE_CONTINUE)
 815                 return false;
 816
 817         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 818         return true;
 819 }
 820
 821 bool stream_decoder_read_frame_header_(FLAC__StreamDecoder *decoder)
 822 {
 823         uint32 x;
 824         uint64 xx;
 825         unsigned i, blocksize_hint = 0, sample_rate_hint = 0;
 826         byte crc8, raw_header[16]; /* MAGIC NUMBER based on the maximum frame header size, including CRC */
 827         unsigned raw_header_len;
 828         bool is_unparseable = false;
 829         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);
 830         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);
 831
 832         assert(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 833
 834         /* init the raw header with the saved bits from synchronization */
 835         raw_header[0] = decoder->guts->header_warmup[0];
 836         raw_header[1] = decoder->guts->header_warmup[1];
 837         raw_header_len = 2;
 838
 839         /*
 840          * check to make sure that the reserved bits are 0
 841          */
 842         if(raw_header[1] & 0x03) { /* MAGIC NUMBER */
 843                 is_unparseable = true;
 844         }
 845
 846         /*
 847          * Note that along the way as we read the header, we look for a sync
 848          * code inside.  If we find one it would indicate that our original
 849          * sync was bad since there cannot be a sync code in a valid header.
 850          */
 851
 852         /*
 853          * read in the raw header as bytes so we can CRC it, and parse it on the way
 854          */
 855         for(i = 0; i < 2; i++) {
 856                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 857                         return false; /* the read_callback_ sets the state for us */
 858                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 859                         /* if we get here it means our original sync was erroneous since the sync code cannot appear in the header */
 860                         decoder->guts->lookahead = (byte)x;
 861                         decoder->guts->cached = true;
 862                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 863                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 864                         return true;
 865                 }
 866                 raw_header[raw_header_len++] = (byte)x;
 867         }
 868
 869         switch(x = raw_header[2] >> 4) {
 870                 case 0:
 871                         if(is_known_fixed_blocksize_stream)
 872                                 decoder->guts->frame.header.blocksize = decoder->guts->stream_info.data.stream_info.min_blocksize;
 873                         else
 874                                 is_unparseable = true;
 875                         break;
 876                 case 1:
 877                         decoder->guts->frame.header.blocksize = 192;
 878                         break;
 879                 case 2:
 880                 case 3:
 881                 case 4:
 882                 case 5:
 883                         decoder->guts->frame.header.blocksize = 576 << (x-2);
 884                         break;
 885                 case 6:
 886                 case 7:
 887                         blocksize_hint = x;
 888                         break;
 889                 case 8:
 890                 case 9:
 891                 case 10:
 892                 case 11:
 893                 case 12:
 894                 case 13:
 895                 case 14:
 896                 case 15:
 897                         decoder->guts->frame.header.blocksize = 256 << (x-8);
 898                         break;
 899                 default:
 900                         assert(0);
 901                         break;
 902         }
 903
 904         switch(x = raw_header[2] & 0x0f) {
 905                 case 0:
 906                         if(decoder->guts->has_stream_info)
 907                                 decoder->guts->frame.header.sample_rate = decoder->guts->stream_info.data.stream_info.sample_rate;
 908                         else
 909                                 is_unparseable = true;
 910                         break;
 911                 case 1:
 912                 case 2:
 913                 case 3:
 914                         is_unparseable = true;
 915                         break;
 916                 case 4:
 917                         decoder->guts->frame.header.sample_rate = 8000;
 918                         break;
 919                 case 5:
 920                         decoder->guts->frame.header.sample_rate = 16000;
 921                         break;
 922                 case 6:
 923                         decoder->guts->frame.header.sample_rate = 22050;
 924                         break;
 925                 case 7:
 926                         decoder->guts->frame.header.sample_rate = 24000;
 927                         break;
 928                 case 8:
 929                         decoder->guts->frame.header.sample_rate = 32000;
 930                         break;
 931                 case 9:
 932                         decoder->guts->frame.header.sample_rate = 44100;
 933                         break;
 934                 case 10:
 935                         decoder->guts->frame.header.sample_rate = 48000;
 936                         break;
 937                 case 11:
 938                         decoder->guts->frame.header.sample_rate = 96000;
 939                         break;
 940                 case 12:
 941                 case 13:
 942                 case 14:
 943                         sample_rate_hint = x;
 944                         break;
 945                 case 15:
 946                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 947                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 948                         return true;
 949                 default:
 950                         assert(0);
 951         }
 952
 953         x = (unsigned)(raw_header[3] >> 4);
 954         if(x & 8) {
 955                 decoder->guts->frame.header.channels = 2;
 956                 switch(x & 7) {
 957                         case 0:
 958                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE;
 959                                 break;
 960                         case 1:
 961                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE;
 962                                 break;
 963                         case 2:
 964                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_MID_SIDE;
 965                                 break;
 966                         default:
 967                                 is_unparseable = true;
 968                                 break;
 969                 }
 970         }
 971         else {
 972                 decoder->guts->frame.header.channels = (unsigned)x + 1;
 973                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT;
 974         }
 975
 976         switch(x = (unsigned)(raw_header[3] & 0x0e) >> 1) {
 977                 case 0:
 978                         if(decoder->guts->has_stream_info)
 979                                 decoder->guts->frame.header.bits_per_sample = decoder->guts->stream_info.data.stream_info.bits_per_sample;
 980                         else
 981                                 is_unparseable = true;
 982                         break;
 983                 case 1:
 984                         decoder->guts->frame.header.bits_per_sample = 8;
 985                         break;
 986                 case 2:
 987                         decoder->guts->frame.header.bits_per_sample = 12;
 988                         break;
 989                 case 4:
 990                         decoder->guts->frame.header.bits_per_sample = 16;
 991                         break;
 992                 case 5:
 993                         decoder->guts->frame.header.bits_per_sample = 20;
 994                         break;
 995                 case 6:
 996                         decoder->guts->frame.header.bits_per_sample = 24;
 997                         break;
 998                 case 3:
 999                 case 7:
1000                         is_unparseable = true;
1001                         break;
1002                 default:
1003                         assert(0);
1004                         break;
1005         }
1006
1007         if(raw_header[3] & 0x01) { /* this should be a zero padding bit */
1008                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1009                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1010                 return true;
1011         }
1012
1013         if(blocksize_hint && is_known_variable_blocksize_stream) {
1014                 if(!FLAC__bitbuffer_read_utf8_uint64(&decoder->guts->input, &xx, read_callback_, decoder, raw_header, &raw_header_len))
1015                         return false; /* the read_callback_ sets the state for us */
1016                 if(xx == 0xffffffffffffffff) { /* i.e. non-UTF8 code... */
1017                         decoder->guts->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
1018                         decoder->guts->cached = true;
1019                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1020                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1021                         return true;
1022                 }
1023                 decoder->guts->frame.header.number.sample_number = xx;
1024         }
1025         else {
1026                 if(!FLAC__bitbuffer_read_utf8_uint32(&decoder->guts->input, &x, read_callback_, decoder, raw_header, &raw_header_len))
1027                         return false; /* the read_callback_ sets the state for us */
1028                 if(x == 0xffffffff) { /* i.e. non-UTF8 code... */
1029                         decoder->guts->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
1030                         decoder->guts->cached = true;
1031                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1032                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1033                         return true;
1034                 }
1035                 decoder->guts->last_frame_number = x;
1036                 if(decoder->guts->has_stream_info) {
1037                         decoder->guts->frame.header.number.sample_number = (int64)decoder->guts->stream_info.data.stream_info.min_blocksize * (int64)x;
1038                 }
1039                 else {
1040                         is_unparseable = true;
1041                 }
1042         }
1043
1044         if(blocksize_hint) {
1045                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1046                         return false; /* the read_callback_ sets the state for us */
1047                 raw_header[raw_header_len++] = (byte)x;
1048                 if(blocksize_hint == 7) {
1049                         uint32 _x;
1050                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &_x, 8, read_callback_, decoder))
1051                                 return false; /* the read_callback_ sets the state for us */
1052                         raw_header[raw_header_len++] = (byte)_x;
1053                         x = (x << 8) | _x;
1054                 }
1055                 decoder->guts->frame.header.blocksize = x+1;
1056         }
1057
1058         if(sample_rate_hint) {
1059                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1060                         return false; /* the read_callback_ sets the state for us */
1061                 raw_header[raw_header_len++] = (byte)x;
1062                 if(sample_rate_hint != 12) {
1063                         uint32 _x;
1064                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &_x, 8, read_callback_, decoder))
1065                                 return false; /* the read_callback_ sets the state for us */
1066                         raw_header[raw_header_len++] = (byte)_x;
1067                         x = (x << 8) | _x;
1068                 }
1069                 if(sample_rate_hint == 12)
1070                         decoder->guts->frame.header.sample_rate = x*1000;
1071                 else if(sample_rate_hint == 13)
1072                         decoder->guts->frame.header.sample_rate = x;
1073                 else
1074                         decoder->guts->frame.header.sample_rate = x*10;
1075         }
1076
1077         /* read the CRC-8 byte */
1078         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1079                 return false; /* the read_callback_ sets the state for us */
1080         crc8 = (byte)x;
1081
1082         if(FLAC__crc8(raw_header, raw_header_len) != crc8) {
1083                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1084                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1085                 return true;
1086         }
1087
1088         if(is_unparseable) {
1089                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1090                 return false;
1091         }
1092
1093         return true;
1094 }
1095
1096 bool stream_decoder_read_subframe_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1097 {
1098         uint32 x;
1099         bool wasted_bits;
1100
1101         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder)) /* MAGIC NUMBER */
1102                 return false; /* the read_callback_ sets the state for us */
1103
1104         wasted_bits = (x & 1);
1105         x &= 0xfe;
1106
1107         if(wasted_bits) {
1108                 unsigned u;
1109                 if(!FLAC__bitbuffer_read_unary_unsigned(&decoder->guts->input, &u, read_callback_, decoder))
1110                         return false; /* the read_callback_ sets the state for us */
1111                 decoder->guts->frame.subframes[channel].wasted_bits = u+1;
1112                 bps -= decoder->guts->frame.subframes[channel].wasted_bits;
1113         }
1114         else
1115                 decoder->guts->frame.subframes[channel].wasted_bits = 0;
1116
1117         /*
1118          * Lots of magic numbers here
1119          */
1120         if(x & 0x80) {
1121                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1122                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1123                 return true;
1124         }
1125         else if(x == 0) {
1126                 if(!stream_decoder_read_subframe_constant_(decoder, channel, bps))
1127                         return false;
1128         }
1129         else if(x == 2) {
1130                 if(!stream_decoder_read_subframe_verbatim_(decoder, channel, bps))
1131                         return false;
1132         }
1133         else if(x < 16) {
1134                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1135                 return false;
1136         }
1137         else if(x <= 24) {
1138                 if(!stream_decoder_read_subframe_fixed_(decoder, channel, bps, (x>>1)&7))
1139                         return false;
1140         }
1141         else if(x < 64) {
1142                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1143                 return false;
1144         }
1145         else {
1146                 if(!stream_decoder_read_subframe_lpc_(decoder, channel, bps, ((x>>1)&31)+1))
1147                         return false;
1148         }
1149
1150         if(wasted_bits) {
1151                 unsigned i;
1152                 x = decoder->guts->frame.subframes[channel].wasted_bits;
1153                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
1154                         decoder->guts->output[channel][i] <<= x;
1155         }
1156
1157         return true;
1158 }
1159
1160 bool stream_decoder_read_subframe_constant_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1161 {
1162         FLAC__Subframe_Constant *subframe = &decoder->guts->frame.subframes[channel].data.constant;
1163         int32 x;
1164         unsigned i;
1165         int32 *output = decoder->guts->output[channel];
1166
1167         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_CONSTANT;
1168
1169         if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &x, bps, read_callback_, decoder))
1170                 return false; /* the read_callback_ sets the state for us */
1171
1172         subframe->value = x;
1173
1174         /* decode the subframe */
1175         for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
1176                 output[i] = x;
1177
1178         return true;
1179 }
1180
1181 bool stream_decoder_read_subframe_fixed_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order)
1182 {
1183         FLAC__Subframe_Fixed *subframe = &decoder->guts->frame.subframes[channel].data.fixed;
1184         int32 i32;
1185         uint32 u32;
1186         unsigned u;
1187
1188         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_FIXED;
1189
1190         subframe->residual = decoder->guts->residual[channel];
1191         subframe->order = order;
1192
1193         /* read warm-up samples */
1194         for(u = 0; u < order; u++) {
1195                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, bps, read_callback_, decoder))
1196                         return false; /* the read_callback_ sets the state for us */
1197                 subframe->warmup[u] = i32;
1198         }
1199
1200         /* read entropy coding method info */
1201         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN, read_callback_, decoder))
1202                 return false; /* the read_callback_ sets the state for us */
1203         subframe->entropy_coding_method.type = u32;
1204         switch(subframe->entropy_coding_method.type) {
1205                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1206                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN, read_callback_, decoder))
1207                                 return false; /* the read_callback_ sets the state for us */
1208                         subframe->entropy_coding_method.data.partitioned_rice.order = u32;
1209                         break;
1210                 default:
1211                         decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1212                         return false;
1213         }
1214
1215         /* read residual */
1216         switch(subframe->entropy_coding_method.type) {
1217                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1218                         if(!stream_decoder_read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, decoder->guts->residual[channel]))
1219                                 return false;
1220                         break;
1221                 default:
1222                         assert(0);
1223         }
1224
1225         /* decode the subframe */
1226         memcpy(decoder->guts->output[channel], subframe->warmup, sizeof(int32) * order);
1227         FLAC__fixed_restore_signal(decoder->guts->residual[channel], decoder->guts->frame.header.blocksize-order, order, decoder->guts->output[channel]+order);
1228
1229         return true;
1230 }
1231
1232 bool stream_decoder_read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order)
1233 {
1234         FLAC__Subframe_LPC *subframe = &decoder->guts->frame.subframes[channel].data.lpc;
1235         int32 i32;
1236         uint32 u32;
1237         unsigned u;
1238
1239         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_LPC;
1240
1241         subframe->residual = decoder->guts->residual[channel];
1242         subframe->order = order;
1243
1244         /* read warm-up samples */
1245         for(u = 0; u < order; u++) {
1246                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, bps, read_callback_, decoder))
1247                         return false; /* the read_callback_ sets the state for us */
1248                 subframe->warmup[u] = i32;
1249         }
1250
1251         /* read qlp coeff precision */
1252         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN, read_callback_, decoder))
1253                 return false; /* the read_callback_ sets the state for us */
1254         if(u32 == (1u << FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN) - 1) {
1255                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1256                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1257                 return true;
1258         }
1259         subframe->qlp_coeff_precision = u32+1;
1260
1261         /* read qlp shift */
1262         if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN, read_callback_, decoder))
1263                 return false; /* the read_callback_ sets the state for us */
1264         subframe->quantization_level = i32;
1265
1266         /* read quantized lp coefficiencts */
1267         for(u = 0; u < order; u++) {
1268                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, subframe->qlp_coeff_precision, read_callback_, decoder))
1269                         return false; /* the read_callback_ sets the state for us */
1270                 subframe->qlp_coeff[u] = i32;
1271         }
1272
1273         /* read entropy coding method info */
1274         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN, read_callback_, decoder))
1275                 return false; /* the read_callback_ sets the state for us */
1276         subframe->entropy_coding_method.type = u32;
1277         switch(subframe->entropy_coding_method.type) {
1278                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1279                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN, read_callback_, decoder))
1280                                 return false; /* the read_callback_ sets the state for us */
1281                         subframe->entropy_coding_method.data.partitioned_rice.order = u32;
1282                         break;
1283                 default:
1284                         decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1285                         return false;
1286         }
1287
1288         /* read residual */
1289         switch(subframe->entropy_coding_method.type) {
1290                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1291                         if(!stream_decoder_read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, decoder->guts->residual[channel]))
1292                                 return false;
1293                         break;
1294                 default:
1295                         assert(0);
1296         }
1297
1298         /* decode the subframe */
1299         memcpy(decoder->guts->output[channel], subframe->warmup, sizeof(int32) * order);
1300         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);
1301
1302         return true;
1303 }
1304
1305 bool stream_decoder_read_subframe_verbatim_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1306 {
1307         FLAC__Subframe_Verbatim *subframe = &decoder->guts->frame.subframes[channel].data.verbatim;
1308         int32 x, *residual = decoder->guts->residual[channel];
1309         unsigned i;
1310
1311         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_VERBATIM;
1312
1313         subframe->data = residual;
1314
1315         for(i = 0; i < decoder->guts->frame.header.blocksize; i++) {
1316                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &x, bps, read_callback_, decoder))
1317                         return false; /* the read_callback_ sets the state for us */
1318                 residual[i] = x;
1319         }
1320
1321         /* decode the subframe */
1322         memcpy(decoder->guts->output[channel], subframe->data, sizeof(int32) * decoder->guts->frame.header.blocksize);
1323
1324         return true;
1325 }
1326
1327 bool stream_decoder_read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, unsigned predictor_order, unsigned partition_order, int32 *residual)
1328 {
1329         uint32 rice_parameter;
1330         int i;
1331         unsigned partition, sample, u;
1332         const unsigned partitions = 1u << partition_order;
1333         const unsigned partition_samples = partition_order > 0? decoder->guts->frame.header.blocksize >> partition_order : decoder->guts->frame.header.blocksize - predictor_order;
1334
1335         sample = 0;
1336         for(partition = 0; partition < partitions; partition++) {
1337                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &rice_parameter, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN, read_callback_, decoder))
1338                         return false; /* the read_callback_ sets the state for us */
1339                 if(rice_parameter < FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER) {
1340                         for(u = (partition_order == 0 || partition > 0)? 0 : predictor_order; u < partition_samples; u++, sample++) {
1341 #ifdef FLAC__SYMMETRIC_RICE
1342                                 if(!FLAC__bitbuffer_read_symmetric_rice_signed(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1343                                         return false; /* the read_callback_ sets the state for us */
1344 #else
1345                                 if(!FLAC__bitbuffer_read_rice_signed(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1346                                         return false; /* the read_callback_ sets the state for us */
1347 #endif
1348                                 residual[sample] = i;
1349                         }
1350                 }
1351                 else {
1352                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &rice_parameter, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN, read_callback_, decoder))
1353                                 return false; /* the read_callback_ sets the state for us */
1354                         for(u = (partition_order == 0 || partition > 0)? 0 : predictor_order; u < partition_samples; u++, sample++) {
1355                                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1356                                         return false; /* the read_callback_ sets the state for us */
1357                                 residual[sample] = i;
1358                         }
1359                 }
1360         }
1361
1362         return true;
1363 }
1364
1365 bool stream_decoder_read_zero_padding_(FLAC__StreamDecoder *decoder)
1366 {
1367         if(decoder->guts->input.consumed_bits != 0) {
1368                 uint32 zero = 0;
1369                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &zero, 8-decoder->guts->input.consumed_bits, read_callback_, decoder))
1370                         return false; /* the read_callback_ sets the state for us */
1371                 if(zero != 0) {
1372                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1373                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1374                 }
1375         }
1376         return true;
1377 }
1378
1379 bool read_callback_(byte buffer[], unsigned *bytes, void *client_data)
1380 {
1381         FLAC__StreamDecoder *decoder = (FLAC__StreamDecoder *)client_data;
1382         FLAC__StreamDecoderReadStatus status;
1383         status = decoder->guts->read_callback(decoder, buffer, bytes, decoder->guts->client_data);
1384         if(status == FLAC__STREAM_DECODER_READ_END_OF_STREAM)
1385                 decoder->state = FLAC__STREAM_DECODER_END_OF_STREAM;
1386         else if(status == FLAC__STREAM_DECODER_READ_ABORT)
1387                 decoder->state = FLAC__STREAM_DECODER_ABORTED;
1388         return status == FLAC__STREAM_DECODER_READ_CONTINUE;
1389 }