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 #if 0
 174                 /* @@@ MMX version needs bps check */
 175                 if(decoder->guts->cpuinfo.data.ia32.mmx && @@@bps check here@@@)
 176                         decoder->guts->local_lpc_restore_signal = FLAC__lpc_restore_signal_asm_i386_mmx;
 177                 else
 178 #endif
 179 fprintf(stderr,"@@@ got _asm_i386 of lpc_restore_signal()\n");
 180                         decoder->guts->local_lpc_restore_signal = FLAC__lpc_restore_signal_asm_i386;
 181 #endif
 182         }
 183
 184         return decoder->state;
 185 }
 186
 187 void FLAC__stream_decoder_finish(FLAC__StreamDecoder *decoder)
 188 {
 189         unsigned i;
 190         assert(decoder != 0);
 191         if(decoder->state == FLAC__STREAM_DECODER_UNINITIALIZED)
 192                 return;
 193         if(decoder->guts != 0) {
 194                 if(decoder->guts->has_seek_table) {
 195                         free(decoder->guts->seek_table.data.seek_table.points);
 196                         decoder->guts->seek_table.data.seek_table.points = 0;
 197                 }
 198                 FLAC__bitbuffer_free(&decoder->guts->input);
 199                 for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 200                         if(decoder->guts->output[i] != 0) {
 201                                 free(decoder->guts->output[i]);
 202                                 decoder->guts->output[i] = 0;
 203                         }
 204                         if(decoder->guts->residual[i] != 0) {
 205                                 free(decoder->guts->residual[i]);
 206                                 decoder->guts->residual[i] = 0;
 207                         }
 208                 }
 209                 free(decoder->guts);
 210                 decoder->guts = 0;
 211         }
 212         decoder->state = FLAC__STREAM_DECODER_UNINITIALIZED;
 213 }
 214
 215 bool FLAC__stream_decoder_flush(FLAC__StreamDecoder *decoder)
 216 {
 217         assert(decoder != 0);
 218
 219         if(!FLAC__bitbuffer_clear(&decoder->guts->input)) {
 220                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 221                 return false;
 222         }
 223
 224         return true;
 225 }
 226
 227 bool FLAC__stream_decoder_reset(FLAC__StreamDecoder *decoder)
 228 {
 229         assert(decoder != 0);
 230
 231         if(!FLAC__stream_decoder_flush(decoder)) {
 232                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 233                 return false;
 234         }
 235         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;
 236
 237         decoder->guts->samples_decoded = 0;
 238
 239         return true;
 240 }
 241
 242 bool FLAC__stream_decoder_process_whole_stream(FLAC__StreamDecoder *decoder)
 243 {
 244         bool dummy;
 245         assert(decoder != 0);
 246
 247         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 248                 return true;
 249
 250         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_METADATA);
 251
 252         if(!FLAC__stream_decoder_reset(decoder)) {
 253                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 254                 return false;
 255         }
 256
 257         while(1) {
 258                 switch(decoder->state) {
 259                         case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
 260                                 if(!stream_decoder_find_metadata_(decoder))
 261                                         return false; /* above function sets the status for us */
 262                                 break;
 263                         case FLAC__STREAM_DECODER_READ_METADATA:
 264                                 if(!stream_decoder_read_metadata_(decoder))
 265                                         return false; /* above function sets the status for us */
 266                                 break;
 267                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 268                                 if(!stream_decoder_frame_sync_(decoder))
 269                                         return true; /* above function sets the status for us */
 270                                 break;
 271                         case FLAC__STREAM_DECODER_READ_FRAME:
 272                                 if(!stream_decoder_read_frame_(decoder, &dummy))
 273                                         return false; /* above function sets the status for us */
 274                                 break;
 275                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 276                                 return true;
 277                         default:
 278                                 assert(0);
 279                 }
 280         }
 281 }
 282
 283 bool FLAC__stream_decoder_process_metadata(FLAC__StreamDecoder *decoder)
 284 {
 285         assert(decoder != 0);
 286
 287         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 288                 return true;
 289
 290         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_METADATA);
 291
 292         if(!FLAC__stream_decoder_reset(decoder)) {
 293                 decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 294                 return false;
 295         }
 296
 297         while(1) {
 298                 switch(decoder->state) {
 299                         case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
 300                                 if(!stream_decoder_find_metadata_(decoder))
 301                                         return false; /* above function sets the status for us */
 302                                 break;
 303                         case FLAC__STREAM_DECODER_READ_METADATA:
 304                                 if(!stream_decoder_read_metadata_(decoder))
 305                                         return false; /* above function sets the status for us */
 306                                 break;
 307                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 308                                 return true;
 309                                 break;
 310                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 311                                 return true;
 312                         default:
 313                                 assert(0);
 314                 }
 315         }
 316 }
 317
 318 bool FLAC__stream_decoder_process_one_frame(FLAC__StreamDecoder *decoder)
 319 {
 320         bool got_a_frame;
 321         assert(decoder != 0);
 322
 323         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 324                 return true;
 325
 326         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC);
 327
 328         while(1) {
 329                 switch(decoder->state) {
 330                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 331                                 if(!stream_decoder_frame_sync_(decoder))
 332                                         return true; /* above function sets the status for us */
 333                                 break;
 334                         case FLAC__STREAM_DECODER_READ_FRAME:
 335                                 if(!stream_decoder_read_frame_(decoder, &got_a_frame))
 336                                         return false; /* above function sets the status for us */
 337                                 if(got_a_frame)
 338                                         return true; /* above function sets the status for us */
 339                                 break;
 340                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 341                                 return true;
 342                         default:
 343                                 assert(0);
 344                 }
 345         }
 346 }
 347
 348 bool FLAC__stream_decoder_process_remaining_frames(FLAC__StreamDecoder *decoder)
 349 {
 350         bool dummy;
 351         assert(decoder != 0);
 352
 353         if(decoder->state == FLAC__STREAM_DECODER_END_OF_STREAM)
 354                 return true;
 355
 356         assert(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC);
 357
 358         while(1) {
 359                 switch(decoder->state) {
 360                         case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
 361                                 if(!stream_decoder_frame_sync_(decoder))
 362                                         return true; /* above function sets the status for us */
 363                                 break;
 364                         case FLAC__STREAM_DECODER_READ_FRAME:
 365                                 if(!stream_decoder_read_frame_(decoder, &dummy))
 366                                         return false; /* above function sets the status for us */
 367                                 break;
 368                         case FLAC__STREAM_DECODER_END_OF_STREAM:
 369                                 return true;
 370                         default:
 371                                 assert(0);
 372                 }
 373         }
 374 }
 375
 376 unsigned FLAC__stream_decoder_input_bytes_unconsumed(FLAC__StreamDecoder *decoder)
 377 {
 378         assert(decoder != 0);
 379         return decoder->guts->input.bytes - decoder->guts->input.consumed_bytes;
 380 }
 381
 382 bool stream_decoder_allocate_output_(FLAC__StreamDecoder *decoder, unsigned size, unsigned channels)
 383 {
 384         unsigned i;
 385         int32 *tmp;
 386
 387         if(size <= decoder->guts->output_capacity && channels <= decoder->guts->output_channels)
 388                 return true;
 389
 390         /* @@@ should change to use realloc() */
 391
 392         for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
 393                 if(decoder->guts->output[i] != 0) {
 394                         free(decoder->guts->output[i]);
 395                         decoder->guts->output[i] = 0;
 396                 }
 397                 if(decoder->guts->residual[i] != 0) {
 398                         free(decoder->guts->residual[i]);
 399                         decoder->guts->residual[i] = 0;
 400                 }
 401         }
 402
 403         for(i = 0; i < channels; i++) {
 404                 tmp = (int32*)malloc(sizeof(int32)*size);
 405                 if(tmp == 0) {
 406                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 407                         return false;
 408                 }
 409                 decoder->guts->output[i] = tmp;
 410
 411                 tmp = (int32*)malloc(sizeof(int32)*size);
 412                 if(tmp == 0) {
 413                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 414                         return false;
 415                 }
 416                 decoder->guts->residual[i] = tmp;
 417         }
 418
 419         decoder->guts->output_capacity = size;
 420         decoder->guts->output_channels = channels;
 421
 422         return true;
 423 }
 424
 425 bool stream_decoder_find_metadata_(FLAC__StreamDecoder *decoder)
 426 {
 427         uint32 x;
 428         unsigned i, id;
 429         bool first = true;
 430
 431         assert(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 432
 433         for(i = id = 0; i < 4; ) {
 434                 if(decoder->guts->cached) {
 435                         x = (uint32)decoder->guts->lookahead;
 436                         decoder->guts->cached = false;
 437                 }
 438                 else {
 439                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 440                                 return false; /* the read_callback_ sets the state for us */
 441                 }
 442                 if(x == FLAC__STREAM_SYNC_STRING[i]) {
 443                         first = true;
 444                         i++;
 445                         id = 0;
 446                         continue;
 447                 }
 448                 if(x == ID3V2_TAG_[id]) {
 449                         id++;
 450                         i = 0;
 451                         if(id == 3) {
 452                                 if(!stream_decoder_skip_id3v2_tag_(decoder))
 453                                         return false; /* the read_callback_ sets the state for us */
 454                         }
 455                         continue;
 456                 }
 457                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 458                         decoder->guts->header_warmup[0] = (byte)x;
 459                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 460                                 return false; /* the read_callback_ sets the state for us */
 461
 462                         /* 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 */
 463                         /* else we have to check if the second byte is the end of a sync code */
 464                         if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 465                                 decoder->guts->lookahead = (byte)x;
 466                                 decoder->guts->cached = true;
 467                         }
 468                         else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
 469                                 decoder->guts->header_warmup[1] = (byte)x;
 470                                 decoder->state = FLAC__STREAM_DECODER_READ_FRAME;
 471                                 return true;
 472                         }
 473                 }
 474                 i = 0;
 475                 if(first) {
 476                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
 477                         first = false;
 478                 }
 479         }
 480
 481         decoder->state = FLAC__STREAM_DECODER_READ_METADATA;
 482         return true;
 483 }
 484
 485 bool stream_decoder_read_metadata_(FLAC__StreamDecoder *decoder)
 486 {
 487         uint32 i, x, last_block, type, length;
 488         uint64 xx;
 489
 490         assert(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 491
 492         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &last_block, FLAC__STREAM_METADATA_IS_LAST_LEN, read_callback_, decoder))
 493                 return false; /* the read_callback_ sets the state for us */
 494         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &type, FLAC__STREAM_METADATA_TYPE_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, &length, FLAC__STREAM_METADATA_LENGTH_LEN, read_callback_, decoder))
 497                 return false; /* the read_callback_ sets the state for us */
 498         if(type == FLAC__METADATA_TYPE_STREAMINFO) {
 499                 unsigned used_bits = 0;
 500                 decoder->guts->stream_info.type = type;
 501                 decoder->guts->stream_info.is_last = last_block;
 502                 decoder->guts->stream_info.length = length;
 503
 504                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN, read_callback_, decoder))
 505                         return false; /* the read_callback_ sets the state for us */
 506                 decoder->guts->stream_info.data.stream_info.min_blocksize = x;
 507                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN;
 508
 509                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_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.max_blocksize = x;
 512                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN;
 513
 514                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN, read_callback_, decoder))
 515                         return false; /* the read_callback_ sets the state for us */
 516                 decoder->guts->stream_info.data.stream_info.min_framesize = x;
 517                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN;
 518
 519                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_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.max_framesize = x;
 522                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN;
 523
 524                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN, read_callback_, decoder))
 525                         return false; /* the read_callback_ sets the state for us */
 526                 decoder->guts->stream_info.data.stream_info.sample_rate = x;
 527                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN;
 528
 529                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN, read_callback_, decoder))
 530                         return false; /* the read_callback_ sets the state for us */
 531                 decoder->guts->stream_info.data.stream_info.channels = x+1;
 532                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN;
 533
 534                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN, read_callback_, decoder))
 535                         return false; /* the read_callback_ sets the state for us */
 536                 decoder->guts->stream_info.data.stream_info.bits_per_sample = x+1;
 537                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN;
 538
 539                 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))
 540                         return false; /* the read_callback_ sets the state for us */
 541                 used_bits += FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN;
 542
 543                 for(i = 0; i < 16; i++) {
 544                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 545                                 return false; /* the read_callback_ sets the state for us */
 546                         decoder->guts->stream_info.data.stream_info.md5sum[i] = (byte)x;
 547                 }
 548                 used_bits += i*8;
 549
 550                 /* skip the rest of the block */
 551                 assert(used_bits % 8 == 0);
 552                 length -= (used_bits / 8);
 553                 for(i = 0; i < length; i++) {
 554                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 555                                 return false; /* the read_callback_ sets the state for us */
 556                 }
 557
 558                 decoder->guts->has_stream_info = true;
 559                 decoder->guts->metadata_callback(decoder, &decoder->guts->stream_info, decoder->guts->client_data);
 560         }
 561         else if(type == FLAC__METADATA_TYPE_SEEKTABLE) {
 562                 unsigned real_points;
 563
 564                 decoder->guts->seek_table.type = type;
 565                 decoder->guts->seek_table.is_last = last_block;
 566                 decoder->guts->seek_table.length = length;
 567
 568                 decoder->guts->seek_table.data.seek_table.num_points = length / FLAC__STREAM_METADATA_SEEKPOINT_LEN;
 569
 570                 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)))) {
 571                         decoder->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
 572                         return false;
 573                 }
 574                 for(i = real_points = 0; i < decoder->guts->seek_table.data.seek_table.num_points; i++) {
 575                         if(!FLAC__bitbuffer_read_raw_uint64(&decoder->guts->input, &xx, FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN, read_callback_, decoder))
 576                                 return false; /* the read_callback_ sets the state for us */
 577                         decoder->guts->seek_table.data.seek_table.points[real_points].sample_number = xx;
 578
 579                         if(!FLAC__bitbuffer_read_raw_uint64(&decoder->guts->input, &xx, FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN, read_callback_, decoder))
 580                                 return false; /* the read_callback_ sets the state for us */
 581                         decoder->guts->seek_table.data.seek_table.points[real_points].stream_offset = xx;
 582
 583                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__STREAM_METADATA_SEEKPOINT_FRAME_SAMPLES_LEN, read_callback_, decoder))
 584                                 return false; /* the read_callback_ sets the state for us */
 585                         decoder->guts->seek_table.data.seek_table.points[real_points].frame_samples = x;
 586
 587                         if(decoder->guts->seek_table.data.seek_table.points[real_points].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER)
 588                                 real_points++;
 589                 }
 590                 decoder->guts->seek_table.data.seek_table.num_points = real_points;
 591
 592                 decoder->guts->has_seek_table = true;
 593                 decoder->guts->metadata_callback(decoder, &decoder->guts->seek_table, decoder->guts->client_data);
 594         }
 595         else {
 596                 /* skip other metadata blocks */
 597                 for(i = 0; i < length; i++) {
 598                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 599                                 return false; /* the read_callback_ sets the state for us */
 600                 }
 601         }
 602
 603         if(last_block)
 604                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 605
 606         return true;
 607 }
 608
 609 bool stream_decoder_skip_id3v2_tag_(FLAC__StreamDecoder *decoder)
 610 {
 611         uint32 x;
 612         unsigned i, skip;
 613
 614         /* skip the version and flags bytes */
 615         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 24, read_callback_, decoder))
 616                 return false; /* the read_callback_ sets the state for us */
 617         /* get the size (in bytes) to skip */
 618         skip = 0;
 619         for(i = 0; i < 4; i++) {
 620                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 621                         return false; /* the read_callback_ sets the state for us */
 622                 skip <<= 7;
 623                 skip |= (x & 0x7f);
 624         }
 625         /* skip the rest of the tag */
 626         for(i = 0; i < skip; i++) {
 627                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 628                         return false; /* the read_callback_ sets the state for us */
 629         }
 630         return true;
 631 }
 632
 633 bool stream_decoder_frame_sync_(FLAC__StreamDecoder *decoder)
 634 {
 635         uint32 x;
 636         bool first = true;
 637
 638         /* If we know the total number of samples in the stream, stop if we've read that many. */
 639         /* This will stop us, for example, from wasting time trying to sync on an ID3V1 tag. */
 640         if(decoder->guts->has_stream_info && decoder->guts->stream_info.data.stream_info.total_samples) {
 641                 if(decoder->guts->samples_decoded >= decoder->guts->stream_info.data.stream_info.total_samples) {
 642                         decoder->state = FLAC__STREAM_DECODER_END_OF_STREAM;
 643                         return true;
 644                 }
 645         }
 646
 647         /* make sure we're byte aligned */
 648         if(decoder->guts->input.consumed_bits != 0) {
 649                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8-decoder->guts->input.consumed_bits, read_callback_, decoder))
 650                         return false; /* the read_callback_ sets the state for us */
 651         }
 652
 653         while(1) {
 654                 if(decoder->guts->cached) {
 655                         x = (uint32)decoder->guts->lookahead;
 656                         decoder->guts->cached = false;
 657                 }
 658                 else {
 659                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 660                                 return false; /* the read_callback_ sets the state for us */
 661                 }
 662                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 663                         decoder->guts->header_warmup[0] = (byte)x;
 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                         /* 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 */
 668                         /* else we have to check if the second byte is the end of a sync code */
 669                         if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 670                                 decoder->guts->lookahead = (byte)x;
 671                                 decoder->guts->cached = true;
 672                         }
 673                         else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
 674                                 decoder->guts->header_warmup[1] = (byte)x;
 675                                 decoder->state = FLAC__STREAM_DECODER_READ_FRAME;
 676                                 return true;
 677                         }
 678                 }
 679                 if(first) {
 680                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
 681                         first = 0;
 682                 }
 683         }
 684
 685         return true;
 686 }
 687
 688 bool stream_decoder_read_frame_(FLAC__StreamDecoder *decoder, bool *got_a_frame)
 689 {
 690         unsigned channel;
 691         unsigned i;
 692         int32 mid, side, left, right;
 693         uint16 frame_crc; /* the one we calculate from the input stream */
 694         uint32 x;
 695
 696         *got_a_frame = false;
 697
 698         /* init the CRC */
 699         frame_crc = 0;
 700         FLAC__CRC16_UPDATE(decoder->guts->header_warmup[0], frame_crc);
 701         FLAC__CRC16_UPDATE(decoder->guts->header_warmup[1], frame_crc);
 702         FLAC__bitbuffer_init_read_crc16(&decoder->guts->input, frame_crc);
 703
 704         if(!stream_decoder_read_frame_header_(decoder))
 705                 return false;
 706         if(decoder->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC)
 707                 return true;
 708         if(!stream_decoder_allocate_output_(decoder, decoder->guts->frame.header.blocksize, decoder->guts->frame.header.channels))
 709                 return false;
 710         for(channel = 0; channel < decoder->guts->frame.header.channels; channel++) {
 711                 /*
 712                  * first figure the correct bits-per-sample of the subframe
 713                  */
 714                 unsigned bps = decoder->guts->frame.header.bits_per_sample;
 715                 switch(decoder->guts->frame.header.channel_assignment) {
 716                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 717                                 /* no adjustment needed */
 718                                 break;
 719                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 720                                 assert(decoder->guts->frame.header.channels == 2);
 721                                 if(channel == 1)
 722                                         bps++;
 723                                 break;
 724                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 725                                 assert(decoder->guts->frame.header.channels == 2);
 726                                 if(channel == 0)
 727                                         bps++;
 728                                 break;
 729                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 730                                 assert(decoder->guts->frame.header.channels == 2);
 731                                 if(channel == 1)
 732                                         bps++;
 733                                 break;
 734                         default:
 735                                 assert(0);
 736                 }
 737                 /*
 738                  * now read it
 739                  */
 740                 if(!stream_decoder_read_subframe_(decoder, channel, bps))
 741                         return false;
 742                 if(decoder->state != FLAC__STREAM_DECODER_READ_FRAME) {
 743                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 744                         return true;
 745                 }
 746         }
 747         if(!stream_decoder_read_zero_padding_(decoder))
 748                 return false;
 749
 750         /*
 751          * Read the frame CRC-16 from the footer and check
 752          */
 753         frame_crc = decoder->guts->input.read_crc16;
 754         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, FLAC__FRAME_FOOTER_CRC_LEN, read_callback_, decoder))
 755                 return false; /* the read_callback_ sets the state for us */
 756         if(frame_crc == (uint16)x) {
 757                 /* Undo any special channel coding */
 758                 switch(decoder->guts->frame.header.channel_assignment) {
 759                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 760                                 /* do nothing */
 761                                 break;
 762                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 763                                 assert(decoder->guts->frame.header.channels == 2);
 764                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
 765                                         decoder->guts->output[1][i] = decoder->guts->output[0][i] - decoder->guts->output[1][i];
 766                                 break;
 767                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 768                                 assert(decoder->guts->frame.header.channels == 2);
 769                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
 770                                         decoder->guts->output[0][i] += decoder->guts->output[1][i];
 771                                 break;
 772                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 773                                 assert(decoder->guts->frame.header.channels == 2);
 774                                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++) {
 775                                         mid = decoder->guts->output[0][i];
 776                                         side = decoder->guts->output[1][i];
 777                                         mid <<= 1;
 778                                         if(side & 1) /* i.e. if 'side' is odd... */
 779                                                 mid++;
 780                                         left = mid + side;
 781                                         right = mid - side;
 782                                         decoder->guts->output[0][i] = left >> 1;
 783                                         decoder->guts->output[1][i] = right >> 1;
 784                                 }
 785                                 break;
 786                         default:
 787                                 assert(0);
 788                                 break;
 789                 }
 790         }
 791         else {
 792                 /* Bad frame, emit error and zero the output signal */
 793                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_FRAME_CRC_MISMATCH, decoder->guts->client_data);
 794                 for(channel = 0; channel < decoder->guts->frame.header.channels; channel++) {
 795                         memset(decoder->guts->output[channel], 0, sizeof(int32) * decoder->guts->frame.header.blocksize);
 796                 }
 797         }
 798
 799         *got_a_frame = true;
 800
 801         /* put the latest values into the public section of the decoder instance */
 802         decoder->channels = decoder->guts->frame.header.channels;
 803         decoder->channel_assignment = decoder->guts->frame.header.channel_assignment;
 804         decoder->bits_per_sample = decoder->guts->frame.header.bits_per_sample;
 805         decoder->sample_rate = decoder->guts->frame.header.sample_rate;
 806         decoder->blocksize = decoder->guts->frame.header.blocksize;
 807
 808         decoder->guts->samples_decoded = decoder->guts->frame.header.number.sample_number + decoder->guts->frame.header.blocksize;
 809
 810         /* write it */
 811         /* 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: */
 812         if(decoder->guts->write_callback(decoder, &decoder->guts->frame, decoder->guts->output, decoder->guts->client_data) != FLAC__STREAM_DECODER_WRITE_CONTINUE)
 813                 return false;
 814
 815         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 816         return true;
 817 }
 818
 819 bool stream_decoder_read_frame_header_(FLAC__StreamDecoder *decoder)
 820 {
 821         uint32 x;
 822         uint64 xx;
 823         unsigned i, blocksize_hint = 0, sample_rate_hint = 0;
 824         byte crc8, raw_header[16]; /* MAGIC NUMBER based on the maximum frame header size, including CRC */
 825         unsigned raw_header_len;
 826         bool is_unparseable = false;
 827         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);
 828         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);
 829
 830         assert(decoder->guts->input.consumed_bits == 0); /* make sure we're byte aligned */
 831
 832         /* init the raw header with the saved bits from synchronization */
 833         raw_header[0] = decoder->guts->header_warmup[0];
 834         raw_header[1] = decoder->guts->header_warmup[1];
 835         raw_header_len = 2;
 836
 837         /*
 838          * check to make sure that the reserved bits are 0
 839          */
 840         if(raw_header[1] & 0x03) { /* MAGIC NUMBER */
 841                 is_unparseable = true;
 842         }
 843
 844         /*
 845          * Note that along the way as we read the header, we look for a sync
 846          * code inside.  If we find one it would indicate that our original
 847          * sync was bad since there cannot be a sync code in a valid header.
 848          */
 849
 850         /*
 851          * read in the raw header as bytes so we can CRC it, and parse it on the way
 852          */
 853         for(i = 0; i < 2; i++) {
 854                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
 855                         return false; /* the read_callback_ sets the state for us */
 856                 if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
 857                         /* if we get here it means our original sync was erroneous since the sync code cannot appear in the header */
 858                         decoder->guts->lookahead = (byte)x;
 859                         decoder->guts->cached = true;
 860                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 861                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 862                         return true;
 863                 }
 864                 raw_header[raw_header_len++] = (byte)x;
 865         }
 866
 867         switch(x = raw_header[2] >> 4) {
 868                 case 0:
 869                         if(is_known_fixed_blocksize_stream)
 870                                 decoder->guts->frame.header.blocksize = decoder->guts->stream_info.data.stream_info.min_blocksize;
 871                         else
 872                                 is_unparseable = true;
 873                         break;
 874                 case 1:
 875                         decoder->guts->frame.header.blocksize = 192;
 876                         break;
 877                 case 2:
 878                 case 3:
 879                 case 4:
 880                 case 5:
 881                         decoder->guts->frame.header.blocksize = 576 << (x-2);
 882                         break;
 883                 case 6:
 884                 case 7:
 885                         blocksize_hint = x;
 886                         break;
 887                 case 8:
 888                 case 9:
 889                 case 10:
 890                 case 11:
 891                 case 12:
 892                 case 13:
 893                 case 14:
 894                 case 15:
 895                         decoder->guts->frame.header.blocksize = 256 << (x-8);
 896                         break;
 897                 default:
 898                         assert(0);
 899                         break;
 900         }
 901
 902         switch(x = raw_header[2] & 0x0f) {
 903                 case 0:
 904                         if(decoder->guts->has_stream_info)
 905                                 decoder->guts->frame.header.sample_rate = decoder->guts->stream_info.data.stream_info.sample_rate;
 906                         else
 907                                 is_unparseable = true;
 908                         break;
 909                 case 1:
 910                 case 2:
 911                 case 3:
 912                         is_unparseable = true;
 913                         break;
 914                 case 4:
 915                         decoder->guts->frame.header.sample_rate = 8000;
 916                         break;
 917                 case 5:
 918                         decoder->guts->frame.header.sample_rate = 16000;
 919                         break;
 920                 case 6:
 921                         decoder->guts->frame.header.sample_rate = 22050;
 922                         break;
 923                 case 7:
 924                         decoder->guts->frame.header.sample_rate = 24000;
 925                         break;
 926                 case 8:
 927                         decoder->guts->frame.header.sample_rate = 32000;
 928                         break;
 929                 case 9:
 930                         decoder->guts->frame.header.sample_rate = 44100;
 931                         break;
 932                 case 10:
 933                         decoder->guts->frame.header.sample_rate = 48000;
 934                         break;
 935                 case 11:
 936                         decoder->guts->frame.header.sample_rate = 96000;
 937                         break;
 938                 case 12:
 939                 case 13:
 940                 case 14:
 941                         sample_rate_hint = x;
 942                         break;
 943                 case 15:
 944                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
 945                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
 946                         return true;
 947                 default:
 948                         assert(0);
 949         }
 950
 951         x = (unsigned)(raw_header[3] >> 4);
 952         if(x & 8) {
 953                 decoder->guts->frame.header.channels = 2;
 954                 switch(x & 7) {
 955                         case 0:
 956                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE;
 957                                 break;
 958                         case 1:
 959                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE;
 960                                 break;
 961                         case 2:
 962                                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_MID_SIDE;
 963                                 break;
 964                         default:
 965                                 is_unparseable = true;
 966                                 break;
 967                 }
 968         }
 969         else {
 970                 decoder->guts->frame.header.channels = (unsigned)x + 1;
 971                 decoder->guts->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT;
 972         }
 973
 974         switch(x = (unsigned)(raw_header[3] & 0x0e) >> 1) {
 975                 case 0:
 976                         if(decoder->guts->has_stream_info)
 977                                 decoder->guts->frame.header.bits_per_sample = decoder->guts->stream_info.data.stream_info.bits_per_sample;
 978                         else
 979                                 is_unparseable = true;
 980                         break;
 981                 case 1:
 982                         decoder->guts->frame.header.bits_per_sample = 8;
 983                         break;
 984                 case 2:
 985                         decoder->guts->frame.header.bits_per_sample = 12;
 986                         break;
 987                 case 4:
 988                         decoder->guts->frame.header.bits_per_sample = 16;
 989                         break;
 990                 case 5:
 991                         decoder->guts->frame.header.bits_per_sample = 20;
 992                         break;
 993                 case 6:
 994                         decoder->guts->frame.header.bits_per_sample = 24;
 995                         break;
 996                 case 3:
 997                 case 7:
 998                         is_unparseable = true;
 999                         break;
1000                 default:
1001                         assert(0);
1002                         break;
1003         }
1004
1005         if(raw_header[3] & 0x01) { /* this should be a zero padding bit */
1006                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1007                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1008                 return true;
1009         }
1010
1011         if(blocksize_hint && is_known_variable_blocksize_stream) {
1012                 if(!FLAC__bitbuffer_read_utf8_uint64(&decoder->guts->input, &xx, read_callback_, decoder, raw_header, &raw_header_len))
1013                         return false; /* the read_callback_ sets the state for us */
1014                 if(xx == 0xffffffffffffffff) { /* i.e. non-UTF8 code... */
1015                         decoder->guts->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
1016                         decoder->guts->cached = true;
1017                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1018                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1019                         return true;
1020                 }
1021                 decoder->guts->frame.header.number.sample_number = xx;
1022         }
1023         else {
1024                 if(!FLAC__bitbuffer_read_utf8_uint32(&decoder->guts->input, &x, read_callback_, decoder, raw_header, &raw_header_len))
1025                         return false; /* the read_callback_ sets the state for us */
1026                 if(x == 0xffffffff) { /* i.e. non-UTF8 code... */
1027                         decoder->guts->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
1028                         decoder->guts->cached = true;
1029                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1030                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1031                         return true;
1032                 }
1033                 decoder->guts->last_frame_number = x;
1034                 if(decoder->guts->has_stream_info) {
1035                         decoder->guts->frame.header.number.sample_number = (int64)decoder->guts->stream_info.data.stream_info.min_blocksize * (int64)x;
1036                 }
1037                 else {
1038                         is_unparseable = true;
1039                 }
1040         }
1041
1042         if(blocksize_hint) {
1043                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1044                         return false; /* the read_callback_ sets the state for us */
1045                 raw_header[raw_header_len++] = (byte)x;
1046                 if(blocksize_hint == 7) {
1047                         uint32 _x;
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                         x = (x << 8) | _x;
1052                 }
1053                 decoder->guts->frame.header.blocksize = x+1;
1054         }
1055
1056         if(sample_rate_hint) {
1057                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1058                         return false; /* the read_callback_ sets the state for us */
1059                 raw_header[raw_header_len++] = (byte)x;
1060                 if(sample_rate_hint != 12) {
1061                         uint32 _x;
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                         x = (x << 8) | _x;
1066                 }
1067                 if(sample_rate_hint == 12)
1068                         decoder->guts->frame.header.sample_rate = x*1000;
1069                 else if(sample_rate_hint == 13)
1070                         decoder->guts->frame.header.sample_rate = x;
1071                 else
1072                         decoder->guts->frame.header.sample_rate = x*10;
1073         }
1074
1075         /* read the CRC-8 byte */
1076         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder))
1077                 return false; /* the read_callback_ sets the state for us */
1078         crc8 = (byte)x;
1079
1080         if(FLAC__crc8(raw_header, raw_header_len) != crc8) {
1081                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_BAD_HEADER, decoder->guts->client_data);
1082                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1083                 return true;
1084         }
1085
1086         if(is_unparseable) {
1087                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1088                 return false;
1089         }
1090
1091         return true;
1092 }
1093
1094 bool stream_decoder_read_subframe_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1095 {
1096         uint32 x;
1097         bool wasted_bits;
1098
1099         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &x, 8, read_callback_, decoder)) /* MAGIC NUMBER */
1100                 return false; /* the read_callback_ sets the state for us */
1101
1102         wasted_bits = (x & 1);
1103         x &= 0xfe;
1104
1105         if(wasted_bits) {
1106                 unsigned u;
1107                 if(!FLAC__bitbuffer_read_unary_unsigned(&decoder->guts->input, &u, read_callback_, decoder))
1108                         return false; /* the read_callback_ sets the state for us */
1109                 decoder->guts->frame.subframes[channel].wasted_bits = u+1;
1110                 bps -= decoder->guts->frame.subframes[channel].wasted_bits;
1111         }
1112         else
1113                 decoder->guts->frame.subframes[channel].wasted_bits = 0;
1114
1115         /*
1116          * Lots of magic numbers here
1117          */
1118         if(x & 0x80) {
1119                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1120                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1121                 return true;
1122         }
1123         else if(x == 0) {
1124                 if(!stream_decoder_read_subframe_constant_(decoder, channel, bps))
1125                         return false;
1126         }
1127         else if(x == 2) {
1128                 if(!stream_decoder_read_subframe_verbatim_(decoder, channel, bps))
1129                         return false;
1130         }
1131         else if(x < 16) {
1132                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1133                 return false;
1134         }
1135         else if(x <= 24) {
1136                 if(!stream_decoder_read_subframe_fixed_(decoder, channel, bps, (x>>1)&7))
1137                         return false;
1138         }
1139         else if(x < 64) {
1140                 decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1141                 return false;
1142         }
1143         else {
1144                 if(!stream_decoder_read_subframe_lpc_(decoder, channel, bps, ((x>>1)&31)+1))
1145                         return false;
1146         }
1147
1148         if(wasted_bits) {
1149                 unsigned i;
1150                 x = decoder->guts->frame.subframes[channel].wasted_bits;
1151                 for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
1152                         decoder->guts->output[channel][i] <<= x;
1153         }
1154
1155         return true;
1156 }
1157
1158 bool stream_decoder_read_subframe_constant_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1159 {
1160         FLAC__Subframe_Constant *subframe = &decoder->guts->frame.subframes[channel].data.constant;
1161         int32 x;
1162         unsigned i;
1163         int32 *output = decoder->guts->output[channel];
1164
1165         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_CONSTANT;
1166
1167         if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &x, bps, read_callback_, decoder))
1168                 return false; /* the read_callback_ sets the state for us */
1169
1170         subframe->value = x;
1171
1172         /* decode the subframe */
1173         for(i = 0; i < decoder->guts->frame.header.blocksize; i++)
1174                 output[i] = x;
1175
1176         return true;
1177 }
1178
1179 bool stream_decoder_read_subframe_fixed_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order)
1180 {
1181         FLAC__Subframe_Fixed *subframe = &decoder->guts->frame.subframes[channel].data.fixed;
1182         int32 i32;
1183         uint32 u32;
1184         unsigned u;
1185
1186         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_FIXED;
1187
1188         subframe->residual = decoder->guts->residual[channel];
1189         subframe->order = order;
1190
1191         /* read warm-up samples */
1192         for(u = 0; u < order; u++) {
1193                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, bps, read_callback_, decoder))
1194                         return false; /* the read_callback_ sets the state for us */
1195                 subframe->warmup[u] = i32;
1196         }
1197
1198         /* read entropy coding method info */
1199         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN, read_callback_, decoder))
1200                 return false; /* the read_callback_ sets the state for us */
1201         subframe->entropy_coding_method.type = u32;
1202         switch(subframe->entropy_coding_method.type) {
1203                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1204                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN, read_callback_, decoder))
1205                                 return false; /* the read_callback_ sets the state for us */
1206                         subframe->entropy_coding_method.data.partitioned_rice.order = u32;
1207                         break;
1208                 default:
1209                         decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1210                         return false;
1211         }
1212
1213         /* read residual */
1214         switch(subframe->entropy_coding_method.type) {
1215                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1216                         if(!stream_decoder_read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, decoder->guts->residual[channel]))
1217                                 return false;
1218                         break;
1219                 default:
1220                         assert(0);
1221         }
1222
1223         /* decode the subframe */
1224         memcpy(decoder->guts->output[channel], subframe->warmup, sizeof(int32) * order);
1225         FLAC__fixed_restore_signal(decoder->guts->residual[channel], decoder->guts->frame.header.blocksize-order, order, decoder->guts->output[channel]+order);
1226
1227         return true;
1228 }
1229
1230 bool stream_decoder_read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order)
1231 {
1232         FLAC__Subframe_LPC *subframe = &decoder->guts->frame.subframes[channel].data.lpc;
1233         int32 i32;
1234         uint32 u32;
1235         unsigned u;
1236
1237         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_LPC;
1238
1239         subframe->residual = decoder->guts->residual[channel];
1240         subframe->order = order;
1241
1242         /* read warm-up samples */
1243         for(u = 0; u < order; u++) {
1244                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, bps, read_callback_, decoder))
1245                         return false; /* the read_callback_ sets the state for us */
1246                 subframe->warmup[u] = i32;
1247         }
1248
1249         /* read qlp coeff precision */
1250         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN, read_callback_, decoder))
1251                 return false; /* the read_callback_ sets the state for us */
1252         if(u32 == (1u << FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN) - 1) {
1253                 decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1254                 decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1255                 return true;
1256         }
1257         subframe->qlp_coeff_precision = u32+1;
1258
1259         /* read qlp shift */
1260         if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN, read_callback_, decoder))
1261                 return false; /* the read_callback_ sets the state for us */
1262         subframe->quantization_level = i32;
1263
1264         /* read quantized lp coefficiencts */
1265         for(u = 0; u < order; u++) {
1266                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i32, subframe->qlp_coeff_precision, read_callback_, decoder))
1267                         return false; /* the read_callback_ sets the state for us */
1268                 subframe->qlp_coeff[u] = i32;
1269         }
1270
1271         /* read entropy coding method info */
1272         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN, read_callback_, decoder))
1273                 return false; /* the read_callback_ sets the state for us */
1274         subframe->entropy_coding_method.type = u32;
1275         switch(subframe->entropy_coding_method.type) {
1276                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1277                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN, read_callback_, decoder))
1278                                 return false; /* the read_callback_ sets the state for us */
1279                         subframe->entropy_coding_method.data.partitioned_rice.order = u32;
1280                         break;
1281                 default:
1282                         decoder->state = FLAC__STREAM_DECODER_UNPARSEABLE_STREAM;
1283                         return false;
1284         }
1285
1286         /* read residual */
1287         switch(subframe->entropy_coding_method.type) {
1288                 case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
1289                         if(!stream_decoder_read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, decoder->guts->residual[channel]))
1290                                 return false;
1291                         break;
1292                 default:
1293                         assert(0);
1294         }
1295
1296         /* decode the subframe */
1297         memcpy(decoder->guts->output[channel], subframe->warmup, sizeof(int32) * order);
1298         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);
1299
1300         return true;
1301 }
1302
1303 bool stream_decoder_read_subframe_verbatim_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps)
1304 {
1305         FLAC__Subframe_Verbatim *subframe = &decoder->guts->frame.subframes[channel].data.verbatim;
1306         int32 x, *residual = decoder->guts->residual[channel];
1307         unsigned i;
1308
1309         decoder->guts->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_VERBATIM;
1310
1311         subframe->data = residual;
1312
1313         for(i = 0; i < decoder->guts->frame.header.blocksize; i++) {
1314                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &x, bps, read_callback_, decoder))
1315                         return false; /* the read_callback_ sets the state for us */
1316                 residual[i] = x;
1317         }
1318
1319         /* decode the subframe */
1320         memcpy(decoder->guts->output[channel], subframe->data, sizeof(int32) * decoder->guts->frame.header.blocksize);
1321
1322         return true;
1323 }
1324
1325 bool stream_decoder_read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, unsigned predictor_order, unsigned partition_order, int32 *residual)
1326 {
1327         uint32 rice_parameter;
1328         int i;
1329         unsigned partition, sample, u;
1330         const unsigned partitions = 1u << partition_order;
1331         const unsigned partition_samples = partition_order > 0? decoder->guts->frame.header.blocksize >> partition_order : decoder->guts->frame.header.blocksize - predictor_order;
1332
1333         sample = 0;
1334         for(partition = 0; partition < partitions; partition++) {
1335                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &rice_parameter, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN, read_callback_, decoder))
1336                         return false; /* the read_callback_ sets the state for us */
1337                 if(rice_parameter < FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER) {
1338                         for(u = (partition_order == 0 || partition > 0)? 0 : predictor_order; u < partition_samples; u++, sample++) {
1339 #ifdef FLAC__SYMMETRIC_RICE
1340                                 if(!FLAC__bitbuffer_read_symmetric_rice_signed(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1341                                         return false; /* the read_callback_ sets the state for us */
1342 #else
1343                                 if(!FLAC__bitbuffer_read_rice_signed(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1344                                         return false; /* the read_callback_ sets the state for us */
1345 #endif
1346                                 residual[sample] = i;
1347                         }
1348                 }
1349                 else {
1350                         if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &rice_parameter, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN, read_callback_, decoder))
1351                                 return false; /* the read_callback_ sets the state for us */
1352                         for(u = (partition_order == 0 || partition > 0)? 0 : predictor_order; u < partition_samples; u++, sample++) {
1353                                 if(!FLAC__bitbuffer_read_raw_int32(&decoder->guts->input, &i, rice_parameter, read_callback_, decoder))
1354                                         return false; /* the read_callback_ sets the state for us */
1355                                 residual[sample] = i;
1356                         }
1357                 }
1358         }
1359
1360         return true;
1361 }
1362
1363 bool stream_decoder_read_zero_padding_(FLAC__StreamDecoder *decoder)
1364 {
1365         if(decoder->guts->input.consumed_bits != 0) {
1366                 uint32 zero = 0;
1367                 if(!FLAC__bitbuffer_read_raw_uint32(&decoder->guts->input, &zero, 8-decoder->guts->input.consumed_bits, read_callback_, decoder))
1368                         return false; /* the read_callback_ sets the state for us */
1369                 if(zero != 0) {
1370                         decoder->guts->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_LOST_SYNC, decoder->guts->client_data);
1371                         decoder->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
1372                 }
1373         }
1374         return true;
1375 }
1376
1377 bool read_callback_(byte buffer[], unsigned *bytes, void *client_data)
1378 {
1379         FLAC__StreamDecoder *decoder = (FLAC__StreamDecoder *)client_data;
1380         FLAC__StreamDecoderReadStatus status;
1381         status = decoder->guts->read_callback(decoder, buffer, bytes, decoder->guts->client_data);
1382         if(status == FLAC__STREAM_DECODER_READ_END_OF_STREAM)
1383                 decoder->state = FLAC__STREAM_DECODER_END_OF_STREAM;
1384         else if(status == FLAC__STREAM_DECODER_READ_ABORT)
1385                 decoder->state = FLAC__STREAM_DECODER_ABORTED;
1386         return status == FLAC__STREAM_DECODER_READ_CONTINUE;
1387 }