src/libFLAC/bitwriter.c

   1 /* libFLAC - Free Lossless Audio Codec library
   2  * Copyright (C) 2000-2009  Josh Coalson
   3  * Copyright (C) 2011-2013  Xiph.Org Foundation
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  *
  12  * - Redistributions in binary form must reproduce the above copyright
  13  * notice, this list of conditions and the following disclaimer in the
  14  * documentation and/or other materials provided with the distribution.
  15  *
  16  * - Neither the name of the Xiph.org Foundation nor the names of its
  17  * contributors may be used to endorse or promote products derived from
  18  * this software without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  23  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
  24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  27  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  29  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  30  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 #if HAVE_CONFIG_H
  34 #  include <config.h>
  35 #endif
  36
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include "private/bitwriter.h"
  40 #include "private/crc.h"
  41 #include "private/macros.h"
  42 #include "FLAC/assert.h"
  43 #include "share/alloc.h"
  44 #include "share/compat.h"
  45 #include "share/endswap.h"
  46
  47 /* Things should be fastest when this matches the machine word size */
  48 /* WATCHOUT: if you change this you must also change the following #defines down to SWAP_BE_WORD_TO_HOST below to match */
  49 /* WATCHOUT: there are a few places where the code will not work unless uint32_t is >= 32 bits wide */
  50 #define FLAC__BYTES_PER_WORD 4
  51 #define FLAC__BITS_PER_WORD 32
  52 #define FLAC__WORD_ALL_ONES ((FLAC__uint32)0xffffffff)
  53 /* SWAP_BE_WORD_TO_HOST swaps bytes in a uint32_t (which is always big-endian) if necessary to match host byte order */
  54 #if WORDS_BIGENDIAN
  55 #define SWAP_BE_WORD_TO_HOST(x) (x)
  56 #else
  57 #define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_32(x)
  58 #endif
  59
  60 /*
  61  * The default capacity here doesn't matter too much.  The buffer always grows
  62  * to hold whatever is written to it.  Usually the encoder will stop adding at
  63  * a frame or metadata block, then write that out and clear the buffer for the
  64  * next one.
  65  */
  66 static const unsigned FLAC__BITWRITER_DEFAULT_CAPACITY = 32768u / sizeof(uint32_t); /* size in words */
  67 /* When growing, increment 4K at a time */
  68 static const unsigned FLAC__BITWRITER_DEFAULT_INCREMENT = 4096u / sizeof(uint32_t); /* size in words */
  69
  70 #define FLAC__WORDS_TO_BITS(words) ((words) * FLAC__BITS_PER_WORD)
  71 #define FLAC__TOTAL_BITS(bw) (FLAC__WORDS_TO_BITS((bw)->words) + (bw)->bits)
  72
  73 struct FLAC__BitWriter {
  74         uint32_t *buffer;
  75         uint32_t accum; /* accumulator; bits are right-justified; when full, accum is appended to buffer */
  76         unsigned capacity; /* capacity of buffer in words */
  77         unsigned words; /* # of complete words in buffer */
  78         unsigned bits; /* # of used bits in accum */
  79 };
  80
  81 /* * WATCHOUT: The current implementation only grows the buffer. */
  82 static FLAC__bool bitwriter_grow_(FLAC__BitWriter *bw, unsigned bits_to_add)
  83 {
  84         unsigned new_capacity;
  85         uint32_t *new_buffer;
  86
  87         FLAC__ASSERT(0 != bw);
  88         FLAC__ASSERT(0 != bw->buffer);
  89
  90         /* calculate total words needed to store 'bits_to_add' additional bits */
  91         new_capacity = bw->words + ((bw->bits + bits_to_add + FLAC__BITS_PER_WORD - 1) / FLAC__BITS_PER_WORD);
  92
  93         /* it's possible (due to pessimism in the growth estimation that
  94          * leads to this call) that we don't actually need to grow
  95          */
  96         if(bw->capacity >= new_capacity)
  97                 return true;
  98
  99         /* round up capacity increase to the nearest FLAC__BITWRITER_DEFAULT_INCREMENT */
 100         if((new_capacity - bw->capacity) % FLAC__BITWRITER_DEFAULT_INCREMENT)
 101                 new_capacity += FLAC__BITWRITER_DEFAULT_INCREMENT - ((new_capacity - bw->capacity) % FLAC__BITWRITER_DEFAULT_INCREMENT);
 102         /* make sure we got everything right */
 103         FLAC__ASSERT(0 == (new_capacity - bw->capacity) % FLAC__BITWRITER_DEFAULT_INCREMENT);
 104         FLAC__ASSERT(new_capacity > bw->capacity);
 105         FLAC__ASSERT(new_capacity >= bw->words + ((bw->bits + bits_to_add + FLAC__BITS_PER_WORD - 1) / FLAC__BITS_PER_WORD));
 106
 107         new_buffer = safe_realloc_mul_2op_(bw->buffer, sizeof(uint32_t), /*times*/new_capacity);
 108         if(new_buffer == 0)
 109                 return false;
 110         bw->buffer = new_buffer;
 111         bw->capacity = new_capacity;
 112         return true;
 113 }
 114
 115
 116 /***********************************************************************
 117  *
 118  * Class constructor/destructor
 119  *
 120  ***********************************************************************/
 121
 122 FLAC__BitWriter *FLAC__bitwriter_new(void)
 123 {
 124         FLAC__BitWriter *bw = calloc(1, sizeof(FLAC__BitWriter));
 125         /* note that calloc() sets all members to 0 for us */
 126         return bw;
 127 }
 128
 129 void FLAC__bitwriter_delete(FLAC__BitWriter *bw)
 130 {
 131         FLAC__ASSERT(0 != bw);
 132
 133         FLAC__bitwriter_free(bw);
 134         free(bw);
 135 }
 136
 137 /***********************************************************************
 138  *
 139  * Public class methods
 140  *
 141  ***********************************************************************/
 142
 143 FLAC__bool FLAC__bitwriter_init(FLAC__BitWriter *bw)
 144 {
 145         FLAC__ASSERT(0 != bw);
 146
 147         bw->words = bw->bits = 0;
 148         bw->capacity = FLAC__BITWRITER_DEFAULT_CAPACITY;
 149         bw->buffer = malloc(sizeof(uint32_t) * bw->capacity);
 150         if(bw->buffer == 0)
 151                 return false;
 152
 153         return true;
 154 }
 155
 156 void FLAC__bitwriter_free(FLAC__BitWriter *bw)
 157 {
 158         FLAC__ASSERT(0 != bw);
 159
 160         if(0 != bw->buffer)
 161                 free(bw->buffer);
 162         bw->buffer = 0;
 163         bw->capacity = 0;
 164         bw->words = bw->bits = 0;
 165 }
 166
 167 void FLAC__bitwriter_clear(FLAC__BitWriter *bw)
 168 {
 169         bw->words = bw->bits = 0;
 170 }
 171
 172 void FLAC__bitwriter_dump(const FLAC__BitWriter *bw, FILE *out)
 173 {
 174         unsigned i, j;
 175         if(bw == 0) {
 176                 fprintf(out, "bitwriter is NULL\n");
 177         }
 178         else {
 179                 fprintf(out, "bitwriter: capacity=%u words=%u bits=%u total_bits=%u\n", bw->capacity, bw->words, bw->bits, FLAC__TOTAL_BITS(bw));
 180
 181                 for(i = 0; i < bw->words; i++) {
 182                         fprintf(out, "%08X: ", i);
 183                         for(j = 0; j < FLAC__BITS_PER_WORD; j++)
 184                                 fprintf(out, "%01u", bw->buffer[i] & (1 << (FLAC__BITS_PER_WORD-j-1)) ? 1:0);
 185                         fprintf(out, "\n");
 186                 }
 187                 if(bw->bits > 0) {
 188                         fprintf(out, "%08X: ", i);
 189                         for(j = 0; j < bw->bits; j++)
 190                                 fprintf(out, "%01u", bw->accum & (1 << (bw->bits-j-1)) ? 1:0);
 191                         fprintf(out, "\n");
 192                 }
 193         }
 194 }
 195
 196 FLAC__bool FLAC__bitwriter_get_write_crc16(FLAC__BitWriter *bw, FLAC__uint16 *crc)
 197 {
 198         const FLAC__byte *buffer;
 199         size_t bytes;
 200
 201         FLAC__ASSERT((bw->bits & 7) == 0); /* assert that we're byte-aligned */
 202
 203         if(!FLAC__bitwriter_get_buffer(bw, &buffer, &bytes))
 204                 return false;
 205
 206         *crc = (FLAC__uint16)FLAC__crc16(buffer, bytes);
 207         FLAC__bitwriter_release_buffer(bw);
 208         return true;
 209 }
 210
 211 FLAC__bool FLAC__bitwriter_get_write_crc8(FLAC__BitWriter *bw, FLAC__byte *crc)
 212 {
 213         const FLAC__byte *buffer;
 214         size_t bytes;
 215
 216         FLAC__ASSERT((bw->bits & 7) == 0); /* assert that we're byte-aligned */
 217
 218         if(!FLAC__bitwriter_get_buffer(bw, &buffer, &bytes))
 219                 return false;
 220
 221         *crc = FLAC__crc8(buffer, bytes);
 222         FLAC__bitwriter_release_buffer(bw);
 223         return true;
 224 }
 225
 226 FLAC__bool FLAC__bitwriter_is_byte_aligned(const FLAC__BitWriter *bw)
 227 {
 228         return ((bw->bits & 7) == 0);
 229 }
 230
 231 unsigned FLAC__bitwriter_get_input_bits_unconsumed(const FLAC__BitWriter *bw)
 232 {
 233         return FLAC__TOTAL_BITS(bw);
 234 }
 235
 236 FLAC__bool FLAC__bitwriter_get_buffer(FLAC__BitWriter *bw, const FLAC__byte **buffer, size_t *bytes)
 237 {
 238         FLAC__ASSERT((bw->bits & 7) == 0);
 239         /* double protection */
 240         if(bw->bits & 7)
 241                 return false;
 242         /* if we have bits in the accumulator we have to flush those to the buffer first */
 243         if(bw->bits) {
 244                 FLAC__ASSERT(bw->words <= bw->capacity);
 245                 if(bw->words == bw->capacity && !bitwriter_grow_(bw, FLAC__BITS_PER_WORD))
 246                         return false;
 247                 /* append bits as complete word to buffer, but don't change bw->accum or bw->bits */
 248                 bw->buffer[bw->words] = SWAP_BE_WORD_TO_HOST(bw->accum << (FLAC__BITS_PER_WORD-bw->bits));
 249         }
 250         /* now we can just return what we have */
 251         *buffer = (FLAC__byte*)bw->buffer;
 252         *bytes = (FLAC__BYTES_PER_WORD * bw->words) + (bw->bits >> 3);
 253         return true;
 254 }
 255
 256 void FLAC__bitwriter_release_buffer(FLAC__BitWriter *bw)
 257 {
 258         /* nothing to do.  in the future, strict checking of a 'writer-is-in-
 259          * get-mode' flag could be added everywhere and then cleared here
 260          */
 261         (void)bw;
 262 }
 263
 264 inline FLAC__bool FLAC__bitwriter_write_zeroes(FLAC__BitWriter *bw, unsigned bits)
 265 {
 266         unsigned n;
 267
 268         FLAC__ASSERT(0 != bw);
 269         FLAC__ASSERT(0 != bw->buffer);
 270
 271         if(bits == 0)
 272                 return true;
 273         /* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+bits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
 274         if(bw->capacity <= bw->words + bits && !bitwriter_grow_(bw, bits))
 275                 return false;
 276         /* first part gets to word alignment */
 277         if(bw->bits) {
 278                 n = flac_min(FLAC__BITS_PER_WORD - bw->bits, bits);
 279                 bw->accum <<= n;
 280                 bits -= n;
 281                 bw->bits += n;
 282                 if(bw->bits == FLAC__BITS_PER_WORD) {
 283                         bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
 284                         bw->bits = 0;
 285                 }
 286                 else
 287                         return true;
 288         }
 289         /* do whole words */
 290         while(bits >= FLAC__BITS_PER_WORD) {
 291                 bw->buffer[bw->words++] = 0;
 292                 bits -= FLAC__BITS_PER_WORD;
 293         }
 294         /* do any leftovers */
 295         if(bits > 0) {
 296                 bw->accum = 0;
 297                 bw->bits = bits;
 298         }
 299         return true;
 300 }
 301
 302 inline FLAC__bool FLAC__bitwriter_write_raw_uint32(FLAC__BitWriter *bw, FLAC__uint32 val, unsigned bits)
 303 {
 304         register unsigned left;
 305
 306         /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
 307         FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
 308
 309         FLAC__ASSERT(0 != bw);
 310         FLAC__ASSERT(0 != bw->buffer);
 311
 312         FLAC__ASSERT(bits <= 32);
 313         if(bits == 0)
 314                 return true;
 315
 316         /* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+bits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
 317         if(bw->capacity <= bw->words + bits && !bitwriter_grow_(bw, bits))
 318                 return false;
 319
 320         left = FLAC__BITS_PER_WORD - bw->bits;
 321         if(bits < left) {
 322                 bw->accum <<= bits;
 323                 bw->accum |= val;
 324                 bw->bits += bits;
 325         }
 326         else if(bw->bits) { /* WATCHOUT: if bw->bits == 0, left==FLAC__BITS_PER_WORD and bw->accum<<=left is a NOP instead of setting to 0 */
 327                 bw->accum <<= left;
 328                 bw->accum |= val >> (bw->bits = bits - left);
 329                 bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
 330                 bw->accum = val;
 331         }
 332         else {
 333                 bw->accum = val;
 334                 bw->bits = 0;
 335                 bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(val);
 336         }
 337
 338         return true;
 339 }
 340
 341 inline FLAC__bool FLAC__bitwriter_write_raw_int32(FLAC__BitWriter *bw, FLAC__int32 val, unsigned bits)
 342 {
 343         /* zero-out unused bits */
 344         if(bits < 32)
 345                 val &= (~(0xffffffff << bits));
 346
 347         return FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, bits);
 348 }
 349
 350 inline FLAC__bool FLAC__bitwriter_write_raw_uint64(FLAC__BitWriter *bw, FLAC__uint64 val, unsigned bits)
 351 {
 352         /* this could be a little faster but it's not used for much */
 353         if(bits > 32) {
 354                 return
 355                         FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)(val>>32), bits-32) &&
 356                         FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, 32);
 357         }
 358         else
 359                 return FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, bits);
 360 }
 361
 362 inline FLAC__bool FLAC__bitwriter_write_raw_uint32_little_endian(FLAC__BitWriter *bw, FLAC__uint32 val)
 363 {
 364         /* this doesn't need to be that fast as currently it is only used for vorbis comments */
 365
 366         if(!FLAC__bitwriter_write_raw_uint32(bw, val & 0xff, 8))
 367                 return false;
 368         if(!FLAC__bitwriter_write_raw_uint32(bw, (val>>8) & 0xff, 8))
 369                 return false;
 370         if(!FLAC__bitwriter_write_raw_uint32(bw, (val>>16) & 0xff, 8))
 371                 return false;
 372         if(!FLAC__bitwriter_write_raw_uint32(bw, val>>24, 8))
 373                 return false;
 374
 375         return true;
 376 }
 377
 378 inline FLAC__bool FLAC__bitwriter_write_byte_block(FLAC__BitWriter *bw, const FLAC__byte vals[], unsigned nvals)
 379 {
 380         unsigned i;
 381
 382         /* this could be faster but currently we don't need it to be since it's only used for writing metadata */
 383         for(i = 0; i < nvals; i++) {
 384                 if(!FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)(vals[i]), 8))
 385                         return false;
 386         }
 387
 388         return true;
 389 }
 390
 391 FLAC__bool FLAC__bitwriter_write_unary_unsigned(FLAC__BitWriter *bw, unsigned val)
 392 {
 393         if(val < 32)
 394                 return FLAC__bitwriter_write_raw_uint32(bw, 1, ++val);
 395         else
 396                 return
 397                         FLAC__bitwriter_write_zeroes(bw, val) &&
 398                         FLAC__bitwriter_write_raw_uint32(bw, 1, 1);
 399 }
 400
 401 unsigned FLAC__bitwriter_rice_bits(FLAC__int32 val, unsigned parameter)
 402 {
 403         FLAC__uint32 uval;
 404
 405         FLAC__ASSERT(parameter < sizeof(unsigned)*8);
 406
 407         /* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
 408         uval = (val<<1) ^ (val>>31);
 409
 410         return 1 + parameter + (uval >> parameter);
 411 }
 412
 413 #if 0 /* UNUSED */
 414 unsigned FLAC__bitwriter_golomb_bits_signed(int val, unsigned parameter)
 415 {
 416         unsigned bits, msbs, uval;
 417         unsigned k;
 418
 419         FLAC__ASSERT(parameter > 0);
 420
 421         /* fold signed to unsigned */
 422         if(val < 0)
 423                 uval = (unsigned)(((-(++val)) << 1) + 1);
 424         else
 425                 uval = (unsigned)(val << 1);
 426
 427         k = FLAC__bitmath_ilog2(parameter);
 428         if(parameter == 1u<<k) {
 429                 FLAC__ASSERT(k <= 30);
 430
 431                 msbs = uval >> k;
 432                 bits = 1 + k + msbs;
 433         }
 434         else {
 435                 unsigned q, r, d;
 436
 437                 d = (1 << (k+1)) - parameter;
 438                 q = uval / parameter;
 439                 r = uval - (q * parameter);
 440
 441                 bits = 1 + q + k;
 442                 if(r >= d)
 443                         bits++;
 444         }
 445         return bits;
 446 }
 447
 448 unsigned FLAC__bitwriter_golomb_bits_unsigned(unsigned uval, unsigned parameter)
 449 {
 450         unsigned bits, msbs;
 451         unsigned k;
 452
 453         FLAC__ASSERT(parameter > 0);
 454
 455         k = FLAC__bitmath_ilog2(parameter);
 456         if(parameter == 1u<<k) {
 457                 FLAC__ASSERT(k <= 30);
 458
 459                 msbs = uval >> k;
 460                 bits = 1 + k + msbs;
 461         }
 462         else {
 463                 unsigned q, r, d;
 464
 465                 d = (1 << (k+1)) - parameter;
 466                 q = uval / parameter;
 467                 r = uval - (q * parameter);
 468
 469                 bits = 1 + q + k;
 470                 if(r >= d)
 471                         bits++;
 472         }
 473         return bits;
 474 }
 475 #endif /* UNUSED */
 476
 477 FLAC__bool FLAC__bitwriter_write_rice_signed(FLAC__BitWriter *bw, FLAC__int32 val, unsigned parameter)
 478 {
 479         unsigned total_bits, interesting_bits, msbs;
 480         FLAC__uint32 uval, pattern;
 481
 482         FLAC__ASSERT(0 != bw);
 483         FLAC__ASSERT(0 != bw->buffer);
 484         FLAC__ASSERT(parameter < 8*sizeof(uval));
 485
 486         /* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
 487         uval = (val<<1) ^ (val>>31);
 488
 489         msbs = uval >> parameter;
 490         interesting_bits = 1 + parameter;
 491         total_bits = interesting_bits + msbs;
 492         pattern = 1 << parameter; /* the unary end bit */
 493         pattern |= (uval & ((1<<parameter)-1)); /* the binary LSBs */
 494
 495         if(total_bits <= 32)
 496                 return FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits);
 497         else
 498                 return
 499                         FLAC__bitwriter_write_zeroes(bw, msbs) && /* write the unary MSBs */
 500                         FLAC__bitwriter_write_raw_uint32(bw, pattern, interesting_bits); /* write the unary end bit and binary LSBs */
 501 }
 502
 503 FLAC__bool FLAC__bitwriter_write_rice_signed_block(FLAC__BitWriter *bw, const FLAC__int32 *vals, unsigned nvals, unsigned parameter)
 504 {
 505         const FLAC__uint32 mask1 = FLAC__WORD_ALL_ONES << parameter; /* we val|=mask1 to set the stop bit above it... */
 506         const FLAC__uint32 mask2 = FLAC__WORD_ALL_ONES >> (31-parameter); /* ...then mask off the bits above the stop bit with val&=mask2*/
 507         FLAC__uint32 uval;
 508         unsigned left;
 509         const unsigned lsbits = 1 + parameter;
 510         unsigned msbits;
 511
 512         FLAC__ASSERT(0 != bw);
 513         FLAC__ASSERT(0 != bw->buffer);
 514         FLAC__ASSERT(parameter < 8*sizeof(uint32_t)-1);
 515         /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
 516         FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
 517
 518         while(nvals) {
 519                 /* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
 520                 uval = (*vals<<1) ^ (*vals>>31);
 521
 522                 msbits = uval >> parameter;
 523
 524 #if 0 /* OPT: can remove this special case if it doesn't make up for the extra compare (doesn't make a statistically significant difference with msvc or gcc/x86) */
 525                 if(bw->bits && bw->bits + msbits + lsbits <= FLAC__BITS_PER_WORD) { /* i.e. if the whole thing fits in the current uint32_t */
 526                         /* ^^^ if bw->bits is 0 then we may have filled the buffer and have no free uint32_t to work in */
 527                         bw->bits = bw->bits + msbits + lsbits;
 528                         uval |= mask1; /* set stop bit */
 529                         uval &= mask2; /* mask off unused top bits */
 530                         /* NOT: bw->accum <<= msbits + lsbits because msbits+lsbits could be 32, then the shift would be a NOP */
 531                         bw->accum <<= msbits;
 532                         bw->accum <<= lsbits;
 533                         bw->accum |= uval;
 534                         if(bw->bits == FLAC__BITS_PER_WORD) {
 535                                 bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
 536                                 bw->bits = 0;
 537                                 /* burying the capacity check down here means we have to grow the buffer a little if there are more vals to do */
 538                                 if(bw->capacity <= bw->words && nvals > 1 && !bitwriter_grow_(bw, 1)) {
 539                                         FLAC__ASSERT(bw->capacity == bw->words);
 540                                         return false;
 541                                 }
 542                         }
 543                 }
 544                 else {
 545 #elif 1 /*@@@@@@ OPT: try this version with MSVC6 to see if better, not much difference for gcc-4 */
 546                 if(bw->bits && bw->bits + msbits + lsbits < FLAC__BITS_PER_WORD) { /* i.e. if the whole thing fits in the current uint32_t */
 547                         /* ^^^ if bw->bits is 0 then we may have filled the buffer and have no free uint32_t to work in */
 548                         bw->bits = bw->bits + msbits + lsbits;
 549                         uval |= mask1; /* set stop bit */
 550                         uval &= mask2; /* mask off unused top bits */
 551                         bw->accum <<= msbits + lsbits;
 552                         bw->accum |= uval;
 553                 }
 554                 else {
 555 #endif
 556                         /* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+msbits+lsbits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
 557                         /* OPT: pessimism may cause flurry of false calls to grow_ which eat up all savings before it */
 558                         if(bw->capacity <= bw->words + bw->bits + msbits + 1/*lsbits always fit in 1 uint32_t*/ && !bitwriter_grow_(bw, msbits+lsbits))
 559                                 return false;
 560
 561                         if(msbits) {
 562                                 /* first part gets to word alignment */
 563                                 if(bw->bits) {
 564                                         left = FLAC__BITS_PER_WORD - bw->bits;
 565                                         if(msbits < left) {
 566                                                 bw->accum <<= msbits;
 567                                                 bw->bits += msbits;
 568                                                 goto break1;
 569                                         }
 570                                         else {
 571                                                 bw->accum <<= left;
 572                                                 msbits -= left;
 573                                                 bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
 574                                                 bw->bits = 0;
 575                                         }
 576                                 }
 577                                 /* do whole words */
 578                                 while(msbits >= FLAC__BITS_PER_WORD) {
 579                                         bw->buffer[bw->words++] = 0;
 580                                         msbits -= FLAC__BITS_PER_WORD;
 581                                 }
 582                                 /* do any leftovers */
 583                                 if(msbits > 0) {
 584                                         bw->accum = 0;
 585                                         bw->bits = msbits;
 586                                 }
 587                         }
 588 break1:
 589                         uval |= mask1; /* set stop bit */
 590                         uval &= mask2; /* mask off unused top bits */
 591
 592                         left = FLAC__BITS_PER_WORD - bw->bits;
 593                         if(lsbits < left) {
 594                                 bw->accum <<= lsbits;
 595                                 bw->accum |= uval;
 596                                 bw->bits += lsbits;
 597                         }
 598                         else {
 599                                 /* if bw->bits == 0, left==FLAC__BITS_PER_WORD which will always
 600                                  * be > lsbits (because of previous assertions) so it would have
 601                                  * triggered the (lsbits<left) case above.
 602                                  */
 603                                 FLAC__ASSERT(bw->bits);
 604                                 FLAC__ASSERT(left < FLAC__BITS_PER_WORD);
 605                                 bw->accum <<= left;
 606                                 bw->accum |= uval >> (bw->bits = lsbits - left);
 607                                 bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
 608                                 bw->accum = uval;
 609                         }
 610 #if 1
 611                 }
 612 #endif
 613                 vals++;
 614                 nvals--;
 615         }
 616         return true;
 617 }
 618
 619 #if 0 /* UNUSED */
 620 FLAC__bool FLAC__bitwriter_write_golomb_signed(FLAC__BitWriter *bw, int val, unsigned parameter)
 621 {
 622         unsigned total_bits, msbs, uval;
 623         unsigned k;
 624
 625         FLAC__ASSERT(0 != bw);
 626         FLAC__ASSERT(0 != bw->buffer);
 627         FLAC__ASSERT(parameter > 0);
 628
 629         /* fold signed to unsigned */
 630         if(val < 0)
 631                 uval = (unsigned)(((-(++val)) << 1) + 1);
 632         else
 633                 uval = (unsigned)(val << 1);
 634
 635         k = FLAC__bitmath_ilog2(parameter);
 636         if(parameter == 1u<<k) {
 637                 unsigned pattern;
 638
 639                 FLAC__ASSERT(k <= 30);
 640
 641                 msbs = uval >> k;
 642                 total_bits = 1 + k + msbs;
 643                 pattern = 1 << k; /* the unary end bit */
 644                 pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */
 645
 646                 if(total_bits <= 32) {
 647                         if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits))
 648                                 return false;
 649                 }
 650                 else {
 651                         /* write the unary MSBs */
 652                         if(!FLAC__bitwriter_write_zeroes(bw, msbs))
 653                                 return false;
 654                         /* write the unary end bit and binary LSBs */
 655                         if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, k+1))
 656                                 return false;
 657                 }
 658         }
 659         else {
 660                 unsigned q, r, d;
 661
 662                 d = (1 << (k+1)) - parameter;
 663                 q = uval / parameter;
 664                 r = uval - (q * parameter);
 665                 /* write the unary MSBs */
 666                 if(!FLAC__bitwriter_write_zeroes(bw, q))
 667                         return false;
 668                 /* write the unary end bit */
 669                 if(!FLAC__bitwriter_write_raw_uint32(bw, 1, 1))
 670                         return false;
 671                 /* write the binary LSBs */
 672                 if(r >= d) {
 673                         if(!FLAC__bitwriter_write_raw_uint32(bw, r+d, k+1))
 674                                 return false;
 675                 }
 676                 else {
 677                         if(!FLAC__bitwriter_write_raw_uint32(bw, r, k))
 678                                 return false;
 679                 }
 680         }
 681         return true;
 682 }
 683
 684 FLAC__bool FLAC__bitwriter_write_golomb_unsigned(FLAC__BitWriter *bw, unsigned uval, unsigned parameter)
 685 {
 686         unsigned total_bits, msbs;
 687         unsigned k;
 688
 689         FLAC__ASSERT(0 != bw);
 690         FLAC__ASSERT(0 != bw->buffer);
 691         FLAC__ASSERT(parameter > 0);
 692
 693         k = FLAC__bitmath_ilog2(parameter);
 694         if(parameter == 1u<<k) {
 695                 unsigned pattern;
 696
 697                 FLAC__ASSERT(k <= 30);
 698
 699                 msbs = uval >> k;
 700                 total_bits = 1 + k + msbs;
 701                 pattern = 1 << k; /* the unary end bit */
 702                 pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */
 703
 704                 if(total_bits <= 32) {
 705                         if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits))
 706                                 return false;
 707                 }
 708                 else {
 709                         /* write the unary MSBs */
 710                         if(!FLAC__bitwriter_write_zeroes(bw, msbs))
 711                                 return false;
 712                         /* write the unary end bit and binary LSBs */
 713                         if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, k+1))
 714                                 return false;
 715                 }
 716         }
 717         else {
 718                 unsigned q, r, d;
 719
 720                 d = (1 << (k+1)) - parameter;
 721                 q = uval / parameter;
 722                 r = uval - (q * parameter);
 723                 /* write the unary MSBs */
 724                 if(!FLAC__bitwriter_write_zeroes(bw, q))
 725                         return false;
 726                 /* write the unary end bit */
 727                 if(!FLAC__bitwriter_write_raw_uint32(bw, 1, 1))
 728                         return false;
 729                 /* write the binary LSBs */
 730                 if(r >= d) {
 731                         if(!FLAC__bitwriter_write_raw_uint32(bw, r+d, k+1))
 732                                 return false;
 733                 }
 734                 else {
 735                         if(!FLAC__bitwriter_write_raw_uint32(bw, r, k))
 736                                 return false;
 737                 }
 738         }
 739         return true;
 740 }
 741 #endif /* UNUSED */
 742
 743 FLAC__bool FLAC__bitwriter_write_utf8_uint32(FLAC__BitWriter *bw, FLAC__uint32 val)
 744 {
 745         FLAC__bool ok = 1;
 746
 747         FLAC__ASSERT(0 != bw);
 748         FLAC__ASSERT(0 != bw->buffer);
 749
 750         FLAC__ASSERT(!(val & 0x80000000)); /* this version only handles 31 bits */
 751
 752         if(val < 0x80) {
 753                 return FLAC__bitwriter_write_raw_uint32(bw, val, 8);
 754         }
 755         else if(val < 0x800) {
 756                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xC0 | (val>>6), 8);
 757                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
 758         }
 759         else if(val < 0x10000) {
 760                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xE0 | (val>>12), 8);
 761                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>6)&0x3F), 8);
 762                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
 763         }
 764         else if(val < 0x200000) {
 765                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xF0 | (val>>18), 8);
 766                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>12)&0x3F), 8);
 767                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>6)&0x3F), 8);
 768                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
 769         }
 770         else if(val < 0x4000000) {
 771                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xF8 | (val>>24), 8);
 772                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>18)&0x3F), 8);
 773                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>12)&0x3F), 8);
 774                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>6)&0x3F), 8);
 775                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
 776         }
 777         else {
 778                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xFC | (val>>30), 8);
 779                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>24)&0x3F), 8);
 780                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>18)&0x3F), 8);
 781                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>12)&0x3F), 8);
 782                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>6)&0x3F), 8);
 783                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
 784         }
 785
 786         return ok;
 787 }
 788
 789 FLAC__bool FLAC__bitwriter_write_utf8_uint64(FLAC__BitWriter *bw, FLAC__uint64 val)
 790 {
 791         FLAC__bool ok = 1;
 792
 793         FLAC__ASSERT(0 != bw);
 794         FLAC__ASSERT(0 != bw->buffer);
 795
 796         FLAC__ASSERT(!(val & FLAC__U64L(0xFFFFFFF000000000))); /* this version only handles 36 bits */
 797
 798         if(val < 0x80) {
 799                 return FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, 8);
 800         }
 801         else if(val < 0x800) {
 802                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xC0 | (FLAC__uint32)(val>>6), 8);
 803                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 804         }
 805         else if(val < 0x10000) {
 806                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xE0 | (FLAC__uint32)(val>>12), 8);
 807                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 808                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 809         }
 810         else if(val < 0x200000) {
 811                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xF0 | (FLAC__uint32)(val>>18), 8);
 812                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
 813                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 814                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 815         }
 816         else if(val < 0x4000000) {
 817                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xF8 | (FLAC__uint32)(val>>24), 8);
 818                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
 819                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
 820                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 821                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 822         }
 823         else if(val < 0x80000000) {
 824                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xFC | (FLAC__uint32)(val>>30), 8);
 825                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>24)&0x3F), 8);
 826                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
 827                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
 828                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 829                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 830         }
 831         else {
 832                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xFE, 8);
 833                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>30)&0x3F), 8);
 834                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>24)&0x3F), 8);
 835                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
 836                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
 837                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 838                 ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 839         }
 840
 841         return ok;
 842 }
 843
 844 FLAC__bool FLAC__bitwriter_zero_pad_to_byte_boundary(FLAC__BitWriter *bw)
 845 {
 846         /* 0-pad to byte boundary */
 847         if(bw->bits & 7u)
 848                 return FLAC__bitwriter_write_zeroes(bw, 8 - (bw->bits & 7u));
 849         else
 850                 return true;
 851 }
 852
 853 /* These functions a declared inline in this file but are also callable as
 854  * externs from elsewhere.
 855  * According to the C99 sepc, section 6.7.4, simply providing a function
 856  * prototype in a header file without 'inline' and making the function inline
 857  * in this file should be sufficient.
 858  * Unfortunately, the Microsoft VS compiler doesn't pick them up externally. To
 859  * fix that we add extern declarations here.
 860  */
 861 extern FLAC__bool FLAC__bitwriter_write_zeroes(FLAC__BitWriter *bw, unsigned bits);
 862 extern FLAC__bool FLAC__bitwriter_write_raw_int32(FLAC__BitWriter *bw, FLAC__int32 val, unsigned bits);
 863 extern FLAC__bool FLAC__bitwriter_write_raw_uint64(FLAC__BitWriter *bw, FLAC__uint64 val, unsigned bits);
 864 extern FLAC__bool FLAC__bitwriter_write_raw_uint32_little_endian(FLAC__BitWriter *bw, FLAC__uint32 val);
 865 extern FLAC__bool FLAC__bitwriter_write_byte_block(FLAC__BitWriter *bw, const FLAC__byte vals[], unsigned nvals);