deps/flac-1.3.2/src/libFLAC/bitwriter.c

   1 /* libFLAC - Free Lossless Audio Codec library
   2  * Copyright (C) 2000-2009  Josh Coalson
   3  * Copyright (C) 2011-2016  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 #ifdef 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 bwword is >= 32 bits wide */
  50
  51 #if (ENABLE_64_BIT_WORDS == 0)
  52
  53 typedef FLAC__uint32 bwword;
  54 #define FLAC__BYTES_PER_WORD 4          /* sizeof bwword */
  55 #define FLAC__BITS_PER_WORD 32
  56 /* SWAP_BE_WORD_TO_HOST swaps bytes in a bwword (which is always big-endian) if necessary to match host byte order */
  57 #if WORDS_BIGENDIAN
  58 #define SWAP_BE_WORD_TO_HOST(x) (x)
  59 #else
  60 #define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_32(x)
  61 #endif
  62
  63 #else
  64
  65 typedef FLAC__uint64 bwword;
  66 #define FLAC__BYTES_PER_WORD 8          /* sizeof bwword */
  67 #define FLAC__BITS_PER_WORD 64
  68 /* SWAP_BE_WORD_TO_HOST swaps bytes in a bwword (which is always big-endian) if necessary to match host byte order */
  69 #if WORDS_BIGENDIAN
  70 #define SWAP_BE_WORD_TO_HOST(x) (x)
  71 #else
  72 #define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_64(x)
  73 #endif
  74
  75 #endif
  76
  77 /*
  78  * The default capacity here doesn't matter too much.  The buffer always grows
  79  * to hold whatever is written to it.  Usually the encoder will stop adding at
  80  * a frame or metadata block, then write that out and clear the buffer for the
  81  * next one.
  82  */
  83 static const unsigned FLAC__BITWRITER_DEFAULT_CAPACITY = 32768u / sizeof(bwword); /* size in words */
  84 /* When growing, increment 4K at a time */
  85 static const unsigned FLAC__BITWRITER_DEFAULT_INCREMENT = 4096u / sizeof(bwword); /* size in words */
  86
  87 #define FLAC__WORDS_TO_BITS(words) ((words) * FLAC__BITS_PER_WORD)
  88 #define FLAC__TOTAL_BITS(bw) (FLAC__WORDS_TO_BITS((bw)->words) + (bw)->bits)
  89
  90 struct FLAC__BitWriter {
  91         bwword *buffer;
  92         bwword accum; /* accumulator; bits are right-justified; when full, accum is appended to buffer */
  93         unsigned capacity; /* capacity of buffer in words */
  94         unsigned words; /* # of complete words in buffer */
  95         unsigned bits; /* # of used bits in accum */
  96 };
  97
  98 /* * WATCHOUT: The current implementation only grows the buffer. */
  99 #ifndef __SUNPRO_C
 100 static
 101 #endif
 102 FLAC__bool bitwriter_grow_(FLAC__BitWriter *bw, unsigned bits_to_add)
 103 {
 104         unsigned new_capacity;
 105         bwword *new_buffer;
 106
 107         FLAC__ASSERT(0 != bw);
 108         FLAC__ASSERT(0 != bw->buffer);
 109
 110         /* calculate total words needed to store 'bits_to_add' additional bits */
 111         new_capacity = bw->words + ((bw->bits + bits_to_add + FLAC__BITS_PER_WORD - 1) / FLAC__BITS_PER_WORD);
 112
 113         /* it's possible (due to pessimism in the growth estimation that
 114          * leads to this call) that we don't actually need to grow
 115          */
 116         if(bw->capacity >= new_capacity)
 117                 return true;
 118
 119         /* round up capacity increase to the nearest FLAC__BITWRITER_DEFAULT_INCREMENT */
 120         if((new_capacity - bw->capacity) % FLAC__BITWRITER_DEFAULT_INCREMENT)
 121                 new_capacity += FLAC__BITWRITER_DEFAULT_INCREMENT - ((new_capacity - bw->capacity) % FLAC__BITWRITER_DEFAULT_INCREMENT);
 122         /* make sure we got everything right */
 123         FLAC__ASSERT(0 == (new_capacity - bw->capacity) % FLAC__BITWRITER_DEFAULT_INCREMENT);
 124         FLAC__ASSERT(new_capacity > bw->capacity);
 125         FLAC__ASSERT(new_capacity >= bw->words + ((bw->bits + bits_to_add + FLAC__BITS_PER_WORD - 1) / FLAC__BITS_PER_WORD));
 126
 127         new_buffer = safe_realloc_mul_2op_(bw->buffer, sizeof(bwword), /*times*/new_capacity);
 128         if(new_buffer == 0)
 129                 return false;
 130         bw->buffer = new_buffer;
 131         bw->capacity = new_capacity;
 132         return true;
 133 }
 134
 135
 136 /***********************************************************************
 137  *
 138  * Class constructor/destructor
 139  *
 140  ***********************************************************************/
 141
 142 FLAC__BitWriter *FLAC__bitwriter_new(void)
 143 {
 144         FLAC__BitWriter *bw = calloc(1, sizeof(FLAC__BitWriter));
 145         /* note that calloc() sets all members to 0 for us */
 146         return bw;
 147 }
 148
 149 void FLAC__bitwriter_delete(FLAC__BitWriter *bw)
 150 {
 151         FLAC__ASSERT(0 != bw);
 152
 153         FLAC__bitwriter_free(bw);
 154         free(bw);
 155 }
 156
 157 /***********************************************************************
 158  *
 159  * Public class methods
 160  *
 161  ***********************************************************************/
 162
 163 FLAC__bool FLAC__bitwriter_init(FLAC__BitWriter *bw)
 164 {
 165         FLAC__ASSERT(0 != bw);
 166
 167         bw->words = bw->bits = 0;
 168         bw->capacity = FLAC__BITWRITER_DEFAULT_CAPACITY;
 169         bw->buffer = malloc(sizeof(bwword) * bw->capacity);
 170         if(bw->buffer == 0)
 171                 return false;
 172
 173         return true;
 174 }
 175
 176 void FLAC__bitwriter_free(FLAC__BitWriter *bw)
 177 {
 178         FLAC__ASSERT(0 != bw);
 179
 180         if(0 != bw->buffer)
 181                 free(bw->buffer);
 182         bw->buffer = 0;
 183         bw->capacity = 0;
 184         bw->words = bw->bits = 0;
 185 }
 186
 187 void FLAC__bitwriter_clear(FLAC__BitWriter *bw)
 188 {
 189         bw->words = bw->bits = 0;
 190 }
 191
 192 void FLAC__bitwriter_dump(const FLAC__BitWriter *bw, FILE *out)
 193 {
 194         unsigned i, j;
 195         if(bw == 0) {
 196                 fprintf(out, "bitwriter is NULL\n");
 197         }
 198         else {
 199                 fprintf(out, "bitwriter: capacity=%u words=%u bits=%u total_bits=%u\n", bw->capacity, bw->words, bw->bits, FLAC__TOTAL_BITS(bw));
 200
 201                 for(i = 0; i < bw->words; i++) {
 202                         fprintf(out, "%08X: ", i);
 203                         for(j = 0; j < FLAC__BITS_PER_WORD; j++)
 204                                 fprintf(out, "%01u", bw->buffer[i] & ((bwword)1 << (FLAC__BITS_PER_WORD-j-1)) ? 1:0);
 205                         fprintf(out, "\n");
 206                 }
 207                 if(bw->bits > 0) {
 208                         fprintf(out, "%08X: ", i);
 209                         for(j = 0; j < bw->bits; j++)
 210                                 fprintf(out, "%01u", bw->accum & ((bwword)1 << (bw->bits-j-1)) ? 1:0);
 211                         fprintf(out, "\n");
 212                 }
 213         }
 214 }
 215
 216 FLAC__bool FLAC__bitwriter_get_write_crc16(FLAC__BitWriter *bw, FLAC__uint16 *crc)
 217 {
 218         const FLAC__byte *buffer;
 219         size_t bytes;
 220
 221         FLAC__ASSERT((bw->bits & 7) == 0); /* assert that we're byte-aligned */
 222
 223         if(!FLAC__bitwriter_get_buffer(bw, &buffer, &bytes))
 224                 return false;
 225
 226         *crc = (FLAC__uint16)FLAC__crc16(buffer, bytes);
 227         FLAC__bitwriter_release_buffer(bw);
 228         return true;
 229 }
 230
 231 FLAC__bool FLAC__bitwriter_get_write_crc8(FLAC__BitWriter *bw, FLAC__byte *crc)
 232 {
 233         const FLAC__byte *buffer;
 234         size_t bytes;
 235
 236         FLAC__ASSERT((bw->bits & 7) == 0); /* assert that we're byte-aligned */
 237
 238         if(!FLAC__bitwriter_get_buffer(bw, &buffer, &bytes))
 239                 return false;
 240
 241         *crc = FLAC__crc8(buffer, bytes);
 242         FLAC__bitwriter_release_buffer(bw);
 243         return true;
 244 }
 245
 246 FLAC__bool FLAC__bitwriter_is_byte_aligned(const FLAC__BitWriter *bw)
 247 {
 248         return ((bw->bits & 7) == 0);
 249 }
 250
 251 unsigned FLAC__bitwriter_get_input_bits_unconsumed(const FLAC__BitWriter *bw)
 252 {
 253         return FLAC__TOTAL_BITS(bw);
 254 }
 255
 256 FLAC__bool FLAC__bitwriter_get_buffer(FLAC__BitWriter *bw, const FLAC__byte **buffer, size_t *bytes)
 257 {
 258         FLAC__ASSERT((bw->bits & 7) == 0);
 259         /* double protection */
 260         if(bw->bits & 7)
 261                 return false;
 262         /* if we have bits in the accumulator we have to flush those to the buffer first */
 263         if(bw->bits) {
 264                 FLAC__ASSERT(bw->words <= bw->capacity);
 265                 if(bw->words == bw->capacity && !bitwriter_grow_(bw, FLAC__BITS_PER_WORD))
 266                         return false;
 267                 /* append bits as complete word to buffer, but don't change bw->accum or bw->bits */
 268                 bw->buffer[bw->words] = SWAP_BE_WORD_TO_HOST(bw->accum << (FLAC__BITS_PER_WORD-bw->bits));
 269         }
 270         /* now we can just return what we have */
 271         *buffer = (FLAC__byte*)bw->buffer;
 272         *bytes = (FLAC__BYTES_PER_WORD * bw->words) + (bw->bits >> 3);
 273         return true;
 274 }
 275
 276 void FLAC__bitwriter_release_buffer(FLAC__BitWriter *bw)
 277 {
 278         /* nothing to do.  in the future, strict checking of a 'writer-is-in-
 279          * get-mode' flag could be added everywhere and then cleared here
 280          */
 281         (void)bw;
 282 }
 283
 284 inline FLAC__bool FLAC__bitwriter_write_zeroes(FLAC__BitWriter *bw, unsigned bits)
 285 {
 286         unsigned n;
 287
 288         FLAC__ASSERT(0 != bw);
 289         FLAC__ASSERT(0 != bw->buffer);
 290
 291         if(bits == 0)
 292                 return true;
 293         /* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+bits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
 294         if(bw->capacity <= bw->words + bits && !bitwriter_grow_(bw, bits))
 295                 return false;
 296         /* first part gets to word alignment */
 297         if(bw->bits) {
 298                 n = flac_min(FLAC__BITS_PER_WORD - bw->bits, bits);
 299                 bw->accum <<= n;
 300                 bits -= n;
 301                 bw->bits += n;
 302                 if(bw->bits == FLAC__BITS_PER_WORD) {
 303                         bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
 304                         bw->bits = 0;
 305                 }
 306                 else
 307                         return true;
 308         }
 309         /* do whole words */
 310         while(bits >= FLAC__BITS_PER_WORD) {
 311                 bw->buffer[bw->words++] = 0;
 312                 bits -= FLAC__BITS_PER_WORD;
 313         }
 314         /* do any leftovers */
 315         if(bits > 0) {
 316                 bw->accum = 0;
 317                 bw->bits = bits;
 318         }
 319         return true;
 320 }
 321
 322 static inline FLAC__bool FLAC__bitwriter_write_raw_uint32_nocheck(FLAC__BitWriter *bw, FLAC__uint32 val, unsigned bits)
 323 {
 324         register unsigned left;
 325
 326         /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
 327         FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
 328
 329         if(bw == 0 || bw->buffer == 0)
 330                 return false;
 331
 332         if (bits > 32)
 333                 return false;
 334
 335         if(bits == 0)
 336                 return true;
 337
 338         FLAC__ASSERT((bits == 32) || (val>>bits == 0));
 339
 340         /* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+bits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
 341         if(bw->capacity <= bw->words + bits && !bitwriter_grow_(bw, bits))
 342                 return false;
 343
 344         left = FLAC__BITS_PER_WORD - bw->bits;
 345         if(bits < left) {
 346                 bw->accum <<= bits;
 347                 bw->accum |= val;
 348                 bw->bits += bits;
 349         }
 350         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 */
 351                 bw->accum <<= left;
 352                 bw->accum |= val >> (bw->bits = bits - left);
 353                 bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
 354                 bw->accum = val; /* unused top bits can contain garbage */
 355         }
 356         else { /* at this point bits == FLAC__BITS_PER_WORD == 32  and  bw->bits == 0 */
 357                 bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST((bwword)val);
 358         }
 359
 360         return true;
 361 }
 362
 363 inline FLAC__bool FLAC__bitwriter_write_raw_uint32(FLAC__BitWriter *bw, FLAC__uint32 val, unsigned bits)
 364 {
 365         /* check that unused bits are unset */
 366         if((bits < 32) && (val>>bits != 0))
 367                 return false;
 368
 369         return FLAC__bitwriter_write_raw_uint32_nocheck(bw, val, bits);
 370 }
 371
 372 inline FLAC__bool FLAC__bitwriter_write_raw_int32(FLAC__BitWriter *bw, FLAC__int32 val, unsigned bits)
 373 {
 374         /* zero-out unused bits */
 375         if(bits < 32)
 376                 val &= (~(0xffffffff << bits));
 377
 378         return FLAC__bitwriter_write_raw_uint32_nocheck(bw, (FLAC__uint32)val, bits);
 379 }
 380
 381 inline FLAC__bool FLAC__bitwriter_write_raw_uint64(FLAC__BitWriter *bw, FLAC__uint64 val, unsigned bits)
 382 {
 383         /* this could be a little faster but it's not used for much */
 384         if(bits > 32) {
 385                 return
 386                         FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)(val>>32), bits-32) &&
 387                         FLAC__bitwriter_write_raw_uint32_nocheck(bw, (FLAC__uint32)val, 32);
 388         }
 389         else
 390                 return FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, bits);
 391 }
 392
 393 inline FLAC__bool FLAC__bitwriter_write_raw_uint32_little_endian(FLAC__BitWriter *bw, FLAC__uint32 val)
 394 {
 395         /* this doesn't need to be that fast as currently it is only used for vorbis comments */
 396
 397         if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, val & 0xff, 8))
 398                 return false;
 399         if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, (val>>8) & 0xff, 8))
 400                 return false;
 401         if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, (val>>16) & 0xff, 8))
 402                 return false;
 403         if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, val>>24, 8))
 404                 return false;
 405
 406         return true;
 407 }
 408
 409 inline FLAC__bool FLAC__bitwriter_write_byte_block(FLAC__BitWriter *bw, const FLAC__byte vals[], unsigned nvals)
 410 {
 411         unsigned i;
 412
 413         /* this could be faster but currently we don't need it to be since it's only used for writing metadata */
 414         for(i = 0; i < nvals; i++) {
 415                 if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, (FLAC__uint32)(vals[i]), 8))
 416                         return false;
 417         }
 418
 419         return true;
 420 }
 421
 422 FLAC__bool FLAC__bitwriter_write_unary_unsigned(FLAC__BitWriter *bw, unsigned val)
 423 {
 424         if(val < 32)
 425                 return FLAC__bitwriter_write_raw_uint32_nocheck(bw, 1, ++val);
 426         else
 427                 return
 428                         FLAC__bitwriter_write_zeroes(bw, val) &&
 429                         FLAC__bitwriter_write_raw_uint32_nocheck(bw, 1, 1);
 430 }
 431
 432 unsigned FLAC__bitwriter_rice_bits(FLAC__int32 val, unsigned parameter)
 433 {
 434         FLAC__uint32 uval;
 435
 436         FLAC__ASSERT(parameter < 32);
 437
 438         /* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
 439         uval = val;
 440         uval <<= 1;
 441         uval ^= (val>>31);
 442
 443         return 1 + parameter + (uval >> parameter);
 444 }
 445
 446 #if 0 /* UNUSED */
 447 unsigned FLAC__bitwriter_golomb_bits_signed(int val, unsigned parameter)
 448 {
 449         unsigned bits, msbs, uval;
 450         unsigned k;
 451
 452         FLAC__ASSERT(parameter > 0);
 453
 454         /* fold signed to unsigned */
 455         if(val < 0)
 456                 uval = (unsigned)(((-(++val)) << 1) + 1);
 457         else
 458                 uval = (unsigned)(val << 1);
 459
 460         k = FLAC__bitmath_ilog2(parameter);
 461         if(parameter == 1u<<k) {
 462                 FLAC__ASSERT(k <= 30);
 463
 464                 msbs = uval >> k;
 465                 bits = 1 + k + msbs;
 466         }
 467         else {
 468                 unsigned q, r, d;
 469
 470                 d = (1 << (k+1)) - parameter;
 471                 q = uval / parameter;
 472                 r = uval - (q * parameter);
 473
 474                 bits = 1 + q + k;
 475                 if(r >= d)
 476                         bits++;
 477         }
 478         return bits;
 479 }
 480
 481 unsigned FLAC__bitwriter_golomb_bits_unsigned(unsigned uval, unsigned parameter)
 482 {
 483         unsigned bits, msbs;
 484         unsigned k;
 485
 486         FLAC__ASSERT(parameter > 0);
 487
 488         k = FLAC__bitmath_ilog2(parameter);
 489         if(parameter == 1u<<k) {
 490                 FLAC__ASSERT(k <= 30);
 491
 492                 msbs = uval >> k;
 493                 bits = 1 + k + msbs;
 494         }
 495         else {
 496                 unsigned q, r, d;
 497
 498                 d = (1 << (k+1)) - parameter;
 499                 q = uval / parameter;
 500                 r = uval - (q * parameter);
 501
 502                 bits = 1 + q + k;
 503                 if(r >= d)
 504                         bits++;
 505         }
 506         return bits;
 507 }
 508 #endif /* UNUSED */
 509
 510 FLAC__bool FLAC__bitwriter_write_rice_signed(FLAC__BitWriter *bw, FLAC__int32 val, unsigned parameter)
 511 {
 512         unsigned total_bits, interesting_bits, msbs;
 513         FLAC__uint32 uval, pattern;
 514
 515         FLAC__ASSERT(0 != bw);
 516         FLAC__ASSERT(0 != bw->buffer);
 517         FLAC__ASSERT(parameter < 32);
 518
 519         /* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
 520         uval = val;
 521         uval <<= 1;
 522         uval ^= (val>>31);
 523
 524         msbs = uval >> parameter;
 525         interesting_bits = 1 + parameter;
 526         total_bits = interesting_bits + msbs;
 527         pattern = 1 << parameter; /* the unary end bit */
 528         pattern |= (uval & ((1<<parameter)-1)); /* the binary LSBs */
 529
 530         if(total_bits <= 32)
 531                 return FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits);
 532         else
 533                 return
 534                         FLAC__bitwriter_write_zeroes(bw, msbs) && /* write the unary MSBs */
 535                         FLAC__bitwriter_write_raw_uint32(bw, pattern, interesting_bits); /* write the unary end bit and binary LSBs */
 536 }
 537
 538 FLAC__bool FLAC__bitwriter_write_rice_signed_block(FLAC__BitWriter *bw, const FLAC__int32 *vals, unsigned nvals, unsigned parameter)
 539 {
 540         const FLAC__uint32 mask1 = (FLAC__uint32)0xffffffff << parameter; /* we val|=mask1 to set the stop bit above it... */
 541         const FLAC__uint32 mask2 = (FLAC__uint32)0xffffffff >> (31-parameter); /* ...then mask off the bits above the stop bit with val&=mask2 */
 542         FLAC__uint32 uval;
 543         unsigned left;
 544         const unsigned lsbits = 1 + parameter;
 545         unsigned msbits, total_bits;
 546
 547         FLAC__ASSERT(0 != bw);
 548         FLAC__ASSERT(0 != bw->buffer);
 549         FLAC__ASSERT(parameter < 31);
 550         /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
 551         FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
 552
 553         while(nvals) {
 554                 /* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
 555                 uval = *vals;
 556                 uval <<= 1;
 557                 uval ^= (*vals>>31);
 558
 559                 msbits = uval >> parameter;
 560                 total_bits = lsbits + msbits;
 561
 562                 if(bw->bits && bw->bits + total_bits < FLAC__BITS_PER_WORD) { /* i.e. if the whole thing fits in the current bwword */
 563                         /* ^^^ if bw->bits is 0 then we may have filled the buffer and have no free bwword to work in */
 564                         bw->bits += total_bits;
 565                         uval |= mask1; /* set stop bit */
 566                         uval &= mask2; /* mask off unused top bits */
 567                         bw->accum <<= total_bits;
 568                         bw->accum |= uval;
 569                 }
 570                 else {
 571                         /* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+msbits+lsbits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
 572                         /* OPT: pessimism may cause flurry of false calls to grow_ which eat up all savings before it */
 573                         if(bw->capacity <= bw->words + bw->bits + msbits + 1 /* lsbits always fit in 1 bwword */ && !bitwriter_grow_(bw, total_bits))
 574                                 return false;
 575
 576                         if(msbits) {
 577                                 /* first part gets to word alignment */
 578                                 if(bw->bits) {
 579                                         left = FLAC__BITS_PER_WORD - bw->bits;
 580                                         if(msbits < left) {
 581                                                 bw->accum <<= msbits;
 582                                                 bw->bits += msbits;
 583                                                 goto break1;
 584                                         }
 585                                         else {
 586                                                 bw->accum <<= left;
 587                                                 msbits -= left;
 588                                                 bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
 589                                                 bw->bits = 0;
 590                                         }
 591                                 }
 592                                 /* do whole words */
 593                                 while(msbits >= FLAC__BITS_PER_WORD) {
 594                                         bw->buffer[bw->words++] = 0;
 595                                         msbits -= FLAC__BITS_PER_WORD;
 596                                 }
 597                                 /* do any leftovers */
 598                                 if(msbits > 0) {
 599                                         bw->accum = 0;
 600                                         bw->bits = msbits;
 601                                 }
 602                         }
 603 break1:
 604                         uval |= mask1; /* set stop bit */
 605                         uval &= mask2; /* mask off unused top bits */
 606
 607                         left = FLAC__BITS_PER_WORD - bw->bits;
 608                         if(lsbits < left) {
 609                                 bw->accum <<= lsbits;
 610                                 bw->accum |= uval;
 611                                 bw->bits += lsbits;
 612                         }
 613                         else {
 614                                 /* if bw->bits == 0, left==FLAC__BITS_PER_WORD which will always
 615                                  * be > lsbits (because of previous assertions) so it would have
 616                                  * triggered the (lsbits<left) case above.
 617                                  */
 618                                 FLAC__ASSERT(bw->bits);
 619                                 FLAC__ASSERT(left < FLAC__BITS_PER_WORD);
 620                                 bw->accum <<= left;
 621                                 bw->accum |= uval >> (bw->bits = lsbits - left);
 622                                 bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
 623                                 bw->accum = uval; /* unused top bits can contain garbage */
 624                         }
 625                 }
 626                 vals++;
 627                 nvals--;
 628         }
 629         return true;
 630 }
 631
 632 #if 0 /* UNUSED */
 633 FLAC__bool FLAC__bitwriter_write_golomb_signed(FLAC__BitWriter *bw, int val, unsigned parameter)
 634 {
 635         unsigned total_bits, msbs, uval;
 636         unsigned k;
 637
 638         FLAC__ASSERT(0 != bw);
 639         FLAC__ASSERT(0 != bw->buffer);
 640         FLAC__ASSERT(parameter > 0);
 641
 642         /* fold signed to unsigned */
 643         if(val < 0)
 644                 uval = (unsigned)(((-(++val)) << 1) + 1);
 645         else
 646                 uval = (unsigned)(val << 1);
 647
 648         k = FLAC__bitmath_ilog2(parameter);
 649         if(parameter == 1u<<k) {
 650                 unsigned pattern;
 651
 652                 FLAC__ASSERT(k <= 30);
 653
 654                 msbs = uval >> k;
 655                 total_bits = 1 + k + msbs;
 656                 pattern = 1 << k; /* the unary end bit */
 657                 pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */
 658
 659                 if(total_bits <= 32) {
 660                         if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits))
 661                                 return false;
 662                 }
 663                 else {
 664                         /* write the unary MSBs */
 665                         if(!FLAC__bitwriter_write_zeroes(bw, msbs))
 666                                 return false;
 667                         /* write the unary end bit and binary LSBs */
 668                         if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, k+1))
 669                                 return false;
 670                 }
 671         }
 672         else {
 673                 unsigned q, r, d;
 674
 675                 d = (1 << (k+1)) - parameter;
 676                 q = uval / parameter;
 677                 r = uval - (q * parameter);
 678                 /* write the unary MSBs */
 679                 if(!FLAC__bitwriter_write_zeroes(bw, q))
 680                         return false;
 681                 /* write the unary end bit */
 682                 if(!FLAC__bitwriter_write_raw_uint32(bw, 1, 1))
 683                         return false;
 684                 /* write the binary LSBs */
 685                 if(r >= d) {
 686                         if(!FLAC__bitwriter_write_raw_uint32(bw, r+d, k+1))
 687                                 return false;
 688                 }
 689                 else {
 690                         if(!FLAC__bitwriter_write_raw_uint32(bw, r, k))
 691                                 return false;
 692                 }
 693         }
 694         return true;
 695 }
 696
 697 FLAC__bool FLAC__bitwriter_write_golomb_unsigned(FLAC__BitWriter *bw, unsigned uval, unsigned parameter)
 698 {
 699         unsigned total_bits, msbs;
 700         unsigned k;
 701
 702         FLAC__ASSERT(0 != bw);
 703         FLAC__ASSERT(0 != bw->buffer);
 704         FLAC__ASSERT(parameter > 0);
 705
 706         k = FLAC__bitmath_ilog2(parameter);
 707         if(parameter == 1u<<k) {
 708                 unsigned pattern;
 709
 710                 FLAC__ASSERT(k <= 30);
 711
 712                 msbs = uval >> k;
 713                 total_bits = 1 + k + msbs;
 714                 pattern = 1 << k; /* the unary end bit */
 715                 pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */
 716
 717                 if(total_bits <= 32) {
 718                         if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits))
 719                                 return false;
 720                 }
 721                 else {
 722                         /* write the unary MSBs */
 723                         if(!FLAC__bitwriter_write_zeroes(bw, msbs))
 724                                 return false;
 725                         /* write the unary end bit and binary LSBs */
 726                         if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, k+1))
 727                                 return false;
 728                 }
 729         }
 730         else {
 731                 unsigned q, r, d;
 732
 733                 d = (1 << (k+1)) - parameter;
 734                 q = uval / parameter;
 735                 r = uval - (q * parameter);
 736                 /* write the unary MSBs */
 737                 if(!FLAC__bitwriter_write_zeroes(bw, q))
 738                         return false;
 739                 /* write the unary end bit */
 740                 if(!FLAC__bitwriter_write_raw_uint32(bw, 1, 1))
 741                         return false;
 742                 /* write the binary LSBs */
 743                 if(r >= d) {
 744                         if(!FLAC__bitwriter_write_raw_uint32(bw, r+d, k+1))
 745                                 return false;
 746                 }
 747                 else {
 748                         if(!FLAC__bitwriter_write_raw_uint32(bw, r, k))
 749                                 return false;
 750                 }
 751         }
 752         return true;
 753 }
 754 #endif /* UNUSED */
 755
 756 FLAC__bool FLAC__bitwriter_write_utf8_uint32(FLAC__BitWriter *bw, FLAC__uint32 val)
 757 {
 758         FLAC__bool ok = 1;
 759
 760         FLAC__ASSERT(0 != bw);
 761         FLAC__ASSERT(0 != bw->buffer);
 762
 763         if((val & 0x80000000) != 0) /* this version only handles 31 bits */
 764                 return false;
 765
 766         if(val < 0x80) {
 767                 return FLAC__bitwriter_write_raw_uint32_nocheck(bw, val, 8);
 768         }
 769         else if(val < 0x800) {
 770                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xC0 | (val>>6), 8);
 771                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
 772         }
 773         else if(val < 0x10000) {
 774                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xE0 | (val>>12), 8);
 775                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>6)&0x3F), 8);
 776                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
 777         }
 778         else if(val < 0x200000) {
 779                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xF0 | (val>>18), 8);
 780                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>12)&0x3F), 8);
 781                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>6)&0x3F), 8);
 782                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
 783         }
 784         else if(val < 0x4000000) {
 785                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xF8 | (val>>24), 8);
 786                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>18)&0x3F), 8);
 787                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>12)&0x3F), 8);
 788                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>6)&0x3F), 8);
 789                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
 790         }
 791         else {
 792                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xFC | (val>>30), 8);
 793                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>24)&0x3F), 8);
 794                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>18)&0x3F), 8);
 795                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>12)&0x3F), 8);
 796                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>6)&0x3F), 8);
 797                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
 798         }
 799
 800         return ok;
 801 }
 802
 803 FLAC__bool FLAC__bitwriter_write_utf8_uint64(FLAC__BitWriter *bw, FLAC__uint64 val)
 804 {
 805         FLAC__bool ok = 1;
 806
 807         FLAC__ASSERT(0 != bw);
 808         FLAC__ASSERT(0 != bw->buffer);
 809
 810         if((val & FLAC__U64L(0xFFFFFFF000000000)) != 0) /* this version only handles 36 bits */
 811                 return false;
 812
 813         if(val < 0x80) {
 814                 return FLAC__bitwriter_write_raw_uint32_nocheck(bw, (FLAC__uint32)val, 8);
 815         }
 816         else if(val < 0x800) {
 817                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xC0 | (FLAC__uint32)(val>>6), 8);
 818                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 819         }
 820         else if(val < 0x10000) {
 821                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xE0 | (FLAC__uint32)(val>>12), 8);
 822                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 823                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 824         }
 825         else if(val < 0x200000) {
 826                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xF0 | (FLAC__uint32)(val>>18), 8);
 827                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
 828                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 829                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 830         }
 831         else if(val < 0x4000000) {
 832                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xF8 | (FLAC__uint32)(val>>24), 8);
 833                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
 834                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
 835                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 836                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 837         }
 838         else if(val < 0x80000000) {
 839                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xFC | (FLAC__uint32)(val>>30), 8);
 840                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>24)&0x3F), 8);
 841                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
 842                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
 843                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 844                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 845         }
 846         else {
 847                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xFE, 8);
 848                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>30)&0x3F), 8);
 849                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>24)&0x3F), 8);
 850                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
 851                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
 852                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
 853                 ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
 854         }
 855
 856         return ok;
 857 }
 858
 859 FLAC__bool FLAC__bitwriter_zero_pad_to_byte_boundary(FLAC__BitWriter *bw)
 860 {
 861         /* 0-pad to byte boundary */
 862         if(bw->bits & 7u)
 863                 return FLAC__bitwriter_write_zeroes(bw, 8 - (bw->bits & 7u));
 864         else
 865                 return true;
 866 }
 867
 868 /* These functions are declared inline in this file but are also callable as
 869  * externs from elsewhere.
 870  * According to the C99 spec, section 6.7.4, simply providing a function
 871  * prototype in a header file without 'inline' and making the function inline
 872  * in this file should be sufficient.
 873  * Unfortunately, the Microsoft VS compiler doesn't pick them up externally. To
 874  * fix that we add extern declarations here.
 875  */
 876 extern FLAC__bool FLAC__bitwriter_write_zeroes(FLAC__BitWriter *bw, unsigned bits);
 877 extern FLAC__bool FLAC__bitwriter_write_raw_uint32(FLAC__BitWriter *bw, FLAC__uint32 val, unsigned bits);
 878 extern FLAC__bool FLAC__bitwriter_write_raw_int32(FLAC__BitWriter *bw, FLAC__int32 val, unsigned bits);
 879 extern FLAC__bool FLAC__bitwriter_write_raw_uint64(FLAC__BitWriter *bw, FLAC__uint64 val, unsigned bits);
 880 extern FLAC__bool FLAC__bitwriter_write_raw_uint32_little_endian(FLAC__BitWriter *bw, FLAC__uint32 val);
 881 extern FLAC__bool FLAC__bitwriter_write_byte_block(FLAC__BitWriter *bw, const FLAC__byte vals[], unsigned nvals);