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      1 /* libFLAC - Free Lossless Audio Codec library
      2  * Copyright (C) 2000,2001,2002,2003,2004,2005,2006,2007  Josh Coalson
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * - Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *
     11  * - Redistributions in binary form must reproduce the above copyright
     12  * notice, this list of conditions and the following disclaimer in the
     13  * documentation and/or other materials provided with the distribution.
     14  *
     15  * - Neither the name of the Xiph.org Foundation nor the names of its
     16  * contributors may be used to endorse or promote products derived from
     17  * this software without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     22  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
     23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #if HAVE_CONFIG_H
     33 #  include <config.h>
     34 #endif
     35 
     36 #include <stdlib.h> /* for malloc() */
     37 #include <string.h> /* for memcpy(), memset() */
     38 #ifdef _MSC_VER
     39 #include <winsock.h> /* for ntohl() */
     40 #elif defined FLAC__SYS_DARWIN
     41 #include <machine/endian.h> /* for ntohl() */
     42 #elif defined __MINGW32__
     43 #include <winsock.h> /* for ntohl() */
     44 #else
     45 #include <netinet/in.h> /* for ntohl() */
     46 #endif
     47 #if 0 /* UNUSED */
     48 #include "private/bitmath.h"
     49 #endif
     50 #include "private/bitwriter.h"
     51 #include "private/crc.h"
     52 #include "FLAC/assert.h"
     53 #include "share/alloc.h"
     54 
     55 /* Things should be fastest when this matches the machine word size */
     56 /* WATCHOUT: if you change this you must also change the following #defines down to SWAP_BE_WORD_TO_HOST below to match */
     57 /* WATCHOUT: there are a few places where the code will not work unless bwword is >= 32 bits wide */
     58 typedef FLAC__uint32 bwword;
     59 #define FLAC__BYTES_PER_WORD 4
     60 #define FLAC__BITS_PER_WORD 32
     61 #define FLAC__WORD_ALL_ONES ((FLAC__uint32)0xffffffff)
     62 /* SWAP_BE_WORD_TO_HOST swaps bytes in a bwword (which is always big-endian) if necessary to match host byte order */
     63 #if WORDS_BIGENDIAN
     64 #define SWAP_BE_WORD_TO_HOST(x) (x)
     65 #else
     66 #ifdef _MSC_VER
     67 #define SWAP_BE_WORD_TO_HOST(x) local_swap32_(x)
     68 #else
     69 #define SWAP_BE_WORD_TO_HOST(x) ntohl(x)
     70 #endif
     71 #endif
     72 
     73 /*
     74  * The default capacity here doesn't matter too much.  The buffer always grows
     75  * to hold whatever is written to it.  Usually the encoder will stop adding at
     76  * a frame or metadata block, then write that out and clear the buffer for the
     77  * next one.
     78  */
     79 static const unsigned FLAC__BITWRITER_DEFAULT_CAPACITY = 32768u / sizeof(bwword); /* size in words */
     80 /* When growing, increment 4K at a time */
     81 static const unsigned FLAC__BITWRITER_DEFAULT_INCREMENT = 4096u / sizeof(bwword); /* size in words */
     82 
     83 #define FLAC__WORDS_TO_BITS(words) ((words) * FLAC__BITS_PER_WORD)
     84 #define FLAC__TOTAL_BITS(bw) (FLAC__WORDS_TO_BITS((bw)->words) + (bw)->bits)
     85 
     86 #ifdef min
     87 #undef min
     88 #endif
     89 #define min(x,y) ((x)<(y)?(x):(y))
     90 
     91 /* adjust for compilers that can't understand using LLU suffix for uint64_t literals */
     92 #ifdef _MSC_VER
     93 #define FLAC__U64L(x) x
     94 #else
     95 #define FLAC__U64L(x) x##LLU
     96 #endif
     97 
     98 #ifndef FLaC__INLINE
     99 #define FLaC__INLINE
    100 #endif
    101 
    102 struct FLAC__BitWriter {
    103 	bwword *buffer;
    104 	bwword accum; /* accumulator; bits are right-justified; when full, accum is appended to buffer */
    105 	unsigned capacity; /* capacity of buffer in words */
    106 	unsigned words; /* # of complete words in buffer */
    107 	unsigned bits; /* # of used bits in accum */
    108 };
    109 
    110 #ifdef _MSC_VER
    111 /* OPT: an MSVC built-in would be better */
    112 static _inline FLAC__uint32 local_swap32_(FLAC__uint32 x)
    113 {
    114 	x = ((x<<8)&0xFF00FF00) | ((x>>8)&0x00FF00FF);
    115 	return (x>>16) | (x<<16);
    116 }
    117 #endif
    118 
    119 /* * WATCHOUT: The current implementation only grows the buffer. */
    120 static FLAC__bool bitwriter_grow_(FLAC__BitWriter *bw, unsigned bits_to_add)
    121 {
    122 	unsigned new_capacity;
    123 	bwword *new_buffer;
    124 
    125 	FLAC__ASSERT(0 != bw);
    126 	FLAC__ASSERT(0 != bw->buffer);
    127 
    128 	/* calculate total words needed to store 'bits_to_add' additional bits */
    129 	new_capacity = bw->words + ((bw->bits + bits_to_add + FLAC__BITS_PER_WORD - 1) / FLAC__BITS_PER_WORD);
    130 
    131 	/* it's possible (due to pessimism in the growth estimation that
    132 	 * leads to this call) that we don't actually need to grow
    133 	 */
    134 	if(bw->capacity >= new_capacity)
    135 		return true;
    136 
    137 	/* round up capacity increase to the nearest FLAC__BITWRITER_DEFAULT_INCREMENT */
    138 	if((new_capacity - bw->capacity) % FLAC__BITWRITER_DEFAULT_INCREMENT)
    139 		new_capacity += FLAC__BITWRITER_DEFAULT_INCREMENT - ((new_capacity - bw->capacity) % FLAC__BITWRITER_DEFAULT_INCREMENT);
    140 	/* make sure we got everything right */
    141 	FLAC__ASSERT(0 == (new_capacity - bw->capacity) % FLAC__BITWRITER_DEFAULT_INCREMENT);
    142 	FLAC__ASSERT(new_capacity > bw->capacity);
    143 	FLAC__ASSERT(new_capacity >= bw->words + ((bw->bits + bits_to_add + FLAC__BITS_PER_WORD - 1) / FLAC__BITS_PER_WORD));
    144 
    145 	new_buffer = (bwword*)safe_realloc_mul_2op_(bw->buffer, sizeof(bwword), /*times*/new_capacity);
    146 	if(new_buffer == 0)
    147 		return false;
    148 	bw->buffer = new_buffer;
    149 	bw->capacity = new_capacity;
    150 	return true;
    151 }
    152 
    153 
    154 /***********************************************************************
    155  *
    156  * Class constructor/destructor
    157  *
    158  ***********************************************************************/
    159 
    160 FLAC__BitWriter *FLAC__bitwriter_new(void)
    161 {
    162 	FLAC__BitWriter *bw = (FLAC__BitWriter*)calloc(1, sizeof(FLAC__BitWriter));
    163 	/* note that calloc() sets all members to 0 for us */
    164 	return bw;
    165 }
    166 
    167 void FLAC__bitwriter_delete(FLAC__BitWriter *bw)
    168 {
    169 	FLAC__ASSERT(0 != bw);
    170 
    171 	FLAC__bitwriter_free(bw);
    172 	free(bw);
    173 }
    174 
    175 /***********************************************************************
    176  *
    177  * Public class methods
    178  *
    179  ***********************************************************************/
    180 
    181 FLAC__bool FLAC__bitwriter_init(FLAC__BitWriter *bw)
    182 {
    183 	FLAC__ASSERT(0 != bw);
    184 
    185 	bw->words = bw->bits = 0;
    186 	bw->capacity = FLAC__BITWRITER_DEFAULT_CAPACITY;
    187 	bw->buffer = (bwword*)malloc(sizeof(bwword) * bw->capacity);
    188 	if(bw->buffer == 0)
    189 		return false;
    190 
    191 	return true;
    192 }
    193 
    194 void FLAC__bitwriter_free(FLAC__BitWriter *bw)
    195 {
    196 	FLAC__ASSERT(0 != bw);
    197 
    198 	if(0 != bw->buffer)
    199 		free(bw->buffer);
    200 	bw->buffer = 0;
    201 	bw->capacity = 0;
    202 	bw->words = bw->bits = 0;
    203 }
    204 
    205 void FLAC__bitwriter_clear(FLAC__BitWriter *bw)
    206 {
    207 	bw->words = bw->bits = 0;
    208 }
    209 
    210 void FLAC__bitwriter_dump(const FLAC__BitWriter *bw, FILE *out)
    211 {
    212 	unsigned i, j;
    213 	if(bw == 0) {
    214 		fprintf(out, "bitwriter is NULL\n");
    215 	}
    216 	else {
    217 		fprintf(out, "bitwriter: capacity=%u words=%u bits=%u total_bits=%u\n", bw->capacity, bw->words, bw->bits, FLAC__TOTAL_BITS(bw));
    218 
    219 		for(i = 0; i < bw->words; i++) {
    220 			fprintf(out, "%08X: ", i);
    221 			for(j = 0; j < FLAC__BITS_PER_WORD; j++)
    222 				fprintf(out, "%01u", bw->buffer[i] & (1 << (FLAC__BITS_PER_WORD-j-1)) ? 1:0);
    223 			fprintf(out, "\n");
    224 		}
    225 		if(bw->bits > 0) {
    226 			fprintf(out, "%08X: ", i);
    227 			for(j = 0; j < bw->bits; j++)
    228 				fprintf(out, "%01u", bw->accum & (1 << (bw->bits-j-1)) ? 1:0);
    229 			fprintf(out, "\n");
    230 		}
    231 	}
    232 }
    233 
    234 FLAC__bool FLAC__bitwriter_get_write_crc16(FLAC__BitWriter *bw, FLAC__uint16 *crc)
    235 {
    236 	const FLAC__byte *buffer;
    237 	size_t bytes;
    238 
    239 	FLAC__ASSERT((bw->bits & 7) == 0); /* assert that we're byte-aligned */
    240 
    241 	if(!FLAC__bitwriter_get_buffer(bw, &buffer, &bytes))
    242 		return false;
    243 
    244 	*crc = (FLAC__uint16)FLAC__crc16(buffer, bytes);
    245 	FLAC__bitwriter_release_buffer(bw);
    246 	return true;
    247 }
    248 
    249 FLAC__bool FLAC__bitwriter_get_write_crc8(FLAC__BitWriter *bw, FLAC__byte *crc)
    250 {
    251 	const FLAC__byte *buffer;
    252 	size_t bytes;
    253 
    254 	FLAC__ASSERT((bw->bits & 7) == 0); /* assert that we're byte-aligned */
    255 
    256 	if(!FLAC__bitwriter_get_buffer(bw, &buffer, &bytes))
    257 		return false;
    258 
    259 	*crc = FLAC__crc8(buffer, bytes);
    260 	FLAC__bitwriter_release_buffer(bw);
    261 	return true;
    262 }
    263 
    264 FLAC__bool FLAC__bitwriter_is_byte_aligned(const FLAC__BitWriter *bw)
    265 {
    266 	return ((bw->bits & 7) == 0);
    267 }
    268 
    269 unsigned FLAC__bitwriter_get_input_bits_unconsumed(const FLAC__BitWriter *bw)
    270 {
    271 	return FLAC__TOTAL_BITS(bw);
    272 }
    273 
    274 FLAC__bool FLAC__bitwriter_get_buffer(FLAC__BitWriter *bw, const FLAC__byte **buffer, size_t *bytes)
    275 {
    276 	FLAC__ASSERT((bw->bits & 7) == 0);
    277 	/* double protection */
    278 	if(bw->bits & 7)
    279 		return false;
    280 	/* if we have bits in the accumulator we have to flush those to the buffer first */
    281 	if(bw->bits) {
    282 		FLAC__ASSERT(bw->words <= bw->capacity);
    283 		if(bw->words == bw->capacity && !bitwriter_grow_(bw, FLAC__BITS_PER_WORD))
    284 			return false;
    285 		/* append bits as complete word to buffer, but don't change bw->accum or bw->bits */
    286 		bw->buffer[bw->words] = SWAP_BE_WORD_TO_HOST(bw->accum << (FLAC__BITS_PER_WORD-bw->bits));
    287 	}
    288 	/* now we can just return what we have */
    289 	*buffer = (FLAC__byte*)bw->buffer;
    290 	*bytes = (FLAC__BYTES_PER_WORD * bw->words) + (bw->bits >> 3);
    291 	return true;
    292 }
    293 
    294 void FLAC__bitwriter_release_buffer(FLAC__BitWriter *bw)
    295 {
    296 	/* nothing to do.  in the future, strict checking of a 'writer-is-in-
    297 	 * get-mode' flag could be added everywhere and then cleared here
    298 	 */
    299 	(void)bw;
    300 }
    301 
    302 FLaC__INLINE FLAC__bool FLAC__bitwriter_write_zeroes(FLAC__BitWriter *bw, unsigned bits)
    303 {
    304 	unsigned n;
    305 
    306 	FLAC__ASSERT(0 != bw);
    307 	FLAC__ASSERT(0 != bw->buffer);
    308 
    309 	if(bits == 0)
    310 		return true;
    311 	/* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+bits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
    312 	if(bw->capacity <= bw->words + bits && !bitwriter_grow_(bw, bits))
    313 		return false;
    314 	/* first part gets to word alignment */
    315 	if(bw->bits) {
    316 		n = min(FLAC__BITS_PER_WORD - bw->bits, bits);
    317 		bw->accum <<= n;
    318 		bits -= n;
    319 		bw->bits += n;
    320 		if(bw->bits == FLAC__BITS_PER_WORD) {
    321 			bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
    322 			bw->bits = 0;
    323 		}
    324 		else
    325 			return true;
    326 	}
    327 	/* do whole words */
    328 	while(bits >= FLAC__BITS_PER_WORD) {
    329 		bw->buffer[bw->words++] = 0;
    330 		bits -= FLAC__BITS_PER_WORD;
    331 	}
    332 	/* do any leftovers */
    333 	if(bits > 0) {
    334 		bw->accum = 0;
    335 		bw->bits = bits;
    336 	}
    337 	return true;
    338 }
    339 
    340 FLaC__INLINE FLAC__bool FLAC__bitwriter_write_raw_uint32(FLAC__BitWriter *bw, FLAC__uint32 val, unsigned bits)
    341 {
    342 	register unsigned left;
    343 
    344 	/* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
    345 	FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
    346 
    347 	FLAC__ASSERT(0 != bw);
    348 	FLAC__ASSERT(0 != bw->buffer);
    349 
    350 	FLAC__ASSERT(bits <= 32);
    351 	if(bits == 0)
    352 		return true;
    353 
    354 	/* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+bits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
    355 	if(bw->capacity <= bw->words + bits && !bitwriter_grow_(bw, bits))
    356 		return false;
    357 
    358 	left = FLAC__BITS_PER_WORD - bw->bits;
    359 	if(bits < left) {
    360 		bw->accum <<= bits;
    361 		bw->accum |= val;
    362 		bw->bits += bits;
    363 	}
    364 	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 */
    365 		bw->accum <<= left;
    366 		bw->accum |= val >> (bw->bits = bits - left);
    367 		bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
    368 		bw->accum = val;
    369 	}
    370 	else {
    371 		bw->accum = val;
    372 		bw->bits = 0;
    373 		bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(val);
    374 	}
    375 
    376 	return true;
    377 }
    378 
    379 FLaC__INLINE FLAC__bool FLAC__bitwriter_write_raw_int32(FLAC__BitWriter *bw, FLAC__int32 val, unsigned bits)
    380 {
    381 	/* zero-out unused bits */
    382 	if(bits < 32)
    383 		val &= (~(0xffffffff << bits));
    384 
    385 	return FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, bits);
    386 }
    387 
    388 FLaC__INLINE FLAC__bool FLAC__bitwriter_write_raw_uint64(FLAC__BitWriter *bw, FLAC__uint64 val, unsigned bits)
    389 {
    390 	/* this could be a little faster but it's not used for much */
    391 	if(bits > 32) {
    392 		return
    393 			FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)(val>>32), bits-32) &&
    394 			FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, 32);
    395 	}
    396 	else
    397 		return FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, bits);
    398 }
    399 
    400 FLaC__INLINE FLAC__bool FLAC__bitwriter_write_raw_uint32_little_endian(FLAC__BitWriter *bw, FLAC__uint32 val)
    401 {
    402 	/* this doesn't need to be that fast as currently it is only used for vorbis comments */
    403 
    404 	if(!FLAC__bitwriter_write_raw_uint32(bw, val & 0xff, 8))
    405 		return false;
    406 	if(!FLAC__bitwriter_write_raw_uint32(bw, (val>>8) & 0xff, 8))
    407 		return false;
    408 	if(!FLAC__bitwriter_write_raw_uint32(bw, (val>>16) & 0xff, 8))
    409 		return false;
    410 	if(!FLAC__bitwriter_write_raw_uint32(bw, val>>24, 8))
    411 		return false;
    412 
    413 	return true;
    414 }
    415 
    416 FLaC__INLINE FLAC__bool FLAC__bitwriter_write_byte_block(FLAC__BitWriter *bw, const FLAC__byte vals[], unsigned nvals)
    417 {
    418 	unsigned i;
    419 
    420 	/* this could be faster but currently we don't need it to be since it's only used for writing metadata */
    421 	for(i = 0; i < nvals; i++) {
    422 		if(!FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)(vals[i]), 8))
    423 			return false;
    424 	}
    425 
    426 	return true;
    427 }
    428 
    429 FLAC__bool FLAC__bitwriter_write_unary_unsigned(FLAC__BitWriter *bw, unsigned val)
    430 {
    431 	if(val < 32)
    432 		return FLAC__bitwriter_write_raw_uint32(bw, 1, ++val);
    433 	else
    434 		return
    435 			FLAC__bitwriter_write_zeroes(bw, val) &&
    436 			FLAC__bitwriter_write_raw_uint32(bw, 1, 1);
    437 }
    438 
    439 unsigned FLAC__bitwriter_rice_bits(FLAC__int32 val, unsigned parameter)
    440 {
    441 	FLAC__uint32 uval;
    442 
    443 	FLAC__ASSERT(parameter < sizeof(unsigned)*8);
    444 
    445 	/* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
    446 	uval = (val<<1) ^ (val>>31);
    447 
    448 	return 1 + parameter + (uval >> parameter);
    449 }
    450 
    451 #if 0 /* UNUSED */
    452 unsigned FLAC__bitwriter_golomb_bits_signed(int val, unsigned parameter)
    453 {
    454 	unsigned bits, msbs, uval;
    455 	unsigned k;
    456 
    457 	FLAC__ASSERT(parameter > 0);
    458 
    459 	/* fold signed to unsigned */
    460 	if(val < 0)
    461 		uval = (unsigned)(((-(++val)) << 1) + 1);
    462 	else
    463 		uval = (unsigned)(val << 1);
    464 
    465 	k = FLAC__bitmath_ilog2(parameter);
    466 	if(parameter == 1u<<k) {
    467 		FLAC__ASSERT(k <= 30);
    468 
    469 		msbs = uval >> k;
    470 		bits = 1 + k + msbs;
    471 	}
    472 	else {
    473 		unsigned q, r, d;
    474 
    475 		d = (1 << (k+1)) - parameter;
    476 		q = uval / parameter;
    477 		r = uval - (q * parameter);
    478 
    479 		bits = 1 + q + k;
    480 		if(r >= d)
    481 			bits++;
    482 	}
    483 	return bits;
    484 }
    485 
    486 unsigned FLAC__bitwriter_golomb_bits_unsigned(unsigned uval, unsigned parameter)
    487 {
    488 	unsigned bits, msbs;
    489 	unsigned k;
    490 
    491 	FLAC__ASSERT(parameter > 0);
    492 
    493 	k = FLAC__bitmath_ilog2(parameter);
    494 	if(parameter == 1u<<k) {
    495 		FLAC__ASSERT(k <= 30);
    496 
    497 		msbs = uval >> k;
    498 		bits = 1 + k + msbs;
    499 	}
    500 	else {
    501 		unsigned q, r, d;
    502 
    503 		d = (1 << (k+1)) - parameter;
    504 		q = uval / parameter;
    505 		r = uval - (q * parameter);
    506 
    507 		bits = 1 + q + k;
    508 		if(r >= d)
    509 			bits++;
    510 	}
    511 	return bits;
    512 }
    513 #endif /* UNUSED */
    514 
    515 FLAC__bool FLAC__bitwriter_write_rice_signed(FLAC__BitWriter *bw, FLAC__int32 val, unsigned parameter)
    516 {
    517 	unsigned total_bits, interesting_bits, msbs;
    518 	FLAC__uint32 uval, pattern;
    519 
    520 	FLAC__ASSERT(0 != bw);
    521 	FLAC__ASSERT(0 != bw->buffer);
    522 	FLAC__ASSERT(parameter < 8*sizeof(uval));
    523 
    524 	/* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
    525 	uval = (val<<1) ^ (val>>31);
    526 
    527 	msbs = uval >> parameter;
    528 	interesting_bits = 1 + parameter;
    529 	total_bits = interesting_bits + msbs;
    530 	pattern = 1 << parameter; /* the unary end bit */
    531 	pattern |= (uval & ((1<<parameter)-1)); /* the binary LSBs */
    532 
    533 	if(total_bits <= 32)
    534 		return FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits);
    535 	else
    536 		return
    537 			FLAC__bitwriter_write_zeroes(bw, msbs) && /* write the unary MSBs */
    538 			FLAC__bitwriter_write_raw_uint32(bw, pattern, interesting_bits); /* write the unary end bit and binary LSBs */
    539 }
    540 
    541 FLAC__bool FLAC__bitwriter_write_rice_signed_block(FLAC__BitWriter *bw, const FLAC__int32 *vals, unsigned nvals, unsigned parameter)
    542 {
    543 	const FLAC__uint32 mask1 = FLAC__WORD_ALL_ONES << parameter; /* we val|=mask1 to set the stop bit above it... */
    544 	const FLAC__uint32 mask2 = FLAC__WORD_ALL_ONES >> (31-parameter); /* ...then mask off the bits above the stop bit with val&=mask2*/
    545 	FLAC__uint32 uval;
    546 	unsigned left;
    547 	const unsigned lsbits = 1 + parameter;
    548 	unsigned msbits;
    549 
    550 	FLAC__ASSERT(0 != bw);
    551 	FLAC__ASSERT(0 != bw->buffer);
    552 	FLAC__ASSERT(parameter < 8*sizeof(bwword)-1);
    553 	/* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
    554 	FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
    555 
    556 	while(nvals) {
    557 		/* fold signed to unsigned; actual formula is: negative(v)? -2v-1 : 2v */
    558 		uval = (*vals<<1) ^ (*vals>>31);
    559 
    560 		msbits = uval >> parameter;
    561 
    562 #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) */
    563 		if(bw->bits && bw->bits + msbits + lsbits <= FLAC__BITS_PER_WORD) { /* i.e. if the whole thing fits in the current bwword */
    564 			/* ^^^ if bw->bits is 0 then we may have filled the buffer and have no free bwword to work in */
    565 			bw->bits = bw->bits + msbits + lsbits;
    566 			uval |= mask1; /* set stop bit */
    567 			uval &= mask2; /* mask off unused top bits */
    568 			/* NOT: bw->accum <<= msbits + lsbits because msbits+lsbits could be 32, then the shift would be a NOP */
    569 			bw->accum <<= msbits;
    570 			bw->accum <<= lsbits;
    571 			bw->accum |= uval;
    572 			if(bw->bits == FLAC__BITS_PER_WORD) {
    573 				bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
    574 				bw->bits = 0;
    575 				/* burying the capacity check down here means we have to grow the buffer a little if there are more vals to do */
    576 				if(bw->capacity <= bw->words && nvals > 1 && !bitwriter_grow_(bw, 1)) {
    577 					FLAC__ASSERT(bw->capacity == bw->words);
    578 					return false;
    579 				}
    580 			}
    581 		}
    582 		else {
    583 #elif 1 /*@@@@@@ OPT: try this version with MSVC6 to see if better, not much difference for gcc-4 */
    584 		if(bw->bits && bw->bits + msbits + lsbits < FLAC__BITS_PER_WORD) { /* i.e. if the whole thing fits in the current bwword */
    585 			/* ^^^ if bw->bits is 0 then we may have filled the buffer and have no free bwword to work in */
    586 			bw->bits = bw->bits + msbits + lsbits;
    587 			uval |= mask1; /* set stop bit */
    588 			uval &= mask2; /* mask off unused top bits */
    589 			bw->accum <<= msbits + lsbits;
    590 			bw->accum |= uval;
    591 		}
    592 		else {
    593 #endif
    594 			/* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+msbits+lsbits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
    595 			/* OPT: pessimism may cause flurry of false calls to grow_ which eat up all savings before it */
    596 			if(bw->capacity <= bw->words + bw->bits + msbits + 1/*lsbits always fit in 1 bwword*/ && !bitwriter_grow_(bw, msbits+lsbits))
    597 				return false;
    598 
    599 			if(msbits) {
    600 				/* first part gets to word alignment */
    601 				if(bw->bits) {
    602 					left = FLAC__BITS_PER_WORD - bw->bits;
    603 					if(msbits < left) {
    604 						bw->accum <<= msbits;
    605 						bw->bits += msbits;
    606 						goto break1;
    607 					}
    608 					else {
    609 						bw->accum <<= left;
    610 						msbits -= left;
    611 						bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
    612 						bw->bits = 0;
    613 					}
    614 				}
    615 				/* do whole words */
    616 				while(msbits >= FLAC__BITS_PER_WORD) {
    617 					bw->buffer[bw->words++] = 0;
    618 					msbits -= FLAC__BITS_PER_WORD;
    619 				}
    620 				/* do any leftovers */
    621 				if(msbits > 0) {
    622 					bw->accum = 0;
    623 					bw->bits = msbits;
    624 				}
    625 			}
    626 break1:
    627 			uval |= mask1; /* set stop bit */
    628 			uval &= mask2; /* mask off unused top bits */
    629 
    630 			left = FLAC__BITS_PER_WORD - bw->bits;
    631 			if(lsbits < left) {
    632 				bw->accum <<= lsbits;
    633 				bw->accum |= uval;
    634 				bw->bits += lsbits;
    635 			}
    636 			else {
    637 				/* if bw->bits == 0, left==FLAC__BITS_PER_WORD which will always
    638 				 * be > lsbits (because of previous assertions) so it would have
    639 				 * triggered the (lsbits<left) case above.
    640 				 */
    641 				FLAC__ASSERT(bw->bits);
    642 				FLAC__ASSERT(left < FLAC__BITS_PER_WORD);
    643 				bw->accum <<= left;
    644 				bw->accum |= uval >> (bw->bits = lsbits - left);
    645 				bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
    646 				bw->accum = uval;
    647 			}
    648 #if 1
    649 		}
    650 #endif
    651 		vals++;
    652 		nvals--;
    653 	}
    654 	return true;
    655 }
    656 
    657 #if 0 /* UNUSED */
    658 FLAC__bool FLAC__bitwriter_write_golomb_signed(FLAC__BitWriter *bw, int val, unsigned parameter)
    659 {
    660 	unsigned total_bits, msbs, uval;
    661 	unsigned k;
    662 
    663 	FLAC__ASSERT(0 != bw);
    664 	FLAC__ASSERT(0 != bw->buffer);
    665 	FLAC__ASSERT(parameter > 0);
    666 
    667 	/* fold signed to unsigned */
    668 	if(val < 0)
    669 		uval = (unsigned)(((-(++val)) << 1) + 1);
    670 	else
    671 		uval = (unsigned)(val << 1);
    672 
    673 	k = FLAC__bitmath_ilog2(parameter);
    674 	if(parameter == 1u<<k) {
    675 		unsigned pattern;
    676 
    677 		FLAC__ASSERT(k <= 30);
    678 
    679 		msbs = uval >> k;
    680 		total_bits = 1 + k + msbs;
    681 		pattern = 1 << k; /* the unary end bit */
    682 		pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */
    683 
    684 		if(total_bits <= 32) {
    685 			if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits))
    686 				return false;
    687 		}
    688 		else {
    689 			/* write the unary MSBs */
    690 			if(!FLAC__bitwriter_write_zeroes(bw, msbs))
    691 				return false;
    692 			/* write the unary end bit and binary LSBs */
    693 			if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, k+1))
    694 				return false;
    695 		}
    696 	}
    697 	else {
    698 		unsigned q, r, d;
    699 
    700 		d = (1 << (k+1)) - parameter;
    701 		q = uval / parameter;
    702 		r = uval - (q * parameter);
    703 		/* write the unary MSBs */
    704 		if(!FLAC__bitwriter_write_zeroes(bw, q))
    705 			return false;
    706 		/* write the unary end bit */
    707 		if(!FLAC__bitwriter_write_raw_uint32(bw, 1, 1))
    708 			return false;
    709 		/* write the binary LSBs */
    710 		if(r >= d) {
    711 			if(!FLAC__bitwriter_write_raw_uint32(bw, r+d, k+1))
    712 				return false;
    713 		}
    714 		else {
    715 			if(!FLAC__bitwriter_write_raw_uint32(bw, r, k))
    716 				return false;
    717 		}
    718 	}
    719 	return true;
    720 }
    721 
    722 FLAC__bool FLAC__bitwriter_write_golomb_unsigned(FLAC__BitWriter *bw, unsigned uval, unsigned parameter)
    723 {
    724 	unsigned total_bits, msbs;
    725 	unsigned k;
    726 
    727 	FLAC__ASSERT(0 != bw);
    728 	FLAC__ASSERT(0 != bw->buffer);
    729 	FLAC__ASSERT(parameter > 0);
    730 
    731 	k = FLAC__bitmath_ilog2(parameter);
    732 	if(parameter == 1u<<k) {
    733 		unsigned pattern;
    734 
    735 		FLAC__ASSERT(k <= 30);
    736 
    737 		msbs = uval >> k;
    738 		total_bits = 1 + k + msbs;
    739 		pattern = 1 << k; /* the unary end bit */
    740 		pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */
    741 
    742 		if(total_bits <= 32) {
    743 			if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits))
    744 				return false;
    745 		}
    746 		else {
    747 			/* write the unary MSBs */
    748 			if(!FLAC__bitwriter_write_zeroes(bw, msbs))
    749 				return false;
    750 			/* write the unary end bit and binary LSBs */
    751 			if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, k+1))
    752 				return false;
    753 		}
    754 	}
    755 	else {
    756 		unsigned q, r, d;
    757 
    758 		d = (1 << (k+1)) - parameter;
    759 		q = uval / parameter;
    760 		r = uval - (q * parameter);
    761 		/* write the unary MSBs */
    762 		if(!FLAC__bitwriter_write_zeroes(bw, q))
    763 			return false;
    764 		/* write the unary end bit */
    765 		if(!FLAC__bitwriter_write_raw_uint32(bw, 1, 1))
    766 			return false;
    767 		/* write the binary LSBs */
    768 		if(r >= d) {
    769 			if(!FLAC__bitwriter_write_raw_uint32(bw, r+d, k+1))
    770 				return false;
    771 		}
    772 		else {
    773 			if(!FLAC__bitwriter_write_raw_uint32(bw, r, k))
    774 				return false;
    775 		}
    776 	}
    777 	return true;
    778 }
    779 #endif /* UNUSED */
    780 
    781 FLAC__bool FLAC__bitwriter_write_utf8_uint32(FLAC__BitWriter *bw, FLAC__uint32 val)
    782 {
    783 	FLAC__bool ok = 1;
    784 
    785 	FLAC__ASSERT(0 != bw);
    786 	FLAC__ASSERT(0 != bw->buffer);
    787 
    788 	FLAC__ASSERT(!(val & 0x80000000)); /* this version only handles 31 bits */
    789 
    790 	if(val < 0x80) {
    791 		return FLAC__bitwriter_write_raw_uint32(bw, val, 8);
    792 	}
    793 	else if(val < 0x800) {
    794 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xC0 | (val>>6), 8);
    795 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
    796 	}
    797 	else if(val < 0x10000) {
    798 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xE0 | (val>>12), 8);
    799 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>6)&0x3F), 8);
    800 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
    801 	}
    802 	else if(val < 0x200000) {
    803 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xF0 | (val>>18), 8);
    804 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>12)&0x3F), 8);
    805 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>6)&0x3F), 8);
    806 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
    807 	}
    808 	else if(val < 0x4000000) {
    809 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xF8 | (val>>24), 8);
    810 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>18)&0x3F), 8);
    811 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>12)&0x3F), 8);
    812 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>6)&0x3F), 8);
    813 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
    814 	}
    815 	else {
    816 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xFC | (val>>30), 8);
    817 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>24)&0x3F), 8);
    818 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>18)&0x3F), 8);
    819 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>12)&0x3F), 8);
    820 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | ((val>>6)&0x3F), 8);
    821 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (val&0x3F), 8);
    822 	}
    823 
    824 	return ok;
    825 }
    826 
    827 FLAC__bool FLAC__bitwriter_write_utf8_uint64(FLAC__BitWriter *bw, FLAC__uint64 val)
    828 {
    829 	FLAC__bool ok = 1;
    830 
    831 	FLAC__ASSERT(0 != bw);
    832 	FLAC__ASSERT(0 != bw->buffer);
    833 
    834 	FLAC__ASSERT(!(val & FLAC__U64L(0xFFFFFFF000000000))); /* this version only handles 36 bits */
    835 
    836 	if(val < 0x80) {
    837 		return FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, 8);
    838 	}
    839 	else if(val < 0x800) {
    840 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xC0 | (FLAC__uint32)(val>>6), 8);
    841 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
    842 	}
    843 	else if(val < 0x10000) {
    844 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xE0 | (FLAC__uint32)(val>>12), 8);
    845 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    846 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
    847 	}
    848 	else if(val < 0x200000) {
    849 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xF0 | (FLAC__uint32)(val>>18), 8);
    850 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
    851 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    852 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
    853 	}
    854 	else if(val < 0x4000000) {
    855 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xF8 | (FLAC__uint32)(val>>24), 8);
    856 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
    857 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
    858 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    859 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
    860 	}
    861 	else if(val < 0x80000000) {
    862 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xFC | (FLAC__uint32)(val>>30), 8);
    863 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>24)&0x3F), 8);
    864 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
    865 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
    866 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    867 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
    868 	}
    869 	else {
    870 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0xFE, 8);
    871 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>30)&0x3F), 8);
    872 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>24)&0x3F), 8);
    873 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
    874 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
    875 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    876 		ok &= FLAC__bitwriter_write_raw_uint32(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
    877 	}
    878 
    879 	return ok;
    880 }
    881 
    882 FLAC__bool FLAC__bitwriter_zero_pad_to_byte_boundary(FLAC__BitWriter *bw)
    883 {
    884 	/* 0-pad to byte boundary */
    885 	if(bw->bits & 7u)
    886 		return FLAC__bitwriter_write_zeroes(bw, 8 - (bw->bits & 7u));
    887 	else
    888 		return true;
    889 }
    890