1 /* libFLAC - Free Lossless Audio Codec library
2 * Copyright (C) 2000-2009 Josh Coalson
3 * Copyright (C) 2011-2022 Xiph.Org Foundation
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
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.
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.
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.
39 #include "private/bitmath.h"
40 #include "private/bitreader.h"
41 #include "private/crc.h"
42 #include "private/macros.h"
43 #include "FLAC/assert.h"
44 #include "share/compat.h"
45 #include "share/endswap.h"
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 COUNT_ZERO_MSBS2 below to match */
49 /* WATCHOUT: there are a few places where the code will not work unless brword is >= 32 bits wide */
50 /* also, some sections currently only have fast versions for 4 or 8 bytes per word */
52 #if (ENABLE_64_BIT_WORDS == 0)
54 typedef FLAC__uint32 brword;
55 #define FLAC__BYTES_PER_WORD 4 /* sizeof brword */
56 #define FLAC__BITS_PER_WORD 32
57 #define FLAC__WORD_ALL_ONES ((FLAC__uint32)0xffffffff)
58 /* SWAP_BE_WORD_TO_HOST swaps bytes in a brword (which is always big-endian) if necessary to match host byte order */
60 #define SWAP_BE_WORD_TO_HOST(x) (x)
62 #define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_32(x)
64 /* counts the # of zero MSBs in a word */
65 #define COUNT_ZERO_MSBS(word) FLAC__clz_uint32(word)
66 #define COUNT_ZERO_MSBS2(word) FLAC__clz2_uint32(word)
70 typedef FLAC__uint64 brword;
71 #define FLAC__BYTES_PER_WORD 8 /* sizeof brword */
72 #define FLAC__BITS_PER_WORD 64
73 #define FLAC__WORD_ALL_ONES ((FLAC__uint64)FLAC__U64L(0xffffffffffffffff))
74 /* SWAP_BE_WORD_TO_HOST swaps bytes in a brword (which is always big-endian) if necessary to match host byte order */
76 #define SWAP_BE_WORD_TO_HOST(x) (x)
78 #define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_64(x)
80 /* counts the # of zero MSBs in a word */
81 #define COUNT_ZERO_MSBS(word) FLAC__clz_uint64(word)
82 #define COUNT_ZERO_MSBS2(word) FLAC__clz2_uint64(word)
87 * This should be at least twice as large as the largest number of words
88 * required to represent any 'number' (in any encoding) you are going to
89 * read. With FLAC this is on the order of maybe a few hundred bits.
90 * If the buffer is smaller than that, the decoder won't be able to read
91 * in a whole number that is in a variable length encoding (e.g. Rice).
92 * But to be practical it should be at least 1K bytes.
94 * Increase this number to decrease the number of read callbacks, at the
95 * expense of using more memory. Or decrease for the reverse effect,
96 * keeping in mind the limit from the first paragraph. The optimal size
97 * also depends on the CPU cache size and other factors; some twiddling
98 * may be necessary to squeeze out the best performance.
100 static const uint32_t FLAC__BITREADER_DEFAULT_CAPACITY = 65536u / FLAC__BITS_PER_WORD; /* in words */
102 struct FLAC__BitReader {
103 /* any partially-consumed word at the head will stay right-justified as bits are consumed from the left */
104 /* any incomplete word at the tail will be left-justified, and bytes from the read callback are added on the right */
106 uint32_t capacity; /* in words */
107 uint32_t words; /* # of completed words in buffer */
108 uint32_t bytes; /* # of bytes in incomplete word at buffer[words] */
109 uint32_t consumed_words; /* #words ... */
110 uint32_t consumed_bits; /* ... + (#bits of head word) already consumed from the front of buffer */
111 uint32_t read_crc16; /* the running frame CRC */
112 uint32_t crc16_offset; /* the number of words in the current buffer that should not be CRC'd */
113 uint32_t crc16_align; /* the number of bits in the current consumed word that should not be CRC'd */
114 FLAC__bool read_limit_set; /* whether reads are limited */
115 uint32_t read_limit; /* the remaining size of what can be read */
116 uint32_t last_seen_framesync; /* the location of the last seen framesync, if it is in the buffer, in bits from front of buffer */
117 FLAC__BitReaderReadCallback read_callback;
121 static inline void crc16_update_word_(FLAC__BitReader *br, brword word)
123 register uint32_t crc = br->read_crc16;
125 for ( ; br->crc16_align < FLAC__BITS_PER_WORD ; br->crc16_align += 8) {
126 uint32_t shift = FLAC__BITS_PER_WORD - 8 - br->crc16_align ;
127 crc = FLAC__CRC16_UPDATE ((uint32_t) (shift < FLAC__BITS_PER_WORD ? (word >> shift) & 0xff : 0), crc);
130 br->read_crc16 = crc;
134 static inline void crc16_update_block_(FLAC__BitReader *br)
136 if(br->consumed_words > br->crc16_offset && br->crc16_align)
137 crc16_update_word_(br, br->buffer[br->crc16_offset++]);
139 /* Prevent OOB read due to wrap-around. */
140 if (br->consumed_words > br->crc16_offset) {
141 #if FLAC__BYTES_PER_WORD == 4
142 br->read_crc16 = FLAC__crc16_update_words32(br->buffer + br->crc16_offset, br->consumed_words - br->crc16_offset, br->read_crc16);
143 #elif FLAC__BYTES_PER_WORD == 8
144 br->read_crc16 = FLAC__crc16_update_words64(br->buffer + br->crc16_offset, br->consumed_words - br->crc16_offset, br->read_crc16);
148 for (i = br->crc16_offset; i < br->consumed_words; i++)
149 crc16_update_word_(br, br->buffer[i]);
153 br->crc16_offset = 0;
156 static FLAC__bool bitreader_read_from_client_(FLAC__BitReader *br)
163 brword preswap_backup;
166 /* invalidate last seen framesync */
167 br->last_seen_framesync = -1;
169 /* first shift the unconsumed buffer data toward the front as much as possible */
170 if(br->consumed_words > 0) {
171 crc16_update_block_(br); /* CRC consumed words */
173 start = br->consumed_words;
174 end = br->words + (br->bytes? 1:0);
175 memmove(br->buffer, br->buffer+start, FLAC__BYTES_PER_WORD * (end - start));
178 br->consumed_words = 0;
182 * set the target for reading, taking into account word alignment and endianness
184 bytes = (br->capacity - br->words) * FLAC__BYTES_PER_WORD - br->bytes;
186 return false; /* no space left, buffer is too small; see note for FLAC__BITREADER_DEFAULT_CAPACITY */
187 target = ((FLAC__byte*)(br->buffer+br->words)) + br->bytes;
189 /* before reading, if the existing reader looks like this (say brword is 32 bits wide)
190 * bitstream : 11 22 33 44 55 br->words=1 br->bytes=1 (partial tail word is left-justified)
191 * buffer[BE]: 11 22 33 44 55 ?? ?? ?? (shown laid out as bytes sequentially in memory)
192 * buffer[LE]: 44 33 22 11 ?? ?? ?? 55 (?? being don't-care)
193 * ^^-------target, bytes=3
194 * on LE machines, have to byteswap the odd tail word so nothing is
199 preswap_backup = br->buffer[br->words];
201 br->buffer[br->words] = SWAP_BE_WORD_TO_HOST(br->buffer[br->words]);
204 /* now it looks like:
205 * bitstream : 11 22 33 44 55 br->words=1 br->bytes=1
206 * buffer[BE]: 11 22 33 44 55 ?? ?? ??
207 * buffer[LE]: 44 33 22 11 55 ?? ?? ??
208 * ^^-------target, bytes=3
211 /* read in the data; note that the callback may return a smaller number of bytes */
212 if(!br->read_callback(target, &bytes, br->client_data)){
213 /* Despite the read callback failing, the data in the target
214 * might be used later, when the buffer is rewound. Therefore
215 * we revert the swap that was just done */
218 br->buffer[br->words] = preswap_backup;
223 /* after reading bytes 66 77 88 99 AA BB CC DD EE FF from the client:
224 * bitstream : 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF
225 * buffer[BE]: 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF ??
226 * buffer[LE]: 44 33 22 11 55 66 77 88 99 AA BB CC DD EE FF ??
227 * now have to byteswap on LE machines:
231 end = (br->words*FLAC__BYTES_PER_WORD + br->bytes + (uint32_t)bytes + (FLAC__BYTES_PER_WORD-1)) / FLAC__BYTES_PER_WORD;
232 for(start = br->words; start < end; start++)
233 br->buffer[start] = SWAP_BE_WORD_TO_HOST(br->buffer[start]);
236 /* now it looks like:
237 * bitstream : 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF
238 * buffer[BE]: 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF ??
239 * buffer[LE]: 44 33 22 11 88 77 66 55 CC BB AA 99 ?? FF EE DD
240 * finally we'll update the reader values:
242 end = br->words*FLAC__BYTES_PER_WORD + br->bytes + (uint32_t)bytes;
243 br->words = end / FLAC__BYTES_PER_WORD;
244 br->bytes = end % FLAC__BYTES_PER_WORD;
249 /***********************************************************************
251 * Class constructor/destructor
253 ***********************************************************************/
255 FLAC__BitReader *FLAC__bitreader_new(void)
257 FLAC__BitReader *br = calloc(1, sizeof(FLAC__BitReader));
260 memset(br, 0, sizeof(FLAC__BitReader));
263 br->words = br->bytes = 0;
264 br->consumed_words = br->consumed_bits = 0;
265 br->read_callback = 0;
271 void FLAC__bitreader_delete(FLAC__BitReader *br)
273 FLAC__ASSERT(0 != br);
275 FLAC__bitreader_free(br);
279 /***********************************************************************
281 * Public class methods
283 ***********************************************************************/
285 FLAC__bool FLAC__bitreader_init(FLAC__BitReader *br, FLAC__BitReaderReadCallback rcb, void *cd)
287 FLAC__ASSERT(0 != br);
289 br->words = br->bytes = 0;
290 br->consumed_words = br->consumed_bits = 0;
291 br->capacity = FLAC__BITREADER_DEFAULT_CAPACITY;
292 br->buffer = malloc(sizeof(brword) * br->capacity);
295 br->read_callback = rcb;
296 br->client_data = cd;
297 br->read_limit_set = false;
299 br->last_seen_framesync = -1;
304 void FLAC__bitreader_free(FLAC__BitReader *br)
306 FLAC__ASSERT(0 != br);
312 br->words = br->bytes = 0;
313 br->consumed_words = br->consumed_bits = 0;
314 br->read_callback = 0;
316 br->read_limit_set = false;
318 br->last_seen_framesync = -1;
321 FLAC__bool FLAC__bitreader_clear(FLAC__BitReader *br)
323 br->words = br->bytes = 0;
324 br->consumed_words = br->consumed_bits = 0;
325 br->read_limit_set = false;
327 br->last_seen_framesync = -1;
331 void FLAC__bitreader_set_framesync_location(FLAC__BitReader *br)
333 br->last_seen_framesync = br->consumed_words * FLAC__BYTES_PER_WORD + br->consumed_bits / 8;
336 FLAC__bool FLAC__bitreader_rewind_to_after_last_seen_framesync(FLAC__BitReader *br)
338 if(br->last_seen_framesync == (uint32_t)-1) {
339 br->consumed_words = br->consumed_bits = 0;
343 br->consumed_words = (br->last_seen_framesync + 1) / FLAC__BYTES_PER_WORD;
344 br->consumed_bits = ((br->last_seen_framesync + 1) % FLAC__BYTES_PER_WORD) * 8;
349 void FLAC__bitreader_dump(const FLAC__BitReader *br, FILE *out)
353 fprintf(out, "bitreader is NULL\n");
356 fprintf(out, "bitreader: capacity=%u words=%u bytes=%u consumed: words=%u, bits=%u\n", br->capacity, br->words, br->bytes, br->consumed_words, br->consumed_bits);
358 for(i = 0; i < br->words; i++) {
359 fprintf(out, "%08X: ", i);
360 for(j = 0; j < FLAC__BITS_PER_WORD; j++)
361 if(i < br->consumed_words || (i == br->consumed_words && j < br->consumed_bits))
364 fprintf(out, "%01d", br->buffer[i] & ((brword)1 << (FLAC__BITS_PER_WORD-j-1)) ? 1:0);
368 fprintf(out, "%08X: ", i);
369 for(j = 0; j < br->bytes*8; j++)
370 if(i < br->consumed_words || (i == br->consumed_words && j < br->consumed_bits))
373 fprintf(out, "%01d", br->buffer[i] & ((brword)1 << (br->bytes*8-j-1)) ? 1:0);
379 void FLAC__bitreader_reset_read_crc16(FLAC__BitReader *br, FLAC__uint16 seed)
381 FLAC__ASSERT(0 != br);
382 FLAC__ASSERT(0 != br->buffer);
383 FLAC__ASSERT((br->consumed_bits & 7) == 0);
385 br->read_crc16 = (uint32_t)seed;
386 br->crc16_offset = br->consumed_words;
387 br->crc16_align = br->consumed_bits;
390 FLAC__uint16 FLAC__bitreader_get_read_crc16(FLAC__BitReader *br)
392 FLAC__ASSERT(0 != br);
393 FLAC__ASSERT(0 != br->buffer);
395 /* CRC consumed words up to here */
396 crc16_update_block_(br);
398 FLAC__ASSERT((br->consumed_bits & 7) == 0);
399 FLAC__ASSERT(br->crc16_align <= br->consumed_bits);
401 /* CRC any tail bytes in a partially-consumed word */
402 if(br->consumed_bits) {
403 const brword tail = br->buffer[br->consumed_words];
404 for( ; br->crc16_align < br->consumed_bits; br->crc16_align += 8)
405 br->read_crc16 = FLAC__CRC16_UPDATE((uint32_t)((tail >> (FLAC__BITS_PER_WORD-8-br->crc16_align)) & 0xff), br->read_crc16);
407 return br->read_crc16;
410 inline FLAC__bool FLAC__bitreader_is_consumed_byte_aligned(const FLAC__BitReader *br)
412 return ((br->consumed_bits & 7) == 0);
415 inline uint32_t FLAC__bitreader_bits_left_for_byte_alignment(const FLAC__BitReader *br)
417 return 8 - (br->consumed_bits & 7);
420 inline uint32_t FLAC__bitreader_get_input_bits_unconsumed(const FLAC__BitReader *br)
422 return (br->words-br->consumed_words)*FLAC__BITS_PER_WORD + br->bytes*8 - br->consumed_bits;
425 void FLAC__bitreader_set_limit(FLAC__BitReader *br, uint32_t limit)
427 br->read_limit = limit;
428 br->read_limit_set = true;
431 void FLAC__bitreader_remove_limit(FLAC__BitReader *br)
433 br->read_limit_set = false;
437 uint32_t FLAC__bitreader_limit_remaining(FLAC__BitReader *br)
439 FLAC__ASSERT(br->read_limit_set);
440 return br->read_limit;
442 void FLAC__bitreader_limit_invalidate(FLAC__BitReader *br)
447 FLAC__bool FLAC__bitreader_read_raw_uint32(FLAC__BitReader *br, FLAC__uint32 *val, uint32_t bits)
449 FLAC__ASSERT(0 != br);
450 FLAC__ASSERT(0 != br->buffer);
452 FLAC__ASSERT(bits <= 32);
453 FLAC__ASSERT((br->capacity*FLAC__BITS_PER_WORD) * 2 >= bits);
454 FLAC__ASSERT(br->consumed_words <= br->words);
456 /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
457 FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
459 if(bits == 0) { /* OPT: investigate if this can ever happen, maybe change to assertion */
464 if(br->read_limit_set && br->read_limit < (uint32_t)-1){
465 if(br->read_limit < bits) {
470 br->read_limit -= bits;
473 while((br->words-br->consumed_words)*FLAC__BITS_PER_WORD + br->bytes*8 - br->consumed_bits < bits) {
474 if(!bitreader_read_from_client_(br))
477 if(br->consumed_words < br->words) { /* if we've not consumed up to a partial tail word... */
478 /* OPT: taking out the consumed_bits==0 "else" case below might make things faster if less code allows the compiler to inline this function */
479 if(br->consumed_bits) {
480 /* this also works when consumed_bits==0, it's just a little slower than necessary for that case */
481 const uint32_t n = FLAC__BITS_PER_WORD - br->consumed_bits;
482 const brword word = br->buffer[br->consumed_words];
483 const brword mask = br->consumed_bits < FLAC__BITS_PER_WORD ? FLAC__WORD_ALL_ONES >> br->consumed_bits : 0;
485 uint32_t shift = n - bits;
486 *val = shift < FLAC__BITS_PER_WORD ? (FLAC__uint32)((word & mask) >> shift) : 0; /* The result has <= 32 non-zero bits */
487 br->consumed_bits += bits;
490 /* (FLAC__BITS_PER_WORD - br->consumed_bits <= bits) ==> (FLAC__WORD_ALL_ONES >> br->consumed_bits) has no more than 'bits' non-zero bits */
491 *val = (FLAC__uint32)(word & mask);
493 br->consumed_words++;
494 br->consumed_bits = 0;
495 if(bits) { /* if there are still bits left to read, there have to be less than 32 so they will all be in the next word */
496 uint32_t shift = FLAC__BITS_PER_WORD - bits;
497 *val = bits < 32 ? *val << bits : 0;
498 *val |= shift < FLAC__BITS_PER_WORD ? (FLAC__uint32)(br->buffer[br->consumed_words] >> shift) : 0;
499 br->consumed_bits = bits;
503 else { /* br->consumed_bits == 0 */
504 const brword word = br->buffer[br->consumed_words];
505 if(bits < FLAC__BITS_PER_WORD) {
506 *val = (FLAC__uint32)(word >> (FLAC__BITS_PER_WORD-bits));
507 br->consumed_bits = bits;
510 /* at this point bits == FLAC__BITS_PER_WORD == 32; because of previous assertions, it can't be larger */
511 *val = (FLAC__uint32)word;
512 br->consumed_words++;
517 /* in this case we're starting our read at a partial tail word;
518 * the reader has guaranteed that we have at least 'bits' bits
519 * available to read, which makes this case simpler.
521 /* OPT: taking out the consumed_bits==0 "else" case below might make things faster if less code allows the compiler to inline this function */
522 if(br->consumed_bits) {
523 /* this also works when consumed_bits==0, it's just a little slower than necessary for that case */
524 FLAC__ASSERT(br->consumed_bits + bits <= br->bytes*8);
525 *val = (FLAC__uint32)((br->buffer[br->consumed_words] & (FLAC__WORD_ALL_ONES >> br->consumed_bits)) >> (FLAC__BITS_PER_WORD-br->consumed_bits-bits));
526 br->consumed_bits += bits;
530 *val = (FLAC__uint32)(br->buffer[br->consumed_words] >> (FLAC__BITS_PER_WORD-bits));
531 br->consumed_bits += bits;
537 FLAC__bool FLAC__bitreader_read_raw_int32(FLAC__BitReader *br, FLAC__int32 *val, uint32_t bits)
539 FLAC__uint32 uval, mask;
540 /* OPT: inline raw uint32 code here, or make into a macro if possible in the .h file */
541 if (bits < 1 || ! FLAC__bitreader_read_raw_uint32(br, &uval, bits))
543 /* sign-extend *val assuming it is currently bits wide. */
544 /* From: https://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend */
545 mask = bits >= 33 ? 0 : 1lu << (bits - 1);
546 *val = (uval ^ mask) - mask;
550 FLAC__bool FLAC__bitreader_read_raw_uint64(FLAC__BitReader *br, FLAC__uint64 *val, uint32_t bits)
555 if(!FLAC__bitreader_read_raw_uint32(br, &hi, bits-32))
557 if(!FLAC__bitreader_read_raw_uint32(br, &lo, 32))
564 if(!FLAC__bitreader_read_raw_uint32(br, &lo, bits))
571 FLAC__bool FLAC__bitreader_read_raw_int64(FLAC__BitReader *br, FLAC__int64 *val, uint32_t bits)
573 FLAC__uint64 uval, mask;
574 /* OPT: inline raw uint64 code here, or make into a macro if possible in the .h file */
575 if (bits < 1 || ! FLAC__bitreader_read_raw_uint64(br, &uval, bits))
577 /* sign-extend *val assuming it is currently bits wide. */
578 /* From: https://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend */
579 mask = bits >= 65 ? 0 : 1llu << (bits - 1);
580 *val = (uval ^ mask) - mask;
584 inline FLAC__bool FLAC__bitreader_read_uint32_little_endian(FLAC__BitReader *br, FLAC__uint32 *val)
586 FLAC__uint32 x8, x32 = 0;
588 /* this doesn't need to be that fast as currently it is only used for vorbis comments */
590 if(!FLAC__bitreader_read_raw_uint32(br, &x32, 8))
593 if(!FLAC__bitreader_read_raw_uint32(br, &x8, 8))
597 if(!FLAC__bitreader_read_raw_uint32(br, &x8, 8))
601 if(!FLAC__bitreader_read_raw_uint32(br, &x8, 8))
609 FLAC__bool FLAC__bitreader_skip_bits_no_crc(FLAC__BitReader *br, uint32_t bits)
612 * OPT: a faster implementation is possible but probably not that useful
613 * since this is only called a couple of times in the metadata readers.
615 FLAC__ASSERT(0 != br);
616 FLAC__ASSERT(0 != br->buffer);
619 const uint32_t n = br->consumed_bits & 7;
624 m = flac_min(8-n, bits);
625 if(!FLAC__bitreader_read_raw_uint32(br, &x, m))
631 if(!FLAC__bitreader_skip_byte_block_aligned_no_crc(br, m))
636 if(!FLAC__bitreader_read_raw_uint32(br, &x, bits))
644 FLAC__bool FLAC__bitreader_skip_byte_block_aligned_no_crc(FLAC__BitReader *br, uint32_t nvals)
648 FLAC__ASSERT(0 != br);
649 FLAC__ASSERT(0 != br->buffer);
650 FLAC__ASSERT(FLAC__bitreader_is_consumed_byte_aligned(br));
652 if(br->read_limit_set && br->read_limit < (uint32_t)-1){
653 if(br->read_limit < nvals*8){
659 /* step 1: skip over partial head word to get word aligned */
660 while(nvals && br->consumed_bits) { /* i.e. run until we read 'nvals' bytes or we hit the end of the head word */
661 if(!FLAC__bitreader_read_raw_uint32(br, &x, 8))
668 /* step 2: skip whole words in chunks */
669 while(nvals >= FLAC__BYTES_PER_WORD) {
670 if(br->consumed_words < br->words) {
671 br->consumed_words++;
672 nvals -= FLAC__BYTES_PER_WORD;
673 if(br->read_limit_set)
674 br->read_limit -= FLAC__BITS_PER_WORD;
676 else if(!bitreader_read_from_client_(br))
679 /* step 3: skip any remainder from partial tail bytes */
681 if(!FLAC__bitreader_read_raw_uint32(br, &x, 8))
689 FLAC__bool FLAC__bitreader_read_byte_block_aligned_no_crc(FLAC__BitReader *br, FLAC__byte *val, uint32_t nvals)
693 FLAC__ASSERT(0 != br);
694 FLAC__ASSERT(0 != br->buffer);
695 FLAC__ASSERT(FLAC__bitreader_is_consumed_byte_aligned(br));
697 if(br->read_limit_set && br->read_limit < (uint32_t)-1){
698 if(br->read_limit < nvals*8){
704 /* step 1: read from partial head word to get word aligned */
705 while(nvals && br->consumed_bits) { /* i.e. run until we read 'nvals' bytes or we hit the end of the head word */
706 if(!FLAC__bitreader_read_raw_uint32(br, &x, 8))
708 *val++ = (FLAC__byte)x;
713 /* step 2: read whole words in chunks */
714 while(nvals >= FLAC__BYTES_PER_WORD) {
715 if(br->consumed_words < br->words) {
716 const brword word = br->buffer[br->consumed_words++];
717 #if FLAC__BYTES_PER_WORD == 4
718 val[0] = (FLAC__byte)(word >> 24);
719 val[1] = (FLAC__byte)(word >> 16);
720 val[2] = (FLAC__byte)(word >> 8);
721 val[3] = (FLAC__byte)word;
722 #elif FLAC__BYTES_PER_WORD == 8
723 val[0] = (FLAC__byte)(word >> 56);
724 val[1] = (FLAC__byte)(word >> 48);
725 val[2] = (FLAC__byte)(word >> 40);
726 val[3] = (FLAC__byte)(word >> 32);
727 val[4] = (FLAC__byte)(word >> 24);
728 val[5] = (FLAC__byte)(word >> 16);
729 val[6] = (FLAC__byte)(word >> 8);
730 val[7] = (FLAC__byte)word;
732 for(x = 0; x < FLAC__BYTES_PER_WORD; x++)
733 val[x] = (FLAC__byte)(word >> (8*(FLAC__BYTES_PER_WORD-x-1)));
735 val += FLAC__BYTES_PER_WORD;
736 nvals -= FLAC__BYTES_PER_WORD;
737 if(br->read_limit_set)
738 br->read_limit -= FLAC__BITS_PER_WORD;
740 else if(!bitreader_read_from_client_(br))
743 /* step 3: read any remainder from partial tail bytes */
745 if(!FLAC__bitreader_read_raw_uint32(br, &x, 8))
747 *val++ = (FLAC__byte)x;
754 FLAC__bool FLAC__bitreader_read_unary_unsigned(FLAC__BitReader *br, uint32_t *val)
755 #if 0 /* slow but readable version */
759 FLAC__ASSERT(0 != br);
760 FLAC__ASSERT(0 != br->buffer);
764 if(!FLAC__bitreader_read_bit(br, &bit))
777 FLAC__ASSERT(0 != br);
778 FLAC__ASSERT(0 != br->buffer);
782 while(br->consumed_words < br->words) { /* if we've not consumed up to a partial tail word... */
783 brword b = br->consumed_bits < FLAC__BITS_PER_WORD ? br->buffer[br->consumed_words] << br->consumed_bits : 0;
785 i = COUNT_ZERO_MSBS(b);
788 br->consumed_bits += i;
789 if(br->consumed_bits >= FLAC__BITS_PER_WORD) { /* faster way of testing if(br->consumed_bits == FLAC__BITS_PER_WORD) */
790 br->consumed_words++;
791 br->consumed_bits = 0;
796 *val += FLAC__BITS_PER_WORD - br->consumed_bits;
797 br->consumed_words++;
798 br->consumed_bits = 0;
799 /* didn't find stop bit yet, have to keep going... */
802 /* at this point we've eaten up all the whole words; have to try
803 * reading through any tail bytes before calling the read callback.
804 * this is a repeat of the above logic adjusted for the fact we
805 * don't have a whole word. note though if the client is feeding
806 * us data a byte at a time (unlikely), br->consumed_bits may not
809 if(br->bytes*8 > br->consumed_bits) {
810 const uint32_t end = br->bytes * 8;
811 brword b = (br->buffer[br->consumed_words] & (FLAC__WORD_ALL_ONES << (FLAC__BITS_PER_WORD-end))) << br->consumed_bits;
813 i = COUNT_ZERO_MSBS(b);
816 br->consumed_bits += i;
817 FLAC__ASSERT(br->consumed_bits < FLAC__BITS_PER_WORD);
821 *val += end - br->consumed_bits;
822 br->consumed_bits = end;
823 FLAC__ASSERT(br->consumed_bits < FLAC__BITS_PER_WORD);
824 /* didn't find stop bit yet, have to keep going... */
827 if(!bitreader_read_from_client_(br))
834 FLAC__bool FLAC__bitreader_read_rice_signed(FLAC__BitReader *br, int *val, uint32_t parameter)
836 FLAC__uint32 lsbs = 0, msbs = 0;
839 FLAC__ASSERT(0 != br);
840 FLAC__ASSERT(0 != br->buffer);
841 FLAC__ASSERT(parameter <= 31);
843 /* read the unary MSBs and end bit */
844 if(!FLAC__bitreader_read_unary_unsigned(br, &msbs))
847 /* read the binary LSBs */
848 if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, parameter))
851 /* compose the value */
852 uval = (msbs << parameter) | lsbs;
854 *val = -((int)(uval >> 1)) - 1;
856 *val = (int)(uval >> 1);
862 /* this is by far the most heavily used reader call. it ain't pretty but it's fast */
863 FLAC__bool FLAC__bitreader_read_rice_signed_block(FLAC__BitReader *br, int vals[], uint32_t nvals, uint32_t parameter)
865 /* try and get br->consumed_words and br->consumed_bits into register;
866 * must remember to flush them back to *br before calling other
867 * bitreader functions that use them, and before returning */
868 uint32_t cwords, words, lsbs, msbs, x, y, limit;
869 uint32_t ucbits; /* keep track of the number of unconsumed bits in word */
873 FLAC__ASSERT(0 != br);
874 FLAC__ASSERT(0 != br->buffer);
875 /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
876 FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
877 FLAC__ASSERT(parameter < 32);
878 /* the above two asserts also guarantee that the binary part never straddles more than 2 words, so we don't have to loop to read it */
880 limit = UINT32_MAX >> parameter; /* Maximal msbs that can occur with residual bounded to int32_t */
887 /* read the unary MSBs and end bit */
888 if(!FLAC__bitreader_read_unary_unsigned(br, &msbs))
890 /* Checking limit here would be overzealous: coding UINT32_MAX
891 * with parameter == 0 would take 4GiB */
892 *val++ = (int)(msbs >> 1) ^ -(int)(msbs & 1);
898 FLAC__ASSERT(parameter > 0);
900 cwords = br->consumed_words;
903 /* if we've not consumed up to a partial tail word... */
904 if(cwords >= words) {
909 ucbits = FLAC__BITS_PER_WORD - br->consumed_bits;
910 b = br->buffer[cwords] << br->consumed_bits; /* keep unconsumed bits aligned to left */
913 /* read the unary MSBs and end bit */
914 x = y = COUNT_ZERO_MSBS2(b);
915 if(x == FLAC__BITS_PER_WORD) {
918 /* didn't find stop bit yet, have to keep going... */
921 goto incomplete_msbs;
922 b = br->buffer[cwords];
923 y = COUNT_ZERO_MSBS2(b);
925 } while(y == FLAC__BITS_PER_WORD);
928 b <<= 1; /* account for stop bit */
929 ucbits = (ucbits - x - 1) % FLAC__BITS_PER_WORD;
935 /* read the binary LSBs */
936 x = (FLAC__uint32)(b >> (FLAC__BITS_PER_WORD - parameter)); /* parameter < 32, so we can cast to 32-bit uint32_t */
937 if(parameter <= ucbits) {
941 /* there are still bits left to read, they will all be in the next word */
944 goto incomplete_lsbs;
945 b = br->buffer[cwords];
946 ucbits += FLAC__BITS_PER_WORD - parameter;
947 x |= (FLAC__uint32)(b >> ucbits);
948 b <<= FLAC__BITS_PER_WORD - ucbits;
952 /* compose the value */
953 x = (msbs << parameter) | lsbs;
954 *val++ = (int)(x >> 1) ^ -(int)(x & 1);
958 /* at this point we've eaten up all the whole words */
963 br->consumed_bits = 0;
964 br->consumed_words = cwords;
967 /* read the unary MSBs and end bit */
968 if(!FLAC__bitreader_read_unary_unsigned(br, &msbs))
975 br->consumed_bits = 0;
976 br->consumed_words = cwords;
979 /* read the binary LSBs */
980 if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, parameter - ucbits))
984 /* compose the value */
985 x = (msbs << parameter) | lsbs;
986 *val++ = (int)(x >> 1) ^ -(int)(x & 1);
989 cwords = br->consumed_words;
991 ucbits = FLAC__BITS_PER_WORD - br->consumed_bits;
992 b = cwords < br->capacity ? br->buffer[cwords] << br->consumed_bits : 0;
993 } while(cwords >= words && val < end);
996 if(ucbits == 0 && cwords < words) {
997 /* don't leave the head word with no unconsumed bits */
999 ucbits = FLAC__BITS_PER_WORD;
1002 br->consumed_bits = FLAC__BITS_PER_WORD - ucbits;
1003 br->consumed_words = cwords;
1009 FLAC__bool FLAC__bitreader_read_golomb_signed(FLAC__BitReader *br, int *val, uint32_t parameter)
1011 FLAC__uint32 lsbs = 0, msbs = 0;
1012 uint32_t bit, uval, k;
1014 FLAC__ASSERT(0 != br);
1015 FLAC__ASSERT(0 != br->buffer);
1017 k = FLAC__bitmath_ilog2(parameter);
1019 /* read the unary MSBs and end bit */
1020 if(!FLAC__bitreader_read_unary_unsigned(br, &msbs))
1023 /* read the binary LSBs */
1024 if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, k))
1027 if(parameter == 1u<<k) {
1028 /* compose the value */
1029 uval = (msbs << k) | lsbs;
1032 uint32_t d = (1 << (k+1)) - parameter;
1034 if(!FLAC__bitreader_read_bit(br, &bit))
1040 /* compose the value */
1041 uval = msbs * parameter + lsbs;
1044 /* unfold uint32_t to signed */
1046 *val = -((int)(uval >> 1)) - 1;
1048 *val = (int)(uval >> 1);
1053 FLAC__bool FLAC__bitreader_read_golomb_unsigned(FLAC__BitReader *br, uint32_t *val, uint32_t parameter)
1055 FLAC__uint32 lsbs, msbs = 0;
1058 FLAC__ASSERT(0 != br);
1059 FLAC__ASSERT(0 != br->buffer);
1061 k = FLAC__bitmath_ilog2(parameter);
1063 /* read the unary MSBs and end bit */
1064 if(!FLAC__bitreader_read_unary_unsigned(br, &msbs))
1067 /* read the binary LSBs */
1068 if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, k))
1071 if(parameter == 1u<<k) {
1072 /* compose the value */
1073 *val = (msbs << k) | lsbs;
1076 uint32_t d = (1 << (k+1)) - parameter;
1078 if(!FLAC__bitreader_read_bit(br, &bit))
1084 /* compose the value */
1085 *val = msbs * parameter + lsbs;
1092 /* on return, if *val == 0xffffffff then the utf-8 sequence was invalid, but the return value will be true */
1093 FLAC__bool FLAC__bitreader_read_utf8_uint32(FLAC__BitReader *br, FLAC__uint32 *val, FLAC__byte *raw, uint32_t *rawlen)
1099 if(!FLAC__bitreader_read_raw_uint32(br, &x, 8))
1102 raw[(*rawlen)++] = (FLAC__byte)x;
1103 if(!(x & 0x80)) { /* 0xxxxxxx */
1107 else if(x & 0xC0 && !(x & 0x20)) { /* 110xxxxx */
1111 else if(x & 0xE0 && !(x & 0x10)) { /* 1110xxxx */
1115 else if(x & 0xF0 && !(x & 0x08)) { /* 11110xxx */
1119 else if(x & 0xF8 && !(x & 0x04)) { /* 111110xx */
1123 else if(x & 0xFC && !(x & 0x02)) { /* 1111110x */
1132 if(!FLAC__bitreader_read_raw_uint32(br, &x, 8))
1135 raw[(*rawlen)++] = (FLAC__byte)x;
1136 if(!(x & 0x80) || (x & 0x40)) { /* 10xxxxxx */
1147 /* on return, if *val == 0xffffffffffffffff then the utf-8 sequence was invalid, but the return value will be true */
1148 FLAC__bool FLAC__bitreader_read_utf8_uint64(FLAC__BitReader *br, FLAC__uint64 *val, FLAC__byte *raw, uint32_t *rawlen)
1154 if(!FLAC__bitreader_read_raw_uint32(br, &x, 8))
1157 raw[(*rawlen)++] = (FLAC__byte)x;
1158 if(!(x & 0x80)) { /* 0xxxxxxx */
1162 else if(x & 0xC0 && !(x & 0x20)) { /* 110xxxxx */
1166 else if(x & 0xE0 && !(x & 0x10)) { /* 1110xxxx */
1170 else if(x & 0xF0 && !(x & 0x08)) { /* 11110xxx */
1174 else if(x & 0xF8 && !(x & 0x04)) { /* 111110xx */
1178 else if(x & 0xFC && !(x & 0x02)) { /* 1111110x */
1182 else if(x & 0xFE && !(x & 0x01)) { /* 11111110 */
1187 *val = FLAC__U64L(0xffffffffffffffff);
1191 if(!FLAC__bitreader_read_raw_uint32(br, &x, 8))
1194 raw[(*rawlen)++] = (FLAC__byte)x;
1195 if(!(x & 0x80) || (x & 0x40)) { /* 10xxxxxx */
1196 *val = FLAC__U64L(0xffffffffffffffff);
1206 /* These functions are declared inline in this file but are also callable as
1207 * externs from elsewhere.
1208 * According to the C99 spec, section 6.7.4, simply providing a function
1209 * prototype in a header file without 'inline' and making the function inline
1210 * in this file should be sufficient.
1211 * Unfortunately, the Microsoft VS compiler doesn't pick them up externally. To
1212 * fix that we add extern declarations here.
1214 extern FLAC__bool FLAC__bitreader_is_consumed_byte_aligned(const FLAC__BitReader *br);
1215 extern uint32_t FLAC__bitreader_bits_left_for_byte_alignment(const FLAC__BitReader *br);
1216 extern uint32_t FLAC__bitreader_get_input_bits_unconsumed(const FLAC__BitReader *br);
1217 extern FLAC__bool FLAC__bitreader_read_uint32_little_endian(FLAC__BitReader *br, FLAC__uint32 *val);