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946a2afe MT |
1 | Index: src/libFLAC/bitreader.c |
2 | =================================================================== | |
3 | RCS file: /cvsroot/flac/flac/src/libFLAC/bitreader.c,v | |
4 | retrieving revision 1.15 | |
5 | diff -u -r1.15 bitreader.c | |
6 | --- src/libFLAC/bitreader.c 28 Feb 2008 05:34:26 -0000 1.15 | |
7 | +++ src/libFLAC/bitreader.c 14 Mar 2008 11:07:07 -0000 | |
8 | @@ -69,13 +69,12 @@ | |
9 | #endif | |
10 | /* counts the # of zero MSBs in a word */ | |
11 | #define COUNT_ZERO_MSBS(word) ( \ | |
12 | - (word) <= 0xffff ? \ | |
13 | - ( (word) <= 0xff? byte_to_unary_table[word] + 24 : byte_to_unary_table[(word) >> 8] + 16 ) : \ | |
14 | - ( (word) <= 0xffffff? byte_to_unary_table[word >> 16] + 8 : byte_to_unary_table[(word) >> 24] ) \ | |
15 | + word > 0xffffff ? byte_to_unary_table[(word) >> 24] : \ | |
16 | + !word ? 32 : \ | |
17 | + word > 0xffff ? byte_to_unary_table[word >> 16] + 8 : \ | |
18 | + word > 0xff ? byte_to_unary_table[(word) >> 8] + 16 : \ | |
19 | + byte_to_unary_table[word] + 24 \ | |
20 | ) | |
21 | -/* this alternate might be slightly faster on some systems/compilers: */ | |
22 | -#define COUNT_ZERO_MSBS2(word) ( (word) <= 0xff ? byte_to_unary_table[word] + 24 : ((word) <= 0xffff ? byte_to_unary_table[(word) >> 8] + 16 : ((word) <= 0xffffff ? byte_to_unary_table[(word) >> 16] + 8 : byte_to_unary_table[(word) >> 24])) ) | |
23 | - | |
24 | ||
25 | /* | |
26 | * This should be at least twice as large as the largest number of words | |
27 | Index: src/libFLAC/bitreader.c | |
28 | =================================================================== | |
29 | RCS file: /cvsroot/flac/flac/src/libFLAC/bitreader.c,v | |
30 | retrieving revision 1.15 | |
31 | diff -u -r1.15 bitreader.c | |
32 | --- src/libFLAC/bitreader.c 28 Feb 2008 05:34:26 -0000 1.15 | |
33 | +++ src/libFLAC/bitreader.c 14 Mar 2008 13:19:46 -0000 | |
34 | @@ -149,6 +148,7 @@ | |
35 | FLAC__CPUInfo cpu_info; | |
36 | }; | |
37 | ||
38 | +#if FLAC__BYTES_PER_WORD == 4 && FLAC__CPU_IA32 | |
39 | #ifdef _MSC_VER | |
40 | /* OPT: an MSVC built-in would be better */ | |
41 | static _inline FLAC__uint32 local_swap32_(FLAC__uint32 x) | |
42 | @@ -173,6 +173,15 @@ | |
43 | done1: | |
44 | } | |
45 | } | |
46 | +#elif __GNUC__ | |
47 | +static void local_swap32_block_(FLAC__uint32 *start, FLAC__uint32 len) | |
48 | +{ | |
49 | + FLAC__uint32 *end; | |
50 | + | |
51 | + for(end = start + len; start < end; start++) | |
52 | + asm ("bswap %0" : "=r"(*start) : "0"(*start)); | |
53 | +} | |
54 | +#endif | |
55 | #endif | |
56 | ||
57 | static FLaC__INLINE void crc16_update_word_(FLAC__BitReader *br, brword word) | |
58 | @@ -263,7 +272,7 @@ | |
59 | #if WORDS_BIGENDIAN | |
60 | #else | |
61 | end = (br->words*FLAC__BYTES_PER_WORD + br->bytes + bytes + (FLAC__BYTES_PER_WORD-1)) / FLAC__BYTES_PER_WORD; | |
62 | -# if defined(_MSC_VER) && (FLAC__BYTES_PER_WORD == 4) | |
63 | +# if FLAC__CPU_IA32 && (__GNUC__ || defined(_MSC_VER)) && FLAC__BYTES_PER_WORD == 4 | |
64 | if(br->cpu_info.type == FLAC__CPUINFO_TYPE_IA32 && br->cpu_info.data.ia32.bswap) { | |
65 | start = br->words; | |
66 | local_swap32_block_(br->buffer + start, end - start); | |
67 | Index: src/libFLAC/bitreader.c | |
68 | =================================================================== | |
69 | RCS file: /cvsroot/flac/flac/src/libFLAC/bitreader.c,v | |
70 | retrieving revision 1.15 | |
71 | diff -u -r1.15 bitreader.c | |
72 | --- src/libFLAC/bitreader.c 28 Feb 2008 05:34:26 -0000 1.15 | |
73 | +++ src/libFLAC/bitreader.c 17 Mar 2008 15:42:57 -0000 | |
74 | @@ -803,379 +812,144 @@ | |
75 | } | |
76 | ||
77 | /* this is by far the most heavily used reader call. it ain't pretty but it's fast */ | |
78 | -/* a lot of the logic is copied, then adapted, from FLAC__bitreader_read_unary_unsigned() and FLAC__bitreader_read_raw_uint32() */ | |
79 | FLAC__bool FLAC__bitreader_read_rice_signed_block(FLAC__BitReader *br, int vals[], unsigned nvals, unsigned parameter) | |
80 | -/* OPT: possibly faster version for use with MSVC */ | |
81 | -#ifdef _MSC_VER | |
82 | { | |
83 | - unsigned i; | |
84 | - unsigned uval = 0; | |
85 | - unsigned bits; /* the # of binary LSBs left to read to finish a rice codeword */ | |
86 | - | |
87 | /* try and get br->consumed_words and br->consumed_bits into register; | |
88 | * must remember to flush them back to *br before calling other | |
89 | - * bitwriter functions that use them, and before returning */ | |
90 | - register unsigned cwords; | |
91 | - register unsigned cbits; | |
92 | + * bitreader functions that use them, and before returning */ | |
93 | + unsigned cwords, words, lsbs, msbs, x, y; | |
94 | + unsigned ucbits; /* keep track of the number of unconsumed bits in word */ | |
95 | + brword b; | |
96 | + int *val, *end; | |
97 | ||
98 | FLAC__ASSERT(0 != br); | |
99 | FLAC__ASSERT(0 != br->buffer); | |
100 | /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */ | |
101 | FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32); | |
102 | FLAC__ASSERT(parameter < 32); | |
103 | - /* the above two asserts also guarantee that the binary part never straddles more that 2 words, so we don't have to loop to read it */ | |
104 | - | |
105 | - if(nvals == 0) | |
106 | - return true; | |
107 | - | |
108 | - cbits = br->consumed_bits; | |
109 | - cwords = br->consumed_words; | |
110 | + /* 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 */ | |
111 | ||
112 | - while(1) { | |
113 | + val = vals; | |
114 | + end = vals + nvals; | |
115 | ||
116 | - /* read unary part */ | |
117 | - while(1) { | |
118 | - while(cwords < br->words) { /* if we've not consumed up to a partial tail word... */ | |
119 | - brword b = br->buffer[cwords] << cbits; | |
120 | - if(b) { | |
121 | -#if 0 /* slower, probably due to bad register allocation... */ && defined FLAC__CPU_IA32 && !defined FLAC__NO_ASM && FLAC__BITS_PER_WORD == 32 | |
122 | - __asm { | |
123 | - bsr eax, b | |
124 | - not eax | |
125 | - and eax, 31 | |
126 | - mov i, eax | |
127 | - } | |
128 | -#else | |
129 | - i = COUNT_ZERO_MSBS(b); | |
130 | -#endif | |
131 | - uval += i; | |
132 | - bits = parameter; | |
133 | - i++; | |
134 | - cbits += i; | |
135 | - if(cbits == FLAC__BITS_PER_WORD) { | |
136 | - crc16_update_word_(br, br->buffer[cwords]); | |
137 | - cwords++; | |
138 | - cbits = 0; | |
139 | - } | |
140 | - goto break1; | |
141 | - } | |
142 | - else { | |
143 | - uval += FLAC__BITS_PER_WORD - cbits; | |
144 | - crc16_update_word_(br, br->buffer[cwords]); | |
145 | - cwords++; | |
146 | - cbits = 0; | |
147 | - /* didn't find stop bit yet, have to keep going... */ | |
148 | - } | |
149 | - } | |
150 | - /* at this point we've eaten up all the whole words; have to try | |
151 | - * reading through any tail bytes before calling the read callback. | |
152 | - * this is a repeat of the above logic adjusted for the fact we | |
153 | - * don't have a whole word. note though if the client is feeding | |
154 | - * us data a byte at a time (unlikely), br->consumed_bits may not | |
155 | - * be zero. | |
156 | - */ | |
157 | - if(br->bytes) { | |
158 | - const unsigned end = br->bytes * 8; | |
159 | - brword b = (br->buffer[cwords] & (FLAC__WORD_ALL_ONES << (FLAC__BITS_PER_WORD-end))) << cbits; | |
160 | - if(b) { | |
161 | - i = COUNT_ZERO_MSBS(b); | |
162 | - uval += i; | |
163 | - bits = parameter; | |
164 | - i++; | |
165 | - cbits += i; | |
166 | - FLAC__ASSERT(cbits < FLAC__BITS_PER_WORD); | |
167 | - goto break1; | |
168 | - } | |
169 | - else { | |
170 | - uval += end - cbits; | |
171 | - cbits += end; | |
172 | - FLAC__ASSERT(cbits < FLAC__BITS_PER_WORD); | |
173 | - /* didn't find stop bit yet, have to keep going... */ | |
174 | - } | |
175 | - } | |
176 | - /* flush registers and read; bitreader_read_from_client_() does | |
177 | - * not touch br->consumed_bits at all but we still need to set | |
178 | - * it in case it fails and we have to return false. | |
179 | - */ | |
180 | - br->consumed_bits = cbits; | |
181 | - br->consumed_words = cwords; | |
182 | - if(!bitreader_read_from_client_(br)) | |
183 | + if(parameter == 0) { | |
184 | + while(val < end) { | |
185 | + /* read the unary MSBs and end bit */ | |
186 | + if(!FLAC__bitreader_read_unary_unsigned(br, &msbs)) | |
187 | return false; | |
188 | - cwords = br->consumed_words; | |
189 | - } | |
190 | -break1: | |
191 | - /* read binary part */ | |
192 | - FLAC__ASSERT(cwords <= br->words); | |
193 | - | |
194 | - if(bits) { | |
195 | - while((br->words-cwords)*FLAC__BITS_PER_WORD + br->bytes*8 - cbits < bits) { | |
196 | - /* flush registers and read; bitreader_read_from_client_() does | |
197 | - * not touch br->consumed_bits at all but we still need to set | |
198 | - * it in case it fails and we have to return false. | |
199 | - */ | |
200 | - br->consumed_bits = cbits; | |
201 | - br->consumed_words = cwords; | |
202 | - if(!bitreader_read_from_client_(br)) | |
203 | - return false; | |
204 | - cwords = br->consumed_words; | |
205 | - } | |
206 | - if(cwords < br->words) { /* if we've not consumed up to a partial tail word... */ | |
207 | - if(cbits) { | |
208 | - /* this also works when consumed_bits==0, it's just a little slower than necessary for that case */ | |
209 | - const unsigned n = FLAC__BITS_PER_WORD - cbits; | |
210 | - const brword word = br->buffer[cwords]; | |
211 | - if(bits < n) { | |
212 | - uval <<= bits; | |
213 | - uval |= (word & (FLAC__WORD_ALL_ONES >> cbits)) >> (n-bits); | |
214 | - cbits += bits; | |
215 | - goto break2; | |
216 | - } | |
217 | - uval <<= n; | |
218 | - uval |= word & (FLAC__WORD_ALL_ONES >> cbits); | |
219 | - bits -= n; | |
220 | - crc16_update_word_(br, word); | |
221 | - cwords++; | |
222 | - cbits = 0; | |
223 | - 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 */ | |
224 | - uval <<= bits; | |
225 | - uval |= (br->buffer[cwords] >> (FLAC__BITS_PER_WORD-bits)); | |
226 | - cbits = bits; | |
227 | - } | |
228 | - goto break2; | |
229 | - } | |
230 | - else { | |
231 | - FLAC__ASSERT(bits < FLAC__BITS_PER_WORD); | |
232 | - uval <<= bits; | |
233 | - uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-bits); | |
234 | - cbits = bits; | |
235 | - goto break2; | |
236 | - } | |
237 | - } | |
238 | - else { | |
239 | - /* in this case we're starting our read at a partial tail word; | |
240 | - * the reader has guaranteed that we have at least 'bits' bits | |
241 | - * available to read, which makes this case simpler. | |
242 | - */ | |
243 | - uval <<= bits; | |
244 | - if(cbits) { | |
245 | - /* this also works when consumed_bits==0, it's just a little slower than necessary for that case */ | |
246 | - FLAC__ASSERT(cbits + bits <= br->bytes*8); | |
247 | - uval |= (br->buffer[cwords] & (FLAC__WORD_ALL_ONES >> cbits)) >> (FLAC__BITS_PER_WORD-cbits-bits); | |
248 | - cbits += bits; | |
249 | - goto break2; | |
250 | - } | |
251 | - else { | |
252 | - uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-bits); | |
253 | - cbits += bits; | |
254 | - goto break2; | |
255 | - } | |
256 | - } | |
257 | - } | |
258 | -break2: | |
259 | - /* compose the value */ | |
260 | - *vals = (int)(uval >> 1 ^ -(int)(uval & 1)); | |
261 | ||
262 | - /* are we done? */ | |
263 | - --nvals; | |
264 | - if(nvals == 0) { | |
265 | - br->consumed_bits = cbits; | |
266 | - br->consumed_words = cwords; | |
267 | - return true; | |
268 | + *val++ = (int)(msbs >> 1) ^ -(int)(msbs & 1); | |
269 | } | |
270 | ||
271 | - uval = 0; | |
272 | - ++vals; | |
273 | - | |
274 | + return true; | |
275 | } | |
276 | -} | |
277 | -#else | |
278 | -{ | |
279 | - unsigned i; | |
280 | - unsigned uval = 0; | |
281 | ||
282 | - /* try and get br->consumed_words and br->consumed_bits into register; | |
283 | - * must remember to flush them back to *br before calling other | |
284 | - * bitwriter functions that use them, and before returning */ | |
285 | - register unsigned cwords; | |
286 | - register unsigned cbits; | |
287 | - unsigned ucbits; /* keep track of the number of unconsumed bits in the buffer */ | |
288 | + FLAC__ASSERT(parameter > 0); | |
289 | ||
290 | - FLAC__ASSERT(0 != br); | |
291 | - FLAC__ASSERT(0 != br->buffer); | |
292 | - /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */ | |
293 | - FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32); | |
294 | - FLAC__ASSERT(parameter < 32); | |
295 | - /* 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 */ | |
296 | + cwords = br->consumed_words; | |
297 | + words = br->words; | |
298 | ||
299 | - if(nvals == 0) | |
300 | - return true; | |
301 | + /* if we've not consumed up to a partial tail word... */ | |
302 | + if(cwords >= words) { | |
303 | + x = 0; | |
304 | + goto process_tail; | |
305 | + } | |
306 | + | |
307 | + ucbits = FLAC__BITS_PER_WORD - br->consumed_bits; | |
308 | + b = br->buffer[cwords] << br->consumed_bits; /* keep unconsumed bits aligned to left */ | |
309 | + | |
310 | + while(val < end) { | |
311 | + /* read the unary MSBs and end bit */ | |
312 | + x = y = COUNT_ZERO_MSBS(b); | |
313 | + if(x == FLAC__BITS_PER_WORD) { | |
314 | + x = ucbits; | |
315 | + do { | |
316 | + /* didn't find stop bit yet, have to keep going... */ | |
317 | + crc16_update_word_(br, br->buffer[cwords++]); | |
318 | + if (cwords >= words) | |
319 | + goto incomplete_msbs; | |
320 | + b = br->buffer[cwords]; | |
321 | + y = COUNT_ZERO_MSBS(b); | |
322 | + x += y; | |
323 | + } while(y == FLAC__BITS_PER_WORD); | |
324 | + } | |
325 | + b <<= y; | |
326 | + b <<= 1; /* account for stop bit */ | |
327 | + ucbits = (ucbits - x - 1) % FLAC__BITS_PER_WORD; | |
328 | + msbs = x; | |
329 | + | |
330 | + /* read the binary LSBs */ | |
331 | + x = b >> (FLAC__BITS_PER_WORD - parameter); | |
332 | + if(parameter <= ucbits) { | |
333 | + ucbits -= parameter; | |
334 | + b <<= parameter; | |
335 | + } else { | |
336 | + /* there are still bits left to read, they will all be in the next word */ | |
337 | + crc16_update_word_(br, br->buffer[cwords++]); | |
338 | + if (cwords >= words) | |
339 | + goto incomplete_lsbs; | |
340 | + b = br->buffer[cwords]; | |
341 | + ucbits += FLAC__BITS_PER_WORD - parameter; | |
342 | + x |= b >> ucbits; | |
343 | + b <<= FLAC__BITS_PER_WORD - ucbits; | |
344 | + } | |
345 | + lsbs = x; | |
346 | ||
347 | - cbits = br->consumed_bits; | |
348 | - cwords = br->consumed_words; | |
349 | - ucbits = (br->words-cwords)*FLAC__BITS_PER_WORD + br->bytes*8 - cbits; | |
350 | + /* compose the value */ | |
351 | + x = (msbs << parameter) | lsbs; | |
352 | + *val++ = (int)(x >> 1) ^ -(int)(x & 1); | |
353 | ||
354 | - while(1) { | |
355 | + continue; | |
356 | ||
357 | - /* read unary part */ | |
358 | - while(1) { | |
359 | - while(cwords < br->words) { /* if we've not consumed up to a partial tail word... */ | |
360 | - brword b = br->buffer[cwords] << cbits; | |
361 | - if(b) { | |
362 | -#if 0 /* is not discernably faster... */ && defined FLAC__CPU_IA32 && !defined FLAC__NO_ASM && FLAC__BITS_PER_WORD == 32 && defined __GNUC__ | |
363 | - asm volatile ( | |
364 | - "bsrl %1, %0;" | |
365 | - "notl %0;" | |
366 | - "andl $31, %0;" | |
367 | - : "=r"(i) | |
368 | - : "r"(b) | |
369 | - ); | |
370 | -#else | |
371 | - i = COUNT_ZERO_MSBS(b); | |
372 | -#endif | |
373 | - uval += i; | |
374 | - cbits += i; | |
375 | - cbits++; /* skip over stop bit */ | |
376 | - if(cbits >= FLAC__BITS_PER_WORD) { /* faster way of testing if(cbits == FLAC__BITS_PER_WORD) */ | |
377 | - crc16_update_word_(br, br->buffer[cwords]); | |
378 | - cwords++; | |
379 | - cbits = 0; | |
380 | - } | |
381 | - goto break1; | |
382 | - } | |
383 | - else { | |
384 | - uval += FLAC__BITS_PER_WORD - cbits; | |
385 | - crc16_update_word_(br, br->buffer[cwords]); | |
386 | - cwords++; | |
387 | - cbits = 0; | |
388 | - /* didn't find stop bit yet, have to keep going... */ | |
389 | - } | |
390 | - } | |
391 | - /* at this point we've eaten up all the whole words; have to try | |
392 | - * reading through any tail bytes before calling the read callback. | |
393 | - * this is a repeat of the above logic adjusted for the fact we | |
394 | - * don't have a whole word. note though if the client is feeding | |
395 | - * us data a byte at a time (unlikely), br->consumed_bits may not | |
396 | - * be zero. | |
397 | - */ | |
398 | - if(br->bytes) { | |
399 | - const unsigned end = br->bytes * 8; | |
400 | - brword b = (br->buffer[cwords] & ~(FLAC__WORD_ALL_ONES >> end)) << cbits; | |
401 | - if(b) { | |
402 | - i = COUNT_ZERO_MSBS(b); | |
403 | - uval += i; | |
404 | - cbits += i; | |
405 | - cbits++; /* skip over stop bit */ | |
406 | - FLAC__ASSERT(cbits < FLAC__BITS_PER_WORD); | |
407 | - goto break1; | |
408 | - } | |
409 | - else { | |
410 | - uval += end - cbits; | |
411 | - cbits += end; | |
412 | - FLAC__ASSERT(cbits < FLAC__BITS_PER_WORD); | |
413 | - /* didn't find stop bit yet, have to keep going... */ | |
414 | - } | |
415 | + /* at this point we've eaten up all the whole words */ | |
416 | +process_tail: | |
417 | + do { | |
418 | + if(0) { | |
419 | +incomplete_msbs: | |
420 | + br->consumed_bits = 0; | |
421 | + br->consumed_words = cwords; | |
422 | } | |
423 | - /* flush registers and read; bitreader_read_from_client_() does | |
424 | - * not touch br->consumed_bits at all but we still need to set | |
425 | - * it in case it fails and we have to return false. | |
426 | - */ | |
427 | - br->consumed_bits = cbits; | |
428 | - br->consumed_words = cwords; | |
429 | - if(!bitreader_read_from_client_(br)) | |
430 | + | |
431 | + /* read the unary MSBs and end bit */ | |
432 | + if(!FLAC__bitreader_read_unary_unsigned(br, &msbs)) | |
433 | return false; | |
434 | - cwords = br->consumed_words; | |
435 | - ucbits = (br->words-cwords)*FLAC__BITS_PER_WORD + br->bytes*8 - cbits + uval; | |
436 | - /* + uval to offset our count by the # of unary bits already | |
437 | - * consumed before the read, because we will add these back | |
438 | - * in all at once at break1 | |
439 | - */ | |
440 | - } | |
441 | -break1: | |
442 | - ucbits -= uval; | |
443 | - ucbits--; /* account for stop bit */ | |
444 | - | |
445 | - /* read binary part */ | |
446 | - FLAC__ASSERT(cwords <= br->words); | |
447 | - | |
448 | - if(parameter) { | |
449 | - while(ucbits < parameter) { | |
450 | - /* flush registers and read; bitreader_read_from_client_() does | |
451 | - * not touch br->consumed_bits at all but we still need to set | |
452 | - * it in case it fails and we have to return false. | |
453 | - */ | |
454 | - br->consumed_bits = cbits; | |
455 | + msbs += x; | |
456 | + x = ucbits = 0; | |
457 | + | |
458 | + if(0) { | |
459 | +incomplete_lsbs: | |
460 | + br->consumed_bits = 0; | |
461 | br->consumed_words = cwords; | |
462 | - if(!bitreader_read_from_client_(br)) | |
463 | - return false; | |
464 | - cwords = br->consumed_words; | |
465 | - ucbits = (br->words-cwords)*FLAC__BITS_PER_WORD + br->bytes*8 - cbits; | |
466 | - } | |
467 | - if(cwords < br->words) { /* if we've not consumed up to a partial tail word... */ | |
468 | - if(cbits) { | |
469 | - /* this also works when consumed_bits==0, it's just slower than necessary for that case */ | |
470 | - const unsigned n = FLAC__BITS_PER_WORD - cbits; | |
471 | - const brword word = br->buffer[cwords]; | |
472 | - if(parameter < n) { | |
473 | - uval <<= parameter; | |
474 | - uval |= (word & (FLAC__WORD_ALL_ONES >> cbits)) >> (n-parameter); | |
475 | - cbits += parameter; | |
476 | - } | |
477 | - else { | |
478 | - uval <<= n; | |
479 | - uval |= word & (FLAC__WORD_ALL_ONES >> cbits); | |
480 | - crc16_update_word_(br, word); | |
481 | - cwords++; | |
482 | - cbits = parameter - n; | |
483 | - if(cbits) { /* parameter > n, i.e. if there are still bits left to read, there have to be less than 32 so they will all be in the next word */ | |
484 | - uval <<= cbits; | |
485 | - uval |= (br->buffer[cwords] >> (FLAC__BITS_PER_WORD-cbits)); | |
486 | - } | |
487 | - } | |
488 | - } | |
489 | - else { | |
490 | - cbits = parameter; | |
491 | - uval <<= parameter; | |
492 | - uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-cbits); | |
493 | - } | |
494 | } | |
495 | - else { | |
496 | - /* in this case we're starting our read at a partial tail word; | |
497 | - * the reader has guaranteed that we have at least 'parameter' | |
498 | - * bits available to read, which makes this case simpler. | |
499 | - */ | |
500 | - uval <<= parameter; | |
501 | - if(cbits) { | |
502 | - /* this also works when consumed_bits==0, it's just a little slower than necessary for that case */ | |
503 | - FLAC__ASSERT(cbits + parameter <= br->bytes*8); | |
504 | - uval |= (br->buffer[cwords] & (FLAC__WORD_ALL_ONES >> cbits)) >> (FLAC__BITS_PER_WORD-cbits-parameter); | |
505 | - cbits += parameter; | |
506 | - } | |
507 | - else { | |
508 | - cbits = parameter; | |
509 | - uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-cbits); | |
510 | - } | |
511 | - } | |
512 | - } | |
513 | ||
514 | - ucbits -= parameter; | |
515 | - | |
516 | - /* compose the value */ | |
517 | - *vals = (int)(uval >> 1 ^ -(int)(uval & 1)); | |
518 | + /* read the binary LSBs */ | |
519 | + if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, parameter - ucbits)) | |
520 | + return false; | |
521 | + lsbs = x | lsbs; | |
522 | ||
523 | - /* are we done? */ | |
524 | - --nvals; | |
525 | - if(nvals == 0) { | |
526 | - br->consumed_bits = cbits; | |
527 | - br->consumed_words = cwords; | |
528 | - return true; | |
529 | - } | |
530 | + /* compose the value */ | |
531 | + x = (msbs << parameter) | lsbs; | |
532 | + *val++ = (int)(x >> 1) ^ -(int)(x & 1); | |
533 | + x = 0; | |
534 | ||
535 | - uval = 0; | |
536 | - ++vals; | |
537 | + cwords = br->consumed_words; | |
538 | + words = br->words; | |
539 | + ucbits = FLAC__BITS_PER_WORD - br->consumed_bits; | |
540 | + b = br->buffer[cwords] << br->consumed_bits; | |
541 | + } while(cwords >= words && val < end); | |
542 | + } | |
543 | ||
544 | + if(ucbits == 0 && cwords < words) { | |
545 | + /* don't leave the head word with no unconsumed bits */ | |
546 | + crc16_update_word_(br, br->buffer[cwords++]); | |
547 | + ucbits = FLAC__BITS_PER_WORD; | |
548 | } | |
549 | + | |
550 | + br->consumed_bits = FLAC__BITS_PER_WORD - ucbits; | |
551 | + br->consumed_words = cwords; | |
552 | + | |
553 | + return true; | |
554 | } | |
555 | -#endif | |
556 | ||
557 | #if 0 /* UNUSED */ | |
558 | FLAC__bool FLAC__bitreader_read_golomb_signed(FLAC__BitReader *br, int *val, unsigned parameter) |