consistent include usage
[libav.git] / libavcodec / common.c
CommitLineData
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1/*
2 * Common bit i/o utils
3 * Copyright (c) 2000, 2001 Gerard Lantau.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27a3e2c5 18 *
17592475 19 * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
de6d9b64 20 */
de6d9b64 21#include "common.h"
a9b3f630 22
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23void init_put_bits(PutBitContext *s,
24 UINT8 *buffer, int buffer_size,
25 void *opaque,
26 void (*write_data)(void *, UINT8 *, int))
27{
28 s->buf = buffer;
de6d9b64 29 s->buf_end = s->buf + buffer_size;
de6d9b64 30 s->data_out_size = 0;
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31 if(write_data!=NULL)
32 {
33 fprintf(stderr, "write Data callback is not supported\n");
34 }
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35#ifdef ALT_BITSTREAM_WRITER
36 s->index=0;
37 ((uint32_t*)(s->buf))[0]=0;
38// memset(buffer, 0, buffer_size);
17592475 39#else
17592475 40 s->buf_ptr = s->buf;
d8cf5aea 41 s->bit_left=32;
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42 s->bit_buf=0;
43#endif
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44}
45
de6d9b64 46/* return the number of bits output */
1a565432 47INT64 get_bit_count(PutBitContext *s)
de6d9b64 48{
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49#ifdef ALT_BITSTREAM_WRITER
50 return s->data_out_size * 8 + s->index;
51#else
d8cf5aea 52 return (s->buf_ptr - s->buf + s->data_out_size) * 8 + 32 - (INT64)s->bit_left;
17592475 53#endif
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54}
55
56void align_put_bits(PutBitContext *s)
57{
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58#ifdef ALT_BITSTREAM_WRITER
59 put_bits(s,( - s->index) & 7,0);
60#else
d8cf5aea 61 put_bits(s,s->bit_left & 7,0);
17592475 62#endif
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63}
64
65/* pad the end of the output stream with zeros */
66void flush_put_bits(PutBitContext *s)
67{
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68#ifdef ALT_BITSTREAM_WRITER
69 align_put_bits(s);
70#else
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71 s->bit_buf<<= s->bit_left;
72 while (s->bit_left < 32) {
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73 /* XXX: should test end of buffer */
74 *s->buf_ptr++=s->bit_buf >> 24;
75 s->bit_buf<<=8;
d8cf5aea 76 s->bit_left+=8;
de6d9b64 77 }
d8cf5aea 78 s->bit_left=32;
de6d9b64 79 s->bit_buf=0;
17592475 80#endif
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81}
82
de6d9b64 83/* pad the end of the output stream with zeros */
17592475 84#ifndef ALT_BITSTREAM_WRITER
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85void jflush_put_bits(PutBitContext *s)
86{
87 unsigned int b;
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88 s->bit_buf<<= s->bit_left;
89 s->bit_buf |= ~1U >> (32 - s->bit_left); /* set all the unused bits to one */
de6d9b64 90
d8cf5aea 91 while (s->bit_left < 32) {
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92 b = s->bit_buf >> 24;
93 *s->buf_ptr++ = b;
94 if (b == 0xff)
95 *s->buf_ptr++ = 0;
96 s->bit_buf<<=8;
d8cf5aea 97 s->bit_left+=8;
de6d9b64 98 }
d8cf5aea 99 s->bit_left=32;
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100 s->bit_buf=0;
101}
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102#else
103void jflush_put_bits(PutBitContext *s)
104{
105 int num= ( - s->index) & 7;
106 jput_bits(s, num,0xFF>>(8-num));
107}
108#endif
de6d9b64 109
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110void put_string(PutBitContext * pbc, char *s)
111{
112 while(*s){
113 put_bits(pbc, 8, *s);
114 s++;
115 }
116 put_bits(pbc, 8, 0);
117}
118
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119/* bit input functions */
120
121void init_get_bits(GetBitContext *s,
122 UINT8 *buffer, int buffer_size)
123{
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124#ifdef ALT_BITSTREAM_READER
125 s->index=0;
126 s->buffer= buffer;
127#else
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128 s->buf = buffer;
129 s->buf_ptr = buffer;
130 s->buf_end = buffer + buffer_size;
131 s->bit_cnt = 0;
132 s->bit_buf = 0;
133 while (s->buf_ptr < s->buf_end &&
134 s->bit_cnt < 32) {
135 s->bit_buf |= (*s->buf_ptr++ << (24 - s->bit_cnt));
136 s->bit_cnt += 8;
137 }
27a3e2c5 138#endif
45870f57 139 s->size= buffer_size;
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140}
141
27a3e2c5 142#ifndef ALT_BITSTREAM_READER
de6d9b64 143/* n must be >= 1 and <= 32 */
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144/* also true: n > s->bit_cnt */
145unsigned int get_bits_long(GetBitContext *s, int n)
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146{
147 unsigned int val;
148 int bit_cnt;
149 unsigned int bit_buf;
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150
151#ifdef STATS
152 st_bit_counts[st_current_index] += n;
153#endif
154
de6d9b64 155 bit_buf = s->bit_buf;
2931ecb9 156 bit_cnt = s->bit_cnt - n;
de6d9b64 157
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158// if (bit_cnt >= 0) {
159// val = bit_buf >> (32 - n);
160// bit_buf <<= n;
161// } else
162 {
163 UINT8 *buf_ptr;
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164 val = bit_buf >> (32 - n);
165 buf_ptr = s->buf_ptr;
166 buf_ptr += 4;
167 /* handle common case: we can read everything */
168 if (buf_ptr <= s->buf_end) {
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169#if ARCH_X86
170 bit_buf = bswap_32(*((unsigned long*)(&buf_ptr[-4])));
171#else
172 bit_buf = (buf_ptr[-4] << 24) |
173 (buf_ptr[-3] << 16) |
de6d9b64 174 (buf_ptr[-2] << 8) |
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175 (buf_ptr[-1]);
176#endif
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177 } else {
178 buf_ptr -= 4;
179 bit_buf = 0;
180 if (buf_ptr < s->buf_end)
181 bit_buf |= *buf_ptr++ << 24;
182 if (buf_ptr < s->buf_end)
183 bit_buf |= *buf_ptr++ << 16;
184 if (buf_ptr < s->buf_end)
185 bit_buf |= *buf_ptr++ << 8;
186 if (buf_ptr < s->buf_end)
187 bit_buf |= *buf_ptr++;
188 }
189 s->buf_ptr = buf_ptr;
190 val |= bit_buf >> (32 + bit_cnt);
191 bit_buf <<= - bit_cnt;
192 bit_cnt += 32;
193 }
194 s->bit_buf = bit_buf;
195 s->bit_cnt = bit_cnt;
196 return val;
197}
27a3e2c5 198#endif
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199
200void align_get_bits(GetBitContext *s)
201{
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202#ifdef ALT_BITSTREAM_READER
203 s->index= (s->index + 7) & (~7);
204#else
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205 int n;
206 n = s->bit_cnt & 7;
207 if (n > 0) {
208 get_bits(s, n);
209 }
27a3e2c5 210#endif
de6d9b64 211}
27a3e2c5 212
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213int check_marker(GetBitContext *s, char *msg)
214{
215 int bit= get_bits1(s);
216 if(!bit) printf("Marker bit missing %s\n", msg);
217
218 return bit;
219}
220
27a3e2c5 221#ifndef ALT_BITSTREAM_READER
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222/* This function is identical to get_bits_long(), the */
223/* only diference is that it doesn't touch the buffer */
224/* it is usefull to see the buffer. */
225
226unsigned int show_bits_long(GetBitContext *s, int n)
227{
228 unsigned int val;
229 int bit_cnt;
230 unsigned int bit_buf;
231 UINT8 *buf_ptr;
232
233 bit_buf = s->bit_buf;
234 bit_cnt = s->bit_cnt - n;
235
236 val = bit_buf >> (32 - n);
237 buf_ptr = s->buf_ptr;
238 buf_ptr += 4;
239
240 /* handle common case: we can read everything */
241 if (buf_ptr <= s->buf_end) {
242#ifdef ARCH_X86
243 bit_buf = bswap_32(*((unsigned long*)(&buf_ptr[-4])));
244#else
245 bit_buf = (buf_ptr[-4] << 24) |
246 (buf_ptr[-3] << 16) |
247 (buf_ptr[-2] << 8) |
248 (buf_ptr[-1]);
249#endif
250 } else {
251 buf_ptr -= 4;
252 bit_buf = 0;
253 if (buf_ptr < s->buf_end)
254 bit_buf |= *buf_ptr++ << 24;
255 if (buf_ptr < s->buf_end)
256 bit_buf |= *buf_ptr++ << 16;
257 if (buf_ptr < s->buf_end)
258 bit_buf |= *buf_ptr++ << 8;
259 if (buf_ptr < s->buf_end)
260 bit_buf |= *buf_ptr++;
261 }
262 val |= bit_buf >> (32 + bit_cnt);
263 bit_buf <<= - bit_cnt;
264 bit_cnt += 32;
265
266 return val;
267}
27a3e2c5 268#endif
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269
270/* VLC decoding */
271
272//#define DEBUG_VLC
273
274#define GET_DATA(v, table, i, wrap, size) \
275{\
276 UINT8 *ptr = (UINT8 *)table + i * wrap;\
277 switch(size) {\
278 case 1:\
279 v = *(UINT8 *)ptr;\
280 break;\
281 case 2:\
282 v = *(UINT16 *)ptr;\
283 break;\
284 default:\
285 v = *(UINT32 *)ptr;\
286 break;\
287 }\
288}
289
290
291static int alloc_table(VLC *vlc, int size)
292{
293 int index;
294 index = vlc->table_size;
295 vlc->table_size += size;
296 if (vlc->table_size > vlc->table_allocated) {
297 vlc->table_allocated += (1 << vlc->bits);
298 vlc->table_bits = realloc(vlc->table_bits,
299 sizeof(INT8) * vlc->table_allocated);
300 vlc->table_codes = realloc(vlc->table_codes,
301 sizeof(INT16) * vlc->table_allocated);
302 if (!vlc->table_bits ||
303 !vlc->table_codes)
304 return -1;
305 }
306 return index;
307}
308
309static int build_table(VLC *vlc, int table_nb_bits,
310 int nb_codes,
311 const void *bits, int bits_wrap, int bits_size,
312 const void *codes, int codes_wrap, int codes_size,
313 UINT32 code_prefix, int n_prefix)
314{
315 int i, j, k, n, table_size, table_index, nb, n1, index;
316 UINT32 code;
317 INT8 *table_bits;
318 INT16 *table_codes;
319
320 table_size = 1 << table_nb_bits;
321 table_index = alloc_table(vlc, table_size);
322#ifdef DEBUG_VLC
323 printf("new table index=%d size=%d code_prefix=%x n=%d\n",
324 table_index, table_size, code_prefix, n_prefix);
325#endif
326 if (table_index < 0)
327 return -1;
328 table_bits = &vlc->table_bits[table_index];
329 table_codes = &vlc->table_codes[table_index];
330
331 for(i=0;i<table_size;i++) {
332 table_bits[i] = 0;
333 table_codes[i] = -1;
334 }
335
336 /* first pass: map codes and compute auxillary table sizes */
337 for(i=0;i<nb_codes;i++) {
338 GET_DATA(n, bits, i, bits_wrap, bits_size);
339 GET_DATA(code, codes, i, codes_wrap, codes_size);
340 /* we accept tables with holes */
341 if (n <= 0)
342 continue;
343#if defined(DEBUG_VLC) && 0
344 printf("i=%d n=%d code=0x%x\n", i, n, code);
345#endif
346 /* if code matches the prefix, it is in the table */
347 n -= n_prefix;
348 if (n > 0 && (code >> n) == code_prefix) {
349 if (n <= table_nb_bits) {
350 /* no need to add another table */
351 j = (code << (table_nb_bits - n)) & (table_size - 1);
352 nb = 1 << (table_nb_bits - n);
353 for(k=0;k<nb;k++) {
354#ifdef DEBUG_VLC
355 printf("%4x: code=%d n=%d\n",
356 j, i, n);
357#endif
358 if (table_bits[j] != 0) {
359 fprintf(stderr, "incorrect codes\n");
360 exit(1);
361 }
362 table_bits[j] = n;
363 table_codes[j] = i;
364 j++;
365 }
366 } else {
367 n -= table_nb_bits;
368 j = (code >> n) & ((1 << table_nb_bits) - 1);
369#ifdef DEBUG_VLC
370 printf("%4x: n=%d (subtable)\n",
371 j, n);
372#endif
373 /* compute table size */
374 n1 = -table_bits[j];
375 if (n > n1)
376 n1 = n;
377 table_bits[j] = -n1;
378 }
379 }
380 }
381
382 /* second pass : fill auxillary tables recursively */
383 for(i=0;i<table_size;i++) {
384 n = table_bits[i];
385 if (n < 0) {
386 n = -n;
387 if (n > table_nb_bits) {
388 n = table_nb_bits;
389 table_bits[i] = -n;
390 }
391 index = build_table(vlc, n, nb_codes,
392 bits, bits_wrap, bits_size,
393 codes, codes_wrap, codes_size,
394 (code_prefix << table_nb_bits) | i,
395 n_prefix + table_nb_bits);
396 if (index < 0)
397 return -1;
398 /* note: realloc has been done, so reload tables */
399 table_bits = &vlc->table_bits[table_index];
400 table_codes = &vlc->table_codes[table_index];
401 table_codes[i] = index;
402 }
403 }
404 return table_index;
405}
406
407
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408/* Build VLC decoding tables suitable for use with get_vlc().
409
410 'nb_bits' set thee decoding table size (2^nb_bits) entries. The
411 bigger it is, the faster is the decoding. But it should not be too
412 big to save memory and L1 cache. '9' is a good compromise.
413
414 'nb_codes' : number of vlcs codes
415
416 'bits' : table which gives the size (in bits) of each vlc code.
417
418 'codes' : table which gives the bit pattern of of each vlc code.
419
420 'xxx_wrap' : give the number of bytes between each entry of the
421 'bits' or 'codes' tables.
422
423 'xxx_size' : gives the number of bytes of each entry of the 'bits'
424 or 'codes' tables.
425
426 'wrap' and 'size' allows to use any memory configuration and types
427 (byte/word/long) to store the 'bits' and 'codes' tables.
428*/
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429int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
430 const void *bits, int bits_wrap, int bits_size,
431 const void *codes, int codes_wrap, int codes_size)
432{
433 vlc->bits = nb_bits;
434 vlc->table_bits = NULL;
435 vlc->table_codes = NULL;
436 vlc->table_allocated = 0;
437 vlc->table_size = 0;
438#ifdef DEBUG_VLC
439 printf("build table nb_codes=%d\n", nb_codes);
440#endif
441
442 if (build_table(vlc, nb_bits, nb_codes,
443 bits, bits_wrap, bits_size,
444 codes, codes_wrap, codes_size,
445 0, 0) < 0) {
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446 av_free(vlc->table_bits);
447 av_free(vlc->table_codes);
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448 return -1;
449 }
450 return 0;
451}
452
453
454void free_vlc(VLC *vlc)
455{
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456 av_free(vlc->table_bits);
457 av_free(vlc->table_codes);
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458}
459
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460int ff_gcd(int a, int b){
461 if(b) return ff_gcd(b, a%b);
462 else return a;
463}