Remove '\p', '\c' and '\e' doxygen markup from doxy, as it should
[libav.git] / libavcodec / put_bits.h
1 /*
2 * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 /**
22 * @file libavcodec/put_bits.h
23 * bitstream writer API
24 */
25
26 #ifndef AVCODEC_PUT_BITS_H
27 #define AVCODEC_PUT_BITS_H
28
29 #include <stdint.h>
30 #include <stdlib.h>
31 #include <assert.h>
32 #include "libavutil/bswap.h"
33 #include "libavutil/common.h"
34 #include "libavutil/intreadwrite.h"
35 #include "libavutil/log.h"
36 #include "mathops.h"
37
38 //#define ALT_BITSTREAM_WRITER
39 //#define ALIGNED_BITSTREAM_WRITER
40
41 /* buf and buf_end must be present and used by every alternative writer. */
42 typedef struct PutBitContext {
43 #ifdef ALT_BITSTREAM_WRITER
44 uint8_t *buf, *buf_end;
45 int index;
46 #else
47 uint32_t bit_buf;
48 int bit_left;
49 uint8_t *buf, *buf_ptr, *buf_end;
50 #endif
51 int size_in_bits;
52 } PutBitContext;
53
54 /**
55 * Initializes the PutBitContext s.
56 *
57 * @param buffer the buffer where to put bits
58 * @param buffer_size the size in bytes of buffer
59 */
60 static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
61 {
62 if(buffer_size < 0) {
63 buffer_size = 0;
64 buffer = NULL;
65 }
66
67 s->size_in_bits= 8*buffer_size;
68 s->buf = buffer;
69 s->buf_end = s->buf + buffer_size;
70 #ifdef ALT_BITSTREAM_WRITER
71 s->index=0;
72 ((uint32_t*)(s->buf))[0]=0;
73 // memset(buffer, 0, buffer_size);
74 #else
75 s->buf_ptr = s->buf;
76 s->bit_left=32;
77 s->bit_buf=0;
78 #endif
79 }
80
81 /**
82 * Returns the total number of bits written to the bitstream.
83 */
84 static inline int put_bits_count(PutBitContext *s)
85 {
86 #ifdef ALT_BITSTREAM_WRITER
87 return s->index;
88 #else
89 return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
90 #endif
91 }
92
93 /**
94 * Pads the end of the output stream with zeros.
95 */
96 static inline void flush_put_bits(PutBitContext *s)
97 {
98 #ifdef ALT_BITSTREAM_WRITER
99 align_put_bits(s);
100 #else
101 #ifndef BITSTREAM_WRITER_LE
102 s->bit_buf<<= s->bit_left;
103 #endif
104 while (s->bit_left < 32) {
105 /* XXX: should test end of buffer */
106 #ifdef BITSTREAM_WRITER_LE
107 *s->buf_ptr++=s->bit_buf;
108 s->bit_buf>>=8;
109 #else
110 *s->buf_ptr++=s->bit_buf >> 24;
111 s->bit_buf<<=8;
112 #endif
113 s->bit_left+=8;
114 }
115 s->bit_left=32;
116 s->bit_buf=0;
117 #endif
118 }
119
120 /**
121 * Pads the bitstream with zeros up to the next byte boundary.
122 */
123 void align_put_bits(PutBitContext *s);
124
125 /**
126 * Puts the string s in the bitstream.
127 *
128 * @param terminate_string 0-terminates the written string if value is 1
129 */
130 void ff_put_string(PutBitContext * pbc, const char *s, int terminate_string);
131
132 /**
133 * Copies the content of src to the bitstream.
134 *
135 * @param length the number of bits of src to copy
136 */
137 void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length);
138
139 static inline void put_bits(PutBitContext *s, int n, unsigned int value)
140 #ifndef ALT_BITSTREAM_WRITER
141 {
142 unsigned int bit_buf;
143 int bit_left;
144
145 // printf("put_bits=%d %x\n", n, value);
146 assert(n == 32 || value < (1U << n));
147
148 bit_buf = s->bit_buf;
149 bit_left = s->bit_left;
150
151 // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
152 /* XXX: optimize */
153 #ifdef BITSTREAM_WRITER_LE
154 bit_buf |= value << (32 - bit_left);
155 if (n >= bit_left) {
156 #if !HAVE_FAST_UNALIGNED
157 if (3 & (intptr_t) s->buf_ptr) {
158 AV_WL32(s->buf_ptr, bit_buf);
159 } else
160 #endif
161 *(uint32_t *)s->buf_ptr = le2me_32(bit_buf);
162 s->buf_ptr+=4;
163 bit_buf = (bit_left==32)?0:value >> bit_left;
164 bit_left+=32;
165 }
166 bit_left-=n;
167 #else
168 if (n < bit_left) {
169 bit_buf = (bit_buf<<n) | value;
170 bit_left-=n;
171 } else {
172 bit_buf<<=bit_left;
173 bit_buf |= value >> (n - bit_left);
174 #if !HAVE_FAST_UNALIGNED
175 if (3 & (intptr_t) s->buf_ptr) {
176 AV_WB32(s->buf_ptr, bit_buf);
177 } else
178 #endif
179 *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
180 //printf("bitbuf = %08x\n", bit_buf);
181 s->buf_ptr+=4;
182 bit_left+=32 - n;
183 bit_buf = value;
184 }
185 #endif
186
187 s->bit_buf = bit_buf;
188 s->bit_left = bit_left;
189 }
190 #else /* ALT_BITSTREAM_WRITER defined */
191 {
192 # ifdef ALIGNED_BITSTREAM_WRITER
193 # if ARCH_X86
194 __asm__ volatile(
195 "movl %0, %%ecx \n\t"
196 "xorl %%eax, %%eax \n\t"
197 "shrdl %%cl, %1, %%eax \n\t"
198 "shrl %%cl, %1 \n\t"
199 "movl %0, %%ecx \n\t"
200 "shrl $3, %%ecx \n\t"
201 "andl $0xFFFFFFFC, %%ecx \n\t"
202 "bswapl %1 \n\t"
203 "orl %1, (%2, %%ecx) \n\t"
204 "bswapl %%eax \n\t"
205 "addl %3, %0 \n\t"
206 "movl %%eax, 4(%2, %%ecx) \n\t"
207 : "=&r" (s->index), "=&r" (value)
208 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
209 : "%eax", "%ecx"
210 );
211 # else
212 int index= s->index;
213 uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
214
215 value<<= 32-n;
216
217 ptr[0] |= be2me_32(value>>(index&31));
218 ptr[1] = be2me_32(value<<(32-(index&31)));
219 //if(n>24) printf("%d %d\n", n, value);
220 index+= n;
221 s->index= index;
222 # endif
223 # else //ALIGNED_BITSTREAM_WRITER
224 # if ARCH_X86
225 __asm__ volatile(
226 "movl $7, %%ecx \n\t"
227 "andl %0, %%ecx \n\t"
228 "addl %3, %%ecx \n\t"
229 "negl %%ecx \n\t"
230 "shll %%cl, %1 \n\t"
231 "bswapl %1 \n\t"
232 "movl %0, %%ecx \n\t"
233 "shrl $3, %%ecx \n\t"
234 "orl %1, (%%ecx, %2) \n\t"
235 "addl %3, %0 \n\t"
236 "movl $0, 4(%%ecx, %2) \n\t"
237 : "=&r" (s->index), "=&r" (value)
238 : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
239 : "%ecx"
240 );
241 # else
242 int index= s->index;
243 uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
244
245 ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
246 ptr[1] = 0;
247 //if(n>24) printf("%d %d\n", n, value);
248 index+= n;
249 s->index= index;
250 # endif
251 # endif //!ALIGNED_BITSTREAM_WRITER
252 }
253 #endif
254
255 static inline void put_sbits(PutBitContext *pb, int bits, int32_t val)
256 {
257 assert(bits >= 0 && bits <= 31);
258
259 put_bits(pb, bits, val & ((1<<bits)-1));
260 }
261
262 /**
263 * Returns the pointer to the byte where the bitstream writer will put
264 * the next bit.
265 */
266 static inline uint8_t* put_bits_ptr(PutBitContext *s)
267 {
268 #ifdef ALT_BITSTREAM_WRITER
269 return s->buf + (s->index>>3);
270 #else
271 return s->buf_ptr;
272 #endif
273 }
274
275 /**
276 * Skips the given number of bytes.
277 * PutBitContext must be flushed & aligned to a byte boundary before calling this.
278 */
279 static inline void skip_put_bytes(PutBitContext *s, int n){
280 assert((put_bits_count(s)&7)==0);
281 #ifdef ALT_BITSTREAM_WRITER
282 FIXME may need some cleaning of the buffer
283 s->index += n<<3;
284 #else
285 assert(s->bit_left==32);
286 s->buf_ptr += n;
287 #endif
288 }
289
290 /**
291 * Skips the given number of bits.
292 * Must only be used if the actual values in the bitstream do not matter.
293 * If n is 0 the behavior is undefined.
294 */
295 static inline void skip_put_bits(PutBitContext *s, int n){
296 #ifdef ALT_BITSTREAM_WRITER
297 s->index += n;
298 #else
299 s->bit_left -= n;
300 s->buf_ptr-= 4*(s->bit_left>>5);
301 s->bit_left &= 31;
302 #endif
303 }
304
305 /**
306 * Changes the end of the buffer.
307 *
308 * @param size the new size in bytes of the buffer where to put bits
309 */
310 static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
311 s->buf_end= s->buf + size;
312 }
313
314 #endif /* AVCODEC_PUT_BITS_H */