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ffmpeg / libavcodec / bitstream.h @ 017c0811

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1
/*
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 * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file libavcodec/bitstream.h
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 * bitstream api header.
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 */
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#ifndef AVCODEC_BITSTREAM_H
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#define AVCODEC_BITSTREAM_H
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#include <stdint.h>
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#include <stdlib.h>
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#include <assert.h>
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#include "libavutil/bswap.h"
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#include "libavutil/common.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/log.h"
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#include "mathops.h"
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#if defined(ALT_BITSTREAM_READER_LE) && !defined(ALT_BITSTREAM_READER)
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#   define ALT_BITSTREAM_READER
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#endif
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//#define ALT_BITSTREAM_WRITER
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//#define ALIGNED_BITSTREAM_WRITER
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#if !defined(LIBMPEG2_BITSTREAM_READER) && !defined(A32_BITSTREAM_READER) && !defined(ALT_BITSTREAM_READER)
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#   if ARCH_ARM
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#       define A32_BITSTREAM_READER
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#   else
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#       define ALT_BITSTREAM_READER
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//#define LIBMPEG2_BITSTREAM_READER
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//#define A32_BITSTREAM_READER
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#   endif
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#endif
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extern const uint8_t ff_reverse[256];
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#if ARCH_X86
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// avoid +32 for shift optimization (gcc should do that ...)
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static inline  int32_t NEG_SSR32( int32_t a, int8_t s){
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    __asm__ ("sarl %1, %0\n\t"
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         : "+r" (a)
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         : "ic" ((uint8_t)(-s))
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    );
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    return a;
64
}
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static inline uint32_t NEG_USR32(uint32_t a, int8_t s){
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    __asm__ ("shrl %1, %0\n\t"
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         : "+r" (a)
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         : "ic" ((uint8_t)(-s))
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    );
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    return a;
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}
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#else
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#    define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s)))
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#    define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
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#endif
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/* bit output */
78

    
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/* buf and buf_end must be present and used by every alternative writer. */
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typedef struct PutBitContext {
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#ifdef ALT_BITSTREAM_WRITER
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    uint8_t *buf, *buf_end;
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    int index;
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#else
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    uint32_t bit_buf;
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    int bit_left;
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    uint8_t *buf, *buf_ptr, *buf_end;
88
#endif
89
    int size_in_bits;
90
} PutBitContext;
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static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
93
{
94
    if(buffer_size < 0) {
95
        buffer_size = 0;
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        buffer = NULL;
97
    }
98

    
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    s->size_in_bits= 8*buffer_size;
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    s->buf = buffer;
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    s->buf_end = s->buf + buffer_size;
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#ifdef ALT_BITSTREAM_WRITER
103
    s->index=0;
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    ((uint32_t*)(s->buf))[0]=0;
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//    memset(buffer, 0, buffer_size);
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#else
107
    s->buf_ptr = s->buf;
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    s->bit_left=32;
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    s->bit_buf=0;
110
#endif
111
}
112

    
113
/* return the number of bits output */
114
static inline int put_bits_count(PutBitContext *s)
115
{
116
#ifdef ALT_BITSTREAM_WRITER
117
    return s->index;
118
#else
119
    return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
120
#endif
121
}
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123
/* pad the end of the output stream with zeros */
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static inline void flush_put_bits(PutBitContext *s)
125
{
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#ifdef ALT_BITSTREAM_WRITER
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    align_put_bits(s);
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#else
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#ifndef BITSTREAM_WRITER_LE
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    s->bit_buf<<= s->bit_left;
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#endif
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    while (s->bit_left < 32) {
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        /* XXX: should test end of buffer */
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#ifdef BITSTREAM_WRITER_LE
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        *s->buf_ptr++=s->bit_buf;
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        s->bit_buf>>=8;
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#else
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        *s->buf_ptr++=s->bit_buf >> 24;
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        s->bit_buf<<=8;
140
#endif
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        s->bit_left+=8;
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    }
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    s->bit_left=32;
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    s->bit_buf=0;
145
#endif
146
}
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148
void align_put_bits(PutBitContext *s);
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void ff_put_string(PutBitContext * pbc, const char *s, int put_zero);
150
void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length);
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152
/* bit input */
153
/* buffer, buffer_end and size_in_bits must be present and used by every reader */
154
typedef struct GetBitContext {
155
    const uint8_t *buffer, *buffer_end;
156
#ifdef ALT_BITSTREAM_READER
157
    int index;
158
#elif defined LIBMPEG2_BITSTREAM_READER
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    uint8_t *buffer_ptr;
160
    uint32_t cache;
161
    int bit_count;
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#elif defined A32_BITSTREAM_READER
163
    uint32_t *buffer_ptr;
164
    uint32_t cache0;
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    uint32_t cache1;
166
    int bit_count;
167
#endif
168
    int size_in_bits;
169
} GetBitContext;
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171
#define VLC_TYPE int16_t
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173
typedef struct VLC {
174
    int bits;
175
    VLC_TYPE (*table)[2]; ///< code, bits
176
    int table_size, table_allocated;
177
} VLC;
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179
typedef struct RL_VLC_ELEM {
180
    int16_t level;
181
    int8_t len;
182
    uint8_t run;
183
} RL_VLC_ELEM;
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185
#ifndef ALT_BITSTREAM_WRITER
186
static inline void put_bits(PutBitContext *s, int n, unsigned int value)
187
{
188
    unsigned int bit_buf;
189
    int bit_left;
190

    
191
    //    printf("put_bits=%d %x\n", n, value);
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    assert(n == 32 || value < (1U << n));
193

    
194
    bit_buf = s->bit_buf;
195
    bit_left = s->bit_left;
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197
    //    printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
198
    /* XXX: optimize */
199
#ifdef BITSTREAM_WRITER_LE
200
    bit_buf |= value << (32 - bit_left);
201
    if (n >= bit_left) {
202
#if !HAVE_FAST_UNALIGNED
203
        if (3 & (intptr_t) s->buf_ptr) {
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            AV_WL32(s->buf_ptr, bit_buf);
205
        } else
206
#endif
207
        *(uint32_t *)s->buf_ptr = le2me_32(bit_buf);
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        s->buf_ptr+=4;
209
        bit_buf = (bit_left==32)?0:value >> bit_left;
210
        bit_left+=32;
211
    }
212
    bit_left-=n;
213
#else
214
    if (n < bit_left) {
215
        bit_buf = (bit_buf<<n) | value;
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        bit_left-=n;
217
    } else {
218
        bit_buf<<=bit_left;
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        bit_buf |= value >> (n - bit_left);
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#if !HAVE_FAST_UNALIGNED
221
        if (3 & (intptr_t) s->buf_ptr) {
222
            AV_WB32(s->buf_ptr, bit_buf);
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        } else
224
#endif
225
        *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
226
        //printf("bitbuf = %08x\n", bit_buf);
227
        s->buf_ptr+=4;
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        bit_left+=32 - n;
229
        bit_buf = value;
230
    }
231
#endif
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233
    s->bit_buf = bit_buf;
234
    s->bit_left = bit_left;
235
}
236
#endif
237

    
238

    
239
#ifdef ALT_BITSTREAM_WRITER
240
static inline void put_bits(PutBitContext *s, int n, unsigned int value)
241
{
242
#    ifdef ALIGNED_BITSTREAM_WRITER
243
#        if ARCH_X86
244
    __asm__ volatile(
245
        "movl %0, %%ecx                 \n\t"
246
        "xorl %%eax, %%eax              \n\t"
247
        "shrdl %%cl, %1, %%eax          \n\t"
248
        "shrl %%cl, %1                  \n\t"
249
        "movl %0, %%ecx                 \n\t"
250
        "shrl $3, %%ecx                 \n\t"
251
        "andl $0xFFFFFFFC, %%ecx        \n\t"
252
        "bswapl %1                      \n\t"
253
        "orl %1, (%2, %%ecx)            \n\t"
254
        "bswapl %%eax                   \n\t"
255
        "addl %3, %0                    \n\t"
256
        "movl %%eax, 4(%2, %%ecx)       \n\t"
257
        : "=&r" (s->index), "=&r" (value)
258
        : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
259
        : "%eax", "%ecx"
260
    );
261
#        else
262
    int index= s->index;
263
    uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
264

    
265
    value<<= 32-n;
266

    
267
    ptr[0] |= be2me_32(value>>(index&31));
268
    ptr[1]  = be2me_32(value<<(32-(index&31)));
269
//if(n>24) printf("%d %d\n", n, value);
270
    index+= n;
271
    s->index= index;
272
#        endif
273
#    else //ALIGNED_BITSTREAM_WRITER
274
#        if ARCH_X86
275
    __asm__ volatile(
276
        "movl $7, %%ecx                 \n\t"
277
        "andl %0, %%ecx                 \n\t"
278
        "addl %3, %%ecx                 \n\t"
279
        "negl %%ecx                     \n\t"
280
        "shll %%cl, %1                  \n\t"
281
        "bswapl %1                      \n\t"
282
        "movl %0, %%ecx                 \n\t"
283
        "shrl $3, %%ecx                 \n\t"
284
        "orl %1, (%%ecx, %2)            \n\t"
285
        "addl %3, %0                    \n\t"
286
        "movl $0, 4(%%ecx, %2)          \n\t"
287
        : "=&r" (s->index), "=&r" (value)
288
        : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
289
        : "%ecx"
290
    );
291
#        else
292
    int index= s->index;
293
    uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
294

    
295
    ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
296
    ptr[1] = 0;
297
//if(n>24) printf("%d %d\n", n, value);
298
    index+= n;
299
    s->index= index;
300
#        endif
301
#    endif //!ALIGNED_BITSTREAM_WRITER
302
}
303
#endif
304

    
305
static inline void put_sbits(PutBitContext *pb, int bits, int32_t val)
306
{
307
    assert(bits >= 0 && bits <= 31);
308

    
309
    put_bits(pb, bits, val & ((1<<bits)-1));
310
}
311

    
312

    
313
static inline uint8_t* pbBufPtr(PutBitContext *s)
314
{
315
#ifdef ALT_BITSTREAM_WRITER
316
        return s->buf + (s->index>>3);
317
#else
318
        return s->buf_ptr;
319
#endif
320
}
321

    
322
/**
323
 *
324
 * PutBitContext must be flushed & aligned to a byte boundary before calling this.
325
 */
326
static inline void skip_put_bytes(PutBitContext *s, int n){
327
        assert((put_bits_count(s)&7)==0);
328
#ifdef ALT_BITSTREAM_WRITER
329
        FIXME may need some cleaning of the buffer
330
        s->index += n<<3;
331
#else
332
        assert(s->bit_left==32);
333
        s->buf_ptr += n;
334
#endif
335
}
336

    
337
/**
338
 * Skips the given number of bits.
339
 * Must only be used if the actual values in the bitstream do not matter.
340
 */
341
static inline void skip_put_bits(PutBitContext *s, int n){
342
#ifdef ALT_BITSTREAM_WRITER
343
    s->index += n;
344
#else
345
    s->bit_left -= n;
346
    s->buf_ptr-= s->bit_left>>5;
347
    s->bit_left &= 31;
348
#endif
349
}
350

    
351
/**
352
 * Changes the end of the buffer.
353
 */
354
static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
355
    s->buf_end= s->buf + size;
356
}
357

    
358
/* Bitstream reader API docs:
359
name
360
    arbitrary name which is used as prefix for the internal variables
361

362
gb
363
    getbitcontext
364

365
OPEN_READER(name, gb)
366
    loads gb into local variables
367

368
CLOSE_READER(name, gb)
369
    stores local vars in gb
370

371
UPDATE_CACHE(name, gb)
372
    refills the internal cache from the bitstream
373
    after this call at least MIN_CACHE_BITS will be available,
374

375
GET_CACHE(name, gb)
376
    will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
377

378
SHOW_UBITS(name, gb, num)
379
    will return the next num bits
380

381
SHOW_SBITS(name, gb, num)
382
    will return the next num bits and do sign extension
383

384
SKIP_BITS(name, gb, num)
385
    will skip over the next num bits
386
    note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
387

388
SKIP_CACHE(name, gb, num)
389
    will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
390

391
SKIP_COUNTER(name, gb, num)
392
    will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
393

394
LAST_SKIP_CACHE(name, gb, num)
395
    will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
396

397
LAST_SKIP_BITS(name, gb, num)
398
    is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
399

400
for examples see get_bits, show_bits, skip_bits, get_vlc
401
*/
402

    
403
#ifdef ALT_BITSTREAM_READER
404
#   define MIN_CACHE_BITS 25
405

    
406
#   define OPEN_READER(name, gb)\
407
        int name##_index= (gb)->index;\
408
        int name##_cache= 0;\
409

    
410
#   define CLOSE_READER(name, gb)\
411
        (gb)->index= name##_index;\
412

    
413
# ifdef ALT_BITSTREAM_READER_LE
414
#   define UPDATE_CACHE(name, gb)\
415
        name##_cache= AV_RL32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
416

    
417
#   define SKIP_CACHE(name, gb, num)\
418
        name##_cache >>= (num);
419
# else
420
#   define UPDATE_CACHE(name, gb)\
421
        name##_cache= AV_RB32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
422

    
423
#   define SKIP_CACHE(name, gb, num)\
424
        name##_cache <<= (num);
425
# endif
426

    
427
// FIXME name?
428
#   define SKIP_COUNTER(name, gb, num)\
429
        name##_index += (num);\
430

    
431
#   define SKIP_BITS(name, gb, num)\
432
        {\
433
            SKIP_CACHE(name, gb, num)\
434
            SKIP_COUNTER(name, gb, num)\
435
        }\
436

    
437
#   define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
438
#   define LAST_SKIP_CACHE(name, gb, num) ;
439

    
440
# ifdef ALT_BITSTREAM_READER_LE
441
#   define SHOW_UBITS(name, gb, num)\
442
        ((name##_cache) & (NEG_USR32(0xffffffff,num)))
443

    
444
#   define SHOW_SBITS(name, gb, num)\
445
        NEG_SSR32((name##_cache)<<(32-(num)), num)
446
# else
447
#   define SHOW_UBITS(name, gb, num)\
448
        NEG_USR32(name##_cache, num)
449

    
450
#   define SHOW_SBITS(name, gb, num)\
451
        NEG_SSR32(name##_cache, num)
452
# endif
453

    
454
#   define GET_CACHE(name, gb)\
455
        ((uint32_t)name##_cache)
456

    
457
static inline int get_bits_count(GetBitContext *s){
458
    return s->index;
459
}
460

    
461
static inline void skip_bits_long(GetBitContext *s, int n){
462
    s->index += n;
463
}
464

    
465
#elif defined LIBMPEG2_BITSTREAM_READER
466
//libmpeg2 like reader
467

    
468
#   define MIN_CACHE_BITS 17
469

    
470
#   define OPEN_READER(name, gb)\
471
        int name##_bit_count=(gb)->bit_count;\
472
        int name##_cache= (gb)->cache;\
473
        uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
474

    
475
#   define CLOSE_READER(name, gb)\
476
        (gb)->bit_count= name##_bit_count;\
477
        (gb)->cache= name##_cache;\
478
        (gb)->buffer_ptr= name##_buffer_ptr;\
479

    
480
#   define UPDATE_CACHE(name, gb)\
481
    if(name##_bit_count >= 0){\
482
        name##_cache+= AV_RB16(name##_buffer_ptr) << name##_bit_count; \
483
        name##_buffer_ptr+=2;\
484
        name##_bit_count-= 16;\
485
    }\
486

    
487
#   define SKIP_CACHE(name, gb, num)\
488
        name##_cache <<= (num);\
489

    
490
#   define SKIP_COUNTER(name, gb, num)\
491
        name##_bit_count += (num);\
492

    
493
#   define SKIP_BITS(name, gb, num)\
494
        {\
495
            SKIP_CACHE(name, gb, num)\
496
            SKIP_COUNTER(name, gb, num)\
497
        }\
498

    
499
#   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
500
#   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
501

    
502
#   define SHOW_UBITS(name, gb, num)\
503
        NEG_USR32(name##_cache, num)
504

    
505
#   define SHOW_SBITS(name, gb, num)\
506
        NEG_SSR32(name##_cache, num)
507

    
508
#   define GET_CACHE(name, gb)\
509
        ((uint32_t)name##_cache)
510

    
511
static inline int get_bits_count(GetBitContext *s){
512
    return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
513
}
514

    
515
static inline void skip_bits_long(GetBitContext *s, int n){
516
    OPEN_READER(re, s)
517
    re_bit_count += n;
518
    re_buffer_ptr += 2*(re_bit_count>>4);
519
    re_bit_count &= 15;
520
    re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count);
521
    UPDATE_CACHE(re, s)
522
    CLOSE_READER(re, s)
523
}
524

    
525
#elif defined A32_BITSTREAM_READER
526

    
527
#   define MIN_CACHE_BITS 32
528

    
529
#   define OPEN_READER(name, gb)\
530
        int name##_bit_count=(gb)->bit_count;\
531
        uint32_t name##_cache0= (gb)->cache0;\
532
        uint32_t name##_cache1= (gb)->cache1;\
533
        uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
534

    
535
#   define CLOSE_READER(name, gb)\
536
        (gb)->bit_count= name##_bit_count;\
537
        (gb)->cache0= name##_cache0;\
538
        (gb)->cache1= name##_cache1;\
539
        (gb)->buffer_ptr= name##_buffer_ptr;\
540

    
541
#   define UPDATE_CACHE(name, gb)\
542
    if(name##_bit_count > 0){\
543
        const uint32_t next= be2me_32( *name##_buffer_ptr );\
544
        name##_cache0 |= NEG_USR32(next,name##_bit_count);\
545
        name##_cache1 |= next<<name##_bit_count;\
546
        name##_buffer_ptr++;\
547
        name##_bit_count-= 32;\
548
    }\
549

    
550
#if ARCH_X86
551
#   define SKIP_CACHE(name, gb, num)\
552
        __asm__(\
553
            "shldl %2, %1, %0          \n\t"\
554
            "shll %2, %1               \n\t"\
555
            : "+r" (name##_cache0), "+r" (name##_cache1)\
556
            : "Ic" ((uint8_t)(num))\
557
           );
558
#else
559
#   define SKIP_CACHE(name, gb, num)\
560
        name##_cache0 <<= (num);\
561
        name##_cache0 |= NEG_USR32(name##_cache1,num);\
562
        name##_cache1 <<= (num);
563
#endif
564

    
565
#   define SKIP_COUNTER(name, gb, num)\
566
        name##_bit_count += (num);\
567

    
568
#   define SKIP_BITS(name, gb, num)\
569
        {\
570
            SKIP_CACHE(name, gb, num)\
571
            SKIP_COUNTER(name, gb, num)\
572
        }\
573

    
574
#   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
575
#   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
576

    
577
#   define SHOW_UBITS(name, gb, num)\
578
        NEG_USR32(name##_cache0, num)
579

    
580
#   define SHOW_SBITS(name, gb, num)\
581
        NEG_SSR32(name##_cache0, num)
582

    
583
#   define GET_CACHE(name, gb)\
584
        (name##_cache0)
585

    
586
static inline int get_bits_count(GetBitContext *s){
587
    return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
588
}
589

    
590
static inline void skip_bits_long(GetBitContext *s, int n){
591
    OPEN_READER(re, s)
592
    re_bit_count += n;
593
    re_buffer_ptr += re_bit_count>>5;
594
    re_bit_count &= 31;
595
    re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count;
596
    re_cache1 = 0;
597
    UPDATE_CACHE(re, s)
598
    CLOSE_READER(re, s)
599
}
600

    
601
#endif
602

    
603
/**
604
 * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
605
 * if MSB not set it is negative
606
 * @param n length in bits
607
 * @author BERO
608
 */
609
static inline int get_xbits(GetBitContext *s, int n){
610
    register int sign;
611
    register int32_t cache;
612
    OPEN_READER(re, s)
613
    UPDATE_CACHE(re, s)
614
    cache = GET_CACHE(re,s);
615
    sign=(~cache)>>31;
616
    LAST_SKIP_BITS(re, s, n)
617
    CLOSE_READER(re, s)
618
    return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
619
}
620

    
621
static inline int get_sbits(GetBitContext *s, int n){
622
    register int tmp;
623
    OPEN_READER(re, s)
624
    UPDATE_CACHE(re, s)
625
    tmp= SHOW_SBITS(re, s, n);
626
    LAST_SKIP_BITS(re, s, n)
627
    CLOSE_READER(re, s)
628
    return tmp;
629
}
630

    
631
/**
632
 * reads 1-17 bits.
633
 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
634
 */
635
static inline unsigned int get_bits(GetBitContext *s, int n){
636
    register int tmp;
637
    OPEN_READER(re, s)
638
    UPDATE_CACHE(re, s)
639
    tmp= SHOW_UBITS(re, s, n);
640
    LAST_SKIP_BITS(re, s, n)
641
    CLOSE_READER(re, s)
642
    return tmp;
643
}
644

    
645
/**
646
 * shows 1-17 bits.
647
 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
648
 */
649
static inline unsigned int show_bits(GetBitContext *s, int n){
650
    register int tmp;
651
    OPEN_READER(re, s)
652
    UPDATE_CACHE(re, s)
653
    tmp= SHOW_UBITS(re, s, n);
654
//    CLOSE_READER(re, s)
655
    return tmp;
656
}
657

    
658
static inline void skip_bits(GetBitContext *s, int n){
659
 //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
660
    OPEN_READER(re, s)
661
    UPDATE_CACHE(re, s)
662
    LAST_SKIP_BITS(re, s, n)
663
    CLOSE_READER(re, s)
664
}
665

    
666
static inline unsigned int get_bits1(GetBitContext *s){
667
#ifdef ALT_BITSTREAM_READER
668
    int index= s->index;
669
    uint8_t result= s->buffer[ index>>3 ];
670
#ifdef ALT_BITSTREAM_READER_LE
671
    result>>= (index&0x07);
672
    result&= 1;
673
#else
674
    result<<= (index&0x07);
675
    result>>= 8 - 1;
676
#endif
677
    index++;
678
    s->index= index;
679

    
680
    return result;
681
#else
682
    return get_bits(s, 1);
683
#endif
684
}
685

    
686
static inline unsigned int show_bits1(GetBitContext *s){
687
    return show_bits(s, 1);
688
}
689

    
690
static inline void skip_bits1(GetBitContext *s){
691
    skip_bits(s, 1);
692
}
693

    
694
/**
695
 * reads 0-32 bits.
696
 */
697
static inline unsigned int get_bits_long(GetBitContext *s, int n){
698
    if(n<=17) return get_bits(s, n);
699
    else{
700
#ifdef ALT_BITSTREAM_READER_LE
701
        int ret= get_bits(s, 16);
702
        return ret | (get_bits(s, n-16) << 16);
703
#else
704
        int ret= get_bits(s, 16) << (n-16);
705
        return ret | get_bits(s, n-16);
706
#endif
707
    }
708
}
709

    
710
/**
711
 * reads 0-32 bits as a signed integer.
712
 */
713
static inline int get_sbits_long(GetBitContext *s, int n) {
714
    return sign_extend(get_bits_long(s, n), n);
715
}
716

    
717
/**
718
 * shows 0-32 bits.
719
 */
720
static inline unsigned int show_bits_long(GetBitContext *s, int n){
721
    if(n<=17) return show_bits(s, n);
722
    else{
723
        GetBitContext gb= *s;
724
        return get_bits_long(&gb, n);
725
    }
726
}
727

    
728
static inline int check_marker(GetBitContext *s, const char *msg)
729
{
730
    int bit= get_bits1(s);
731
    if(!bit)
732
        av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
733

    
734
    return bit;
735
}
736

    
737
/**
738
 * init GetBitContext.
739
 * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
740
 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
741
 * @param bit_size the size of the buffer in bits
742
 */
743
static inline void init_get_bits(GetBitContext *s,
744
                   const uint8_t *buffer, int bit_size)
745
{
746
    int buffer_size= (bit_size+7)>>3;
747
    if(buffer_size < 0 || bit_size < 0) {
748
        buffer_size = bit_size = 0;
749
        buffer = NULL;
750
    }
751

    
752
    s->buffer= buffer;
753
    s->size_in_bits= bit_size;
754
    s->buffer_end= buffer + buffer_size;
755
#ifdef ALT_BITSTREAM_READER
756
    s->index=0;
757
#elif defined LIBMPEG2_BITSTREAM_READER
758
    s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));
759
    s->bit_count = 16 + 8*((intptr_t)buffer&1);
760
    skip_bits_long(s, 0);
761
#elif defined A32_BITSTREAM_READER
762
    s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3));
763
    s->bit_count = 32 + 8*((intptr_t)buffer&3);
764
    skip_bits_long(s, 0);
765
#endif
766
}
767

    
768
static inline void align_get_bits(GetBitContext *s)
769
{
770
    int n= (-get_bits_count(s)) & 7;
771
    if(n) skip_bits(s, n);
772
}
773

    
774
#define init_vlc(vlc, nb_bits, nb_codes,\
775
                 bits, bits_wrap, bits_size,\
776
                 codes, codes_wrap, codes_size,\
777
                 flags)\
778
        init_vlc_sparse(vlc, nb_bits, nb_codes,\
779
                 bits, bits_wrap, bits_size,\
780
                 codes, codes_wrap, codes_size,\
781
                 NULL, 0, 0, flags)
782

    
783
int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
784
             const void *bits, int bits_wrap, int bits_size,
785
             const void *codes, int codes_wrap, int codes_size,
786
             const void *symbols, int symbols_wrap, int symbols_size,
787
             int flags);
788
#define INIT_VLC_USE_STATIC 1 ///< VERY strongly deprecated and forbidden
789
#define INIT_VLC_LE         2
790
#define INIT_VLC_USE_NEW_STATIC 4
791
void free_vlc(VLC *vlc);
792

    
793
#define INIT_VLC_STATIC(vlc, bits, a,b,c,d,e,f,g, static_size)\
794
{\
795
    static VLC_TYPE table[static_size][2];\
796
    (vlc)->table= table;\
797
    (vlc)->table_allocated= static_size;\
798
    init_vlc(vlc, bits, a,b,c,d,e,f,g, INIT_VLC_USE_NEW_STATIC);\
799
}
800

    
801

    
802
/**
803
 *
804
 * if the vlc code is invalid and max_depth=1 than no bits will be removed
805
 * if the vlc code is invalid and max_depth>1 than the number of bits removed
806
 * is undefined
807
 */
808
#define GET_VLC(code, name, gb, table, bits, max_depth)\
809
{\
810
    int n, index, nb_bits;\
811
\
812
    index= SHOW_UBITS(name, gb, bits);\
813
    code = table[index][0];\
814
    n    = table[index][1];\
815
\
816
    if(max_depth > 1 && n < 0){\
817
        LAST_SKIP_BITS(name, gb, bits)\
818
        UPDATE_CACHE(name, gb)\
819
\
820
        nb_bits = -n;\
821
\
822
        index= SHOW_UBITS(name, gb, nb_bits) + code;\
823
        code = table[index][0];\
824
        n    = table[index][1];\
825
        if(max_depth > 2 && n < 0){\
826
            LAST_SKIP_BITS(name, gb, nb_bits)\
827
            UPDATE_CACHE(name, gb)\
828
\
829
            nb_bits = -n;\
830
\
831
            index= SHOW_UBITS(name, gb, nb_bits) + code;\
832
            code = table[index][0];\
833
            n    = table[index][1];\
834
        }\
835
    }\
836
    SKIP_BITS(name, gb, n)\
837
}
838

    
839
#define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
840
{\
841
    int n, index, nb_bits;\
842
\
843
    index= SHOW_UBITS(name, gb, bits);\
844
    level = table[index].level;\
845
    n     = table[index].len;\
846
\
847
    if(max_depth > 1 && n < 0){\
848
        SKIP_BITS(name, gb, bits)\
849
        if(need_update){\
850
            UPDATE_CACHE(name, gb)\
851
        }\
852
\
853
        nb_bits = -n;\
854
\
855
        index= SHOW_UBITS(name, gb, nb_bits) + level;\
856
        level = table[index].level;\
857
        n     = table[index].len;\
858
    }\
859
    run= table[index].run;\
860
    SKIP_BITS(name, gb, n)\
861
}
862

    
863

    
864
/**
865
 * parses a vlc code, faster then get_vlc()
866
 * @param bits is the number of bits which will be read at once, must be
867
 *             identical to nb_bits in init_vlc()
868
 * @param max_depth is the number of times bits bits must be read to completely
869
 *                  read the longest vlc code
870
 *                  = (max_vlc_length + bits - 1) / bits
871
 */
872
static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
873
                                  int bits, int max_depth)
874
{
875
    int code;
876

    
877
    OPEN_READER(re, s)
878
    UPDATE_CACHE(re, s)
879

    
880
    GET_VLC(code, re, s, table, bits, max_depth)
881

    
882
    CLOSE_READER(re, s)
883
    return code;
884
}
885

    
886
//#define TRACE
887

    
888
#ifdef TRACE
889
static inline void print_bin(int bits, int n){
890
    int i;
891

    
892
    for(i=n-1; i>=0; i--){
893
        av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
894
    }
895
    for(i=n; i<24; i++)
896
        av_log(NULL, AV_LOG_DEBUG, " ");
897
}
898

    
899
static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
900
    int r= get_bits(s, n);
901

    
902
    print_bin(r, n);
903
    av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d bit @%5d in %s %s:%d\n", r, n, r, get_bits_count(s)-n, file, func, line);
904
    return r;
905
}
906
static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
907
    int show= show_bits(s, 24);
908
    int pos= get_bits_count(s);
909
    int r= get_vlc2(s, table, bits, max_depth);
910
    int len= get_bits_count(s) - pos;
911
    int bits2= show>>(24-len);
912

    
913
    print_bin(bits2, len);
914

    
915
    av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
916
    return r;
917
}
918
static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
919
    int show= show_bits(s, n);
920
    int r= get_xbits(s, n);
921

    
922
    print_bin(show, n);
923
    av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d xbt @%5d in %s %s:%d\n", show, n, r, get_bits_count(s)-n, file, func, line);
924
    return r;
925
}
926

    
927
#define get_bits(s, n)  get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
928
#define get_bits1(s)    get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
929
#define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
930
#define get_vlc(s, vlc)            get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
931
#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
932

    
933
#define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__)
934

    
935
#else //TRACE
936
#define tprintf(p, ...) {}
937
#endif
938

    
939
static inline int decode012(GetBitContext *gb){
940
    int n;
941
    n = get_bits1(gb);
942
    if (n == 0)
943
        return 0;
944
    else
945
        return get_bits1(gb) + 1;
946
}
947

    
948
static inline int decode210(GetBitContext *gb){
949
    if (get_bits1(gb))
950
        return 0;
951
    else
952
        return 2 - get_bits1(gb);
953
}
954

    
955
#endif /* AVCODEC_BITSTREAM_H */