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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 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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#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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#   ifdef 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 defined(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;
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}
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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)))
74
#endif
75

    
76
/* bit output */
77

    
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/* buf and buf_end must be present and used by every alternative writer. */
79
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;
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#endif
88
} PutBitContext;
89

    
90
static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
91
{
92
    if(buffer_size < 0) {
93
        buffer_size = 0;
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        buffer = NULL;
95
    }
96

    
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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
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    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
104
    s->buf_ptr = s->buf;
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    s->bit_left=32;
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    s->bit_buf=0;
107
#endif
108
}
109

    
110
/* return the number of bits output */
111
static inline int put_bits_count(PutBitContext *s)
112
{
113
#ifdef ALT_BITSTREAM_WRITER
114
    return s->index;
115
#else
116
    return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
117
#endif
118
}
119

    
120
/* pad the end of the output stream with zeros */
121
static inline void flush_put_bits(PutBitContext *s)
122
{
123
#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;
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#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;
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#endif
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}
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void align_put_bits(PutBitContext *s);
146
void ff_put_string(PutBitContext * pbc, const char *s, int put_zero);
147
void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length);
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/* bit input */
150
/* buffer, buffer_end and size_in_bits must be present and used by every reader */
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typedef struct GetBitContext {
152
    const uint8_t *buffer, *buffer_end;
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#ifdef ALT_BITSTREAM_READER
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    int index;
155
#elif defined LIBMPEG2_BITSTREAM_READER
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    uint8_t *buffer_ptr;
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    uint32_t cache;
158
    int bit_count;
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#elif defined A32_BITSTREAM_READER
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    uint32_t *buffer_ptr;
161
    uint32_t cache0;
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    uint32_t cache1;
163
    int bit_count;
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#endif
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    int size_in_bits;
166
} GetBitContext;
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168
#define VLC_TYPE int16_t
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170
typedef struct VLC {
171
    int bits;
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    VLC_TYPE (*table)[2]; ///< code, bits
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    int table_size, table_allocated;
174
} VLC;
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176
typedef struct RL_VLC_ELEM {
177
    int16_t level;
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    int8_t len;
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    uint8_t run;
180
} RL_VLC_ELEM;
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182
#if defined(ARCH_SPARC) || defined(ARCH_ARM) || defined(ARCH_MIPS) || defined(ARCH_BFIN)
183
#define UNALIGNED_STORES_ARE_BAD
184
#endif
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186
#ifndef ALT_BITSTREAM_WRITER
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static inline void put_bits(PutBitContext *s, int n, unsigned int value)
188
{
189
    unsigned int bit_buf;
190
    int bit_left;
191

    
192
    //    printf("put_bits=%d %x\n", n, value);
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    assert(n == 32 || value < (1U << n));
194

    
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    bit_buf = s->bit_buf;
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    bit_left = s->bit_left;
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    //    printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
199
    /* XXX: optimize */
200
#ifdef BITSTREAM_WRITER_LE
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    bit_buf |= value << (32 - bit_left);
202
    if (n >= bit_left) {
203
#ifdef UNALIGNED_STORES_ARE_BAD
204
        if (3 & (intptr_t) s->buf_ptr) {
205
            s->buf_ptr[0] = bit_buf      ;
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            s->buf_ptr[1] = bit_buf >>  8;
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            s->buf_ptr[2] = bit_buf >> 16;
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            s->buf_ptr[3] = bit_buf >> 24;
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        } else
210
#endif
211
        *(uint32_t *)s->buf_ptr = le2me_32(bit_buf);
212
        s->buf_ptr+=4;
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        bit_buf = (bit_left==32)?0:value >> bit_left;
214
        bit_left+=32;
215
    }
216
    bit_left-=n;
217
#else
218
    if (n < bit_left) {
219
        bit_buf = (bit_buf<<n) | value;
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        bit_left-=n;
221
    } else {
222
        bit_buf<<=bit_left;
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        bit_buf |= value >> (n - bit_left);
224
#ifdef UNALIGNED_STORES_ARE_BAD
225
        if (3 & (intptr_t) s->buf_ptr) {
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            s->buf_ptr[0] = bit_buf >> 24;
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            s->buf_ptr[1] = bit_buf >> 16;
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            s->buf_ptr[2] = bit_buf >>  8;
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            s->buf_ptr[3] = bit_buf      ;
230
        } else
231
#endif
232
        *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
233
        //printf("bitbuf = %08x\n", bit_buf);
234
        s->buf_ptr+=4;
235
        bit_left+=32 - n;
236
        bit_buf = value;
237
    }
238
#endif
239

    
240
    s->bit_buf = bit_buf;
241
    s->bit_left = bit_left;
242
}
243
#endif
244

    
245

    
246
#ifdef ALT_BITSTREAM_WRITER
247
static inline void put_bits(PutBitContext *s, int n, unsigned int value)
248
{
249
#    ifdef ALIGNED_BITSTREAM_WRITER
250
#        if defined(ARCH_X86)
251
    __asm__ volatile(
252
        "movl %0, %%ecx                 \n\t"
253
        "xorl %%eax, %%eax              \n\t"
254
        "shrdl %%cl, %1, %%eax          \n\t"
255
        "shrl %%cl, %1                  \n\t"
256
        "movl %0, %%ecx                 \n\t"
257
        "shrl $3, %%ecx                 \n\t"
258
        "andl $0xFFFFFFFC, %%ecx        \n\t"
259
        "bswapl %1                      \n\t"
260
        "orl %1, (%2, %%ecx)            \n\t"
261
        "bswapl %%eax                   \n\t"
262
        "addl %3, %0                    \n\t"
263
        "movl %%eax, 4(%2, %%ecx)       \n\t"
264
        : "=&r" (s->index), "=&r" (value)
265
        : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
266
        : "%eax", "%ecx"
267
    );
268
#        else
269
    int index= s->index;
270
    uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
271

    
272
    value<<= 32-n;
273

    
274
    ptr[0] |= be2me_32(value>>(index&31));
275
    ptr[1]  = be2me_32(value<<(32-(index&31)));
276
//if(n>24) printf("%d %d\n", n, value);
277
    index+= n;
278
    s->index= index;
279
#        endif
280
#    else //ALIGNED_BITSTREAM_WRITER
281
#        if defined(ARCH_X86)
282
    __asm__ volatile(
283
        "movl $7, %%ecx                 \n\t"
284
        "andl %0, %%ecx                 \n\t"
285
        "addl %3, %%ecx                 \n\t"
286
        "negl %%ecx                     \n\t"
287
        "shll %%cl, %1                  \n\t"
288
        "bswapl %1                      \n\t"
289
        "movl %0, %%ecx                 \n\t"
290
        "shrl $3, %%ecx                 \n\t"
291
        "orl %1, (%%ecx, %2)            \n\t"
292
        "addl %3, %0                    \n\t"
293
        "movl $0, 4(%%ecx, %2)          \n\t"
294
        : "=&r" (s->index), "=&r" (value)
295
        : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
296
        : "%ecx"
297
    );
298
#        else
299
    int index= s->index;
300
    uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
301

    
302
    ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
303
    ptr[1] = 0;
304
//if(n>24) printf("%d %d\n", n, value);
305
    index+= n;
306
    s->index= index;
307
#        endif
308
#    endif //!ALIGNED_BITSTREAM_WRITER
309
}
310
#endif
311

    
312
static inline void put_sbits(PutBitContext *pb, int bits, int32_t val)
313
{
314
    assert(bits >= 0 && bits <= 31);
315

    
316
    put_bits(pb, bits, val & ((1<<bits)-1));
317
}
318

    
319

    
320
static inline uint8_t* pbBufPtr(PutBitContext *s)
321
{
322
#ifdef ALT_BITSTREAM_WRITER
323
        return s->buf + (s->index>>3);
324
#else
325
        return s->buf_ptr;
326
#endif
327
}
328

    
329
/**
330
 *
331
 * PutBitContext must be flushed & aligned to a byte boundary before calling this.
332
 */
333
static inline void skip_put_bytes(PutBitContext *s, int n){
334
        assert((put_bits_count(s)&7)==0);
335
#ifdef ALT_BITSTREAM_WRITER
336
        FIXME may need some cleaning of the buffer
337
        s->index += n<<3;
338
#else
339
        assert(s->bit_left==32);
340
        s->buf_ptr += n;
341
#endif
342
}
343

    
344
/**
345
 * Skips the given number of bits.
346
 * Must only be used if the actual values in the bitstream do not matter.
347
 */
348
static inline void skip_put_bits(PutBitContext *s, int n){
349
#ifdef ALT_BITSTREAM_WRITER
350
    s->index += n;
351
#else
352
    s->bit_left -= n;
353
    s->buf_ptr-= s->bit_left>>5;
354
    s->bit_left &= 31;
355
#endif
356
}
357

    
358
/**
359
 * Changes the end of the buffer.
360
 */
361
static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
362
    s->buf_end= s->buf + size;
363
}
364

    
365
/* Bitstream reader API docs:
366
name
367
    arbitrary name which is used as prefix for the internal variables
368

369
gb
370
    getbitcontext
371

372
OPEN_READER(name, gb)
373
    loads gb into local variables
374

375
CLOSE_READER(name, gb)
376
    stores local vars in gb
377

378
UPDATE_CACHE(name, gb)
379
    refills the internal cache from the bitstream
380
    after this call at least MIN_CACHE_BITS will be available,
381

382
GET_CACHE(name, gb)
383
    will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
384

385
SHOW_UBITS(name, gb, num)
386
    will return the next num bits
387

388
SHOW_SBITS(name, gb, num)
389
    will return the next num bits and do sign extension
390

391
SKIP_BITS(name, gb, num)
392
    will skip over the next num bits
393
    note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
394

395
SKIP_CACHE(name, gb, num)
396
    will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
397

398
SKIP_COUNTER(name, gb, num)
399
    will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
400

401
LAST_SKIP_CACHE(name, gb, num)
402
    will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
403

404
LAST_SKIP_BITS(name, gb, num)
405
    is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
406

407
for examples see get_bits, show_bits, skip_bits, get_vlc
408
*/
409

    
410
#ifdef ALT_BITSTREAM_READER
411
#   define MIN_CACHE_BITS 25
412

    
413
#   define OPEN_READER(name, gb)\
414
        int name##_index= (gb)->index;\
415
        int name##_cache= 0;\
416

    
417
#   define CLOSE_READER(name, gb)\
418
        (gb)->index= name##_index;\
419

    
420
# ifdef ALT_BITSTREAM_READER_LE
421
#   define UPDATE_CACHE(name, gb)\
422
        name##_cache= AV_RL32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
423

    
424
#   define SKIP_CACHE(name, gb, num)\
425
        name##_cache >>= (num);
426
# else
427
#   define UPDATE_CACHE(name, gb)\
428
        name##_cache= AV_RB32( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
429

    
430
#   define SKIP_CACHE(name, gb, num)\
431
        name##_cache <<= (num);
432
# endif
433

    
434
// FIXME name?
435
#   define SKIP_COUNTER(name, gb, num)\
436
        name##_index += (num);\
437

    
438
#   define SKIP_BITS(name, gb, num)\
439
        {\
440
            SKIP_CACHE(name, gb, num)\
441
            SKIP_COUNTER(name, gb, num)\
442
        }\
443

    
444
#   define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
445
#   define LAST_SKIP_CACHE(name, gb, num) ;
446

    
447
# ifdef ALT_BITSTREAM_READER_LE
448
#   define SHOW_UBITS(name, gb, num)\
449
        ((name##_cache) & (NEG_USR32(0xffffffff,num)))
450

    
451
#   define SHOW_SBITS(name, gb, num)\
452
        NEG_SSR32((name##_cache)<<(32-(num)), num)
453
# else
454
#   define SHOW_UBITS(name, gb, num)\
455
        NEG_USR32(name##_cache, num)
456

    
457
#   define SHOW_SBITS(name, gb, num)\
458
        NEG_SSR32(name##_cache, num)
459
# endif
460

    
461
#   define GET_CACHE(name, gb)\
462
        ((uint32_t)name##_cache)
463

    
464
static inline int get_bits_count(GetBitContext *s){
465
    return s->index;
466
}
467

    
468
static inline void skip_bits_long(GetBitContext *s, int n){
469
    s->index += n;
470
}
471

    
472
#elif defined LIBMPEG2_BITSTREAM_READER
473
//libmpeg2 like reader
474

    
475
#   define MIN_CACHE_BITS 17
476

    
477
#   define OPEN_READER(name, gb)\
478
        int name##_bit_count=(gb)->bit_count;\
479
        int name##_cache= (gb)->cache;\
480
        uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
481

    
482
#   define CLOSE_READER(name, gb)\
483
        (gb)->bit_count= name##_bit_count;\
484
        (gb)->cache= name##_cache;\
485
        (gb)->buffer_ptr= name##_buffer_ptr;\
486

    
487
#   define UPDATE_CACHE(name, gb)\
488
    if(name##_bit_count >= 0){\
489
        name##_cache+= AV_RB16(name##_buffer_ptr) << name##_bit_count; \
490
        name##_buffer_ptr+=2;\
491
        name##_bit_count-= 16;\
492
    }\
493

    
494
#   define SKIP_CACHE(name, gb, num)\
495
        name##_cache <<= (num);\
496

    
497
#   define SKIP_COUNTER(name, gb, num)\
498
        name##_bit_count += (num);\
499

    
500
#   define SKIP_BITS(name, gb, num)\
501
        {\
502
            SKIP_CACHE(name, gb, num)\
503
            SKIP_COUNTER(name, gb, num)\
504
        }\
505

    
506
#   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
507
#   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
508

    
509
#   define SHOW_UBITS(name, gb, num)\
510
        NEG_USR32(name##_cache, num)
511

    
512
#   define SHOW_SBITS(name, gb, num)\
513
        NEG_SSR32(name##_cache, num)
514

    
515
#   define GET_CACHE(name, gb)\
516
        ((uint32_t)name##_cache)
517

    
518
static inline int get_bits_count(GetBitContext *s){
519
    return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
520
}
521

    
522
static inline void skip_bits_long(GetBitContext *s, int n){
523
    OPEN_READER(re, s)
524
    re_bit_count += n;
525
    re_buffer_ptr += 2*(re_bit_count>>4);
526
    re_bit_count &= 15;
527
    re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count);
528
    UPDATE_CACHE(re, s)
529
    CLOSE_READER(re, s)
530
}
531

    
532
#elif defined A32_BITSTREAM_READER
533

    
534
#   define MIN_CACHE_BITS 32
535

    
536
#   define OPEN_READER(name, gb)\
537
        int name##_bit_count=(gb)->bit_count;\
538
        uint32_t name##_cache0= (gb)->cache0;\
539
        uint32_t name##_cache1= (gb)->cache1;\
540
        uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
541

    
542
#   define CLOSE_READER(name, gb)\
543
        (gb)->bit_count= name##_bit_count;\
544
        (gb)->cache0= name##_cache0;\
545
        (gb)->cache1= name##_cache1;\
546
        (gb)->buffer_ptr= name##_buffer_ptr;\
547

    
548
#   define UPDATE_CACHE(name, gb)\
549
    if(name##_bit_count > 0){\
550
        const uint32_t next= be2me_32( *name##_buffer_ptr );\
551
        name##_cache0 |= NEG_USR32(next,name##_bit_count);\
552
        name##_cache1 |= next<<name##_bit_count;\
553
        name##_buffer_ptr++;\
554
        name##_bit_count-= 32;\
555
    }\
556

    
557
#if defined(ARCH_X86)
558
#   define SKIP_CACHE(name, gb, num)\
559
        __asm__(\
560
            "shldl %2, %1, %0          \n\t"\
561
            "shll %2, %1               \n\t"\
562
            : "+r" (name##_cache0), "+r" (name##_cache1)\
563
            : "Ic" ((uint8_t)(num))\
564
           );
565
#else
566
#   define SKIP_CACHE(name, gb, num)\
567
        name##_cache0 <<= (num);\
568
        name##_cache0 |= NEG_USR32(name##_cache1,num);\
569
        name##_cache1 <<= (num);
570
#endif
571

    
572
#   define SKIP_COUNTER(name, gb, num)\
573
        name##_bit_count += (num);\
574

    
575
#   define SKIP_BITS(name, gb, num)\
576
        {\
577
            SKIP_CACHE(name, gb, num)\
578
            SKIP_COUNTER(name, gb, num)\
579
        }\
580

    
581
#   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
582
#   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
583

    
584
#   define SHOW_UBITS(name, gb, num)\
585
        NEG_USR32(name##_cache0, num)
586

    
587
#   define SHOW_SBITS(name, gb, num)\
588
        NEG_SSR32(name##_cache0, num)
589

    
590
#   define GET_CACHE(name, gb)\
591
        (name##_cache0)
592

    
593
static inline int get_bits_count(GetBitContext *s){
594
    return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
595
}
596

    
597
static inline void skip_bits_long(GetBitContext *s, int n){
598
    OPEN_READER(re, s)
599
    re_bit_count += n;
600
    re_buffer_ptr += re_bit_count>>5;
601
    re_bit_count &= 31;
602
    re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count;
603
    re_cache1 = 0;
604
    UPDATE_CACHE(re, s)
605
    CLOSE_READER(re, s)
606
}
607

    
608
#endif
609

    
610
/**
611
 * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
612
 * if MSB not set it is negative
613
 * @param n length in bits
614
 * @author BERO
615
 */
616
static inline int get_xbits(GetBitContext *s, int n){
617
    register int sign;
618
    register int32_t cache;
619
    OPEN_READER(re, s)
620
    UPDATE_CACHE(re, s)
621
    cache = GET_CACHE(re,s);
622
    sign=(~cache)>>31;
623
    LAST_SKIP_BITS(re, s, n)
624
    CLOSE_READER(re, s)
625
    return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
626
}
627

    
628
static inline int get_sbits(GetBitContext *s, int n){
629
    register int tmp;
630
    OPEN_READER(re, s)
631
    UPDATE_CACHE(re, s)
632
    tmp= SHOW_SBITS(re, s, n);
633
    LAST_SKIP_BITS(re, s, n)
634
    CLOSE_READER(re, s)
635
    return tmp;
636
}
637

    
638
/**
639
 * reads 1-17 bits.
640
 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
641
 */
642
static inline unsigned int get_bits(GetBitContext *s, int n){
643
    register int tmp;
644
    OPEN_READER(re, s)
645
    UPDATE_CACHE(re, s)
646
    tmp= SHOW_UBITS(re, s, n);
647
    LAST_SKIP_BITS(re, s, n)
648
    CLOSE_READER(re, s)
649
    return tmp;
650
}
651

    
652
/**
653
 * shows 1-17 bits.
654
 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
655
 */
656
static inline unsigned int show_bits(GetBitContext *s, int n){
657
    register int tmp;
658
    OPEN_READER(re, s)
659
    UPDATE_CACHE(re, s)
660
    tmp= SHOW_UBITS(re, s, n);
661
//    CLOSE_READER(re, s)
662
    return tmp;
663
}
664

    
665
static inline void skip_bits(GetBitContext *s, int n){
666
 //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
667
    OPEN_READER(re, s)
668
    UPDATE_CACHE(re, s)
669
    LAST_SKIP_BITS(re, s, n)
670
    CLOSE_READER(re, s)
671
}
672

    
673
static inline unsigned int get_bits1(GetBitContext *s){
674
#ifdef ALT_BITSTREAM_READER
675
    int index= s->index;
676
    uint8_t result= s->buffer[ index>>3 ];
677
#ifdef ALT_BITSTREAM_READER_LE
678
    result>>= (index&0x07);
679
    result&= 1;
680
#else
681
    result<<= (index&0x07);
682
    result>>= 8 - 1;
683
#endif
684
    index++;
685
    s->index= index;
686

    
687
    return result;
688
#else
689
    return get_bits(s, 1);
690
#endif
691
}
692

    
693
static inline unsigned int show_bits1(GetBitContext *s){
694
    return show_bits(s, 1);
695
}
696

    
697
static inline void skip_bits1(GetBitContext *s){
698
    skip_bits(s, 1);
699
}
700

    
701
/**
702
 * reads 0-32 bits.
703
 */
704
static inline unsigned int get_bits_long(GetBitContext *s, int n){
705
    if(n<=17) return get_bits(s, n);
706
    else{
707
#ifdef ALT_BITSTREAM_READER_LE
708
        int ret= get_bits(s, 16);
709
        return ret | (get_bits(s, n-16) << 16);
710
#else
711
        int ret= get_bits(s, 16) << (n-16);
712
        return ret | get_bits(s, n-16);
713
#endif
714
    }
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
        int ret= get_bits_long(s, n);
725
        *s= gb;
726
        return ret;
727
    }
728
}
729

    
730
static inline int check_marker(GetBitContext *s, const char *msg)
731
{
732
    int bit= get_bits1(s);
733
    if(!bit)
734
        av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
735

    
736
    return bit;
737
}
738

    
739
/**
740
 * init GetBitContext.
741
 * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
742
 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
743
 * @param bit_size the size of the buffer in bits
744
 */
745
static inline void init_get_bits(GetBitContext *s,
746
                   const uint8_t *buffer, int bit_size)
747
{
748
    int buffer_size= (bit_size+7)>>3;
749
    if(buffer_size < 0 || bit_size < 0) {
750
        buffer_size = bit_size = 0;
751
        buffer = NULL;
752
    }
753

    
754
    s->buffer= buffer;
755
    s->size_in_bits= bit_size;
756
    s->buffer_end= buffer + buffer_size;
757
#ifdef ALT_BITSTREAM_READER
758
    s->index=0;
759
#elif defined LIBMPEG2_BITSTREAM_READER
760
    s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));
761
    s->bit_count = 16 + 8*((intptr_t)buffer&1);
762
    skip_bits_long(s, 0);
763
#elif defined A32_BITSTREAM_READER
764
    s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3));
765
    s->bit_count = 32 + 8*((intptr_t)buffer&3);
766
    skip_bits_long(s, 0);
767
#endif
768
}
769

    
770
static inline void align_get_bits(GetBitContext *s)
771
{
772
    int n= (-get_bits_count(s)) & 7;
773
    if(n) skip_bits(s, n);
774
}
775

    
776
#define init_vlc(vlc, nb_bits, nb_codes,\
777
                 bits, bits_wrap, bits_size,\
778
                 codes, codes_wrap, codes_size,\
779
                 flags)\
780
        init_vlc_sparse(vlc, nb_bits, nb_codes,\
781
                 bits, bits_wrap, bits_size,\
782
                 codes, codes_wrap, codes_size,\
783
                 NULL, 0, 0, flags)
784

    
785
int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
786
             const void *bits, int bits_wrap, int bits_size,
787
             const void *codes, int codes_wrap, int codes_size,
788
             const void *symbols, int symbols_wrap, int symbols_size,
789
             int flags);
790
#define INIT_VLC_USE_STATIC 1 ///< VERY strongly deprecated and forbidden
791
#define INIT_VLC_LE         2
792
#define INIT_VLC_USE_NEW_STATIC 4
793
void free_vlc(VLC *vlc);
794

    
795
#define INIT_VLC_STATIC(vlc, bits, a,b,c,d,e,f,g, static_size)\
796
{\
797
    static VLC_TYPE table[static_size][2];\
798
    (vlc)->table= table;\
799
    (vlc)->table_allocated= static_size;\
800
    init_vlc(vlc, bits, a,b,c,d,e,f,g, INIT_VLC_USE_NEW_STATIC);\
801
}
802

    
803

    
804
/**
805
 *
806
 * if the vlc code is invalid and max_depth=1 than no bits will be removed
807
 * if the vlc code is invalid and max_depth>1 than the number of bits removed
808
 * is undefined
809
 */
810
#define GET_VLC(code, name, gb, table, bits, max_depth)\
811
{\
812
    int n, index, nb_bits;\
813
\
814
    index= SHOW_UBITS(name, gb, bits);\
815
    code = table[index][0];\
816
    n    = table[index][1];\
817
\
818
    if(max_depth > 1 && n < 0){\
819
        LAST_SKIP_BITS(name, gb, bits)\
820
        UPDATE_CACHE(name, gb)\
821
\
822
        nb_bits = -n;\
823
\
824
        index= SHOW_UBITS(name, gb, nb_bits) + code;\
825
        code = table[index][0];\
826
        n    = table[index][1];\
827
        if(max_depth > 2 && n < 0){\
828
            LAST_SKIP_BITS(name, gb, nb_bits)\
829
            UPDATE_CACHE(name, gb)\
830
\
831
            nb_bits = -n;\
832
\
833
            index= SHOW_UBITS(name, gb, nb_bits) + code;\
834
            code = table[index][0];\
835
            n    = table[index][1];\
836
        }\
837
    }\
838
    SKIP_BITS(name, gb, n)\
839
}
840

    
841
#define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
842
{\
843
    int n, index, nb_bits;\
844
\
845
    index= SHOW_UBITS(name, gb, bits);\
846
    level = table[index].level;\
847
    n     = table[index].len;\
848
\
849
    if(max_depth > 1 && n < 0){\
850
        SKIP_BITS(name, gb, bits)\
851
        if(need_update){\
852
            UPDATE_CACHE(name, gb)\
853
        }\
854
\
855
        nb_bits = -n;\
856
\
857
        index= SHOW_UBITS(name, gb, nb_bits) + level;\
858
        level = table[index].level;\
859
        n     = table[index].len;\
860
    }\
861
    run= table[index].run;\
862
    SKIP_BITS(name, gb, n)\
863
}
864

    
865

    
866
/**
867
 * parses a vlc code, faster then get_vlc()
868
 * @param bits is the number of bits which will be read at once, must be
869
 *             identical to nb_bits in init_vlc()
870
 * @param max_depth is the number of times bits bits must be read to completely
871
 *                  read the longest vlc code
872
 *                  = (max_vlc_length + bits - 1) / bits
873
 */
874
static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
875
                                  int bits, int max_depth)
876
{
877
    int code;
878

    
879
    OPEN_READER(re, s)
880
    UPDATE_CACHE(re, s)
881

    
882
    GET_VLC(code, re, s, table, bits, max_depth)
883

    
884
    CLOSE_READER(re, s)
885
    return code;
886
}
887

    
888
//#define TRACE
889

    
890
#ifdef TRACE
891
static inline void print_bin(int bits, int n){
892
    int i;
893

    
894
    for(i=n-1; i>=0; i--){
895
        av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
896
    }
897
    for(i=n; i<24; i++)
898
        av_log(NULL, AV_LOG_DEBUG, " ");
899
}
900

    
901
static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
902
    int r= get_bits(s, n);
903

    
904
    print_bin(r, n);
905
    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);
906
    return r;
907
}
908
static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
909
    int show= show_bits(s, 24);
910
    int pos= get_bits_count(s);
911
    int r= get_vlc2(s, table, bits, max_depth);
912
    int len= get_bits_count(s) - pos;
913
    int bits2= show>>(24-len);
914

    
915
    print_bin(bits2, len);
916

    
917
    av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
918
    return r;
919
}
920
static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
921
    int show= show_bits(s, n);
922
    int r= get_xbits(s, n);
923

    
924
    print_bin(show, n);
925
    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);
926
    return r;
927
}
928

    
929
#define get_bits(s, n)  get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
930
#define get_bits1(s)    get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
931
#define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
932
#define get_vlc(s, vlc)            get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
933
#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
934

    
935
#define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__)
936

    
937
#else //TRACE
938
#define tprintf(p, ...) {}
939
#endif
940

    
941
static inline int decode012(GetBitContext *gb){
942
    int n;
943
    n = get_bits1(gb);
944
    if (n == 0)
945
        return 0;
946
    else
947
        return get_bits1(gb) + 1;
948
}
949

    
950
static inline int decode210(GetBitContext *gb){
951
    if (get_bits1(gb))
952
        return 0;
953
    else
954
        return 2 - get_bits1(gb);
955
}
956

    
957
#endif /* AVCODEC_BITSTREAM_H */