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ffmpeg / libavcodec / bitstream.h @ 755bfeab

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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 BITSTREAM_H
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#define BITSTREAM_H
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#include "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_ARMV4L
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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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#define LIBMPEG2_BITSTREAM_READER_HACK //add BERO
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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)))
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#endif
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/* bit output */
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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;
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#endif
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} PutBitContext;
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static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
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{
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    if(buffer_size < 0) {
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        buffer_size = 0;
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        buffer = NULL;
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    }
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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
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    s->buf_ptr = s->buf;
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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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/* return the number of bits output */
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static inline int put_bits_count(PutBitContext *s)
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{
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#ifdef ALT_BITSTREAM_WRITER
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    return s->index;
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#else
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    return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
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#endif
113
}
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/* pad the end of the output stream with zeros */
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static inline void flush_put_bits(PutBitContext *s)
117
{
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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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    s->bit_buf<<= s->bit_left;
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    while (s->bit_left < 32) {
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        /* XXX: should test end of buffer */
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        *s->buf_ptr++=s->bit_buf >> 24;
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        s->bit_buf<<=8;
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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
131
}
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void align_put_bits(PutBitContext *s);
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void ff_put_string(PutBitContext * pbc, char *s, int put_zero);
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/* bit input */
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/* buffer, buffer_end and size_in_bits must be present and used by every reader */
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typedef struct GetBitContext {
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    const uint8_t *buffer, *buffer_end;
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#ifdef ALT_BITSTREAM_READER
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    int index;
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#elif defined LIBMPEG2_BITSTREAM_READER
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    uint8_t *buffer_ptr;
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    uint32_t cache;
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    int bit_count;
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#elif defined A32_BITSTREAM_READER
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    uint32_t *buffer_ptr;
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    uint32_t cache0;
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    uint32_t cache1;
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    int bit_count;
151
#endif
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    int size_in_bits;
153
} GetBitContext;
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#define VLC_TYPE int16_t
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157
typedef struct VLC {
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    int bits;
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    VLC_TYPE (*table)[2]; ///< code, bits
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    int table_size, table_allocated;
161
} VLC;
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typedef struct RL_VLC_ELEM {
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    int16_t level;
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    int8_t len;
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    uint8_t run;
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} RL_VLC_ELEM;
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#if defined(ARCH_SPARC) || defined(ARCH_ARMV4L) || defined(ARCH_MIPS) || defined(ARCH_BFIN)
170
#define UNALIGNED_STORES_ARE_BAD
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#endif
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/* used to avoid missaligned exceptions on some archs (alpha, ...) */
174
#if defined(ARCH_X86)
175
#    define unaligned16(a) (*(const uint16_t*)(a))
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#    define unaligned32(a) (*(const uint32_t*)(a))
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#    define unaligned64(a) (*(const uint64_t*)(a))
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#else
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#    ifdef __GNUC__
180
#    define unaligned(x)                                \
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static inline uint##x##_t unaligned##x(const void *v) { \
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    struct Unaligned {                                  \
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        uint##x##_t i;                                  \
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    } __attribute__((packed));                          \
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                                                        \
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    return ((const struct Unaligned *) v)->i;           \
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}
188
#    elif defined(__DECC)
189
#    define unaligned(x)                                        \
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static inline uint##x##_t unaligned##x(const void *v) {         \
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    return *(const __unaligned uint##x##_t *) v;                \
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}
193
#    else
194
#    define unaligned(x)                                        \
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static inline uint##x##_t unaligned##x(const void *v) {         \
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    return *(const uint##x##_t *) v;                            \
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}
198
#    endif
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unaligned(16)
200
unaligned(32)
201
unaligned(64)
202
#undef unaligned
203
#endif /* defined(ARCH_X86) */
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#ifndef ALT_BITSTREAM_WRITER
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static inline void put_bits(PutBitContext *s, int n, unsigned int value)
207
{
208
    unsigned int bit_buf;
209
    int bit_left;
210

    
211
    //    printf("put_bits=%d %x\n", n, value);
212
    assert(n == 32 || value < (1U << n));
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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);
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    /* XXX: optimize */
219
    if (n < bit_left) {
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        bit_buf = (bit_buf<<n) | value;
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        bit_left-=n;
222
    } else {
223
        bit_buf<<=bit_left;
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        bit_buf |= value >> (n - bit_left);
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#ifdef UNALIGNED_STORES_ARE_BAD
226
        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      ;
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        } else
232
#endif
233
        *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
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        //printf("bitbuf = %08x\n", bit_buf);
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        s->buf_ptr+=4;
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        bit_left+=32 - n;
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        bit_buf = value;
238
    }
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    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"
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        "xorl %%eax, %%eax              \n\t"
254
        "shrdl %%cl, %1, %%eax          \n\t"
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        "shrl %%cl, %1                  \n\t"
256
        "movl %0, %%ecx                 \n\t"
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        "shrl $3, %%ecx                 \n\t"
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        "andl $0xFFFFFFFC, %%ecx        \n\t"
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        "bswapl %1                      \n\t"
260
        "orl %1, (%2, %%ecx)            \n\t"
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        "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

    
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
    abritary 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
static inline int unaligned32_be(const void *v)
404
{
405
#ifdef CONFIG_ALIGN
406
        const uint8_t *p=v;
407
        return (((p[0]<<8) | p[1])<<16) | (p[2]<<8) | (p[3]);
408
#else
409
        return be2me_32( unaligned32(v)); //original
410
#endif
411
}
412

    
413
static inline int unaligned32_le(const void *v)
414
{
415
#ifdef CONFIG_ALIGN
416
       const uint8_t *p=v;
417
       return (((p[3]<<8) | p[2])<<16) | (p[1]<<8) | (p[0]);
418
#else
419
       return le2me_32( unaligned32(v)); //original
420
#endif
421
}
422

    
423
#ifdef ALT_BITSTREAM_READER
424
#   define MIN_CACHE_BITS 25
425

    
426
#   define OPEN_READER(name, gb)\
427
        int name##_index= (gb)->index;\
428
        int name##_cache= 0;\
429

    
430
#   define CLOSE_READER(name, gb)\
431
        (gb)->index= name##_index;\
432

    
433
# ifdef ALT_BITSTREAM_READER_LE
434
#   define UPDATE_CACHE(name, gb)\
435
        name##_cache= unaligned32_le( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
436

    
437
#   define SKIP_CACHE(name, gb, num)\
438
        name##_cache >>= (num);
439
# else
440
#   define UPDATE_CACHE(name, gb)\
441
        name##_cache= unaligned32_be( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
442

    
443
#   define SKIP_CACHE(name, gb, num)\
444
        name##_cache <<= (num);
445
# endif
446

    
447
// FIXME name?
448
#   define SKIP_COUNTER(name, gb, num)\
449
        name##_index += (num);\
450

    
451
#   define SKIP_BITS(name, gb, num)\
452
        {\
453
            SKIP_CACHE(name, gb, num)\
454
            SKIP_COUNTER(name, gb, num)\
455
        }\
456

    
457
#   define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
458
#   define LAST_SKIP_CACHE(name, gb, num) ;
459

    
460
# ifdef ALT_BITSTREAM_READER_LE
461
#   define SHOW_UBITS(name, gb, num)\
462
        ((name##_cache) & (NEG_USR32(0xffffffff,num)))
463

    
464
#   define SHOW_SBITS(name, gb, num)\
465
        NEG_SSR32((name##_cache)<<(32-(num)), num)
466
# else
467
#   define SHOW_UBITS(name, gb, num)\
468
        NEG_USR32(name##_cache, num)
469

    
470
#   define SHOW_SBITS(name, gb, num)\
471
        NEG_SSR32(name##_cache, num)
472
# endif
473

    
474
#   define GET_CACHE(name, gb)\
475
        ((uint32_t)name##_cache)
476

    
477
static inline int get_bits_count(GetBitContext *s){
478
    return s->index;
479
}
480

    
481
static inline void skip_bits_long(GetBitContext *s, int n){
482
    s->index += n;
483
}
484

    
485
#elif defined LIBMPEG2_BITSTREAM_READER
486
//libmpeg2 like reader
487

    
488
#   define MIN_CACHE_BITS 17
489

    
490
#   define OPEN_READER(name, gb)\
491
        int name##_bit_count=(gb)->bit_count;\
492
        int name##_cache= (gb)->cache;\
493
        uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
494

    
495
#   define CLOSE_READER(name, gb)\
496
        (gb)->bit_count= name##_bit_count;\
497
        (gb)->cache= name##_cache;\
498
        (gb)->buffer_ptr= name##_buffer_ptr;\
499

    
500
#ifdef LIBMPEG2_BITSTREAM_READER_HACK
501

    
502
#   define UPDATE_CACHE(name, gb)\
503
    if(name##_bit_count >= 0){\
504
        name##_cache+= (int)be2me_16(*(uint16_t*)name##_buffer_ptr) << name##_bit_count;\
505
        name##_buffer_ptr += 2;\
506
        name##_bit_count-= 16;\
507
    }\
508

    
509
#else
510

    
511
#   define UPDATE_CACHE(name, gb)\
512
    if(name##_bit_count >= 0){\
513
        name##_cache+= ((name##_buffer_ptr[0]<<8) + name##_buffer_ptr[1]) << name##_bit_count;\
514
        name##_buffer_ptr+=2;\
515
        name##_bit_count-= 16;\
516
    }\
517

    
518
#endif
519

    
520
#   define SKIP_CACHE(name, gb, num)\
521
        name##_cache <<= (num);\
522

    
523
#   define SKIP_COUNTER(name, gb, num)\
524
        name##_bit_count += (num);\
525

    
526
#   define SKIP_BITS(name, gb, num)\
527
        {\
528
            SKIP_CACHE(name, gb, num)\
529
            SKIP_COUNTER(name, gb, num)\
530
        }\
531

    
532
#   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
533
#   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
534

    
535
#   define SHOW_UBITS(name, gb, num)\
536
        NEG_USR32(name##_cache, num)
537

    
538
#   define SHOW_SBITS(name, gb, num)\
539
        NEG_SSR32(name##_cache, num)
540

    
541
#   define GET_CACHE(name, gb)\
542
        ((uint32_t)name##_cache)
543

    
544
static inline int get_bits_count(GetBitContext *s){
545
    return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
546
}
547

    
548
static inline void skip_bits_long(GetBitContext *s, int n){
549
    OPEN_READER(re, s)
550
    re_bit_count += n;
551
    re_buffer_ptr += 2*(re_bit_count>>4);
552
    re_bit_count &= 15;
553
    re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count);
554
    UPDATE_CACHE(re, s)
555
    CLOSE_READER(re, s)
556
}
557

    
558
#elif defined A32_BITSTREAM_READER
559

    
560
#   define MIN_CACHE_BITS 32
561

    
562
#   define OPEN_READER(name, gb)\
563
        int name##_bit_count=(gb)->bit_count;\
564
        uint32_t name##_cache0= (gb)->cache0;\
565
        uint32_t name##_cache1= (gb)->cache1;\
566
        uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
567

    
568
#   define CLOSE_READER(name, gb)\
569
        (gb)->bit_count= name##_bit_count;\
570
        (gb)->cache0= name##_cache0;\
571
        (gb)->cache1= name##_cache1;\
572
        (gb)->buffer_ptr= name##_buffer_ptr;\
573

    
574
#   define UPDATE_CACHE(name, gb)\
575
    if(name##_bit_count > 0){\
576
        const uint32_t next= be2me_32( *name##_buffer_ptr );\
577
        name##_cache0 |= NEG_USR32(next,name##_bit_count);\
578
        name##_cache1 |= next<<name##_bit_count;\
579
        name##_buffer_ptr++;\
580
        name##_bit_count-= 32;\
581
    }\
582

    
583
#if defined(ARCH_X86)
584
#   define SKIP_CACHE(name, gb, num)\
585
        asm(\
586
            "shldl %2, %1, %0          \n\t"\
587
            "shll %2, %1               \n\t"\
588
            : "+r" (name##_cache0), "+r" (name##_cache1)\
589
            : "Ic" ((uint8_t)(num))\
590
           );
591
#else
592
#   define SKIP_CACHE(name, gb, num)\
593
        name##_cache0 <<= (num);\
594
        name##_cache0 |= NEG_USR32(name##_cache1,num);\
595
        name##_cache1 <<= (num);
596
#endif
597

    
598
#   define SKIP_COUNTER(name, gb, num)\
599
        name##_bit_count += (num);\
600

    
601
#   define SKIP_BITS(name, gb, num)\
602
        {\
603
            SKIP_CACHE(name, gb, num)\
604
            SKIP_COUNTER(name, gb, num)\
605
        }\
606

    
607
#   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
608
#   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
609

    
610
#   define SHOW_UBITS(name, gb, num)\
611
        NEG_USR32(name##_cache0, num)
612

    
613
#   define SHOW_SBITS(name, gb, num)\
614
        NEG_SSR32(name##_cache0, num)
615

    
616
#   define GET_CACHE(name, gb)\
617
        (name##_cache0)
618

    
619
static inline int get_bits_count(GetBitContext *s){
620
    return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
621
}
622

    
623
static inline void skip_bits_long(GetBitContext *s, int n){
624
    OPEN_READER(re, s)
625
    re_bit_count += n;
626
    re_buffer_ptr += re_bit_count>>5;
627
    re_bit_count &= 31;
628
    re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count;
629
    re_cache1 = 0;
630
    UPDATE_CACHE(re, s)
631
    CLOSE_READER(re, s)
632
}
633

    
634
#endif
635

    
636
/**
637
 * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
638
 * if MSB not set it is negative
639
 * @param n length in bits
640
 * @author BERO
641
 */
642
static inline int get_xbits(GetBitContext *s, int n){
643
    register int sign;
644
    register int32_t cache;
645
    OPEN_READER(re, s)
646
    UPDATE_CACHE(re, s)
647
    cache = GET_CACHE(re,s);
648
    sign=(~cache)>>31;
649
    LAST_SKIP_BITS(re, s, n)
650
    CLOSE_READER(re, s)
651
    return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
652
}
653

    
654
static inline int get_sbits(GetBitContext *s, int n){
655
    register int tmp;
656
    OPEN_READER(re, s)
657
    UPDATE_CACHE(re, s)
658
    tmp= SHOW_SBITS(re, s, n);
659
    LAST_SKIP_BITS(re, s, n)
660
    CLOSE_READER(re, s)
661
    return tmp;
662
}
663

    
664
/**
665
 * reads 1-17 bits.
666
 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
667
 */
668
static inline unsigned int get_bits(GetBitContext *s, int n){
669
    register int tmp;
670
    OPEN_READER(re, s)
671
    UPDATE_CACHE(re, s)
672
    tmp= SHOW_UBITS(re, s, n);
673
    LAST_SKIP_BITS(re, s, n)
674
    CLOSE_READER(re, s)
675
    return tmp;
676
}
677

    
678
/**
679
 * shows 1-17 bits.
680
 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
681
 */
682
static inline unsigned int show_bits(GetBitContext *s, int n){
683
    register int tmp;
684
    OPEN_READER(re, s)
685
    UPDATE_CACHE(re, s)
686
    tmp= SHOW_UBITS(re, s, n);
687
//    CLOSE_READER(re, s)
688
    return tmp;
689
}
690

    
691
static inline void skip_bits(GetBitContext *s, int n){
692
 //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
693
    OPEN_READER(re, s)
694
    UPDATE_CACHE(re, s)
695
    LAST_SKIP_BITS(re, s, n)
696
    CLOSE_READER(re, s)
697
}
698

    
699
static inline unsigned int get_bits1(GetBitContext *s){
700
#ifdef ALT_BITSTREAM_READER
701
    int index= s->index;
702
    uint8_t result= s->buffer[ index>>3 ];
703
#ifdef ALT_BITSTREAM_READER_LE
704
    result>>= (index&0x07);
705
    result&= 1;
706
#else
707
    result<<= (index&0x07);
708
    result>>= 8 - 1;
709
#endif
710
    index++;
711
    s->index= index;
712

    
713
    return result;
714
#else
715
    return get_bits(s, 1);
716
#endif
717
}
718

    
719
static inline unsigned int show_bits1(GetBitContext *s){
720
    return show_bits(s, 1);
721
}
722

    
723
static inline void skip_bits1(GetBitContext *s){
724
    skip_bits(s, 1);
725
}
726

    
727
/**
728
 * reads 0-32 bits.
729
 */
730
static inline unsigned int get_bits_long(GetBitContext *s, int n){
731
    if(n<=17) return get_bits(s, n);
732
    else{
733
#ifdef ALT_BITSTREAM_READER_LE
734
        int ret= get_bits(s, 16);
735
        return ret | (get_bits(s, n-16) << 16);
736
#else
737
        int ret= get_bits(s, 16) << (n-16);
738
        return ret | get_bits(s, n-16);
739
#endif
740
    }
741
}
742

    
743
/**
744
 * shows 0-32 bits.
745
 */
746
static inline unsigned int show_bits_long(GetBitContext *s, int n){
747
    if(n<=17) return show_bits(s, n);
748
    else{
749
        GetBitContext gb= *s;
750
        int ret= get_bits_long(s, n);
751
        *s= gb;
752
        return ret;
753
    }
754
}
755

    
756
static inline int check_marker(GetBitContext *s, const char *msg)
757
{
758
    int bit= get_bits1(s);
759
    if(!bit)
760
        av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
761

    
762
    return bit;
763
}
764

    
765
/**
766
 * init GetBitContext.
767
 * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
768
 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
769
 * @param bit_size the size of the buffer in bits
770
 */
771
static inline void init_get_bits(GetBitContext *s,
772
                   const uint8_t *buffer, int bit_size)
773
{
774
    int buffer_size= (bit_size+7)>>3;
775
    if(buffer_size < 0 || bit_size < 0) {
776
        buffer_size = bit_size = 0;
777
        buffer = NULL;
778
    }
779

    
780
    s->buffer= buffer;
781
    s->size_in_bits= bit_size;
782
    s->buffer_end= buffer + buffer_size;
783
#ifdef ALT_BITSTREAM_READER
784
    s->index=0;
785
#elif defined LIBMPEG2_BITSTREAM_READER
786
    s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));
787
    s->bit_count = 16 + 8*((intptr_t)buffer&1);
788
    skip_bits_long(s, 0);
789
#elif defined A32_BITSTREAM_READER
790
    s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3));
791
    s->bit_count = 32 + 8*((intptr_t)buffer&3);
792
    skip_bits_long(s, 0);
793
#endif
794
}
795

    
796
static inline void align_get_bits(GetBitContext *s)
797
{
798
    int n= (-get_bits_count(s)) & 7;
799
    if(n) skip_bits(s, n);
800
}
801

    
802
#define init_vlc(vlc, nb_bits, nb_codes,\
803
                 bits, bits_wrap, bits_size,\
804
                 codes, codes_wrap, codes_size,\
805
                 flags)\
806
        init_vlc_sparse(vlc, nb_bits, nb_codes,\
807
                 bits, bits_wrap, bits_size,\
808
                 codes, codes_wrap, codes_size,\
809
                 NULL, 0, 0, flags)
810

    
811
int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
812
             const void *bits, int bits_wrap, int bits_size,
813
             const void *codes, int codes_wrap, int codes_size,
814
             const void *symbols, int symbols_wrap, int symbols_size,
815
             int flags);
816
#define INIT_VLC_USE_STATIC 1
817
#define INIT_VLC_LE         2
818
void free_vlc(VLC *vlc);
819

    
820
/**
821
 *
822
 * if the vlc code is invalid and max_depth=1 than no bits will be removed
823
 * if the vlc code is invalid and max_depth>1 than the number of bits removed
824
 * is undefined
825
 */
826
#define GET_VLC(code, name, gb, table, bits, max_depth)\
827
{\
828
    int n, index, nb_bits;\
829
\
830
    index= SHOW_UBITS(name, gb, bits);\
831
    code = table[index][0];\
832
    n    = table[index][1];\
833
\
834
    if(max_depth > 1 && n < 0){\
835
        LAST_SKIP_BITS(name, gb, bits)\
836
        UPDATE_CACHE(name, gb)\
837
\
838
        nb_bits = -n;\
839
\
840
        index= SHOW_UBITS(name, gb, nb_bits) + code;\
841
        code = table[index][0];\
842
        n    = table[index][1];\
843
        if(max_depth > 2 && n < 0){\
844
            LAST_SKIP_BITS(name, gb, nb_bits)\
845
            UPDATE_CACHE(name, gb)\
846
\
847
            nb_bits = -n;\
848
\
849
            index= SHOW_UBITS(name, gb, nb_bits) + code;\
850
            code = table[index][0];\
851
            n    = table[index][1];\
852
        }\
853
    }\
854
    SKIP_BITS(name, gb, n)\
855
}
856

    
857
#define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
858
{\
859
    int n, index, nb_bits;\
860
\
861
    index= SHOW_UBITS(name, gb, bits);\
862
    level = table[index].level;\
863
    n     = table[index].len;\
864
\
865
    if(max_depth > 1 && n < 0){\
866
        SKIP_BITS(name, gb, bits)\
867
        if(need_update){\
868
            UPDATE_CACHE(name, gb)\
869
        }\
870
\
871
        nb_bits = -n;\
872
\
873
        index= SHOW_UBITS(name, gb, nb_bits) + level;\
874
        level = table[index].level;\
875
        n     = table[index].len;\
876
    }\
877
    run= table[index].run;\
878
    SKIP_BITS(name, gb, n)\
879
}
880

    
881

    
882
/**
883
 * parses a vlc code, faster then get_vlc()
884
 * @param bits is the number of bits which will be read at once, must be
885
 *             identical to nb_bits in init_vlc()
886
 * @param max_depth is the number of times bits bits must be read to completely
887
 *                  read the longest vlc code
888
 *                  = (max_vlc_length + bits - 1) / bits
889
 */
890
static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
891
                                  int bits, int max_depth)
892
{
893
    int code;
894

    
895
    OPEN_READER(re, s)
896
    UPDATE_CACHE(re, s)
897

    
898
    GET_VLC(code, re, s, table, bits, max_depth)
899

    
900
    CLOSE_READER(re, s)
901
    return code;
902
}
903

    
904
//#define TRACE
905

    
906
#ifdef TRACE
907
static inline void print_bin(int bits, int n){
908
    int i;
909

    
910
    for(i=n-1; i>=0; i--){
911
        av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
912
    }
913
    for(i=n; i<24; i++)
914
        av_log(NULL, AV_LOG_DEBUG, " ");
915
}
916

    
917
static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
918
    int r= get_bits(s, n);
919

    
920
    print_bin(r, n);
921
    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);
922
    return r;
923
}
924
static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
925
    int show= show_bits(s, 24);
926
    int pos= get_bits_count(s);
927
    int r= get_vlc2(s, table, bits, max_depth);
928
    int len= get_bits_count(s) - pos;
929
    int bits2= show>>(24-len);
930

    
931
    print_bin(bits2, len);
932

    
933
    av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
934
    return r;
935
}
936
static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
937
    int show= show_bits(s, n);
938
    int r= get_xbits(s, n);
939

    
940
    print_bin(show, n);
941
    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);
942
    return r;
943
}
944

    
945
#define get_bits(s, n)  get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
946
#define get_bits1(s)    get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
947
#define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
948
#define get_vlc(s, vlc)            get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
949
#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
950

    
951
#define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__)
952

    
953
#else //TRACE
954
#define tprintf(p, ...) {}
955
#endif
956

    
957
static inline int decode012(GetBitContext *gb){
958
    int n;
959
    n = get_bits1(gb);
960
    if (n == 0)
961
        return 0;
962
    else
963
        return get_bits1(gb) + 1;
964
}
965

    
966
#endif /* BITSTREAM_H */