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ffmpeg / libavcodec / bitstream.h @ a7702890

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1
/**
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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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//#define ALT_BITSTREAM_WRITER
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//#define ALIGNED_BITSTREAM_WRITER
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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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#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) || defined(ARCH_X86_64)
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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
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}
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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)
86
{
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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
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}
101

    
102
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;
120
#endif
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    int size_in_bits;
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} GetBitContext;
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#define VLC_TYPE int16_t
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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;
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} 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)
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#define UNALIGNED_STORES_ARE_BAD
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#endif
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/* used to avoid missaligned exceptions on some archs (alpha, ...) */
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#if defined(ARCH_X86) || defined(ARCH_X86_64)
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#    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__
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#    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));                          \
154
                                                        \
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    return ((const struct Unaligned *) v)->i;           \
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}
157
#    elif defined(__DECC)
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#    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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}
162
#    else
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#    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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}
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#    endif
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unaligned(16)
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unaligned(32)
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unaligned(64)
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#undef unaligned
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#endif //!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)
176
{
177
    unsigned int bit_buf;
178
    int bit_left;
179

    
180
    //    printf("put_bits=%d %x\n", n, value);
181
    assert(n == 32 || value < (1U << n));
182

    
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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);
187
    /* XXX: optimize */
188
    if (n < bit_left) {
189
        bit_buf = (bit_buf<<n) | value;
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        bit_left-=n;
191
    } else {
192
        bit_buf<<=bit_left;
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        bit_buf |= value >> (n - bit_left);
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#ifdef UNALIGNED_STORES_ARE_BAD
195
        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
201
#endif
202
        *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
203
        //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;
207
    }
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    s->bit_buf = bit_buf;
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    s->bit_left = bit_left;
211
}
212
#endif
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#ifdef ALT_BITSTREAM_WRITER
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static inline void put_bits(PutBitContext *s, int n, unsigned int value)
217
{
218
#    ifdef ALIGNED_BITSTREAM_WRITER
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#        if defined(ARCH_X86) || defined(ARCH_X86_64)
220
    asm volatile(
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        "movl %0, %%ecx                 \n\t"
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        "xorl %%eax, %%eax              \n\t"
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        "shrdl %%cl, %1, %%eax          \n\t"
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        "shrl %%cl, %1                  \n\t"
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        "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"
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        "orl %1, (%2, %%ecx)            \n\t"
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        "bswapl %%eax                   \n\t"
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        "addl %3, %0                    \n\t"
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        "movl %%eax, 4(%2, %%ecx)       \n\t"
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        : "=&r" (s->index), "=&r" (value)
234
        : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
235
        : "%eax", "%ecx"
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    );
237
#        else
238
    int index= s->index;
239
    uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
240

    
241
    value<<= 32-n;
242

    
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    ptr[0] |= be2me_32(value>>(index&31));
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    ptr[1]  = be2me_32(value<<(32-(index&31)));
245
//if(n>24) printf("%d %d\n", n, value);
246
    index+= n;
247
    s->index= index;
248
#        endif
249
#    else //ALIGNED_BITSTREAM_WRITER
250
#        if defined(ARCH_X86) || defined(ARCH_X86_64)
251
    asm volatile(
252
        "movl $7, %%ecx                 \n\t"
253
        "andl %0, %%ecx                 \n\t"
254
        "addl %3, %%ecx                 \n\t"
255
        "negl %%ecx                     \n\t"
256
        "shll %%cl, %1                  \n\t"
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        "bswapl %1                      \n\t"
258
        "movl %0, %%ecx                 \n\t"
259
        "shrl $3, %%ecx                 \n\t"
260
        "orl %1, (%%ecx, %2)            \n\t"
261
        "addl %3, %0                    \n\t"
262
        "movl $0, 4(%%ecx, %2)          \n\t"
263
        : "=&r" (s->index), "=&r" (value)
264
        : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
265
        : "%ecx"
266
    );
267
#        else
268
    int index= s->index;
269
    uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
270

    
271
    ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
272
    ptr[1] = 0;
273
//if(n>24) printf("%d %d\n", n, value);
274
    index+= n;
275
    s->index= index;
276
#        endif
277
#    endif //!ALIGNED_BITSTREAM_WRITER
278
}
279
#endif
280

    
281

    
282
static inline uint8_t* pbBufPtr(PutBitContext *s)
283
{
284
#ifdef ALT_BITSTREAM_WRITER
285
        return s->buf + (s->index>>3);
286
#else
287
        return s->buf_ptr;
288
#endif
289
}
290

    
291
/**
292
 *
293
 * PutBitContext must be flushed & aligned to a byte boundary before calling this.
294
 */
295
static inline void skip_put_bytes(PutBitContext *s, int n){
296
        assert((put_bits_count(s)&7)==0);
297
#ifdef ALT_BITSTREAM_WRITER
298
        FIXME may need some cleaning of the buffer
299
        s->index += n<<3;
300
#else
301
        assert(s->bit_left==32);
302
        s->buf_ptr += n;
303
#endif
304
}
305

    
306
/**
307
 * skips the given number of bits.
308
 * must only be used if the actual values in the bitstream dont matter
309
 */
310
static inline void skip_put_bits(PutBitContext *s, int n){
311
#ifdef ALT_BITSTREAM_WRITER
312
    s->index += n;
313
#else
314
    s->bit_left -= n;
315
    s->buf_ptr-= s->bit_left>>5;
316
    s->bit_left &= 31;
317
#endif
318
}
319

    
320
/**
321
 * Changes the end of the buffer.
322
 */
323
static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
324
    s->buf_end= s->buf + size;
325
}
326

    
327
/* Bitstream reader API docs:
328
name
329
    abritary name which is used as prefix for the internal variables
330

331
gb
332
    getbitcontext
333

334
OPEN_READER(name, gb)
335
    loads gb into local variables
336

337
CLOSE_READER(name, gb)
338
    stores local vars in gb
339

340
UPDATE_CACHE(name, gb)
341
    refills the internal cache from the bitstream
342
    after this call at least MIN_CACHE_BITS will be available,
343

344
GET_CACHE(name, gb)
345
    will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
346

347
SHOW_UBITS(name, gb, num)
348
    will return the next num bits
349

350
SHOW_SBITS(name, gb, num)
351
    will return the next num bits and do sign extension
352

353
SKIP_BITS(name, gb, num)
354
    will skip over the next num bits
355
    note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
356

357
SKIP_CACHE(name, gb, num)
358
    will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
359

360
SKIP_COUNTER(name, gb, num)
361
    will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
362

363
LAST_SKIP_CACHE(name, gb, num)
364
    will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
365

366
LAST_SKIP_BITS(name, gb, num)
367
    is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
368

369
for examples see get_bits, show_bits, skip_bits, get_vlc
370
*/
371

    
372
static inline int unaligned32_be(const void *v)
373
{
374
#ifdef CONFIG_ALIGN
375
        const uint8_t *p=v;
376
        return (((p[0]<<8) | p[1])<<16) | (p[2]<<8) | (p[3]);
377
#else
378
        return be2me_32( unaligned32(v)); //original
379
#endif
380
}
381

    
382
static inline int unaligned32_le(const void *v)
383
{
384
#ifdef CONFIG_ALIGN
385
       const uint8_t *p=v;
386
       return (((p[3]<<8) | p[2])<<16) | (p[1]<<8) | (p[0]);
387
#else
388
       return le2me_32( unaligned32(v)); //original
389
#endif
390
}
391

    
392
#ifdef ALT_BITSTREAM_READER
393
#   define MIN_CACHE_BITS 25
394

    
395
#   define OPEN_READER(name, gb)\
396
        int name##_index= (gb)->index;\
397
        int name##_cache= 0;\
398

    
399
#   define CLOSE_READER(name, gb)\
400
        (gb)->index= name##_index;\
401

    
402
# ifdef ALT_BITSTREAM_READER_LE
403
#   define UPDATE_CACHE(name, gb)\
404
        name##_cache= unaligned32_le( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
405

    
406
#   define SKIP_CACHE(name, gb, num)\
407
        name##_cache >>= (num);
408
# else
409
#   define UPDATE_CACHE(name, gb)\
410
        name##_cache= unaligned32_be( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
411

    
412
#   define SKIP_CACHE(name, gb, num)\
413
        name##_cache <<= (num);
414
# endif
415

    
416
// FIXME name?
417
#   define SKIP_COUNTER(name, gb, num)\
418
        name##_index += (num);\
419

    
420
#   define SKIP_BITS(name, gb, num)\
421
        {\
422
            SKIP_CACHE(name, gb, num)\
423
            SKIP_COUNTER(name, gb, num)\
424
        }\
425

    
426
#   define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
427
#   define LAST_SKIP_CACHE(name, gb, num) ;
428

    
429
# ifdef ALT_BITSTREAM_READER_LE
430
#   define SHOW_UBITS(name, gb, num)\
431
        ((name##_cache) & (NEG_USR32(0xffffffff,num)))
432
# else
433
#   define SHOW_UBITS(name, gb, num)\
434
        NEG_USR32(name##_cache, num)
435
# endif
436

    
437
#   define SHOW_SBITS(name, gb, num)\
438
        NEG_SSR32(name##_cache, num)
439

    
440
#   define GET_CACHE(name, gb)\
441
        ((uint32_t)name##_cache)
442

    
443
static inline int get_bits_count(GetBitContext *s){
444
    return s->index;
445
}
446
#elif defined LIBMPEG2_BITSTREAM_READER
447
//libmpeg2 like reader
448

    
449
#   define MIN_CACHE_BITS 17
450

    
451
#   define OPEN_READER(name, gb)\
452
        int name##_bit_count=(gb)->bit_count;\
453
        int name##_cache= (gb)->cache;\
454
        uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
455

    
456
#   define CLOSE_READER(name, gb)\
457
        (gb)->bit_count= name##_bit_count;\
458
        (gb)->cache= name##_cache;\
459
        (gb)->buffer_ptr= name##_buffer_ptr;\
460

    
461
#ifdef LIBMPEG2_BITSTREAM_READER_HACK
462

    
463
#   define UPDATE_CACHE(name, gb)\
464
    if(name##_bit_count >= 0){\
465
        name##_cache+= (int)be2me_16(*(uint16_t*)name##_buffer_ptr) << name##_bit_count;\
466
        name##_buffer_ptr += 2;\
467
        name##_bit_count-= 16;\
468
    }\
469

    
470
#else
471

    
472
#   define UPDATE_CACHE(name, gb)\
473
    if(name##_bit_count >= 0){\
474
        name##_cache+= ((name##_buffer_ptr[0]<<8) + name##_buffer_ptr[1]) << name##_bit_count;\
475
        name##_buffer_ptr+=2;\
476
        name##_bit_count-= 16;\
477
    }\
478

    
479
#endif
480

    
481
#   define SKIP_CACHE(name, gb, num)\
482
        name##_cache <<= (num);\
483

    
484
#   define SKIP_COUNTER(name, gb, num)\
485
        name##_bit_count += (num);\
486

    
487
#   define SKIP_BITS(name, gb, num)\
488
        {\
489
            SKIP_CACHE(name, gb, num)\
490
            SKIP_COUNTER(name, gb, num)\
491
        }\
492

    
493
#   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
494
#   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
495

    
496
#   define SHOW_UBITS(name, gb, num)\
497
        NEG_USR32(name##_cache, num)
498

    
499
#   define SHOW_SBITS(name, gb, num)\
500
        NEG_SSR32(name##_cache, num)
501

    
502
#   define GET_CACHE(name, gb)\
503
        ((uint32_t)name##_cache)
504

    
505
static inline int get_bits_count(GetBitContext *s){
506
    return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
507
}
508

    
509
#elif defined A32_BITSTREAM_READER
510

    
511
#   define MIN_CACHE_BITS 32
512

    
513
#   define OPEN_READER(name, gb)\
514
        int name##_bit_count=(gb)->bit_count;\
515
        uint32_t name##_cache0= (gb)->cache0;\
516
        uint32_t name##_cache1= (gb)->cache1;\
517
        uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
518

    
519
#   define CLOSE_READER(name, gb)\
520
        (gb)->bit_count= name##_bit_count;\
521
        (gb)->cache0= name##_cache0;\
522
        (gb)->cache1= name##_cache1;\
523
        (gb)->buffer_ptr= name##_buffer_ptr;\
524

    
525
#   define UPDATE_CACHE(name, gb)\
526
    if(name##_bit_count > 0){\
527
        const uint32_t next= be2me_32( *name##_buffer_ptr );\
528
        name##_cache0 |= NEG_USR32(next,name##_bit_count);\
529
        name##_cache1 |= next<<name##_bit_count;\
530
        name##_buffer_ptr++;\
531
        name##_bit_count-= 32;\
532
    }\
533

    
534
#if defined(ARCH_X86) || defined(ARCH_X86_64)
535
#   define SKIP_CACHE(name, gb, num)\
536
        asm(\
537
            "shldl %2, %1, %0          \n\t"\
538
            "shll %2, %1               \n\t"\
539
            : "+r" (name##_cache0), "+r" (name##_cache1)\
540
            : "Ic" ((uint8_t)num)\
541
           );
542
#else
543
#   define SKIP_CACHE(name, gb, num)\
544
        name##_cache0 <<= (num);\
545
        name##_cache0 |= NEG_USR32(name##_cache1,num);\
546
        name##_cache1 <<= (num);
547
#endif
548

    
549
#   define SKIP_COUNTER(name, gb, num)\
550
        name##_bit_count += (num);\
551

    
552
#   define SKIP_BITS(name, gb, num)\
553
        {\
554
            SKIP_CACHE(name, gb, num)\
555
            SKIP_COUNTER(name, gb, num)\
556
        }\
557

    
558
#   define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num)
559
#   define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
560

    
561
#   define SHOW_UBITS(name, gb, num)\
562
        NEG_USR32(name##_cache0, num)
563

    
564
#   define SHOW_SBITS(name, gb, num)\
565
        NEG_SSR32(name##_cache0, num)
566

    
567
#   define GET_CACHE(name, gb)\
568
        (name##_cache0)
569

    
570
static inline int get_bits_count(GetBitContext *s){
571
    return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
572
}
573

    
574
#endif
575

    
576
/**
577
 * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
578
 * if MSB not set it is negative
579
 * @param n length in bits
580
 * @author BERO
581
 */
582
static inline int get_xbits(GetBitContext *s, int n){
583
    register int sign;
584
    register int32_t cache;
585
    OPEN_READER(re, s)
586
    UPDATE_CACHE(re, s)
587
    cache = GET_CACHE(re,s);
588
    sign=(~cache)>>31;
589
    LAST_SKIP_BITS(re, s, n)
590
    CLOSE_READER(re, s)
591
    return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
592
}
593

    
594
static inline int get_sbits(GetBitContext *s, int n){
595
    register int tmp;
596
    OPEN_READER(re, s)
597
    UPDATE_CACHE(re, s)
598
    tmp= SHOW_SBITS(re, s, n);
599
    LAST_SKIP_BITS(re, s, n)
600
    CLOSE_READER(re, s)
601
    return tmp;
602
}
603

    
604
/**
605
 * reads 0-17 bits.
606
 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
607
 */
608
static inline unsigned int get_bits(GetBitContext *s, int n){
609
    register int tmp;
610
    OPEN_READER(re, s)
611
    UPDATE_CACHE(re, s)
612
    tmp= SHOW_UBITS(re, s, n);
613
    LAST_SKIP_BITS(re, s, n)
614
    CLOSE_READER(re, s)
615
    return tmp;
616
}
617

    
618
unsigned int get_bits_long(GetBitContext *s, int n);
619

    
620
/**
621
 * shows 0-17 bits.
622
 * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
623
 */
624
static inline unsigned int show_bits(GetBitContext *s, int n){
625
    register int tmp;
626
    OPEN_READER(re, s)
627
    UPDATE_CACHE(re, s)
628
    tmp= SHOW_UBITS(re, s, n);
629
//    CLOSE_READER(re, s)
630
    return tmp;
631
}
632

    
633
unsigned int show_bits_long(GetBitContext *s, int n);
634

    
635
static inline void skip_bits(GetBitContext *s, int n){
636
 //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
637
    OPEN_READER(re, s)
638
    UPDATE_CACHE(re, s)
639
    LAST_SKIP_BITS(re, s, n)
640
    CLOSE_READER(re, s)
641
}
642

    
643
static inline unsigned int get_bits1(GetBitContext *s){
644
#ifdef ALT_BITSTREAM_READER
645
    int index= s->index;
646
    uint8_t result= s->buffer[ index>>3 ];
647
#ifdef ALT_BITSTREAM_READER_LE
648
    result>>= (index&0x07);
649
    result&= 1;
650
#else
651
    result<<= (index&0x07);
652
    result>>= 8 - 1;
653
#endif
654
    index++;
655
    s->index= index;
656

    
657
    return result;
658
#else
659
    return get_bits(s, 1);
660
#endif
661
}
662

    
663
static inline unsigned int show_bits1(GetBitContext *s){
664
    return show_bits(s, 1);
665
}
666

    
667
static inline void skip_bits1(GetBitContext *s){
668
    skip_bits(s, 1);
669
}
670

    
671
/**
672
 * init GetBitContext.
673
 * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
674
 * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
675
 * @param bit_size the size of the buffer in bits
676
 */
677
static inline void init_get_bits(GetBitContext *s,
678
                   const uint8_t *buffer, int bit_size)
679
{
680
    int buffer_size= (bit_size+7)>>3;
681
    if(buffer_size < 0 || bit_size < 0) {
682
        buffer_size = bit_size = 0;
683
        buffer = NULL;
684
    }
685

    
686
    s->buffer= buffer;
687
    s->size_in_bits= bit_size;
688
    s->buffer_end= buffer + buffer_size;
689
#ifdef ALT_BITSTREAM_READER
690
    s->index=0;
691
#elif defined LIBMPEG2_BITSTREAM_READER
692
#ifdef LIBMPEG2_BITSTREAM_READER_HACK
693
  if ((int)buffer&1) {
694
     /* word alignment */
695
    s->cache = (*buffer++)<<24;
696
    s->buffer_ptr = buffer;
697
    s->bit_count = 16-8;
698
  } else
699
#endif
700
  {
701
    s->buffer_ptr = buffer;
702
    s->bit_count = 16;
703
    s->cache = 0;
704
  }
705
#elif defined A32_BITSTREAM_READER
706
    s->buffer_ptr = (uint32_t*)buffer;
707
    s->bit_count = 32;
708
    s->cache0 = 0;
709
    s->cache1 = 0;
710
#endif
711
    {
712
        OPEN_READER(re, s)
713
        UPDATE_CACHE(re, s)
714
        UPDATE_CACHE(re, s)
715
        CLOSE_READER(re, s)
716
    }
717
#ifdef A32_BITSTREAM_READER
718
    s->cache1 = 0;
719
#endif
720
}
721

    
722
int check_marker(GetBitContext *s, const char *msg);
723
void align_get_bits(GetBitContext *s);
724
int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
725
             const void *bits, int bits_wrap, int bits_size,
726
             const void *codes, int codes_wrap, int codes_size,
727
             int flags);
728
#define INIT_VLC_USE_STATIC 1
729
#define INIT_VLC_LE         2
730
void free_vlc(VLC *vlc);
731

    
732
/**
733
 *
734
 * if the vlc code is invalid and max_depth=1 than no bits will be removed
735
 * if the vlc code is invalid and max_depth>1 than the number of bits removed
736
 * is undefined
737
 */
738
#define GET_VLC(code, name, gb, table, bits, max_depth)\
739
{\
740
    int n, index, nb_bits;\
741
\
742
    index= SHOW_UBITS(name, gb, bits);\
743
    code = table[index][0];\
744
    n    = table[index][1];\
745
\
746
    if(max_depth > 1 && n < 0){\
747
        LAST_SKIP_BITS(name, gb, bits)\
748
        UPDATE_CACHE(name, gb)\
749
\
750
        nb_bits = -n;\
751
\
752
        index= SHOW_UBITS(name, gb, nb_bits) + code;\
753
        code = table[index][0];\
754
        n    = table[index][1];\
755
        if(max_depth > 2 && n < 0){\
756
            LAST_SKIP_BITS(name, gb, nb_bits)\
757
            UPDATE_CACHE(name, gb)\
758
\
759
            nb_bits = -n;\
760
\
761
            index= SHOW_UBITS(name, gb, nb_bits) + code;\
762
            code = table[index][0];\
763
            n    = table[index][1];\
764
        }\
765
    }\
766
    SKIP_BITS(name, gb, n)\
767
}
768

    
769
#define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
770
{\
771
    int n, index, nb_bits;\
772
\
773
    index= SHOW_UBITS(name, gb, bits);\
774
    level = table[index].level;\
775
    n     = table[index].len;\
776
\
777
    if(max_depth > 1 && n < 0){\
778
        SKIP_BITS(name, gb, bits)\
779
        if(need_update){\
780
            UPDATE_CACHE(name, gb)\
781
        }\
782
\
783
        nb_bits = -n;\
784
\
785
        index= SHOW_UBITS(name, gb, nb_bits) + level;\
786
        level = table[index].level;\
787
        n     = table[index].len;\
788
    }\
789
    run= table[index].run;\
790
    SKIP_BITS(name, gb, n)\
791
}
792

    
793

    
794
/**
795
 * parses a vlc code, faster then get_vlc()
796
 * @param bits is the number of bits which will be read at once, must be
797
 *             identical to nb_bits in init_vlc()
798
 * @param max_depth is the number of times bits bits must be readed to completly
799
 *                  read the longest vlc code
800
 *                  = (max_vlc_length + bits - 1) / bits
801
 */
802
static always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
803
                                  int bits, int max_depth)
804
{
805
    int code;
806

    
807
    OPEN_READER(re, s)
808
    UPDATE_CACHE(re, s)
809

    
810
    GET_VLC(code, re, s, table, bits, max_depth)
811

    
812
    CLOSE_READER(re, s)
813
    return code;
814
}
815

    
816
//#define TRACE
817

    
818
#ifdef TRACE
819
#include "avcodec.h"
820
static inline void print_bin(int bits, int n){
821
    int i;
822

    
823
    for(i=n-1; i>=0; i--){
824
        av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
825
    }
826
    for(i=n; i<24; i++)
827
        av_log(NULL, AV_LOG_DEBUG, " ");
828
}
829

    
830
static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
831
    int r= get_bits(s, n);
832

    
833
    print_bin(r, n);
834
    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);
835
    return r;
836
}
837
static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
838
    int show= show_bits(s, 24);
839
    int pos= get_bits_count(s);
840
    int r= get_vlc2(s, table, bits, max_depth);
841
    int len= get_bits_count(s) - pos;
842
    int bits2= show>>(24-len);
843

    
844
    print_bin(bits2, len);
845

    
846
    av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
847
    return r;
848
}
849
static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
850
    int show= show_bits(s, n);
851
    int r= get_xbits(s, n);
852

    
853
    print_bin(show, n);
854
    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);
855
    return r;
856
}
857

    
858
#define get_bits(s, n)  get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
859
#define get_bits1(s)    get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
860
#define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
861
#define get_vlc(s, vlc)            get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
862
#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
863

    
864
#define tprintf(...) av_log(NULL, AV_LOG_DEBUG, __VA_ARGS__)
865

    
866
#else //TRACE
867
#define tprintf(...) {}
868
#endif
869

    
870
static inline int decode012(GetBitContext *gb){
871
    int n;
872
    n = get_bits1(gb);
873
    if (n == 0)
874
        return 0;
875
    else
876
        return get_bits1(gb) + 1;
877
}
878

    
879
#endif /* BITSTREAM_H */