rfx_bitstream.h

 
#ifndef FREERDP_LIB_CODEC_RFX_BITSTREAM_H
#define FREERDP_LIB_CODEC_RFX_BITSTREAM_H
 
#include <freerdp/codec/rfx.h>
 
typedef struct
{
  BYTE* buffer;
  int nbytes;
  int byte_pos;
  int bits_left;
} RFX_BITSTREAM;
 
#define rfx_bitstream_attach(bs, _buffer, _nbytes) \
  do                                             \
  {                                              \
    bs->buffer = (BYTE*)(_buffer);             \
    bs->nbytes = (_nbytes);                    \
    bs->byte_pos = 0;                          \
    bs->bits_left = 8;                         \
  } while (0)
 
#define rfx_bitstream_get_bits(bs, _nbits, _r)                                       \
  do                                                                               \
  {                                                                                \
    int nbits = _nbits;                                                          \
    int b;                                                                       \
    UINT16 n = 0;                                                                \
    while (bs->byte_pos < bs->nbytes && nbits > 0)                               \
    {                                                                            \
      b = nbits;                                                               \
      if (b > bs->bits_left)                                                   \
        b = bs->bits_left;                                                   \
      if (n)                                                                   \
        n <<= b;                                                             \
      n |= (bs->buffer[bs->byte_pos] >> (bs->bits_left - b)) & ((1 << b) - 1); \
      bs->bits_left -= b;                                                      \
      nbits -= b;                                                              \
      if (bs->bits_left == 0)                                                  \
      {                                                                        \
        bs->bits_left = 8;                                                   \
        bs->byte_pos++;                                                      \
      }                                                                        \
    }                                                                            \
    _r = n;                                                                      \
  } while (0)
 
#define rfx_bitstream_put_bits(bs, _bits, _nbits)                                \
  do                                                                           \
  {                                                                            \
    UINT16 bits = (_bits);                                                   \
    int nbits = (_nbits);                                                    \
    int b;                                                                   \
    while (bs->byte_pos < bs->nbytes && nbits > 0)                           \
    {                                                                        \
      b = nbits;                                                           \
      if (b > bs->bits_left)                                               \
        b = bs->bits_left;                                               \
      bs->buffer[bs->byte_pos] |= ((bits >> (nbits - b)) & ((1 << b) - 1)) \
                                  << (bs->bits_left - b);                  \
      bs->bits_left -= b;                                                  \
      nbits -= b;                                                          \
      if (bs->bits_left == 0)                                              \
      {                                                                    \
        bs->bits_left = 8;                                               \
        bs->byte_pos++;                                                  \
      }                                                                    \
    }                                                                        \
  } while (0)
#define rfx_bitstream_flush(bs)                    \
  do                                             \
  {                                              \
    if (bs->bits_left != 8)                    \
    {                                          \
      int _nbits = 8 - bs->bits_left;        \
      rfx_bitstream_put_bits(bs, 0, _nbits); \
    }                                          \
  } while (0)
 
#define rfx_bitstream_eos(_bs) ((_bs)->byte_pos >= (_bs)->nbytes)
#define rfx_bitstream_left(_bs)       \
  ((_bs)->byte_pos >= (_bs)->nbytes \
       ? 0                          \
       : ((_bs)->nbytes - (_bs)->byte_pos - 1) * 8 + (_bs)->bits_left)
#define rfx_bitstream_get_processed_bytes(_bs) \
  ((_bs)->bits_left < 8 ? (_bs)->byte_pos + 1 : (_bs)->byte_pos)
 
#endif /* FREERDP_LIB_CODEC_RFX_BITSTREAM_H */