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rfx_bitstream.h
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rfx_bitstream.h
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/**
* FreeRDP: A Remote Desktop Protocol client.
* RemoteFX Codec Library - Bit Stream
*
* Copyright 2011 Vic Lee
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __RFX_BITSTREAM_H
#define __RFX_BITSTREAM_H
#include "rfxcommon.h"
struct _RFX_BITSTREAM
{
uint8 *buffer;
int nbytes;
int byte_pos;
int bits_left;
};
typedef struct _RFX_BITSTREAM RFX_BITSTREAM;
#define rfx_bitstream_attach(bs, _buffer, _nbytes) do { \
bs.buffer = (uint8 *) (_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] &= ~((1 << bs.bits_left) - 1); \
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_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 /* __RFX_BITSTREAM_H */