86 lines
2.3 KiB
C
86 lines
2.3 KiB
C
/**
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* FreeRDP: A Remote Desktop Protocol Implementation
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* RemoteFX Codec Library - Bit Stream
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*
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* Copyright 2011 Vic Lee
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __RFX_BITSTREAM_H
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#define __RFX_BITSTREAM_H
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#include <freerdp/codec/rfx.h>
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struct _RFX_BITSTREAM
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{
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BYTE* buffer;
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int nbytes;
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int byte_pos;
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int bits_left;
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};
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typedef struct _RFX_BITSTREAM RFX_BITSTREAM;
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#define rfx_bitstream_attach(bs, _buffer, _nbytes) do { \
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bs->buffer = (BYTE*) (_buffer); \
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bs->nbytes = (_nbytes); \
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bs->byte_pos = 0; \
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bs->bits_left = 8; } while (0)
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#define rfx_bitstream_get_bits(bs, _nbits, _r) do { \
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int nbits = _nbits; \
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int b; \
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UINT16 n = 0; \
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while (bs->byte_pos < bs->nbytes && nbits > 0) \
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{ \
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b = nbits; \
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if (b > bs->bits_left) \
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b = bs->bits_left; \
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if (n) \
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n <<= b; \
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n |= (bs->buffer[bs->byte_pos] >> (bs->bits_left - b)) & ((1 << b) - 1); \
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bs->bits_left -= b; \
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nbits -= b; \
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if (bs->bits_left == 0) \
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{ \
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bs->bits_left = 8; \
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bs->byte_pos++; \
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} \
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} \
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_r = n; } while (0)
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#define rfx_bitstream_put_bits(bs, _bits, _nbits) do { \
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UINT16 bits = (_bits); \
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int nbits = (_nbits); \
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int b; \
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while (bs->byte_pos < bs->nbytes && nbits > 0) \
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{ \
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b = nbits; \
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if (b > bs->bits_left) \
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b = bs->bits_left; \
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bs->buffer[bs->byte_pos] |= ((bits >> (nbits - b)) & ((1 << b) - 1)) << (bs->bits_left - b); \
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bs->bits_left -= b; \
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nbits -= b; \
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if (bs->bits_left == 0) \
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{ \
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bs->bits_left = 8; \
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bs->byte_pos++; \
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} \
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} } while (0)
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#define rfx_bitstream_eos(_bs) ((_bs)->byte_pos >= (_bs)->nbytes)
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#define rfx_bitstream_left(_bs) ((_bs)->byte_pos >= (_bs)->nbytes ? 0 : ((_bs)->nbytes - (_bs)->byte_pos - 1) * 8 + (_bs)->bits_left)
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#define rfx_bitstream_get_processed_bytes(_bs) ((_bs)->bits_left < 8 ? (_bs)->byte_pos + 1 : (_bs)->byte_pos)
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#endif /* __RFX_BITSTREAM_H */
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