mirror of https://github.com/FreeRDP/FreeRDP
87 lines
1.8 KiB
C
87 lines
1.8 KiB
C
/**
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* FreeRDP: A Remote Desktop Protocol client.
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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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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <freerdp/utils/memory.h>
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#include "rfx_bitstream.h"
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void rfx_bitstream_attach(RFX_BITSTREAM* bs, uint8* buffer, int nbytes)
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{
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bs->buffer = buffer;
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bs->nbytes = nbytes;
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bs->byte_pos = 0;
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bs->bits_left = 8;
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}
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uint16 rfx_bitstream_get_bits(RFX_BITSTREAM* bs, int nbits)
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{
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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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return n;
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}
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void rfx_bitstream_put_bits(RFX_BITSTREAM* bs, uint16 bits, int nbits)
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{
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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] &= ~(((1 << b) - 1) << (bs->bits_left - b));
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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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}
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}
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