82 lines
1.6 KiB
C
82 lines
1.6 KiB
C
/*
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* Copyright (C) 2009, 2010 by Nicole Faerber <nicole.faerber@dpin.de>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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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 "bitstream.h"
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static unsigned char *_BITBUF;
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static unsigned int _BITPOS;
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static unsigned int _BUFLEN;
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void printbits(unsigned int val)
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{
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unsigned char i=0;
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while (i<32)
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if (val & (1<<(31-i++)))
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printf("1 ");
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else
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printf("0 ");
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// printf("\n");
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}
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void printbuf_head(unsigned char *buf)
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{
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//printbits(buf[3]<<24 | buf[2]<<16 | buf[1]<<8 | buf[0]);
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printbits(buf[0]<<24 | buf[1]<<16 | buf[2]<<8 | buf[3]);
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}
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unsigned int bitstream_get_bits(unsigned char *data, unsigned int bitOffset, unsigned int numBits)
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{
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unsigned int val;
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unsigned int mask = (1 << numBits) - 1;
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data += ((bitOffset / 8) -3);
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val = *((int *)data);
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// printf("0x%08x ", val);
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val = val << (bitOffset % 8);
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// printf("0x%08x ", val);
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val = val >> (32-numBits);
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// printf("0x%08x %d ", val, (32-numBits));
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val &= mask;
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// printf("0x%08x\n", val);
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return val;
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}
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int bitstream_bits_remaining(void)
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{
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return (_BUFLEN - _BITPOS);
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}
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unsigned int bitstream_get_next_bits(unsigned int nbits)
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{
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unsigned int res;
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res = bitstream_get_bits(_BITBUF, _BITPOS, nbits);
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_BITPOS += nbits;
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return res;
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}
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void bitstream_start(unsigned char *buf, unsigned int len)
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{
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_BITBUF = buf;
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_BITPOS = 0;
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_BUFLEN = len;
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}
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