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562
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1 /*
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2 getbits
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3
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4 copyright ?-2006 by the mpg123 project - free software under the terms of the LGPL 2.1
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5 see COPYING and AUTHORS files in distribution or http://mpg123.org
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6 initially written by Michael Hipp
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7 */
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8
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9 #ifndef _MPG123_GETBITS_H_
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10 #define _MPG123_GETBITS_H_
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11
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12 /* that's the same file as getits.c but with defines to
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13 force inlining */
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14
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15 #define backbits(fr,nob) ((void)( \
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16 fr->bitindex -= nob, \
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17 fr->wordpointer += (fr->bitindex>>3), \
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18 fr->bitindex &= 0x7 ))
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19
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20 #define getbitoffset(fr) ((-fr->bitindex)&0x7)
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21 #define getbyte(fr) (*fr->wordpointer++)
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22
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23 #define getbits(fr, nob) ( \
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24 fr->ultmp = fr->wordpointer[0], fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[1], \
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25 fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[2], fr->ultmp <<= fr->bitindex, \
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26 fr->ultmp &= 0xffffff, fr->bitindex += nob, \
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27 fr->ultmp >>= (24-nob), fr->wordpointer += (fr->bitindex>>3), \
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28 fr->bitindex &= 7,fr->ultmp)
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29
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30 #define skipbits(fr, nob) fr->ultmp = ( \
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31 fr->ultmp = fr->wordpointer[0], fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[1], \
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32 fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[2], fr->ultmp <<= fr->bitindex, \
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33 fr->ultmp &= 0xffffff, fr->bitindex += nob, \
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34 fr->ultmp >>= (24-nob), fr->wordpointer += (fr->bitindex>>3), \
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35 fr->bitindex &= 7 )
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36
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37 #define getbits_fast(fr, nob) ( \
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38 fr->ultmp = (unsigned char) (fr->wordpointer[0] << fr->bitindex), \
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39 fr->ultmp |= ((unsigned long) fr->wordpointer[1]<<fr->bitindex)>>8, \
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40 fr->ultmp <<= nob, fr->ultmp >>= 8, \
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41 fr->bitindex += nob, fr->wordpointer += (fr->bitindex>>3), \
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42 fr->bitindex &= 7, fr->ultmp )
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43
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44 #define get1bit(fr) ( \
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45 fr->uctmp = *fr->wordpointer << fr->bitindex, fr->bitindex++, \
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46 fr->wordpointer += (fr->bitindex>>3), fr->bitindex &= 7, fr->uctmp>>7 )
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47
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48
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49 #endif
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