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72 lines
2.1 KiB
72 lines
2.1 KiB
/* |
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getbits.h - compact version of famous library mpg123 |
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Copyright (C) 2017 Uncle Mike |
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This program is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation, either version 3 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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*/ |
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#ifndef GETBITS_H |
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#define GETBITS_H |
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#define backbits( fr, nob ) ((void)( \ |
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fr->bitindex -= nob, \ |
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fr->wordpointer += (fr->bitindex>>3), \ |
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fr->bitindex &= 0x7 )) |
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#define getbitoffset( fr ) ((-fr->bitindex) & 0x7) |
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#define getbyte( fr ) (*fr->wordpointer++) |
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#define skipbits( fr, nob ) fr->ultmp = ( \ |
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fr->ultmp = fr->wordpointer[0], fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[1], \ |
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fr->ultmp <<= 8, fr->ultmp |= fr->wordpointer[2], fr->ultmp <<= fr->bitindex, \ |
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fr->ultmp &= 0xffffff, fr->bitindex += nob, \ |
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fr->ultmp >>= (24-nob), fr->wordpointer += (fr->bitindex>>3), \ |
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fr->bitindex &= 7 ) |
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#define getbits_fast( fr, nob )( \ |
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fr->ultmp = (byte) (fr->wordpointer[0] << fr->bitindex), \ |
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fr->ultmp |= ((ulong)fr->wordpointer[1] << fr->bitindex) >> 8, \ |
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fr->ultmp <<= nob, fr->ultmp >>= 8, \ |
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fr->bitindex += nob, fr->wordpointer += (fr->bitindex >> 3), \ |
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fr->bitindex &= 7, fr->ultmp ) |
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#define get1bit( fr ) ( \ |
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fr->uctmp = *fr->wordpointer << fr->bitindex, fr->bitindex++, \ |
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fr->wordpointer += (fr->bitindex >> 3), fr->bitindex &= 7, fr->uctmp >> 7 ) |
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static uint getbits( mpg123_handle_t *fr, int number_of_bits ) |
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{ |
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ulong rval; |
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if( (long)(fr->wordpointer-fr->bsbuf)*8 |
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+ fr->bitindex+number_of_bits > (long)fr->framesize*8 ) |
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return 0; |
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rval = fr->wordpointer[0]; |
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rval <<= 8; |
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rval |= fr->wordpointer[1]; |
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rval <<= 8; |
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rval |= fr->wordpointer[2]; |
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rval <<= fr->bitindex; |
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rval &= 0xffffff; |
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fr->bitindex += number_of_bits; |
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rval >>= (24-number_of_bits); |
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fr->wordpointer += (fr->bitindex>>3); |
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fr->bitindex &= 7; |
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return rval; |
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} |
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#endif//GETBITS_H
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