142 lines
3.4 KiB
C
142 lines
3.4 KiB
C
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/*****************************************************************************
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*
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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 2 of the License, or
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* (at your option) any later version.
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*
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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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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* $Id: bitgolomb.h 292 2005-10-14 20:30:00Z picard $
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*
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* The Core Pocket Media Player
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* Copyright (c) 2004-2005 Gabor Kovacs
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*
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****************************************************************************/
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#ifndef __BITGOLOMB_H
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#define __BITGOLOMB_H
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#define GL2(n) 12-n+1+12-n
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#define assertgolomb(p) //assert(p)
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static const uint8_t golomb_log2[64] =
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{
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GL2(0),
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GL2(1),
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GL2(2),GL2(2),
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GL2(3),GL2(3),GL2(3),GL2(3),
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GL2(4),GL2(4),GL2(4),GL2(4),GL2(4),GL2(4),GL2(4),GL2(4),
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GL2(5),GL2(5),GL2(5),GL2(5),GL2(5),GL2(5),GL2(5),GL2(5),
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GL2(5),GL2(5),GL2(5),GL2(5),GL2(5),GL2(5),GL2(5),GL2(5),
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GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),
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GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),
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GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),
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GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),GL2(6),
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};
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static void bitload(bitstream* p);
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// result: [0..8190]
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static NOINLINE int bitgolomb(bitstream* p)
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{
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int n,v;
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bitbegin_pos2(p);
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bitload_pos2(p);
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assertgolomb(bitshow_pos2(p,13)>0);
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if (bitshow_pos2(p,6))
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n = golomb_log2[bitshow_pos2(p,6)]-12;
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else
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n = golomb_log2[bitshow_pos2(p,12)];
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v = bitshow_pos2(p,n);
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bitflush_pos2(p,n);
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bitend_pos2(p);
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return --v;
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}
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// max: [2..7]
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// result: [0..(1<<max)-2]+1
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static INLINE int bitgolomb_max1(bitstream* p,int max)
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{
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int n;
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bitloadinline(p);
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assertgolomb(bitshow(p,max)>0);
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n = golomb_log2[bitshow(p,max-1)]-(13-max)*2;
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return bitget(p,n);
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}
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static NOINLINE int bitsgolomb(bitstream* p)
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{
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int n,v;
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bitbegin_pos2(p);
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bitload_pos2(p);
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assertgolomb(bitshow_pos2(p,13)>0);
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if (bitshow_pos2(p,6))
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n = golomb_log2[bitshow_pos2(p,6)]-12;
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else
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n = golomb_log2[bitshow_pos2(p,12)];
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v = bitshow_pos2(p,n);
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bitflush_pos2(p,n);
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bitend_pos2(p);
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if (v&1)
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v=-(v>>1);
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else
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v=(v>>1);
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return v;
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}
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#define DECLARE_BITSGOLOMB_LAGER \
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static NOINLINE int bitsgolomb_large(bitstream* p) \
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{ \
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int n; \
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uint32_t v; \
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bitloadinline(p); \
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if (bitshow(p,13)) \
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return bitsgolomb(p); \
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n = 14; \
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bitflush(p,13); \
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bitloadinline(p); \
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while (!bitshow(p,1)) \
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{ \
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bitflush(p,1); \
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++n; \
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} \
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v = bitshowlarge(p,n); \
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bitflush(p,n); \
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if (v&1) \
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return -(int)(v>>1); \
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else \
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return (v>>1); \
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}
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#define DECLARE_BITGOLOMB_LAGER \
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static NOINLINE int bitgolomb_large(bitstream* p) \
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{ \
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int n; \
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uint32_t v; \
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bitloadinline(p); \
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if (bitshow(p,13)) \
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return bitgolomb(p); \
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n = 14; \
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bitflush(p,13); \
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bitloadinline(p); \
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while (!bitshow(p,1)) \
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{ \
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bitflush(p,1); \
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++n; \
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} \
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v = bitshowlarge(p,n); \
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bitflush(p,n); \
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return --v; \
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}
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#endif
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