mirror of
https://github.com/aaru-dps/Aaru.Compression.Native.git
synced 2026-04-23 06:22:15 +00:00
Natalia Portillo
12a4d684f5
- Implement Deflate64 decompression in zip/deflate64.h and zip/deflate64.c. - Add ZIP Implode decompression functionality in zip/implode.h and zip/implode.c. - Introduce ZIP Reduce decompression in zip/reduce.h and zip/reduce.c. - Implement ZIP Shrink decompression in zip/shrink.h and zip/shrink.c. - Create a unified ZIP interface in zip/zip.h and zip/zip.c to handle multiple compression methods including PPMd, WavPack, and WinZip JPEG. - Ensure all new functions adhere to the Aaru Data Preservation Suite licensing and documentation standards.
110 lines
3.0 KiB
C
110 lines
3.0 KiB
C
/*
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* RangeCoder.c
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*
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* Copyright (c) 2017-present, MacPaw Inc. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*/
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#include "RangeCoder.h"
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void InitializePPMdRangeCoder(PPMdRangeCoder *self, PPMdReadFunction *readfunc, void *inputcontext, bool uselow,
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int bottom)
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{
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self->readfunc = readfunc;
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self->inputcontext = inputcontext;
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self->low = 0;
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self->code = 0;
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self->range = 0xffffffff;
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self->uselow = uselow;
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self->bottom = bottom;
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for(int i = 0; i < 4; i++) self->code = (self->code << 8) | readfunc(inputcontext);
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}
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uint32_t PPMdRangeCoderCurrentCount(PPMdRangeCoder *self, uint32_t scale)
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{
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self->range /= scale;
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return (self->code - self->low) / self->range;
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}
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void RemovePPMdRangeCoderSubRange(PPMdRangeCoder *self, uint32_t lowcount, uint32_t highcount)
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{
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if(self->uselow)
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self->low += self->range * lowcount;
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else
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self->code -= self->range * lowcount;
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self->range *= highcount - lowcount;
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NormalizePPMdRangeCoder(self);
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}
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int NextWeightedBitFromPPMdRangeCoder(PPMdRangeCoder *self, int weight, int size)
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{
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uint32_t val = PPMdRangeCoderCurrentCount(self, size);
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if(val < weight)
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{
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RemovePPMdRangeCoderSubRange(self, 0, weight);
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return 0;
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}
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else
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{
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RemovePPMdRangeCoderSubRange(self, weight, size);
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return 1;
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}
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}
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int NextWeightedBitFromPPMdRangeCoder2(PPMdRangeCoder *self, int weight, int shift)
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{
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uint32_t threshold = (self->range >> shift) * weight;
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int bit;
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if(self->code < threshold) // <= ?
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{
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bit = 0;
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self->range = threshold;
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}
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else
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{
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bit = 1;
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self->range -= threshold;
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self->code -= threshold;
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}
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NormalizePPMdRangeCoder(self);
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return bit;
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}
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void NormalizePPMdRangeCoder(PPMdRangeCoder *self)
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{
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for(;;)
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{
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if((self->low ^ (self->low + self->range)) >= 0x1000000)
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{
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if(self->range >= self->bottom)
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break;
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else
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self->range = -self->low & (self->bottom - 1);
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}
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int byte = self->readfunc(self->inputcontext);
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self->code = (self->code << 8) | byte;
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self->range <<= 8;
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self->low <<= 8;
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}
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}
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