mirror of
https://github.com/MacPaw/XADMaster.git
synced 2025-08-29 19:43:47 +02:00
159 lines
3.7 KiB
Objective-C
159 lines
3.7 KiB
Objective-C
/*
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* XADLZHStaticHandle.m
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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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#import "XADLZHStaticHandle.h"
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#import "XADException.h"
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@implementation XADLZHStaticHandle
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-(id)initWithHandle:(CSHandle *)handle length:(off_t)length windowBits:(int)bits
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{
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if((self=[super initWithInputBufferForHandle:handle length:length windowSize:1<<bits]))
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{
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literalcode=distancecode=nil;
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windowbits=bits;
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}
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return self;
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}
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-(void)dealloc
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{
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[literalcode release];
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[distancecode release];
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[super dealloc];
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}
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-(void)resetLZSSHandle
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{
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blocksize=0;
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blockpos=0;
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}
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-(int)nextLiteralOrOffset:(int *)offset andLength:(int *)length atPosition:(off_t)pos
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{
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if(blockpos>=blocksize)
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{
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blocksize=CSInputNextBitString(input,16);
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blockpos=0;
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[literalcode release];
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[distancecode release];
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literalcode=nil;
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distancecode=nil;
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literalcode=[self allocAndParseLiteralCode];
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distancecode=[self allocAndParseCodeOfWidth:windowbits<15?4:5 specialIndex:-1];
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}
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blockpos++;
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int lit=CSInputNextSymbolUsingCode(input,literalcode);
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if(lit<0x100) return lit;
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else
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{
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*length=lit-0x100+3;
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int bit=CSInputNextSymbolUsingCode(input,distancecode);
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if(bit==0) *offset=1;
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else if(bit==1) *offset=2;
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else *offset=(1<<(bit-1))+CSInputNextBitString(input,bit-1)+1;
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return XADLZSSMatch;
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}
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}
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-(XADPrefixCode *)allocAndParseCodeOfWidth:(int)bits specialIndex:(int)specialindex
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{
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int num=CSInputNextBitString(input,bits);
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if(num==0)
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{
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int val=CSInputNextBitString(input,bits);
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XADPrefixCode *code=[XADPrefixCode new];
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[code addValue:val forCodeWithHighBitFirst:0 length:0];
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return code;
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}
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else
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{
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int codelengths[num];
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int n=0;
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while(n<num)
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{
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int len=CSInputNextBitString(input,3);
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if(len==7) while(CSInputNextBit(input)) len++;
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codelengths[n++]=len;
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if(n==specialindex)
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{
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int zeroes=CSInputNextBitString(input,2);
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for(int i=0;i<zeroes;i++) codelengths[n++]=0;
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}
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}
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return [[XADPrefixCode alloc] initWithLengths:codelengths numberOfSymbols:num maximumLength:16 shortestCodeIsZeros:YES];
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}
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}
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-(XADPrefixCode *)allocAndParseLiteralCode
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{
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XADPrefixCode *metacode=[self allocAndParseCodeOfWidth:5 specialIndex:3];
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int num=CSInputNextBitString(input,9);
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if(num==0)
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{
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[metacode release];
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int val=CSInputNextBitString(input,9);
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XADPrefixCode *code=[XADPrefixCode new];
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[code addValue:val forCodeWithHighBitFirst:0 length:0];
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return code;
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}
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else
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{
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int codelengths[num];
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int n=0;
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while(n<num)
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{
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unsigned int c=CSInputNextSymbolUsingCode(input,metacode);
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if(c<=2)
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{
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int zeros;
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switch(c)
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{
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case 0: zeros=1; break;
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case 1: zeros=CSInputNextBitString(input,4)+3; break;
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case 2: zeros=CSInputNextBitString(input,9)+20; break;
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}
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if(n+zeros>num) [XADException raiseIllegalDataException];
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for(int i=0;i<zeros;i++) codelengths[n++]=0;
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}
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else codelengths[n++]=c-2;
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}
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[metacode release];
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return [[XADPrefixCode alloc] initWithLengths:codelengths numberOfSymbols:num maximumLength:16 shortestCodeIsZeros:YES];
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}
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}
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@end
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