mirror of
https://github.com/MacPaw/XADMaster.git
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109 lines
2.9 KiB
Objective-C
109 lines
2.9 KiB
Objective-C
/*
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* XADDiskDoublerADnHandle.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 "XADDiskDoublerADnHandle.h"
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#import "XADException.h"
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static void CopyBytesWithRepeat(uint8_t *dest,uint8_t *src,int length)
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{
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for(int i=0;i<length;i++) dest[i]=src[i];
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}
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@implementation XADDiskDoublerADnHandle
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-(id)initWithHandle:(CSHandle *)handle length:(off_t)length
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{
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return [super initWithInputBufferForHandle:handle length:length];
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}
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-(int)produceBlockAtOffset:(off_t)pos
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{
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uint8_t headxor=0;
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int compsize=CSInputNextUInt16BE(input);
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//if(compsize>0x2000) [XADException raiseIllegalDataException];
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headxor^=compsize^(compsize>>8);
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int uncompsize=CSInputNextUInt16BE(input);
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if(uncompsize>0x2000) [XADException raiseIllegalDataException];
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headxor^=uncompsize^(uncompsize>>8);
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for(int i=0;i<4;i++) headxor^=CSInputNextByte(input);
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int datacorrectxor=CSInputNextByte(input);
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headxor^=datacorrectxor;
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int flags=CSInputNextByte(input);
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headxor^=flags;
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headxor^=CSInputNextByte(input);
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int headcorrectxor=CSInputNextByte(input);
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if(headxor!=headcorrectxor) [XADException raiseIllegalDataException];
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off_t nextblock=CSInputBufferOffset(input)+compsize;
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if(flags&1)
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{
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// Uncompressed block
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for(int i=0;i<uncompsize;i++) outbuffer[i]=CSInputNextByte(input);
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}
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else
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{
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int currpos=0;
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while(currpos<uncompsize)
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{
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int ismatch=CSInputNextBit(input);
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if(!ismatch) outbuffer[currpos++]=CSInputNextBitString(input,8);
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else
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{
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int isfar=CSInputNextBit(input);
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int offset=CSInputNextBitString(input,isfar?12:8);
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if(offset>currpos) [XADException raiseIllegalDataException];
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int length;
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if(CSInputNextBit(input)==0) length=2;
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else
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{
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if(CSInputNextBit(input)==0)
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{
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if(CSInputNextBit(input)==0) length=3;
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else length=4;
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}
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else length=CSInputNextBitString(input,4)+5;
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}
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if(currpos+length>uncompsize) length=uncompsize-currpos;
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if(length>offset) [XADException raiseIllegalDataException];
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CopyBytesWithRepeat(&outbuffer[currpos],&outbuffer[currpos-offset],length);
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currpos+=length;
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}
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}
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}
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CSInputSeekToBufferOffset(input,nextblock);
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[self setBlockPointer:outbuffer];
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return uncompsize;
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}
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@end
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