mirror of
https://github.com/MacPaw/XADMaster.git
synced 2025-08-29 03:23:48 +02:00
124 lines
2.6 KiB
Objective-C
124 lines
2.6 KiB
Objective-C
/*
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* XADStuffItXX86Handle.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 "XADStuffItXX86Handle.h"
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#import "XADException.h"
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@implementation XADStuffItXX86Handle
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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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-(void)resetByteStream
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{
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lasthit=-6;
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bitfield=0;
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numbufferbytes=0;
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currbufferbyte=0;
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}
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-(uint8_t)produceByteAtOffset:(off_t)pos
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{
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if(currbufferbyte<numbufferbytes) return buffer[currbufferbyte++];
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if(CSInputAtEOF(input)) CSByteStreamEOF(self);
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uint8_t b=CSInputNextByte(input);
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if(b==0xe8||b==0xe9)
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{
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int dist=(int)(pos-lasthit);
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lasthit=pos;
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if(dist>5)
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{
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bitfield=0;
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}
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else
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{
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for(int i=0;i<dist;i++)
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{
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bitfield=(bitfield&0x77)<<1;
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}
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}
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// Read offset into buffer.
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for(int i=0;i<4;i++)
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{
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/* if(CSInputAtEOF(input))
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{
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currbufferbyte=0;
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numbufferbytes=i;
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return b;
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}*/
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buffer[i]=CSInputPeekByte(input,i);
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}
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static const BOOL table[8]={YES,YES,YES,NO,YES,NO,NO,NO};
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if(buffer[3]==0x00 || buffer[3]==0xff)
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{
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if(table[(bitfield>>1)&0x07] && (bitfield>>1)<=0x0f)
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{
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int32_t absaddress=CSInt32LE(buffer);
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int32_t reladdress;
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for(;;)
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{
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reladdress=absaddress-(int32_t)pos-6;
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if(bitfield==0) break;
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static const int shifts[8]={24,16,8,8,0,0,0,0};
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int shift=shifts[bitfield>>1];
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int something=(reladdress>>shift)&0xff;
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if(something!=0&&something!=0xff) break;
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absaddress=reladdress^((1<<(shift+8))-1);
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}
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reladdress&=0x1ffffff;
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if(reladdress>=0x1000000) reladdress|=0xff000000;
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CSSetInt32LE(buffer,reladdress);
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currbufferbyte=0;
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numbufferbytes=4;
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bitfield=0;
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CSInputSkipBytes(input,4);
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}
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else
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{
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bitfield|=0x11;
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}
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}
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else
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{
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bitfield|=0x01;
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}
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}
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return b;
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}
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@end
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