mirror of
https://github.com/MacPaw/XADMaster.git
synced 2025-08-28 19:13:49 +02:00
147 lines
3.1 KiB
Objective-C
147 lines
3.1 KiB
Objective-C
/*
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* XADBlockHandle.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 "XADBlockHandle.h"
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@implementation XADBlockHandle
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-(id)initWithHandle:(CSHandle *)handle blockSize:(int)size
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{
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if((self=[super initWithParentHandle:handle]))
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{
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currpos=0;
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length=CSHandleMaxLength;
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numblocks=0;
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blocksize=size;
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blockoffsets=NULL;
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}
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return self;
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}
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-(id)initWithHandle:(CSHandle *)handle length:(off_t)maxlength blockSize:(int)size
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{
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if((self=[super initWithParentHandle:handle]))
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{
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currpos=0;
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length=maxlength;
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numblocks=0;
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blocksize=size;
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blockoffsets=NULL;
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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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free(blockoffsets);
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[super dealloc];
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}
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-(void)setBlockChain:(uint32_t *)blocktable numberOfBlocks:(int)totalblocks
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firstBlock:(uint32_t)first headerSize:(off_t)headersize
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{
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numblocks=0;
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uint32_t block=first;
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while(block<totalblocks)
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{
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block=blocktable[block];
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numblocks++;
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}
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free(blockoffsets);
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if(numblocks==0) blockoffsets=NULL;
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else blockoffsets=malloc(numblocks*sizeof(off_t));
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block=first;
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for(int i=0;i<numblocks;i++)
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{
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blockoffsets[i]=headersize+block*blocksize;
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block=blocktable[block];
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}
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}
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-(off_t)fileSize
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{
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if(length<numblocks*blocksize) return length;
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return numblocks*blocksize;
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}
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-(off_t)offsetInFile
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{
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return currpos;
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}
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-(BOOL)atEndOfFile
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{
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if(currpos==numblocks*blocksize) return YES;
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if(currpos==length) return YES;
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return NO;
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}
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-(void)seekToFileOffset:(off_t)offs
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{
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if(offs<0) [self _raiseEOF];
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if(offs>numblocks*blocksize) [self _raiseEOF];
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if(offs>length) [self _raiseEOF];
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int block=(int)((offs-1)/blocksize);
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[parent seekToFileOffset:blockoffsets[block]+offs-block*blocksize];
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currpos=offs;
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}
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-(void)seekToEndOfFile
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{
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if(length!=CSHandleMaxLength) [self seekToFileOffset:length];
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else [self seekToFileOffset:numblocks*blocksize];
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}
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-(int)readAtMost:(int)num toBuffer:(void *)buffer
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{
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uint8_t *bytebuffer=(uint8_t *)buffer;
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int total=0;
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if(currpos+num>length) num=(int)(length-currpos);
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while(total<num)
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{
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int blockpos=currpos%blocksize;
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if(blockpos==0)
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{
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int block=(int)(currpos/blocksize);
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if(block==numblocks) return total;
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[parent seekToFileOffset:blockoffsets[block]];
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}
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int numbytes=num-total;
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if(numbytes>blocksize-blockpos) numbytes=blocksize-blockpos;
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int actual=[parent readAtMost:numbytes toBuffer:&bytebuffer[total]];
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if(actual==0) return total;
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total+=actual;
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currpos+=actual;
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}
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return total;
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}
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@end
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