XADMaster/CSSubHandle.m
2018-03-21 14:24:50 +02:00

111 lines
2.4 KiB
Objective-C

/*
* CSSubHandle.m
*
* Copyright (c) 2017-present, MacPaw Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
*/
#import "CSSubHandle.h"
@implementation CSSubHandle
-(id)initWithHandle:(CSHandle *)handle from:(off_t)from length:(off_t)length
{
if((self=[super initWithParentHandle:handle]))
{
start=from;
end=from+length;
[parent seekToFileOffset:start];
if(parent) return self;
[self release];
}
return nil;
}
-(id)initAsCopyOf:(CSSubHandle *)other
{
if(self=[super initAsCopyOf:other])
{
start=other->start;
end=other->end;
}
return self;
}
-(void)dealloc
{
[super dealloc];
}
-(off_t)startOffsetInParent { return start; }
-(off_t)fileSize
{
return end-start;
/* off_t parentsize=[parent fileSize];
if(parentsize>end) return end-start;
else if(parentsize<start) return 0;
else return parentsize-start;*/
}
-(off_t)offsetInFile
{
return [parent offsetInFile]-start;
}
-(BOOL)atEndOfFile
{
return [parent offsetInFile]==end||[parent atEndOfFile];
}
-(void)seekToFileOffset:(off_t)offs
{
if(offs<0) [self _raiseNotSupported:_cmd];
if(offs>end) [self _raiseEOF];
[parent seekToFileOffset:offs+start];
}
-(void)seekToEndOfFile
{
// @try
{
[parent seekToFileOffset:end];
}
/* @catch(NSException *e)
{
if([[e name] isEqual:@"CSEndOfFileException"]) [parent seekToEndOfFile];
else @throw;
}*/
}
-(int)readAtMost:(int)num toBuffer:(void *)buffer
{
off_t curr=[parent offsetInFile];
if(curr+num>end) num=(int)(end-curr);
if(num<=0) return 0;
else return [parent readAtMost:num toBuffer:buffer];
}
-(NSString *)description
{
return [NSString stringWithFormat:@"%@ @ %qu from %qu length %qu for %@",
[self class],[self offsetInFile],start,end-start,[parent description]];
}
@end