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

111 lines
2.8 KiB
Objective-C

/*
* XADFastLZSSHandle.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 "XADFastLZSSHandle.h"
// TODO: Seeking
@implementation XADFastLZSSHandle
-(id)initWithParentHandle:(CSHandle *)handle windowSize:(int)windowsize
{
return [self initWithParentHandle:handle length:CSHandleMaxLength windowSize:windowsize];
}
-(id)initWithParentHandle:(CSHandle *)handle length:(off_t)length windowSize:(int)windowsize
{
if((self=[super initWithParentHandle:handle length:length]))
{
InitializeLZSS(&lzss,windowsize);
}
return self;
}
-(id)initWithInputBufferForHandle:(CSHandle *)handle windowSize:(int)windowsize
{
return [self initWithInputBufferForHandle:handle length:CSHandleMaxLength windowSize:windowsize];
}
-(id)initWithInputBufferForHandle:(CSHandle *)handle length:(off_t)length windowSize:(int)windowsize
{
if((self=[super initWithInputBufferForHandle:handle length:length]))
{
InitializeLZSS(&lzss,windowsize);
}
return self;
}
-(void)dealloc
{
CleanupLZSS(&lzss);
[super dealloc];
}
-(void)resetStream
{
RestartLZSS(&lzss);
[self resetLZSSHandle];
}
-(int)streamAtMost:(int)num toBuffer:(void *)buffer
{
bufferpointer=buffer;
bufferpos=streampos;
bufferend=streampos+num;
XADLZSSFlushToBuffer(self);
if(bufferpos!=bufferend)
{
flushbarrier=LZSSPosition(&lzss)+LZSSWindowSize(&lzss);
[self expandFromPosition:LZSSPosition(&lzss)];
XADLZSSFlushToBuffer(self);
}
return (int)(bufferpos-streampos);
}
-(void)resetLZSSHandle {}
-(void)expandFromPosition:(off_t)pos {}
-(void)endLZSSHandle { [self endStream]; }
// TODO: remove usage of bufferpos entirely, it's somewhat redundant.
void XADLZSSFlushToBuffer(XADFastLZSSHandle *self)
{
off_t end=LZSSPosition(&self->lzss);
if(end>self->bufferend) end=self->bufferend;
int available=(int)(end-self->bufferpos);
if(available==0) return;
//if(available<0) [XADException raiseUnknownException]; // TODO: better error
CopyBytesFromLZSSWindow(&self->lzss,self->bufferpointer,self->bufferpos,available);
self->bufferpos+=available;
self->bufferpointer+=available;
self->flushbarrier+=available;
}
@end