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#import "XADLZSSHandle.h"
@implementation XADLZSSHandle
-(id)initWithName:(NSString *)descname windowSize:(int)windowsize
{
return [self initWithName:descname length:CSHandleMaxLength windowSize:windowsize];
}
-(id)initWithName:(NSString *)descname length:(off_t)length windowSize:(int)windowsize
{
if((self=[super initWithName:descname length:length]))
{
nextliteral_ptr=(int (*)(id,SEL,int *,int *,off_t))
[self methodForSelector:@selector(nextLiteralOrOffset:andLength:atPosition:)];
windowbuffer=malloc(windowsize);
windowmask=windowsize-1; // Assumes windows are always power-of-two sized!
}
return self;
}
-(id)initWithHandle:(CSHandle *)handle windowSize:(int)windowsize
{
return [self initWithHandle:handle length:CSHandleMaxLength windowSize:windowsize];
}
-(id)initWithHandle:(CSHandle *)handle length:(off_t)length windowSize:(int)windowsize
{
if((self=[super initWithHandle:handle length:length]))
{
nextliteral_ptr=(int (*)(id,SEL,int *,int *,off_t))
[self methodForSelector:@selector(nextLiteralOrOffset:andLength:atPosition:)];
windowbuffer=malloc(windowsize);
windowmask=windowsize-1; // Assumes windows are always power-of-two sized!
}
return self;
}
-(void)dealloc
{
free(windowbuffer);
[super dealloc];
}
-(void)resetByteStream
{
matchlength=0;
matchoffset=0;
memset(windowbuffer,0,windowmask+1);
[self resetLZSSHandle];
}
-(uint8_t)produceByteAtOffset:(off_t)pos
{
if(!matchlength)
{
int offset,length;
int val=nextliteral_ptr(self,@selector(nextLiteralOrOffset:andLength:atPosition:),&offset,&length,pos);
if(val>=0) return windowbuffer[pos&windowmask]=val;
else if(val==XADLZSSEnd) CSByteStreamEOF(self);
else
{
matchlength=length;
matchoffset=pos-offset;
}
}
matchlength--;
uint8_t byte=windowbuffer[matchoffset++&windowmask];
return windowbuffer[pos&windowmask]=byte;
}
-(void)resetLZSSHandle {}
-(int)nextLiteralOrOffset:(int *)offset andLength:(int *)length atPosition:(off_t)pos { return XADLZSSEnd; }
@end
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