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#import "XADRAR13CryptHandle.h"
// TODO: Find test cases and actually test this code.
static inline uint16_t rol8(uint16_t val,int n) { return (val<<n)|(val>>(8-n)); }
@implementation XADRAR13CryptHandle
-(id)initWithHandle:(CSHandle *)handle length:(off_t)length password:(NSData *)passdata
{
if((self=[super initWithHandle:handle length:length]))
{
password=[passdata retain];
}
return self;
}
-(void)dealloc
{
[password release];
[super dealloc];
}
-(void)resetByteStream
{
int passlength=[password length];
const uint8_t *passbytes=[password bytes];
key1=key2=key3=0;
for(int i=0;i<passlength;i++)
{
uint8_t c=passbytes[i];
key1+=c;
key2^=c;
key3+=c;
key3=rol8(key3,1);
}
}
-(uint8_t)produceByteAtOffset:(off_t)pos
{
key2+=key3;
key1+=key2;
if(CSInputAtEOF(input)) CSByteStreamEOF(self);
return CSInputNextByte(input)-key1;
}
@end
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