1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
#import "XADXORSumHandle.h"
@implementation XADXORSumHandle
-(id)initWithHandle:(CSHandle *)handle length:(off_t)length correctChecksum:(uint8_t)correct
{
if((self=[super initWithName:[handle name] length:length]))
{
parent=[handle retain];
correctchecksum=correct;
}
return self;
}
-(void)dealloc
{
[parent release];
[super dealloc];
}
-(void)resetStream
{
[parent seekToFileOffset:0];
checksum=0;
}
-(int)streamAtMost:(int)num toBuffer:(void *)buffer
{
int actual=[parent readAtMost:num toBuffer:buffer];
uint8_t *bytes=buffer;
for(int i=0;i<actual;i++) checksum^=bytes[i];
return actual;
}
-(BOOL)hasChecksum { return YES; }
-(BOOL)isChecksumCorrect
{
return checksum==correctchecksum;
}
-(double)estimatedProgress { return [parent estimatedProgress]; }
@end
|
