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NSData+HexString.m
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NSData+HexString.m
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#import "NSData+HexString.h"
char ASCIIHexCharacterForNibble(short nibble, BOOL uppercaseLetters) {
char answer ;
short offset ;
if (nibble < 10) {
offset = 0x30 ;
}
else if (uppercaseLetters) {
offset = 0x37 ;
}
else {
offset = 0x57 ;
}
answer = (char)(nibble + offset) ;
return answer ;
}
@implementation NSData (HexString)
- (NSString*)lowercaseHexString {
// Maybe this could have been done easier by chunking it up into
// integer-size numbers and using format strings with %x, but
// that might have raised endian issues. I think this way will
// be endian-agnostic.
NSInteger i ;
char hashCString[33] ;
for (i=0; i<[self length]; i++) {
NSData* dataChunk = [self subdataWithRange:NSMakeRange(i, 1)] ;
unsigned char oneByte ;
[dataChunk getBytes:&oneByte
length:1] ;
NSInteger subscript ;
subscript = 2*i ;
hashCString[subscript] = ASCIIHexCharacterForNibble((oneByte & 0xf0) >> 4, NO) ;
subscript = 2*i+1 ;
hashCString[subscript] = ASCIIHexCharacterForNibble(oneByte & 0x0f, NO) ;
}
hashCString[32] = 0 ; // null termination
NSString* hashedString = [[NSString alloc] initWithUTF8String:hashCString] ;
#if !__has_feature(objc_arc)
[hashedString autorelease];
#endif
return hashedString;
}
@end