Re: Convert hex values in an NSData object to NSString?

FROM : stephen joseph butler
DATE : Thu Nov 29 23:43:15 2007

On Nov 29, 2007 12:27 PM, Dave Batton <<email_removed>> wrote:
> I'm using Andreas Mayer's NSData_AMDigest category to get an MD5
> digest. It returns an NSData object, but what I need now is an
> NSString of the hex characters.
>
> What's the best way to do this? Sorry, I'm an interface guy, and not
> very good at twiddling bits. Any help would be appreciated.


I'd probably just write a quick category on NSData. Something like
this would work nicely:

#import <Foundation/Foundation.h>

@interface NSData (NSData_HexAdditions)
- (NSString*) stringWithHexBytes;
@end

@implementation NSData (NSData_HexAdditions)
- (NSString*) stringWithHexBytes {
   NSMutableString *stringBuffer = [NSMutableString
stringWithCapacity:([self length] * 2)];
   const unsigned char *dataBuffer = [self bytes];
   int i;
   
   for (i = 0; i < [self length]; ++i)
       [stringBuffer appendFormat:@"%02X", (unsigned long)dataBuffer[ i ]];
   
   return [[stringBuffer copy] autorelease];
}
@end
   
int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

   NSLog( @"Hex String = %@", [[@"Here is a test!\n"
dataUsingEncoding:NSUTF16StringEncoding] stringWithHexBytes] );

    [pool release];
    return 0;
}