NSData+HexString.m   [plain text]

//
//  NSData+HexString.m
//  libsecurity_transform
//
//  Copyright (c) 2011 Apple, Inc. All rights reserved.
//

#import "NSData+HexString.h"

@implementation NSData (HexString)

// Not efficent
+(id)dataWithHexString:(NSString *)hex
{
	char buf[3];
	buf[2] = '\0';
	NSAssert(0 == [hex length] % 2, @"Hex strings should have an even number of digits (%@)", hex);
	unsigned char *bytes = malloc([hex length]/2);
	unsigned char *bp = bytes;
	for (CFIndex i = 0; i < [hex length]; i += 2) {
		buf[0] = [hex characterAtIndex:i];
		buf[1] = [hex characterAtIndex:i+1];
		char *b2 = NULL;
		*bp++ = strtol(buf, &b2, 16);
		NSAssert(b2 == buf + 2, @"String should be all hex digits: %@ (bad digit around %d)", hex, i);
	}
	
	return [NSData dataWithBytesNoCopy:bytes length:[hex length]/2 freeWhenDone:YES];
}

@end