OSX/libsecurity_transform/NSData+HexString.m

   1 //
   2 //  NSData+HexString.m
   3 //  libsecurity_transform
   4 //
   5 //  Copyright (c) 2011,2014 Apple Inc. All Rights Reserved.
   6 //
   7
   8 #import "NSData+HexString.h"
   9
  10 @implementation NSData (HexString)
  11
  12 // Not efficent
  13 +(id)dataWithHexString:(NSString *)hex
  14 {
  15         char buf[3];
  16         buf[2] = '\0';
  17         NSAssert(0 == [hex length] % 2, @"Hex strings should have an even number of digits (%@)", hex);
  18         unsigned char *bytes = malloc([hex length]/2);
  19         unsigned char *bp = bytes;
  20         for (CFIndex i = 0; i < [hex length]; i += 2) {
  21                 buf[0] = [hex characterAtIndex:i];
  22                 buf[1] = [hex characterAtIndex:i+1];
  23                 char *b2 = NULL;
  24                 *bp++ = strtol(buf, &b2, 16);
  25                 NSAssert(b2 == buf + 2, @"String should be all hex digits: %@ (bad digit around %ld)", hex, i);
  26         }
  27
  28         return [NSData dataWithBytesNoCopy:bytes length:[hex length]/2 freeWhenDone:YES];
  29 }
  30
  31 @end