NSString+hex.m

//
//  NSString+hex.m
//  
//
//  Created by Shahid Aslam on 3/9/15.
//  Copyright (c) 2015. All rights reserved.
//

#import "NSString+hex.h"

@implementation NSString (hex)

+ (NSString *) stringFromHex:(NSString *)str{
    
    NSMutableData *stringData = [[NSMutableData alloc] init];
    unsigned char whole_byte;
    char byte_chars[3] = {'\0','\0','\0'};
    int i;
    for (i=0; i < [str length] / 2; i++) {
        byte_chars[0] = [str characterAtIndex:i*2];
        byte_chars[1] = [str characterAtIndex:i*2+1];
        whole_byte = strtol(byte_chars, NULL, 16);
        [stringData appendBytes:&whole_byte length:1];
    }
    return [[NSString alloc] initWithData:stringData encoding:NSASCIIStringEncoding];
}

+ (NSString *) stringToHex:(NSString *)str{
    
    NSUInteger len = [str length];
    unichar *chars = malloc(len * sizeof(unichar));
    [str getCharacters:chars];
    
    NSMutableString *hexString = [[NSMutableString alloc] init];
    
    for(NSUInteger i = 0; i < len; i++ )
    {
        [hexString appendString:[NSString stringWithFormat:@"%x", chars[i]]];
    }
    free(chars);
    
    return hexString ;
}

+ (NSString *) stringToHex2:(NSString *)str
{
    NSUInteger len = [str length];
    unichar *chars = malloc(len * sizeof(unichar));
    [str getCharacters:chars];
    
    NSMutableString *hexString = [[NSMutableString alloc] init];
    
    for(NSUInteger i = 0; i < len; i++ )
    {
        NSString *temp = [NSString stringWithFormat:@"%x", chars[i]];
        [hexString appendString:(temp.length <2)? [NSString stringWithFormat:@"0%@",temp] : temp];
    }
    free(chars);
    
    return hexString ;
}


@end