iOS中16進位轉nsdata

//data轉16

+(NSString *)DataToHexStr:(NSData *)data {

    if (!data || [data length] == 0) {

        return @"";

    }

    NSMutableString *string = [[NSMutableString alloc] initWithCapacity:[data length]];

    

    [data enumerateByteRangesUsingBlock:^(const void *bytes, NSRange byteRange, BOOL *stop) {

        unsigned char *dataBytes = (unsigned char*)bytes;

        for (NSInteger i = 0; i < byteRange.length; i++) {

            NSString *hexStr = [NSString stringWithFormat:@"%x", (dataBytes[i]) & 0xff];

            if ([hexStr length] == 2) {

                [string appendString:hexStr];

            } else {

                [string appendFormat:@"0%@", hexStr];

            }

        }

    }];

    

    return string;

}

//16禁止轉data

+(NSData *)HexStrToData:(NSString *)str {

    if (!str || [str length] == 0) {

        return nil;

    }

    

    NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:8];

    NSRange range;

    if ([str length] % 2 == 0) {

        range = NSMakeRange(0, 2);

    } else {

        range = NSMakeRange(0, 1);

    }

    for (NSInteger i = range.location; i < [str length]; i += 2) {

        unsigned int anInt;

        NSString *hexCharStr = [str substringWithRange:range];

        NSScanner *scanner = [[NSScanner alloc] initWithString:hexCharStr];

        

        [scanner scanHexInt:&anInt];

        NSData *entity = [[NSData alloc] initWithBytes:&anInt length:1];

        [hexData appendData:entity];

        

        range.location += range.length;

        range.length = 2;

    }

    return hexData;

}