将表示HEX值的NSString转换为十六进制（@“0d”至0x0d）

Question

我想将包含例如字符串“0d”的ObjectiveC NSString转换为十六进制值0x0d。什么是最简单的方法来实现呢？

实施例：

NSString *str = @"50"; 
unsigned char mac[1]; 
mac[0] = 0x50; //<- how to set mac[0] to 0x50 from "str" string? 

Answer 1

- (NSData *)dataFromHexString { 
    const char *chars = [self UTF8String]; 
    int i = 0, len = self.length; 

    NSMutableData *data = [NSMutableData dataWithCapacity:len/2]; 
    char byteChars[3] = {chars[0],chars[1],'\0'}; 
    unsigned long wholeByte = strtoul(byteChars, NULL, 16); 
    [data appendBytes:&wholeByte length:1]; 

    return data; 
}