NSData Hex String 互转

最近做一个数据缓存的地方用到了NSData Hex String 互转，查阅了相关资料，链接如下
相关链接

https://stackoverflow.com/questions/7317860/converting-hex-nsstring-to-nsdata

https://stackoverflow.com/questions/1305225/best-way-to-serialize-an-nsdata-into-a-hexadeximal-string

代码如下
hex string to NSData

- (NSData *)convertDataBaseStoredStringToData:(NSString *)command
{
    if (![command isKindOfClass:[NSString class]]) {
        return [NSData data];
    }
    command = [command stringByReplacingOccurrencesOfString:@">" withString:@""];
    command = [command stringByReplacingOccurrencesOfString:@"<" withString:@""];
    command = [command stringByReplacingOccurrencesOfString:@" " withString:@""];
    NSMutableData *commandToSend= [[NSMutableData alloc] init];
    unsigned char whole_byte;
    char byte_chars[3] = {'\0','\0','\0'};
    int i;
    for (i=0; i < [command length]/2; i++) {
        byte_chars[0] = [command characterAtIndex:i*2];
        byte_chars[1] = [command characterAtIndex:i*2+1];
        whole_byte = strtol(byte_chars, NULL, 16);
        [commandToSend appendBytes:&whole_byte length:1];
    }
    return commandToSend;
}

NSData to hex String

- (NSMutableString *)dataToHexString:(NSData *)valueData insertSql:(NSMutableString *)insertSql {
    if (@available(iOS 13, *)) {
        if ([valueData isKindOfClass:[NSData class]]) {
            NSMutableString *valueString = [NSMutableString string];
            const char *bytes = valueData.bytes;
            NSInteger count = valueData.length;
            for (int i = 0; i < count; i++) {
                [valueString appendFormat:@"%02x", bytes[i]&0x000000FF];
            }
            
            [insertSql appendFormat:@"'%@',", [valueString stringByReplacingOccurrencesOfString:@"'" withString:@"''"]];
        } else {
            [insertSql appendFormat:@"'%@',", [[NSString stringWithFormat:@"%@", valueData] stringByReplacingOccurrencesOfString:@"'" withString:@"''"]];
        }
    } else {
        [insertSql appendFormat:@"'%@',", [[NSString stringWithFormat:@"%@", valueData] stringByReplacingOccurrencesOfString:@"'" withString:@"''"]];
    }
    return insertSql;
}