Mine

/* Read hex string representation to 'data' repr.
 * takes an allocated buf for the data and the string
 * len is the length of buf
 */
static void read_hex_string (dataptr buf, size_t len, char *string) {	
	size_t str_len = strlen(string);
	size_t read = (len < str_len/2 ? len : str_len/2);
	char str[3];
	
	for (int i = 0; i < read; i++) {
		strncpy(str, string+2*i, 2);
		str[3] = '\0';
		
		buf[i] = strtol(str, NULL, 16);
		//fprintf(stderr, "%s = %02x\n", str, strtol(str, NULL, 16));
	}
}