/* GetLongIP() by Codex` (Hero_Number_Zero) - hero_number_zero@unixbeast.com
 * 
 * Description: Works out integer (long) IP from string IP, also checks
 * to see if the string is a valid IP, returns 0 if it is in-valid and
 * returns the integer IP if it is valid.
 *
 * Note: If the string "0.0.0.0" is passed to the function, the long
 *       IP for that is the same as the error return. There is little
 *       we can do about that using a 4 bit integer, it's lucky nobody
 *       has that IP.
 *
 * Note: I find * 256 to be marginaly faster than << 8, I can't speak for
 *       all compilers/OS' though just the ones I tested on, it's only about
 *       1-2% faster mind you.
 */


#define IsDigit(c)        (c >= '0' && c <= '9' ? 1 : 0)

unsigned int GetLongIP(const char *s)
{
	unsigned int ip = 0, n = 0;
	while (IsDigit(*s))
		n = (n * 10) + (*s++ - '0');
	if (n > 0xff || *s++ != '.' || !IsDigit(*s)) return 0;
 	ip = (ip + n) * 256;
 	n = 0;

	while (IsDigit(*s))
		n = (n * 10) + (*s++ - '0');
	if (n > 0xff || *s++ != '.' || !IsDigit(*s)) return 0;
 	ip = (ip + n) * 256;
 	n = 0;

	while (IsDigit(*s))
		n = (n * 10) + (*s++ - '0');
	if (n > 0xff || *s++ != '.' || !IsDigit(*s)) return 0;
 	ip = (ip + n) * 256;
 	n = 0;

	while (IsDigit(*s))
		n = (n * 10) + (*s++ - '0');
	if (n > 0xff || *s != '\0') return 0;

 	return (ip + n);