/*	inet_addr.c	4.2	82/10/05	*/

#include <sys/types.h>
#include <ctype.h>

/*
 * Internet address interpretation routine.
 * All the network library routines call this
 * routine to interpret entries in the data bases
 * which are expected to be an address.
 */
u_long
inet_addr(cp)
	register char *cp;
{
	register unsigned long val, base, n;
	register char c;
	unsigned long parts[4], *pp = parts;

again:
	val = 0; base = 10;
	if (*cp == '0')
		base = 8, cp++;
	if (*cp == 'x' || *cp == 'X')
		base = 16, cp++;
	while (c = *cp) {
		if (isdigit(c)) {
			val = (val * base) + (c - '0');
			cp++;
			continue;
		}
		if (base == 16 && isxdigit(c)) {
			val = (val << 4) + (c + 10 - (islower(c) ? 'a' : 'A'));
			cp++;
			continue;
		}
		break;
	}
	if (*cp == '.') {
		/*
		 * Internet format:
		 *	a.b.c.d
		 *	a.b.c	(with c treated as 16-bits)
		 *	a.b	(with b treated as 24 bits)
		 */
		if (pp >= parts + 4)
			return (-1);
		*pp++ = val, cp++;
		goto again;
	}
	if (*cp && !isspace(*cp))
		return (-1);
	n = pp - parts;
	if (n > 0) {
		if (n > 4)
			return (-1);
		*pp++ = val; n++;
		val = parts[0];
		if (n > 1)
			val <<= 24;
		if (n > 2)
			val |= (parts[1] & 0xff) << 16;
		if (n > 3)
			val |= (parts[2] & 0xff) << 8;
		if (n > 1)
			val |= parts[n - 1];
#if vax || pdp11
		val = htonl(val);
#endif
	}
	return (val);
}