/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
 */

#include "ctype.h"
#include "types.h"
#include "in.h"

/* TCP_INETADDR -- Internet address interpretation routine.  Decode a network
 * address from the host name table.  The value returned is in network order.
 */
u_long
tcp_inetaddr (cp)
register char *cp;
{
	register u_long val, base, n;
	register char c;
	u_long	parts[4], *pp = parts;

again:
	/* Collect number up to ``.''.
	 * Values are specified as for C:
	 * 0x=hex, 0=octal, other=decimal.
	 */
	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;
	}

	/* Check for trailing characters.
	 */
	if (*cp && !isspace(*cp))
	    return (-1);
	*pp++ = val;

	/* Concoct the address according to
	 * the number of parts specified.
	 */
	n = pp - parts;
	switch (n) {

	case 1:				/* a -- 32 bits */
		val = parts[0];
		break;

	case 2:				/* a.b -- 8.24 bits */
		val = (parts[0] << 24) | (parts[1] & 0xffffff);
		break;

	case 3:				/* a.b.c -- 8.8.16 bits */
		val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) |
			(parts[2] & 0xffff);
		break;

	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
		val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) |
		      ((parts[2] & 0xff) << 8) | (parts[3] & 0xff);
		break;

	default:
		return (-1);
	}

	val = htonl(val);
	return (val);
}
