/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

/*

 * Copyright (c) 1990, 1993

 *	The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <config.h>

/*! \file */

#if defined(LIBC_SCCS) && !defined(lint)

static char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";

#endif /* LIBC_SCCS and not lint */

#include <limits.h>

#include <ctype.h>

#include <errno.h>

#include <isc/stdlib.h>

#include <isc/util.h>

/*!

 * Convert a string to an unsigned long integer.

 *

 * Ignores `locale' stuff.  Assumes that the upper and lower case

 * alphabets and digits are each contiguous.

 */

unsigned long

isc_strtoul(const char *nptr, char **endptr, int base) {

	const char *s = nptr;

	unsigned long acc;

	unsigned char c;

	unsigned long cutoff;

	int neg = 0, any, cutlim;

	/*

	 * See strtol for comments as to the logic used.

	 */

	do {

		c = *s++;

	} while (isspace(c));

	if (c == '-') {

		neg = 1;

		c = *s++;

	} else if (c == '+')

		c = *s++;

	if ((base == 0 || base == 16) &&

	    c == '0' && (*s == 'x' || *s == 'X')) {

		c = s[1];

		s += 2;

		base = 16;

	}

	if (base == 0)

		base = c == '0' ? 8 : 10;

	cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;

	cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;

	for (acc = 0, any = 0;; c = *s++) {

		if (!isascii(c))

			break;

		if (isdigit(c))

			c -= '0';

		else if (isalpha(c))

			c -= isupper(c) ? 'A' - 10 : 'a' - 10;

		else

			break;

		if (c >= base)

			break;

		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))

			any = -1;

		else {

			any = 1;

			acc *= base;

			acc += c;

		}

	}

	if (any < 0) {

		acc = ULONG_MAX;

		errno = ERANGE;

	} else if (neg)

		acc = -acc;

	if (endptr != 0)

		DE_CONST(any ? s - 1 : nptr, *endptr);

	return (acc);

}