1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * From: @(#)strtoul.c	8.1 (Berkeley) 6/4/93
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD$");
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/ctype.h>
41#include <sys/limits.h>
42
43/*
44 * Convert a string to an unsigned long integer.
45 *
46 * Ignores `locale' stuff.  Assumes that the upper and lower case
47 * alphabets and digits are each contiguous.
48 */
49unsigned long
50strtoul(nptr, endptr, base)
51	const char *nptr;
52	char **endptr;
53	int base;
54{
55	const char *s = nptr;
56	unsigned long acc;
57	unsigned char c;
58	unsigned long cutoff;
59	int neg = 0, any, cutlim;
60
61	/*
62	 * See strtol for comments as to the logic used.
63	 */
64	do {
65		c = *s++;
66	} while (isspace(c));
67	if (c == '-') {
68		neg = 1;
69		c = *s++;
70	} else if (c == '+')
71		c = *s++;
72	if ((base == 0 || base == 16) &&
73	    c == '0' && (*s == 'x' || *s == 'X')) {
74		c = s[1];
75		s += 2;
76		base = 16;
77	}
78	if (base == 0)
79		base = c == '0' ? 8 : 10;
80	cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
81	cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
82	for (acc = 0, any = 0;; c = *s++) {
83		if (!isascii(c))
84			break;
85		if (isdigit(c))
86			c -= '0';
87		else if (isalpha(c))
88			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
89		else
90			break;
91		if (c >= base)
92			break;
93		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
94			any = -1;
95		else {
96			any = 1;
97			acc *= base;
98			acc += c;
99		}
100	}
101	if (any < 0) {
102		acc = ULONG_MAX;
103	} else if (neg)
104		acc = -acc;
105	if (endptr != 0)
106		*((const char **)endptr) = any ? s - 1 : nptr;
107	return (acc);
108}
109