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