1/*	$NetBSD: strtoul.c,v 1.1.1.2 2008/05/18 14:29:39 aymeric Exp $ */
2
3/*
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "config.h"
37
38#if defined(LIBC_SCCS) && !defined(lint)
39static const char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";
40#endif /* LIBC_SCCS and not lint */
41
42#include <limits.h>
43#include <ctype.h>
44#include <errno.h>
45#include <stdlib.h>
46
47/*
48 * Convert a string to an unsigned long integer.
49 *
50 * Ignores `locale' stuff.  Assumes that the upper and lower case
51 * alphabets and digits are each contiguous.
52 *
53 * PUBLIC: #ifndef HAVE_STRTOUL
54 * PUBLIC: unsigned long strtoul __P((const char *, char **, int));
55 * PUBLIC: #endif
56 */
57unsigned long
58strtoul(const char *nptr, char **endptr, register int base)
59{
60	register const char *s = nptr;
61	register unsigned long acc;
62	register int c;
63	register unsigned long cutoff;
64	register int neg = 0, any, cutlim;
65
66	/*
67	 * See strtol for comments as to the logic used.
68	 */
69	do {
70		c = *s++;
71	} while (isspace(c));
72	if (c == '-') {
73		neg = 1;
74		c = *s++;
75	} else if (c == '+')
76		c = *s++;
77	if ((base == 0 || base == 16) &&
78	    c == '0' && (*s == 'x' || *s == 'X')) {
79		c = s[1];
80		s += 2;
81		base = 16;
82	}
83	if (base == 0)
84		base = c == '0' ? 8 : 10;
85	cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
86	cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
87	for (acc = 0, any = 0;; c = *s++) {
88		if (isdigit(c))
89			c -= '0';
90		else if (isalpha(c))
91			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
92		else
93			break;
94		if (c >= base)
95			break;
96		if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
97			any = -1;
98		else {
99			any = 1;
100			acc *= base;
101			acc += c;
102		}
103	}
104	if (any < 0) {
105		acc = ULONG_MAX;
106		errno = ERANGE;
107	} else if (neg)
108		acc = -acc;
109	if (endptr != 0)
110		*endptr = (char *)(any ? s - 1 : nptr);
111	return (acc);
112}
113