strtoul.c revision 1.1 
1/*	$NetBSD: strtoul.c,v 1.1 2005/12/20 19:28:52 christos 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. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#if !defined(_KERNEL) && !defined(_STANDALONE)
33#include <sys/cdefs.h>
34#if defined(LIBC_SCCS) && !defined(lint)
35#if 0
36static char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";
37#else
38__RCSID("$NetBSD: strtoul.c,v 1.1 2005/12/20 19:28:52 christos Exp $");
39#endif
40#endif /* LIBC_SCCS and not lint */
41
42#include <assert.h>
43#include <ctype.h>
44#include <errno.h>
45#include <limits.h>
46#include <stdlib.h>
47#else
48#include <sys/param.h>
49#include <lib/libkern/libkern.h>
50#define isspace(x) ((x) == ' ' || (x) == '\t' || (x) == '\n' || (x) == '\r')
51#define isdigit(x) ((x) >= '0' && (x) <= '9')
52#define isalpha(x) (((x) >= 'a' && (x) <= 'z') || ((x) >= 'A' && (x) <= 'Z'))
53#define toupper(x) ((x) & ~0x20)
54#endif
55
56/*
57 * Convert a string to an unsigned long integer.
58 *
59 * Ignores `locale' stuff.  Assumes that the upper and lower case
60 * alphabets and digits are each contiguous.
61 */
62unsigned long
63strtoul(nptr, endptr, base)
64	const char *nptr;
65	char **endptr;
66	int base;
67{
68	const char *s;
69	unsigned long acc, cutoff;
70	int c;
71	int neg, any, cutlim;
72
73	_DIAGASSERT(nptr != NULL);
74	/* endptr may be NULL */
75
76	/*
77	 * See strtol for comments as to the logic used.
78	 */
79	s = nptr;
80	do {
81		c = (unsigned char) *s++;
82	} while (isspace(c));
83	if (c == '-') {
84		neg = 1;
85		c = *s++;
86	} else {
87		neg = 0;
88		if (c == '+')
89			c = *s++;
90	}
91	if ((base == 0 || base == 16) &&
92	    c == '0' && (*s == 'x' || *s == 'X')) {
93		c = s[1];
94		s += 2;
95		base = 16;
96	}
97	if (base == 0)
98		base = c == '0' ? 8 : 10;
99
100	cutoff = ULONG_MAX / (unsigned long)base;
101	cutlim = (int)(ULONG_MAX % (unsigned long)base);
102	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
103		if (isdigit(c))
104			c -= '0';
105		else if (isalpha(c)) {
106#if defined(_KERNEL) || defined(_STANDALONE)
107			c = toupper(c) - 'A' + 10;
108#else
109			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
110#endif
111		} else
112			break;
113		if (c >= base)
114			break;
115		if (any < 0)
116			continue;
117		if (acc > cutoff || (acc == cutoff && c > cutlim)) {
118#if defined(_KERNEL) || defined(_STANDALONE)
119			if (endptr)
120				*endptr = __UNCONST(nptr);
121			return ULONG_MAX;
122#else
123			any = -1;
124			acc = ULONG_MAX;
125			errno = ERANGE;
126#endif
127		} else {
128			any = 1;
129			acc *= (unsigned long)base;
130			acc += c;
131		}
132	}
133	if (neg && any > 0)
134		acc = -acc;
135	if (endptr != NULL)
136		*endptr = __UNCONST(any ? s - 1 : nptr);
137	return (acc);
138}
139