strtoul.c revision 82982 
1/*
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if defined(LIBC_SCCS) && !defined(lint)
35static char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";
36#endif /* LIBC_SCCS and not lint */
37
38#ifndef lint
39static const char rcsid[] =
40"$FreeBSD: head/lib/libc/stdlib/strtoul.c 82982 2001-09-04 17:12:15Z ache $";
41#endif
42
43#include <limits.h>
44#include <ctype.h>
45#include <errno.h>
46#include <stdlib.h>
47
48/*
49 * Convert a string to an unsigned long integer.
50 *
51 * Assumes that the upper and lower case
52 * alphabets and digits are each contiguous.
53 */
54unsigned long
55strtoul(nptr, endptr, base)
56	const char *nptr;
57	char **endptr;
58	register int base;
59{
60	register const char *s;
61	register unsigned long acc;
62	register unsigned char c;
63	register unsigned long cutoff;
64	register int neg, any, cutlim;
65
66	/*
67	 * See strtol for comments as to the logic used.
68	 */
69	s = nptr;
70	do {
71		c = *s++;
72	} while (isspace(c));
73	if (c == '-') {
74		neg = 1;
75		c = *s++;
76	} else {
77		neg = 0;
78		if (c == '+')
79			c = *s++;
80	}
81	if ((base == 0 || base == 16) &&
82	    c == '0' && (*s == 'x' || *s == 'X')) {
83		c = s[1];
84		s += 2;
85		base = 16;
86	}
87	if (base == 0)
88		base = c == '0' ? 8 : 10;
89	acc = any = 0;
90	if (base < 2 || base > 36)
91		goto noconv;
92
93	cutoff = ULONG_MAX / base;
94	cutlim = ULONG_MAX % base;
95	for ( ; ; c = *s++) {
96		if (!isascii(c))
97			break;
98		if (isdigit(c))
99			c -= '0';
100		else if (isalpha(c))
101			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
102		else
103			break;
104		if (c >= base)
105			break;
106		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
107			any = -1;
108		else {
109			any = 1;
110			acc *= base;
111			acc += c;
112		}
113	}
114	if (any < 0) {
115		acc = ULONG_MAX;
116		errno = ERANGE;
117	} else if (!any) {
118noconv:
119		errno = EINVAL;
120	} else if (neg)
121		acc = -acc;
122	if (endptr != NULL)
123		*endptr = (char *)(any ? s - 1 : nptr);
124	return (acc);
125}
126