strtoul.c revision 290001 
1/*
2 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 2003  Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/*
19 * Copyright (c) 1990, 1993
20 *	The Regents of the University of California.  All rights reserved.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the above copyright
26 *    notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 *    notice, this list of conditions and the following disclaimer in the
29 *    documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 *    must display the following acknowledgement:
32 *	This product includes software developed by the University of
33 *	California, Berkeley and its contributors.
34 * 4. Neither the name of the University nor the names of its contributors
35 *    may be used to endorse or promote products derived from this software
36 *    without specific prior written permission.
37 *
38 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
39 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
40 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
41 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
42 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
43 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
44 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
45 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
46 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
47 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48 * SUCH DAMAGE.
49 */
50
51/*! \file */
52#if defined(LIBC_SCCS) && !defined(lint)
53static char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";
54#endif /* LIBC_SCCS and not lint */
55
56/* $Id: strtoul.c,v 1.7 2007/06/19 23:47:17 tbox Exp $ */
57
58#include <config.h>
59
60#include <limits.h>
61#include <ctype.h>
62#include <errno.h>
63
64#include <isc/stdlib.h>
65#include <isc/util.h>
66
67/*!
68 * Convert a string to an unsigned long integer.
69 *
70 * Ignores `locale' stuff.  Assumes that the upper and lower case
71 * alphabets and digits are each contiguous.
72 */
73unsigned long
74isc_strtoul(const char *nptr, char **endptr, int base) {
75	const char *s = nptr;
76	unsigned long acc;
77	unsigned char c;
78	unsigned long cutoff;
79	int neg = 0, any, cutlim;
80
81	/*
82	 * See strtol for comments as to the logic used.
83	 */
84	do {
85		c = *s++;
86	} while (isspace(c));
87	if (c == '-') {
88		neg = 1;
89		c = *s++;
90	} else if (c == '+')
91		c = *s++;
92	if ((base == 0 || base == 16) &&
93	    c == '0' && (*s == 'x' || *s == 'X')) {
94		c = s[1];
95		s += 2;
96		base = 16;
97	}
98	if (base == 0)
99		base = c == '0' ? 8 : 10;
100	cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
101	cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
102	for (acc = 0, any = 0;; c = *s++) {
103		if (!isascii(c))
104			break;
105		if (isdigit(c))
106			c -= '0';
107		else if (isalpha(c))
108			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
109		else
110			break;
111		if (c >= base)
112			break;
113		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
114			any = -1;
115		else {
116			any = 1;
117			acc *= base;
118			acc += c;
119		}
120	}
121	if (any < 0) {
122		acc = ULONG_MAX;
123		errno = ERANGE;
124	} else if (neg)
125		acc = -acc;
126	if (endptr != 0)
127		DE_CONST(any ? s - 1 : nptr, *endptr);
128	return (acc);
129}
130