1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * From: static char sccsid[] = "@(#)strtoul.c 8.1 (Berkeley) 6/4/93";
33 *
34 * $FreeBSD: src/sys/libkern/strtoul.c,v 1.3 1999/12/01 22:56:51 archie Exp $
35 */
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/ctype.h>
40 #include <machine/limits.h>
41
42 /*
43 * Convert a string to an unsigned long integer.
44 *
45 * Ignores `locale' stuff. Assumes that the upper and lower case
46 * alphabets and digits are each contiguous.
47 */
48 unsigned long
strtoul(const char * nptr,char ** endptr,int base)49 strtoul(const char *nptr, char **endptr, int base)
50 {
51 const char *s = nptr;
52 unsigned long acc;
53 unsigned char c;
54 unsigned long cutoff;
55 int neg = 0, any, cutlim;
56
57 /*
58 * See strtol for comments as to the logic used.
59 */
60 do {
61 c = *s++;
62 } while (isspace(c));
63 if (c == '-') {
64 neg = 1;
65 c = *s++;
66 } else if (c == '+')
67 c = *s++;
68 if ((base == 0 || base == 16) &&
69 c == '0' && (*s == 'x' || *s == 'X')) {
70 c = s[1];
71 s += 2;
72 base = 16;
73 }
74 if (base == 0)
75 base = c == '0' ? 8 : 10;
76 cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
77 cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
78 for (acc = 0, any = 0;; c = *s++) {
79 if (!isascii(c))
80 break;
81 if (isdigit(c))
82 c -= '0';
83 else if (isalpha(c))
84 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
85 else
86 break;
87 if (c >= base)
88 break;
89 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
90 any = -1;
91 else {
92 any = 1;
93 acc *= base;
94 acc += c;
95 }
96 }
97 if (any < 0) {
98 acc = ULONG_MAX;
99 } else if (neg)
100 acc = -acc;
101 if (endptr != NULL)
102 *((const char **)(void *)endptr) = any ? s - 1 : nptr;
103 return (acc);
104 }
105