FreeBSD/Linux Kernel Cross Reference
sys/libkern/strtoul.c
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. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * From: @(#)strtoul.c 8.1 (Berkeley) 6/4/93
37 */
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD: releng/5.2/sys/libkern/strtoul.c 116189 2003-06-11 05:37:42Z obrien $");
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/ctype.h>
45 #include <sys/limits.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 unsigned long
54 strtoul(nptr, endptr, base)
55 const char *nptr;
56 char **endptr;
57 int base;
58 {
59 const char *s = nptr;
60 unsigned long acc;
61 unsigned char c;
62 unsigned long cutoff;
63 int neg = 0, any, cutlim;
64
65 /*
66 * See strtol for comments as to the logic used.
67 */
68 do {
69 c = *s++;
70 } while (isspace(c));
71 if (c == '-') {
72 neg = 1;
73 c = *s++;
74 } else if (c == '+')
75 c = *s++;
76 if ((base == 0 || base == 16) &&
77 c == '' && (*s == 'x' || *s == 'X')) {
78 c = s[1];
79 s += 2;
80 base = 16;
81 }
82 if (base == 0)
83 base = c == '' ? 8 : 10;
84 cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
85 cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
86 for (acc = 0, any = 0;; c = *s++) {
87 if (!isascii(c))
88 break;
89 if (isdigit(c))
90 c -= '';
91 else if (isalpha(c))
92 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
93 else
94 break;
95 if (c >= base)
96 break;
97 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
98 any = -1;
99 else {
100 any = 1;
101 acc *= base;
102 acc += c;
103 }
104 }
105 if (any < 0) {
106 acc = ULONG_MAX;
107 } else if (neg)
108 acc = -acc;
109 if (endptr != 0)
110 *((const char **)endptr) = any ? s - 1 : nptr;
111 return (acc);
112 }
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