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 * 4. 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: @(#)strtoul.c 8.1 (Berkeley) 6/4/93
33 */
34
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/ctype.h>
41 #include <sys/limits.h>
42
43 /*
44 * Convert a string to an unsigned long integer.
45 *
46 * Ignores `locale' stuff. Assumes that the upper and lower case
47 * alphabets and digits are each contiguous.
48 */
49 unsigned long
50 strtoul(nptr, endptr, base)
51 const char *nptr;
52 char **endptr;
53 int base;
54 {
55 const char *s = nptr;
56 unsigned long acc;
57 unsigned char c;
58 unsigned long cutoff;
59 int neg = 0, any, cutlim;
60
61 /*
62 * See strtol for comments as to the logic used.
63 */
64 do {
65 c = *s++;
66 } while (isspace(c));
67 if (c == '-') {
68 neg = 1;
69 c = *s++;
70 } else if (c == '+')
71 c = *s++;
72 if ((base == 0 || base == 16) &&
73 c == '' && (*s == 'x' || *s == 'X')) {
74 c = s[1];
75 s += 2;
76 base = 16;
77 }
78 if (base == 0)
79 base = c == '' ? 8 : 10;
80 cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
81 cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
82 for (acc = 0, any = 0;; c = *s++) {
83 if (!isascii(c))
84 break;
85 if (isdigit(c))
86 c -= '';
87 else if (isalpha(c))
88 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
89 else
90 break;
91 if (c >= base)
92 break;
93 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
94 any = -1;
95 else {
96 any = 1;
97 acc *= base;
98 acc += c;
99 }
100 }
101 if (any < 0) {
102 acc = ULONG_MAX;
103 } else if (neg)
104 acc = -acc;
105 if (endptr != 0)
106 *((const char **)endptr) = any ? s - 1 : nptr;
107 return (acc);
108 }
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