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