1 /* SPDX-License-Identifier: BSD-3-Clause */
2
3 /*
4 * Copyright (c) 1990 Regents of the University of California.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <limits.h>
33 #include <ctype.h>
34 #include <errno.h>
35 #include <stdlib.h>
36
37 /*
38 * Convert a string to an unsigned long integer.
39 *
40 * Ignores `locale' stuff. Assumes that the upper and lower case
41 * alphabets and digits are each contiguous.
42 */
strtoul(const char * nptr,char ** endptr,register int base)43 unsigned long strtoul(const char *nptr, char **endptr, register int base)
44 {
45 register const char *s = nptr;
46 register unsigned long acc;
47 register int c;
48 register unsigned long cutoff;
49 register int neg = 0, any, cutlim;
50
51 /*
52 * See strtol for comments as to the logic used.
53 */
54 do {
55 c = *s++;
56 } while (isspace((unsigned char)c) != 0);
57 if (c == '-') {
58 neg = 1;
59 c = *s++;
60 } else if (c == '+') {
61 c = *s++;
62 }
63
64 if (((base == 0) || (base == 16)) &&
65 (c == '0') && ((*s == 'x') || (*s == 'X'))) {
66 c = s[1];
67 s += 2;
68 base = 16;
69 }
70
71 if (base == 0) {
72 base = (c == '0') ? 8 : 10;
73 }
74
75 cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
76 cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
77 for (acc = 0, any = 0;; c = *s++) {
78 if (isdigit((unsigned char)c) != 0) {
79 c -= '0';
80 } else if (isalpha((unsigned char)c) != 0) {
81 c -= isupper((unsigned char)c) != 0 ? 'A' - 10 : 'a' - 10;
82 } else {
83 break;
84 }
85 if (c >= base) {
86 break;
87 }
88 if ((any < 0) || (acc > cutoff) || ((acc == cutoff) && (c > cutlim))) {
89 any = -1;
90 } else {
91 any = 1;
92 acc *= base;
93 acc += c;
94 }
95 }
96 if (any < 0) {
97 acc = ULONG_MAX;
98 errno = ERANGE;
99 } else if (neg != 0) {
100 acc = -acc;
101 }
102 if (endptr != NULL) {
103 *endptr = (char *)(any ? (s - 1) : nptr);
104 }
105 return acc;
106 }
107
