1 /* $OpenBSD: strtoul.c,v 1.7 2005/08/08 08:05:37 espie Exp $ */
2 /*
3 * Copyright (c) 1990 Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 /* OPENBSD ORIGINAL: lib/libc/stdlib/strtoul.c */
32
33 #include "includes.h"
34 #ifndef HAVE_STRTOUL
35
36 #include <ctype.h>
37 #include <errno.h>
38 #include <limits.h>
39 #include <stdlib.h>
40
41 /*
42 * Convert a string to an unsigned long integer.
43 *
44 * Ignores `locale' stuff. Assumes that the upper and lower case
45 * alphabets and digits are each contiguous.
46 */
47 unsigned long
strtoul(const char * nptr,char ** endptr,int base)48 strtoul(const char *nptr, char **endptr, int base)
49 {
50 const char *s;
51 unsigned long acc, cutoff;
52 int c;
53 int neg, any, cutlim;
54
55 /*
56 * See strtol for comments as to the logic used.
57 */
58 s = nptr;
59 do {
60 c = (unsigned char) *s++;
61 } while (isspace(c));
62 if (c == '-') {
63 neg = 1;
64 c = *s++;
65 } else {
66 neg = 0;
67 if (c == '+')
68 c = *s++;
69 }
70 if ((base == 0 || base == 16) &&
71 c == '0' && (*s == 'x' || *s == 'X')) {
72 c = s[1];
73 s += 2;
74 base = 16;
75 }
76 if (base == 0)
77 base = c == '0' ? 8 : 10;
78
79 cutoff = ULONG_MAX / (unsigned long)base;
80 cutlim = ULONG_MAX % (unsigned long)base;
81 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
82 if (isdigit(c))
83 c -= '0';
84 else if (isalpha(c))
85 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
86 else
87 break;
88 if (c >= base)
89 break;
90 if (any < 0)
91 continue;
92 if (acc > cutoff || acc == cutoff && c > cutlim) {
93 any = -1;
94 acc = ULONG_MAX;
95 errno = ERANGE;
96 } else {
97 any = 1;
98 acc *= (unsigned long)base;
99 acc += c;
100 }
101 }
102 if (neg && any > 0)
103 acc = -acc;
104 if (endptr != 0)
105 *endptr = (char *) (any ? s - 1 : nptr);
106 return (acc);
107 }
108 #endif /* !HAVE_STRTOUL */
109