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-rw-r--r--src/lib/libc/stdlib/strtoul.c112
1 files changed, 112 insertions, 0 deletions
diff --git a/src/lib/libc/stdlib/strtoul.c b/src/lib/libc/stdlib/strtoul.c
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1/*
2 * Copyright (c) 1990 Regents of the University of California.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if defined(LIBC_SCCS) && !defined(lint)
35static char *rcsid = "$OpenBSD: strtoul.c,v 1.4 1996/08/19 08:33:52 tholo Exp $";
36#endif /* LIBC_SCCS and not lint */
37
38#include <ctype.h>
39#include <errno.h>
40#include <limits.h>
41#include <stdlib.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 */
49unsigned long
50strtoul(nptr, endptr, base)
51 const char *nptr;
52 char **endptr;
53 register int base;
54{
55 register const char *s;
56 register unsigned long acc, cutoff;
57 register int c;
58 register int neg, any, cutlim;
59
60 /*
61 * See strtol for comments as to the logic used.
62 */
63 s = nptr;
64 do {
65 c = (unsigned char) *s++;
66 } while (isspace(c));
67 if (c == '-') {
68 neg = 1;
69 c = *s++;
70 } else {
71 neg = 0;
72 if (c == '+')
73 c = *s++;
74 }
75 if ((base == 0 || base == 16) &&
76 c == '0' && (*s == 'x' || *s == 'X')) {
77 c = s[1];
78 s += 2;
79 base = 16;
80 }
81 if (base == 0)
82 base = c == '0' ? 8 : 10;
83
84 cutoff = ULONG_MAX / (unsigned long)base;
85 cutlim = ULONG_MAX % (unsigned long)base;
86 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
87 if (isdigit(c))
88 c -= '0';
89 else if (isalpha(c))
90 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
91 else
92 break;
93 if (c >= base)
94 break;
95 if (any < 0)
96 continue;
97 if (acc > cutoff || acc == cutoff && c > cutlim) {
98 any = -1;
99 acc = ULONG_MAX;
100 errno = ERANGE;
101 } else {
102 any = 1;
103 acc *= (unsigned long)base;
104 acc += c;
105 }
106 }
107 if (neg && any > 0)
108 acc = -acc;
109 if (endptr != 0)
110 *endptr = (char *) (any ? s - 1 : nptr);
111 return (acc);
112}