1 /*
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. 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)
35 static char sccsid[] = "@(#)strtoul.c 8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37
38 #include <limits.h>
39 #include <ctype.h>
40 #include <errno.h>
41 #include <stdlib.h>
42
43 #include <sys/cdefs.h>
44
45 /*
46 * Convert a string to an unsigned long integer.
47 *
48 * Ignores `locale' stuff. Assumes that the upper and lower case
49 * alphabets and digits are each contiguous.
50 */
51 unsigned long
strtoul(nptr,endptr,base)52 strtoul(nptr, endptr, base)
53 const char *nptr;
54 char **endptr;
55 register int base;
56 {
57 register const char *s = nptr;
58 register unsigned long acc;
59 register int c;
60 register unsigned long cutoff;
61 register int neg = 0, any, cutlim;
62
63 /*
64 * See strtol for comments as to the logic used.
65 */
66 do {
67 c = *s++;
68 } while (isspace(c));
69 if (c == '-') {
70 neg = 1;
71 c = *s++;
72 } else if (c == '+')
73 c = *s++;
74 if ((base == 0 || base == 16) &&
75 c == '0' && (*s == 'x' || *s == 'X')) {
76 c = s[1];
77 s += 2;
78 base = 16;
79 }
80 if (base == 0)
81 base = c == '0' ? 8 : 10;
82 cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
83 cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
84 for (acc = 0, any = 0;; c = *s++) {
85 if (isdigit(c))
86 c -= '0';
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 errno = ERANGE;
104 } else if (neg)
105 acc = -acc;
106 if (endptr != 0)
107 *endptr = (char *)(any ? s - 1 : nptr);
108 return (acc);
109 }
110