1 /* $Id: strtoul.c,v 1.2 2005/07/07 16:34:06 dron Exp $ */
2
3 /*
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. 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 #if 0
33 static char sccsid[] = "@(#)strtoul.c 8.1 (Berkeley) 6/4/93";
34 __RCSID("$NetBSD: strtoul.c,v 1.16 2003/08/07 16:43:45 agc Exp $");
35 #endif
36
37 #include <ctype.h>
38 #include <errno.h>
39 #include <limits.h>
40 #include <stdlib.h>
41
42 /*
43 * Convert a string to an unsigned long integer.
44 *
45 * Ignores `locale' stuff. Assumes that the upper and lower case
46 * alphabets and digits are each contiguous.
47 */
48 unsigned long
strtoul(const char * nptr,char ** endptr,int base)49 strtoul(const char *nptr, char **endptr, int base)
50 {
51 const char *s;
52 unsigned long acc, cutoff;
53 int c;
54 int neg, any, cutlim;
55
56 /*
57 * See strtol for comments as to the logic used.
58 */
59 s = nptr;
60 do {
61 c = (unsigned char) *s++;
62 } while (isspace(c));
63 if (c == '-') {
64 neg = 1;
65 c = *s++;
66 } else {
67 neg = 0;
68 if (c == '+')
69 c = *s++;
70 }
71 if ((base == 0 || base == 16) &&
72 c == '0' && (*s == 'x' || *s == 'X')) {
73 c = s[1];
74 s += 2;
75 base = 16;
76 }
77 if (base == 0)
78 base = c == '0' ? 8 : 10;
79
80 cutoff = ULONG_MAX / (unsigned long)base;
81 cutlim = (int)(ULONG_MAX % (unsigned long)base);
82 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
83 if (isdigit(c))
84 c -= '0';
85 else if (isalpha(c))
86 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
87 else
88 break;
89 if (c >= base)
90 break;
91 if (any < 0)
92 continue;
93 if (acc > cutoff || (acc == cutoff && c > cutlim)) {
94 any = -1;
95 acc = ULONG_MAX;
96 errno = ERANGE;
97 } else {
98 any = 1;
99 acc *= (unsigned long)base;
100 acc += c;
101 }
102 }
103 if (neg && any > 0)
104 acc = -acc;
105 if (endptr != 0)
106 /* LINTED interface specification */
107 *endptr = (char *)(any ? s - 1 : nptr);
108 return (acc);
109 }
110