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