xref: /illumos-gate/usr/src/lib/libresolv2/common/bsd/strtoul.c (revision afab0816ecb604f0099a09ad8ee398f0d7b77b1c)
1 #if defined(LIBC_SCCS) && !defined(lint)
2 static const char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";
3 static const char rcsid[] = "$Id: strtoul.c,v 1.4 2008/02/18 03:49:08 marka Exp $";
4 #endif /* LIBC_SCCS and not lint */
5 
6 /*
7  * Copyright (c) 1990, 1993
8  *    The Regents of the University of California.  All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  * 	This product includes software developed by the University of
21  * 	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #include "port_before.h"
40 
41 #include <sys/types.h>
42 #include <sys/param.h>
43 
44 #include <ctype.h>
45 #include <errno.h>
46 #include <limits.h>
47 #include <stdlib.h>
48 
49 #include "port_after.h"
50 
51 #ifndef NEED_STRTOUL
52 int __strtoul_unneeded__;
53 #else
54 
55 /*%
56  * Convert a string to an unsigned long integer.
57  *
58  * Ignores `locale' stuff.  Assumes that the upper and lower case
59  * alphabets and digits are each contiguous.
60  */
61 u_long
62 strtoul(const char *nptr, char **endptr, int base) {
63 	const char *s = nptr;
64 	u_long acc, cutoff;
65 	int neg, c, any, cutlim;
66 
67 	neg = 0;
68 
69 	/*
70 	 * See strtol for comments as to the logic used.
71 	 */
72 	do {
73 		c = *(const unsigned char *)s++;
74 	} while (isspace(c));
75 	if (c == '-') {
76 		neg = 1;
77 		c = *s++;
78 	} else if (c == '+')
79 		c = *s++;
80 	if ((base == 0 || base == 16) &&
81 	    c == '0' && (*s == 'x' || *s == 'X')) {
82 		c = s[1];
83 		s += 2;
84 		base = 16;
85 	}
86 	if (base == 0)
87 		base = c == '0' ? 8 : 10;
88 	cutoff = (u_long)ULONG_MAX / (u_long)base;
89 	cutlim = (u_long)ULONG_MAX % (u_long)base;
90 	for (acc = 0, any = 0;; c = *(const unsigned char*)s++) {
91 		if (isdigit(c))
92 			c -= '0';
93 		else if (isalpha(c))
94 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
95 		else
96 			break;
97 		if (c >= base)
98 			break;
99 		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
100 			any = -1;
101 		else {
102 			any = 1;
103 			acc *= base;
104 			acc += c;
105 		}
106 	}
107 	if (any < 0) {
108 		acc = ULONG_MAX;
109 		errno = ERANGE;
110 	} else if (neg)
111 		acc = -acc;
112 	if (endptr != 0)
113 		DE_CONST((any ? s - 1 : nptr), *endptr);
114 	return (acc);
115 }
116 
117 #endif /*NEED_STRTOUL*/
118 
119 /*! \file */
120