xref: /illumos-gate/usr/src/lib/libresolv2/common/bsd/strtoul.c (revision e00bdde3c6d406f40f53f3025defadc22f7ec31a)
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 #include "port_before.h"
35 
36 #include <sys/types.h>
37 #include <sys/param.h>
38 
39 #include <ctype.h>
40 #include <errno.h>
41 #include <limits.h>
42 #include <stdlib.h>
43 
44 #include "port_after.h"
45 
46 #ifndef NEED_STRTOUL
47 int __strtoul_unneeded__;
48 #else
49 
50 /*%
51  * Convert a string to an unsigned long integer.
52  *
53  * Ignores `locale' stuff.  Assumes that the upper and lower case
54  * alphabets and digits are each contiguous.
55  */
56 u_long
57 strtoul(const char *nptr, char **endptr, int base) {
58 	const char *s = nptr;
59 	u_long acc, cutoff;
60 	int neg, c, any, cutlim;
61 
62 	neg = 0;
63 
64 	/*
65 	 * See strtol for comments as to the logic used.
66 	 */
67 	do {
68 		c = *(const unsigned char *)s++;
69 	} while (isspace(c));
70 	if (c == '-') {
71 		neg = 1;
72 		c = *s++;
73 	} else if (c == '+')
74 		c = *s++;
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 	cutoff = (u_long)ULONG_MAX / (u_long)base;
84 	cutlim = (u_long)ULONG_MAX % (u_long)base;
85 	for (acc = 0, any = 0;; c = *(const unsigned char*)s++) {
86 		if (isdigit(c))
87 			c -= '0';
88 		else if (isalpha(c))
89 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
90 		else
91 			break;
92 		if (c >= base)
93 			break;
94 		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
95 			any = -1;
96 		else {
97 			any = 1;
98 			acc *= base;
99 			acc += c;
100 		}
101 	}
102 	if (any < 0) {
103 		acc = ULONG_MAX;
104 		errno = ERANGE;
105 	} else if (neg)
106 		acc = -acc;
107 	if (endptr != 0)
108 		DE_CONST((any ? s - 1 : nptr), *endptr);
109 	return (acc);
110 }
111 
112 #endif /*NEED_STRTOUL*/
113 
114 /*! \file */
115