xref: /freebsd/lib/libc/stdlib/strtoul.c (revision 9d54812421274e490dc5f0fe4722ab8d35d9b258)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Copyright (c) 2011 The FreeBSD Foundation
8  *
9  * Portions of this software were developed by David Chisnall
10  * under sponsorship from the FreeBSD Foundation.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include <limits.h>
44 #include <ctype.h>
45 #include <errno.h>
46 #include <stdlib.h>
47 #include "xlocale_private.h"
48 
49 /*
50  * Convert a string to an unsigned long integer.
51  *
52  * Assumes that the upper and lower case
53  * alphabets and digits are each contiguous.
54  */
55 unsigned long
56 strtoul_l(const char * __restrict nptr, char ** __restrict endptr, int base, locale_t locale)
57 {
58 	const char *s;
59 	unsigned long acc;
60 	char c;
61 	unsigned long cutoff;
62 	int neg, any, cutlim;
63 	FIX_LOCALE(locale);
64 
65 	/*
66 	 * See strtol for comments as to the logic used.
67 	 */
68 	s = nptr;
69 	do {
70 		c = *s++;
71 	} while (isspace_l((unsigned char)c, locale));
72 	if (c == '-') {
73 		neg = 1;
74 		c = *s++;
75 	} else {
76 		neg = 0;
77 		if (c == '+')
78 			c = *s++;
79 	}
80 	if ((base == 0 || base == 16) &&
81 	    c == '0' && (*s == 'x' || *s == 'X') &&
82 	    ((s[1] >= '0' && s[1] <= '9') ||
83 	    (s[1] >= 'A' && s[1] <= 'F') ||
84 	    (s[1] >= 'a' && s[1] <= 'f'))) {
85 		c = s[1];
86 		s += 2;
87 		base = 16;
88 	}
89 	if (base == 0)
90 		base = c == '0' ? 8 : 10;
91 	acc = any = 0;
92 	if (base < 2 || base > 36)
93 		goto noconv;
94 
95 	cutoff = ULONG_MAX / base;
96 	cutlim = ULONG_MAX % base;
97 	for ( ; ; c = *s++) {
98 		if (c >= '0' && c <= '9')
99 			c -= '0';
100 		else if (c >= 'A' && c <= 'Z')
101 			c -= 'A' - 10;
102 		else if (c >= 'a' && c <= 'z')
103 			c -= 'a' - 10;
104 		else
105 			break;
106 		if (c >= base)
107 			break;
108 		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
109 			any = -1;
110 		else {
111 			any = 1;
112 			acc *= base;
113 			acc += c;
114 		}
115 	}
116 	if (any < 0) {
117 		acc = ULONG_MAX;
118 		errno = ERANGE;
119 	} else if (!any) {
120 noconv:
121 		errno = EINVAL;
122 	} else if (neg)
123 		acc = -acc;
124 	if (endptr != NULL)
125 		*endptr = (char *)(any ? s - 1 : nptr);
126 	return (acc);
127 }
128 unsigned long
129 strtoul(const char * __restrict nptr, char ** __restrict endptr, int base)
130 {
131 	return strtoul_l(nptr, endptr, base, __get_locale());
132 }
133