xref: /freebsd/lib/libc/stdlib/strtoul.c (revision 783d3ff6d7fae619db8a7990b8a6387de0c677b5)
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 #include <limits.h>
38 #include <ctype.h>
39 #include <errno.h>
40 #include <stdlib.h>
41 #include "xlocale_private.h"
42 
43 /*
44  * Convert a string to an unsigned long integer.
45  *
46  * Assumes that the upper and lower case
47  * alphabets and digits are each contiguous.
48  */
49 unsigned long
50 strtoul_l(const char * __restrict nptr, char ** __restrict endptr, int base, locale_t locale)
51 {
52 	const char *s;
53 	unsigned long acc;
54 	char c;
55 	unsigned long cutoff;
56 	int neg, any, cutlim;
57 	FIX_LOCALE(locale);
58 
59 	/*
60 	 * See strtol for comments as to the logic used.
61 	 */
62 	s = nptr;
63 	do {
64 		c = *s++;
65 	} while (isspace_l((unsigned char)c, locale));
66 	if (c == '-') {
67 		neg = 1;
68 		c = *s++;
69 	} else {
70 		neg = 0;
71 		if (c == '+')
72 			c = *s++;
73 	}
74 	if ((base == 0 || base == 16) &&
75 	    c == '0' && (*s == 'x' || *s == 'X') &&
76 	    ((s[1] >= '0' && s[1] <= '9') ||
77 	    (s[1] >= 'A' && s[1] <= 'F') ||
78 	    (s[1] >= 'a' && s[1] <= 'f'))) {
79 		c = s[1];
80 		s += 2;
81 		base = 16;
82 	}
83 	if ((base == 0 || base == 2) &&
84 	    c == '0' && (*s == 'b' || *s == 'B') &&
85 	    (s[1] >= '0' && s[1] <= '1')) {
86 		c = s[1];
87 		s += 2;
88 		base = 2;
89 	}
90 	if (base == 0)
91 		base = c == '0' ? 8 : 10;
92 	acc = any = 0;
93 	if (base < 2 || base > 36)
94 		goto noconv;
95 
96 	cutoff = ULONG_MAX / base;
97 	cutlim = ULONG_MAX % base;
98 	for ( ; ; c = *s++) {
99 		if (c >= '0' && c <= '9')
100 			c -= '0';
101 		else if (c >= 'A' && c <= 'Z')
102 			c -= 'A' - 10;
103 		else if (c >= 'a' && c <= 'z')
104 			c -= 'a' - 10;
105 		else
106 			break;
107 		if (c >= base)
108 			break;
109 		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
110 			any = -1;
111 		else {
112 			any = 1;
113 			acc *= base;
114 			acc += c;
115 		}
116 	}
117 	if (any < 0) {
118 		acc = ULONG_MAX;
119 		errno = ERANGE;
120 	} else if (!any) {
121 noconv:
122 		errno = EINVAL;
123 	} else if (neg)
124 		acc = -acc;
125 	if (endptr != NULL)
126 		*endptr = (char *)(any ? s - 1 : nptr);
127 	return (acc);
128 }
129 unsigned long
130 strtoul(const char * __restrict nptr, char ** __restrict endptr, int base)
131 {
132 	return strtoul_l(nptr, endptr, base, __get_locale());
133 }
134