xref: /freebsd/lib/libc/stdlib/strtoumax.c (revision ae83180158c4c937f170e31eff311b18c0286a93)
1 /*-
2  * Copyright (c) 1992, 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 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "from @(#)strtoul.c	8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include <ctype.h>
41 #include <errno.h>
42 #include <stdlib.h>
43 #include <inttypes.h>
44 
45 /*
46  * Convert a string to a uintmax_t integer.
47  *
48  * Assumes that the upper and lower case
49  * alphabets and digits are each contiguous.
50  */
51 uintmax_t
52 strtoumax(const char *__restrict nptr, char **__restrict endptr, int base)
53 {
54 	const char *s;
55 	uintmax_t acc;
56 	char c;
57 	uintmax_t cutoff;
58 	int neg, any, cutlim;
59 
60 	/*
61 	 * See strtoimax for comments as to the logic used.
62 	 */
63 	s = nptr;
64 	do {
65 		c = *s++;
66 	} while (isspace((unsigned char)c));
67 	if (c == '-') {
68 		neg = 1;
69 		c = *s++;
70 	} else {
71 		neg = 0;
72 		if (c == '+')
73 			c = *s++;
74 	}
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 	acc = any = 0;
84 	if (base < 2 || base > 36)
85 		goto noconv;
86 
87 	cutoff = UINTMAX_MAX / base;
88 	cutlim = UINTMAX_MAX % base;
89 	for ( ; ; c = *s++) {
90 		if (c >= '0' && c <= '9')
91 			c -= '0';
92 		else if (c >= 'A' && c <= 'Z')
93 			c -= 'A' - 10;
94 		else if (c >= 'a' && c <= 'z')
95 			c -= 'a' - 10;
96 		else
97 			break;
98 		if (c >= base)
99 			break;
100 		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
101 			any = -1;
102 		else {
103 			any = 1;
104 			acc *= base;
105 			acc += c;
106 		}
107 	}
108 	if (any < 0) {
109 		acc = UINTMAX_MAX;
110 		errno = ERANGE;
111 	} else if (!any) {
112 noconv:
113 		errno = EINVAL;
114 	} else if (neg)
115 		acc = -acc;
116 	if (endptr != NULL)
117 		*endptr = (char *)(any ? s - 1 : nptr);
118 	return (acc);
119 }
120