xref: /freebsd/lib/libc/stdlib/strtoumax.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char sccsid[] = "from @(#)strtoul.c	8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include <ctype.h>
37 #include <errno.h>
38 #include <stdlib.h>
39 #include <inttypes.h>
40 
41 /*
42  * Convert a string to a uintmax_t integer.
43  *
44  * Assumes that the upper and lower case
45  * alphabets and digits are each contiguous.
46  */
47 uintmax_t
48 strtoumax(const char * __restrict nptr, char ** __restrict endptr, int base)
49 {
50 	const char *s;
51 	uintmax_t acc;
52 	char c;
53 	uintmax_t cutoff;
54 	int neg, any, cutlim;
55 
56 	/*
57 	 * See strtoimax for comments as to the logic used.
58 	 */
59 	s = nptr;
60 	do {
61 		c = *s++;
62 	} while (isspace((unsigned char)c));
63 	if (c == '-') {
64 		neg = 1;
65 		c = *s++;
66 	} else {
67 		neg = 0;
68 		if (c == '+')
69 			c = *s++;
70 	}
71 	if ((base == 0 || base == 16) &&
72 	    c == '0' && (*s == 'x' || *s == 'X') &&
73 	    ((s[1] >= '0' && s[1] <= '9') ||
74 	    (s[1] >= 'A' && s[1] <= 'F') ||
75 	    (s[1] >= 'a' && s[1] <= 'f'))) {
76 		c = s[1];
77 		s += 2;
78 		base = 16;
79 	}
80 	if (base == 0)
81 		base = c == '0' ? 8 : 10;
82 	acc = any = 0;
83 	if (base < 2 || base > 36)
84 		goto noconv;
85 
86 	cutoff = UINTMAX_MAX / base;
87 	cutlim = UINTMAX_MAX % base;
88 	for ( ; ; c = *s++) {
89 		if (c >= '0' && c <= '9')
90 			c -= '0';
91 		else if (c >= 'A' && c <= 'Z')
92 			c -= 'A' - 10;
93 		else if (c >= 'a' && c <= 'z')
94 			c -= '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 = UINTMAX_MAX;
109 		errno = ERANGE;
110 	} else if (!any) {
111 noconv:
112 		errno = EINVAL;
113 	} else if (neg)
114 		acc = -acc;
115 	if (endptr != NULL)
116 		*endptr = (char *)(any ? s - 1 : nptr);
117 	return (acc);
118 }
119