xref: /netbsd-src/lib/libc/stdlib/strtouq.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /*	$NetBSD: strtouq.c,v 1.18 2005/11/29 03:12:00 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)strtouq.c	8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: strtouq.c,v 1.18 2005/11/29 03:12:00 christos Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40 
41 #include <sys/types.h>
42 
43 #include <assert.h>
44 #include <ctype.h>
45 #include <errno.h>
46 #include <limits.h>
47 #include <stdlib.h>
48 
49 /*
50  * Convert a string to an unsigned quad integer.
51  *
52  * Ignores `locale' stuff.  Assumes that the upper and lower case
53  * alphabets and digits are each contiguous.
54  */
55 u_quad_t
56 strtouq(nptr, endptr, base)
57 	const char *nptr;
58 	char **endptr;
59 	int base;
60 {
61 	const char *s;
62 	u_quad_t acc, cutoff;
63 	int c;
64 	int neg, any, cutlim;
65 
66 	_DIAGASSERT(nptr != NULL);
67 	/* endptr may be NULL */
68 
69 	/*
70 	 * See strtoq for comments as to the logic used.
71 	 */
72 	s = nptr;
73 	do {
74 		c = (unsigned char) *s++;
75 	} while (isspace(c));
76 	if (c == '-') {
77 		neg = 1;
78 		c = *s++;
79 	} else {
80 		neg = 0;
81 		if (c == '+')
82 			c = *s++;
83 	}
84 	if ((base == 0 || base == 16) &&
85 	    c == '0' && (*s == 'x' || *s == 'X')) {
86 		c = s[1];
87 		s += 2;
88 		base = 16;
89 	}
90 	if (base == 0)
91 		base = c == '0' ? 8 : 10;
92 
93 	cutoff = UQUAD_MAX / (u_quad_t)base;
94 	cutlim = (int)(UQUAD_MAX % (u_quad_t)base);
95 	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
96 		if (isdigit(c))
97 			c -= '0';
98 		else if (isalpha(c))
99 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
100 		else
101 			break;
102 		if (c >= base)
103 			break;
104 		if (any < 0)
105 			continue;
106 		if (acc > cutoff || (acc == cutoff && c > cutlim)) {
107 			any = -1;
108 			acc = UQUAD_MAX;
109 			errno = ERANGE;
110 		} else {
111 			any = 1;
112 			acc *= (u_quad_t)base;
113 			acc += c;
114 		}
115 	}
116 	if (neg && any > 0)
117 		acc = -acc;
118 	if (endptr != 0)
119 		*endptr = __UNCONST(any ? s - 1 : nptr);
120 	return (acc);
121 }
122