xref: /dragonfly/lib/libc/stdlib/strtoull.c (revision 9dbf638f)
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  * @(#)strtouq.c	8.1 (Berkeley) 6/4/93
34  * $FreeBSD: src/lib/libc/stdlib/strtoull.c,v 1.5.2.1 2001/03/02 09:45:20 obrien Exp $
35  * $DragonFly: src/lib/libc/stdlib/strtoull.c,v 1.3 2003/09/06 08:10:46 asmodai Exp $
36  */
37 
38 #include <sys/types.h>
39 
40 #include <limits.h>
41 #include <errno.h>
42 #include <ctype.h>
43 #include <stdlib.h>
44 
45 /*
46  * Convert a string to an unsigned long long integer.
47  *
48  * Ignores `locale' stuff.  Assumes that the upper and lower case
49  * alphabets and digits are each contiguous.
50  */
51 unsigned long long
52 strtoull(nptr, endptr, base)
53 	const char *nptr;
54 	char **endptr;
55 	int base;
56 {
57 	const char *s = nptr;
58 	unsigned long long acc;
59 	unsigned char c;
60 	unsigned long long qbase, cutoff;
61 	int neg, any, cutlim;
62 
63 	/*
64 	 * See strtoq for comments as to the logic used.
65 	 */
66 	s = nptr;
67 	do {
68 		c = *s++;
69 	} while (isspace(c));
70 	if (c == '-') {
71 		neg = 1;
72 		c = *s++;
73 	} else {
74 		neg = 0;
75 		if (c == '+')
76 			c = *s++;
77 	}
78 	if ((base == 0 || base == 16) &&
79 	    c == '0' && (*s == 'x' || *s == 'X')) {
80 		c = s[1];
81 		s += 2;
82 		base = 16;
83 	}
84 	if (base == 0)
85 		base = c == '0' ? 8 : 10;
86 	qbase = (unsigned)base;
87 	cutoff = (unsigned long long)ULLONG_MAX / qbase;
88 	cutlim = (unsigned long long)ULLONG_MAX % qbase;
89 	for (acc = 0, any = 0;; c = *s++) {
90 		if (!isascii(c))
91 			break;
92 		if (isdigit(c))
93 			c -= '0';
94 		else if (isalpha(c))
95 			c -= isupper(c) ? 'A' - 10 : '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 *= qbase;
105 			acc += c;
106 		}
107 	}
108 	if (any < 0) {
109 		acc = ULLONG_MAX;
110 		errno = ERANGE;
111 	} else if (neg)
112 		acc = -acc;
113 	if (endptr != 0)
114 		*endptr = (char *)(any ? s - 1 : nptr);
115 	return (acc);
116 }
117