xref: /freebsd/lib/libc/stdlib/strtoll.c (revision 5521ff5a4d1929056e7ffc982fac3341ca54df7c)
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[] = "@(#)strtoq.c	8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #ifndef lint
39 static const char rcsid[] =
40   "$FreeBSD$";
41 #endif
42 
43 #include <sys/types.h>
44 
45 #include <limits.h>
46 #include <errno.h>
47 #include <ctype.h>
48 #include <stdlib.h>
49 
50 /*
51  * Convert a string to a long long integer.
52  *
53  * Ignores `locale' stuff.  Assumes that the upper and lower case
54  * alphabets and digits are each contiguous.
55  */
56 long long
57 strtoll(nptr, endptr, base)
58 	const char *nptr;
59 	char **endptr;
60 	register int base;
61 {
62 	register const char *s;
63 	register unsigned long long acc;
64 	register unsigned char c;
65 	register unsigned long long qbase, cutoff;
66 	register int neg, any, cutlim;
67 
68 	/*
69 	 * Skip white space and pick up leading +/- sign if any.
70 	 * If base is 0, allow 0x for hex and 0 for octal, else
71 	 * assume decimal; if base is already 16, allow 0x.
72 	 */
73 	s = nptr;
74 	do {
75 		c = *s++;
76 	} while (isspace(c));
77 	if (c == '-') {
78 		neg = 1;
79 		c = *s++;
80 	} else {
81 		neg = 0;
82 		if (c == '+')
83 			c = *s++;
84 	}
85 	if ((base == 0 || base == 16) &&
86 	    c == '0' && (*s == 'x' || *s == 'X')) {
87 		c = s[1];
88 		s += 2;
89 		base = 16;
90 	}
91 	if (base == 0)
92 		base = c == '0' ? 8 : 10;
93 
94 	/*
95 	 * Compute the cutoff value between legal numbers and illegal
96 	 * numbers.  That is the largest legal value, divided by the
97 	 * base.  An input number that is greater than this value, if
98 	 * followed by a legal input character, is too big.  One that
99 	 * is equal to this value may be valid or not; the limit
100 	 * between valid and invalid numbers is then based on the last
101 	 * digit.  For instance, if the range for quads is
102 	 * [-9223372036854775808..9223372036854775807] and the input base
103 	 * is 10, cutoff will be set to 922337203685477580 and cutlim to
104 	 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
105 	 * accumulated a value > 922337203685477580, or equal but the
106 	 * next digit is > 7 (or 8), the number is too big, and we will
107 	 * return a range error.
108 	 *
109 	 * Set any if any `digits' consumed; make it negative to indicate
110 	 * overflow.
111 	 */
112 	qbase = (unsigned)base;
113 	cutoff = neg ? (unsigned long long)-(LLONG_MIN + LLONG_MAX) + LLONG_MAX
114 	    : LLONG_MAX;
115 	cutlim = cutoff % qbase;
116 	cutoff /= qbase;
117 	for (acc = 0, any = 0;; c = *s++) {
118 		if (!isascii(c))
119 			break;
120 		if (isdigit(c))
121 			c -= '0';
122 		else if (isalpha(c))
123 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
124 		else
125 			break;
126 		if (c >= base)
127 			break;
128 		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
129 			any = -1;
130 		else {
131 			any = 1;
132 			acc *= qbase;
133 			acc += c;
134 		}
135 	}
136 	if (any < 0) {
137 		acc = neg ? LLONG_MIN : LLONG_MAX;
138 		errno = ERANGE;
139 	} else if (neg)
140 		acc = -acc;
141 	if (endptr != 0)
142 		*endptr = (char *)(any ? s - 1 : nptr);
143 	return (acc);
144 }
145