xref: /freebsd/lib/libc/stdlib/strtoll.c (revision f8ade0e68ecd31d6659ca470a3e3966e18d1c96b)
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  * $FreeBSD$
34  */
35 
36 #if defined(LIBC_SCCS) && !defined(lint)
37 static char sccsid[] = "@(#)strtoq.c	8.1 (Berkeley) 6/4/93";
38 #endif /* LIBC_SCCS and not lint */
39 
40 #include <limits.h>
41 #include <errno.h>
42 #include <ctype.h>
43 #include <stdlib.h>
44 
45 /*
46  * Convert a string to a long long integer.
47  *
48  * Assumes that the upper and lower case
49  * alphabets and digits are each contiguous.
50  */
51 long long
52 strtoll(nptr, endptr, base)
53 	const char *nptr;
54 	char **endptr;
55 	register int base;
56 {
57 	register const char *s;
58 	register unsigned long long acc;
59 	register unsigned char c;
60 	register unsigned long long cutoff;
61 	register int neg, any, cutlim;
62 
63 	/*
64 	 * Skip white space and pick up leading +/- sign if any.
65 	 * If base is 0, allow 0x for hex and 0 for octal, else
66 	 * assume decimal; if base is already 16, allow 0x.
67 	 */
68 	s = nptr;
69 	do {
70 		c = *s++;
71 	} while (isspace(c));
72 	if (c == '-') {
73 		neg = 1;
74 		c = *s++;
75 	} else {
76 		neg = 0;
77 		if (c == '+')
78 			c = *s++;
79 	}
80 	if ((base == 0 || base == 16) &&
81 	    c == '0' && (*s == 'x' || *s == 'X')) {
82 		c = s[1];
83 		s += 2;
84 		base = 16;
85 	}
86 	if (base == 0)
87 		base = c == '0' ? 8 : 10;
88 	acc = any = 0;
89 	if (base < 2 || base > 36)
90 		goto noconv;
91 
92 	/*
93 	 * Compute the cutoff value between legal numbers and illegal
94 	 * numbers.  That is the largest legal value, divided by the
95 	 * base.  An input number that is greater than this value, if
96 	 * followed by a legal input character, is too big.  One that
97 	 * is equal to this value may be valid or not; the limit
98 	 * between valid and invalid numbers is then based on the last
99 	 * digit.  For instance, if the range for quads is
100 	 * [-9223372036854775808..9223372036854775807] and the input base
101 	 * is 10, cutoff will be set to 922337203685477580 and cutlim to
102 	 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
103 	 * accumulated a value > 922337203685477580, or equal but the
104 	 * next digit is > 7 (or 8), the number is too big, and we will
105 	 * return a range error.
106 	 *
107 	 * Set 'any' if any `digits' consumed; make it negative to indicate
108 	 * overflow.
109 	 */
110 	cutoff = neg ? (unsigned long long)-(LLONG_MIN + LLONG_MAX) + LLONG_MAX
111 	    : LLONG_MAX;
112 	cutlim = cutoff % base;
113 	cutoff /= base;
114 	for ( ; ; c = *s++) {
115 		if (!isascii(c))
116 			break;
117 		if (isdigit(c))
118 			c -= '0';
119 		else if (isalpha(c))
120 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
121 		else
122 			break;
123 		if (c >= base)
124 			break;
125 		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
126 			any = -1;
127 		else {
128 			any = 1;
129 			acc *= base;
130 			acc += c;
131 		}
132 	}
133 	if (any < 0) {
134 		acc = neg ? LLONG_MIN : LLONG_MAX;
135 		errno = ERANGE;
136 	} else if (!any) {
137 noconv:
138 		errno = EINVAL;
139 	} else if (neg)
140 		acc = -acc;
141 	if (endptr != NULL)
142 		*endptr = (char *)(any ? s - 1 : nptr);
143 	return (acc);
144 }
145