xref: /freebsd/lib/libc/stdlib/strtoimax.c (revision 09a53ad8f1318c5daae6cfb19d97f4f6459f0013)
1 /*-
2  * Copyright (c) 1992, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Copyright (c) 2011 The FreeBSD Foundation
6  * All rights reserved.
7  * Portions of this software were developed by David Chisnall
8  * under sponsorship from the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "from @(#)strtol.c	8.1 (Berkeley) 6/4/93";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include <ctype.h>
42 #include <errno.h>
43 #include <stdlib.h>
44 #include <inttypes.h>
45 #include "xlocale_private.h"
46 
47 /*
48  * Convert a string to an intmax_t integer.
49  *
50  * Assumes that the upper and lower case
51  * alphabets and digits are each contiguous.
52  */
53 intmax_t
54 strtoimax_l(const char * __restrict nptr, char ** __restrict endptr, int base,
55 		locale_t locale)
56 {
57 	const char *s;
58 	uintmax_t acc;
59 	char c;
60 	uintmax_t cutoff;
61 	int neg, any, cutlim;
62 	FIX_LOCALE(locale);
63 
64 	/*
65 	 * Skip white space and pick up leading +/- sign if any.
66 	 * If base is 0, allow 0x for hex and 0 for octal, else
67 	 * assume decimal; if base is already 16, allow 0x.
68 	 */
69 	s = nptr;
70 	do {
71 		c = *s++;
72 	} while (isspace_l((unsigned char)c, locale));
73 	if (c == '-') {
74 		neg = 1;
75 		c = *s++;
76 	} else {
77 		neg = 0;
78 		if (c == '+')
79 			c = *s++;
80 	}
81 	if ((base == 0 || base == 16) &&
82 	    c == '0' && (*s == 'x' || *s == 'X') &&
83 	    ((s[1] >= '0' && s[1] <= '9') ||
84 	    (s[1] >= 'A' && s[1] <= 'F') ||
85 	    (s[1] >= 'a' && s[1] <= 'f'))) {
86 		c = s[1];
87 		s += 2;
88 		base = 16;
89 	}
90 	if (base == 0)
91 		base = c == '0' ? 8 : 10;
92 	acc = any = 0;
93 	if (base < 2 || base > 36)
94 		goto noconv;
95 
96 	/*
97 	 * Compute the cutoff value between legal numbers and illegal
98 	 * numbers.  That is the largest legal value, divided by the
99 	 * base.  An input number that is greater than this value, if
100 	 * followed by a legal input character, is too big.  One that
101 	 * is equal to this value may be valid or not; the limit
102 	 * between valid and invalid numbers is then based on the last
103 	 * digit.  For instance, if the range for intmax_t is
104 	 * [-9223372036854775808..9223372036854775807] and the input base
105 	 * is 10, cutoff will be set to 922337203685477580 and cutlim to
106 	 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
107 	 * accumulated a value > 922337203685477580, or equal but the
108 	 * next digit is > 7 (or 8), the number is too big, and we will
109 	 * return a range error.
110 	 *
111 	 * Set 'any' if any `digits' consumed; make it negative to indicate
112 	 * overflow.
113 	 */
114 	cutoff = neg ? (uintmax_t)-(INTMAX_MIN + INTMAX_MAX) + INTMAX_MAX
115 	    : INTMAX_MAX;
116 	cutlim = cutoff % base;
117 	cutoff /= base;
118 	for ( ; ; c = *s++) {
119 		if (c >= '0' && c <= '9')
120 			c -= '0';
121 		else if (c >= 'A' && c <= 'Z')
122 			c -= 'A' - 10;
123 		else if (c >= 'a' && c <= 'z')
124 			c -= 'a' - 10;
125 		else
126 			break;
127 		if (c >= base)
128 			break;
129 		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
130 			any = -1;
131 		else {
132 			any = 1;
133 			acc *= base;
134 			acc += c;
135 		}
136 	}
137 	if (any < 0) {
138 		acc = neg ? INTMAX_MIN : INTMAX_MAX;
139 		errno = ERANGE;
140 	} else if (!any) {
141 noconv:
142 		errno = EINVAL;
143 	} else if (neg)
144 		acc = -acc;
145 	if (endptr != NULL)
146 		*endptr = (char *)(any ? s - 1 : nptr);
147 	return (acc);
148 }
149 intmax_t
150 strtoimax(const char * __restrict nptr, char ** __restrict endptr, int base)
151 {
152 	return strtoimax_l(nptr, endptr, base, __get_locale());
153 }
154