strtol.c revision 329175 
1/*-
2 * Copyright (c) 1990, 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)
36static char sccsid[] = "@(#)strtol.c	8.1 (Berkeley) 6/4/93";
37#endif /* LIBC_SCCS and not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: stable/11/lib/libc/stdlib/strtol.c 329175 2018-02-12 17:44:35Z kevans $");
40
41#include <limits.h>
42#include <ctype.h>
43#include <errno.h>
44#include <stdlib.h>
45#include "xlocale_private.h"
46
47/*
48 * Convert a string to a long integer.
49 *
50 * Assumes that the upper and lower case
51 * alphabets and digits are each contiguous.
52 */
53long
54strtol_l(const char * __restrict nptr, char ** __restrict endptr, int base,
55		locale_t locale)
56{
57	const char *s;
58	unsigned long acc;
59	char c;
60	unsigned long 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 longs is
104	 * [-2147483648..2147483647] and the input base is 10,
105	 * cutoff will be set to 214748364 and cutlim to either
106	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
107	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
108	 * the number is too big, and we will return a range error.
109	 *
110	 * Set 'any' if any `digits' consumed; make it negative to indicate
111	 * overflow.
112	 */
113	cutoff = neg ? (unsigned long)-(LONG_MIN + LONG_MAX) + LONG_MAX
114	    : LONG_MAX;
115	cutlim = cutoff % base;
116	cutoff /= base;
117	for ( ; ; c = *s++) {
118		if (c >= '0' && c <= '9')
119			c -= '0';
120		else if (c >= 'A' && c <= 'Z')
121			c -= 'A' - 10;
122		else if (c >= 'a' && c <= 'z')
123			c -= '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 *= base;
133			acc += c;
134		}
135	}
136	if (any < 0) {
137		acc = neg ? LONG_MIN : LONG_MAX;
138		errno = ERANGE;
139	} else if (!any) {
140noconv:
141		errno = EINVAL;
142	} else if (neg)
143		acc = -acc;
144	if (endptr != NULL)
145		*endptr = (char *)(any ? s - 1 : nptr);
146	return (acc);
147}
148long
149strtol(const char * __restrict nptr, char ** __restrict endptr, int base)
150{
151	return strtol_l(nptr, endptr, base, __get_locale());
152}
153