1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * From: @(#)strtol.c	8.1 (Berkeley) 6/4/93
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD$");
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/ctype.h>
41#include <sys/limits.h>
42
43/*
44 * Convert a string to a long integer.
45 *
46 * Ignores `locale' stuff.  Assumes that the upper and lower case
47 * alphabets and digits are each contiguous.
48 */
49long
50strtol(nptr, endptr, base)
51	const char *nptr;
52	char **endptr;
53	int base;
54{
55	const char *s = nptr;
56	unsigned long acc;
57	unsigned char c;
58	unsigned long cutoff;
59	int neg = 0, any, cutlim;
60
61	/*
62	 * Skip white space and pick up leading +/- sign if any.
63	 * If base is 0, allow 0x for hex and 0 for octal, else
64	 * assume decimal; if base is already 16, allow 0x.
65	 */
66	do {
67		c = *s++;
68	} while (isspace(c));
69	if (c == '-') {
70		neg = 1;
71		c = *s++;
72	} else if (c == '+')
73		c = *s++;
74	if ((base == 0 || base == 16) &&
75	    c == '0' && (*s == 'x' || *s == 'X')) {
76		c = s[1];
77		s += 2;
78		base = 16;
79	}
80	if (base == 0)
81		base = c == '0' ? 8 : 10;
82
83	/*
84	 * Compute the cutoff value between legal numbers and illegal
85	 * numbers.  That is the largest legal value, divided by the
86	 * base.  An input number that is greater than this value, if
87	 * followed by a legal input character, is too big.  One that
88	 * is equal to this value may be valid or not; the limit
89	 * between valid and invalid numbers is then based on the last
90	 * digit.  For instance, if the range for longs is
91	 * [-2147483648..2147483647] and the input base is 10,
92	 * cutoff will be set to 214748364 and cutlim to either
93	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
94	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
95	 * the number is too big, and we will return a range error.
96	 *
97	 * Set any if any `digits' consumed; make it negative to indicate
98	 * overflow.
99	 */
100	cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
101	cutlim = cutoff % (unsigned long)base;
102	cutoff /= (unsigned long)base;
103	for (acc = 0, any = 0;; c = *s++) {
104		if (!isascii(c))
105			break;
106		if (isdigit(c))
107			c -= '0';
108		else if (isalpha(c))
109			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
110		else
111			break;
112		if (c >= base)
113			break;
114		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
115			any = -1;
116		else {
117			any = 1;
118			acc *= base;
119			acc += c;
120		}
121	}
122	if (any < 0) {
123		acc = neg ? LONG_MIN : LONG_MAX;
124	} else if (neg)
125		acc = -acc;
126	if (endptr != 0)
127		*((const char **)endptr) = any ? s - 1 : nptr;
128	return (acc);
129}
130