1/*	$NetBSD$ */
2
3/*-
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "config.h"
37
38#if defined(LIBC_SCCS) && !defined(lint)
39static const char sccsid[] = "@(#)strtol.c	8.1 (Berkeley) 6/4/93";
40#endif /* LIBC_SCCS and not lint */
41
42#include <limits.h>
43#include <ctype.h>
44#include <errno.h>
45#include <stdlib.h>
46
47/*
48 * Convert a string to a long integer.
49 *
50 * Ignores `locale' stuff.  Assumes that the upper and lower case
51 * alphabets and digits are each contiguous.
52 *
53 * PUBLIC: #ifndef HAVE_STRTOL
54 * PUBLIC: long strtol __P((const char *, char **, int));
55 * PUBLIC: #endif
56 */
57long
58strtol(const char *nptr, char **endptr, register int base)
59{
60	register const char *s = nptr;
61	register unsigned long acc;
62	register int c;
63	register unsigned long cutoff;
64	register int neg = 0, any, cutlim;
65
66	/*
67	 * Skip white space and pick up leading +/- sign if any.
68	 * If base is 0, allow 0x for hex and 0 for octal, else
69	 * assume decimal; if base is already 16, allow 0x.
70	 */
71	do {
72		c = *s++;
73	} while (isspace(c));
74	if (c == '-') {
75		neg = 1;
76		c = *s++;
77	} else if (c == '+')
78		c = *s++;
79	if ((base == 0 || base == 16) &&
80	    c == '0' && (*s == 'x' || *s == 'X')) {
81		c = s[1];
82		s += 2;
83		base = 16;
84	}
85	if (base == 0)
86		base = c == '0' ? 8 : 10;
87
88	/*
89	 * Compute the cutoff value between legal numbers and illegal
90	 * numbers.  That is the largest legal value, divided by the
91	 * base.  An input number that is greater than this value, if
92	 * followed by a legal input character, is too big.  One that
93	 * is equal to this value may be valid or not; the limit
94	 * between valid and invalid numbers is then based on the last
95	 * digit.  For instance, if the range for longs is
96	 * [-2147483648..2147483647] and the input base is 10,
97	 * cutoff will be set to 214748364 and cutlim to either
98	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
99	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
100	 * the number is too big, and we will return a range error.
101	 *
102	 * Set any if any `digits' consumed; make it negative to indicate
103	 * overflow.
104	 */
105	cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
106	cutlim = cutoff % (unsigned long)base;
107	cutoff /= (unsigned long)base;
108	for (acc = 0, any = 0;; c = *s++) {
109		if (isdigit(c))
110			c -= '0';
111		else if (isalpha(c))
112			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
113		else
114			break;
115		if (c >= base)
116			break;
117		if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
118			any = -1;
119		else {
120			any = 1;
121			acc *= base;
122			acc += c;
123		}
124	}
125	if (any < 0) {
126		acc = neg ? LONG_MIN : LONG_MAX;
127		errno = ERANGE;
128	} else if (neg)
129		acc = -acc;
130	if (endptr != 0)
131		*endptr = (char *)(any ? s - 1 : nptr);
132	return (acc);
133}
134