1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * 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. [rescinded 22 July 1999]
14 * 4. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31/*
32
33@deftypefn Supplemental {long int} strtol (const char *@var{string}, char **@var{endptr}, int @var{base})
34@deftypefnx Supplemental {unsigned long int} strtoul (const char *@var{string}, char **@var{endptr}, int @var{base})
35
36The @code{strtol} function converts the string in @var{string} to a
37long integer value according to the given @var{base}, which must be
38between 2 and 36 inclusive, or be the special value 0.  If @var{base}
39is 0, @code{strtol} will look for the prefixes @code{0} and @code{0x}
40to indicate bases 8 and 16, respectively, else default to base 10.
41When the base is 16 (either explicitly or implicitly), a prefix of
42@code{0x} is allowed.  The handling of @var{endptr} is as that of
43@code{strtod} above.  The @code{strtoul} function is the same, except
44that the converted value is unsigned.
45
46@end deftypefn
47
48*/
49
50#ifdef HAVE_CONFIG_H
51#include "config.h"
52#endif
53#ifdef HAVE_LIMITS_H
54#include <limits.h>
55#endif
56#ifdef HAVE_SYS_PARAM_H
57#include <sys/param.h>
58#endif
59#include <errno.h>
60#ifdef NEED_DECLARATION_ERRNO
61extern int errno;
62#endif
63#include "safe-ctype.h"
64
65/* FIXME: It'd be nice to configure around these, but the include files are too
66   painful.  These macros should at least be more portable than hardwired hex
67   constants. */
68
69#ifndef ULONG_MAX
70#define	ULONG_MAX	((unsigned long)(~0L))		/* 0xFFFFFFFF */
71#endif
72
73#ifndef LONG_MAX
74#define	LONG_MAX	((long)(ULONG_MAX >> 1))	/* 0x7FFFFFFF */
75#endif
76
77#ifndef LONG_MIN
78#define	LONG_MIN	((long)(~LONG_MAX))		/* 0x80000000 */
79#endif
80
81/*
82 * Convert a string to a long integer.
83 *
84 * Ignores `locale' stuff.  Assumes that the upper and lower case
85 * alphabets and digits are each contiguous.
86 */
87long
88strtol(const char *nptr, char **endptr, register int base)
89{
90	register const char *s = nptr;
91	register unsigned long acc;
92	register int c;
93	register unsigned long cutoff;
94	register int neg = 0, any, cutlim;
95
96	/*
97	 * Skip white space and pick up leading +/- sign if any.
98	 * If base is 0, allow 0x for hex and 0 for octal, else
99	 * assume decimal; if base is already 16, allow 0x.
100	 */
101	do {
102		c = *s++;
103	} while (ISSPACE(c));
104	if (c == '-') {
105		neg = 1;
106		c = *s++;
107	} else if (c == '+')
108		c = *s++;
109	if ((base == 0 || base == 16) &&
110	    c == '0' && (*s == 'x' || *s == 'X')) {
111		c = s[1];
112		s += 2;
113		base = 16;
114	}
115	if (base == 0)
116		base = c == '0' ? 8 : 10;
117
118	/*
119	 * Compute the cutoff value between legal numbers and illegal
120	 * numbers.  That is the largest legal value, divided by the
121	 * base.  An input number that is greater than this value, if
122	 * followed by a legal input character, is too big.  One that
123	 * is equal to this value may be valid or not; the limit
124	 * between valid and invalid numbers is then based on the last
125	 * digit.  For instance, if the range for longs is
126	 * [-2147483648..2147483647] and the input base is 10,
127	 * cutoff will be set to 214748364 and cutlim to either
128	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
129	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
130	 * the number is too big, and we will return a range error.
131	 *
132	 * Set any if any `digits' consumed; make it negative to indicate
133	 * overflow.
134	 */
135	cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
136	cutlim = cutoff % (unsigned long)base;
137	cutoff /= (unsigned long)base;
138	for (acc = 0, any = 0;; c = *s++) {
139		if (ISDIGIT(c))
140			c -= '0';
141		else if (ISALPHA(c))
142			c -= ISUPPER(c) ? 'A' - 10 : 'a' - 10;
143		else
144			break;
145		if (c >= base)
146			break;
147		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
148			any = -1;
149		else {
150			any = 1;
151			acc *= base;
152			acc += c;
153		}
154	}
155	if (any < 0) {
156		acc = neg ? LONG_MIN : LONG_MAX;
157		errno = ERANGE;
158	} else if (neg)
159		acc = -acc;
160	if (endptr != 0)
161		*endptr = (char *) (any ? s - 1 : nptr);
162	return (acc);
163}
164