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 [rescinded 22 July 1999]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}, @
34  char **@var{endptr}, int @var{base})
35@deftypefnx Supplemental {unsigned long int} strtoul (const char *@var{string}, @
36  char **@var{endptr}, int @var{base})
37
38The @code{strtol} function converts the string in @var{string} to a
39long integer value according to the given @var{base}, which must be
40between 2 and 36 inclusive, or be the special value 0.  If @var{base}
41is 0, @code{strtol} will look for the prefixes @code{0} and @code{0x}
42to indicate bases 8 and 16, respectively, else default to base 10.
43When the base is 16 (either explicitly or implicitly), a prefix of
44@code{0x} is allowed.  The handling of @var{endptr} is as that of
45@code{strtod} above.  The @code{strtoul} function is the same, except
46that the converted value is unsigned.
47
48@end deftypefn
49
50*/
51
52#ifdef HAVE_CONFIG_H
53#include "config.h"
54#endif
55#ifdef HAVE_LIMITS_H
56#include <limits.h>
57#endif
58#ifdef HAVE_SYS_PARAM_H
59#include <sys/param.h>
60#endif
61#include <errno.h>
62#ifdef NEED_DECLARATION_ERRNO
63extern int errno;
64#endif
65#include "safe-ctype.h"
66
67/* FIXME: It'd be nice to configure around these, but the include files are too
68   painful.  These macros should at least be more portable than hardwired hex
69   constants. */
70
71#ifndef ULONG_MAX
72#define	ULONG_MAX	((unsigned long)(~0L))		/* 0xFFFFFFFF */
73#endif
74
75#ifndef LONG_MAX
76#define	LONG_MAX	((long)(ULONG_MAX >> 1))	/* 0x7FFFFFFF */
77#endif
78
79#ifndef LONG_MIN
80#define	LONG_MIN	((long)(~LONG_MAX))		/* 0x80000000 */
81#endif
82
83/*
84 * Convert a string to a long integer.
85 *
86 * Ignores `locale' stuff.  Assumes that the upper and lower case
87 * alphabets and digits are each contiguous.
88 */
89long
90strtol(const char *nptr, char **endptr, register int base)
91{
92	register const char *s = nptr;
93	register unsigned long acc;
94	register int c;
95	register unsigned long cutoff;
96	register int neg = 0, any, cutlim;
97
98	/*
99	 * Skip white space and pick up leading +/- sign if any.
100	 * If base is 0, allow 0x for hex and 0 for octal, else
101	 * assume decimal; if base is already 16, allow 0x.
102	 */
103	do {
104		c = *s++;
105	} while (ISSPACE(c));
106	if (c == '-') {
107		neg = 1;
108		c = *s++;
109	} else if (c == '+')
110		c = *s++;
111	if ((base == 0 || base == 16) &&
112	    c == '0' && (*s == 'x' || *s == 'X')) {
113		c = s[1];
114		s += 2;
115		base = 16;
116	}
117	if (base == 0)
118		base = c == '0' ? 8 : 10;
119
120	/*
121	 * Compute the cutoff value between legal numbers and illegal
122	 * numbers.  That is the largest legal value, divided by the
123	 * base.  An input number that is greater than this value, if
124	 * followed by a legal input character, is too big.  One that
125	 * is equal to this value may be valid or not; the limit
126	 * between valid and invalid numbers is then based on the last
127	 * digit.  For instance, if the range for longs is
128	 * [-2147483648..2147483647] and the input base is 10,
129	 * cutoff will be set to 214748364 and cutlim to either
130	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
131	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
132	 * the number is too big, and we will return a range error.
133	 *
134	 * Set any if any `digits' consumed; make it negative to indicate
135	 * overflow.
136	 */
137	cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
138	cutlim = cutoff % (unsigned long)base;
139	cutoff /= (unsigned long)base;
140	for (acc = 0, any = 0;; c = *s++) {
141		if (ISDIGIT(c))
142			c -= '0';
143		else if (ISALPHA(c))
144			c -= ISUPPER(c) ? 'A' - 10 : 'a' - 10;
145		else
146			break;
147		if (c >= base)
148			break;
149		if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
150			any = -1;
151		else {
152			any = 1;
153			acc *= base;
154			acc += c;
155		}
156	}
157	if (any < 0) {
158		acc = neg ? LONG_MIN : LONG_MAX;
159		errno = ERANGE;
160	} else if (neg)
161		acc = -acc;
162	if (endptr != 0)
163		*endptr = (char *) (any ? s - 1 : nptr);
164	return (acc);
165}
166