2 * Copyright (c) 1990 The Regents of the University of California.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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 [rescinded 22 July 1999]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.
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
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33 @deftypefn Supplemental {long int} strtol (const char *@var{string}, char **@var{endptr}, int @var{base})
35 The @code{strtol} function converts the string in @var{string} to a
36 long integer value according to the given @var{base}, which must be
37 between 2 and 36 inclusive, or be the special value 0. If @var{base}
38 is 0, @code{strtol} will look for the prefixes @code{0} and @code{0x}
39 to indicate bases 8 and 16, respectively, else default to base 10.
40 When the base is 16 (either explicitly or implicitly), a prefix of
41 @code{0x} is allowed. The handling of endptr is as that of
54 #ifdef HAVE_SYS_PARAM_H
55 #include <sys/param.h>
58 #ifdef NEED_DECLARATION_ERRNO
61 #include "safe-ctype.h"
63 /* FIXME: It'd be nice to configure around these, but the include files are too
64 painful. These macros should at least be more portable than hardwired hex
68 #define ULONG_MAX ((unsigned long)(~0L)) /* 0xFFFFFFFF */
72 #define LONG_MAX ((long)(ULONG_MAX >> 1)) /* 0x7FFFFFFF */
76 #define LONG_MIN ((long)(~LONG_MAX)) /* 0x80000000 */
80 * Convert a string to a long integer.
82 * Ignores `locale' stuff. Assumes that the upper and lower case
83 * alphabets and digits are each contiguous.
86 strtol(nptr, endptr, base)
91 register const char *s = nptr;
92 register unsigned long acc;
94 register unsigned long cutoff;
95 register int neg = 0, any, cutlim;
98 * Skip white space and pick up leading +/- sign if any.
99 * If base is 0, allow 0x for hex and 0 for octal, else
100 * assume decimal; if base is already 16, allow 0x.
104 } while (ISSPACE(c));
110 if ((base == 0 || base == 16) &&
111 c == '0' && (*s == 'x' || *s == 'X')) {
117 base = c == '0' ? 8 : 10;
120 * Compute the cutoff value between legal numbers and illegal
121 * numbers. That is the largest legal value, divided by the
122 * base. An input number that is greater than this value, if
123 * followed by a legal input character, is too big. One that
124 * is equal to this value may be valid or not; the limit
125 * between valid and invalid numbers is then based on the last
126 * digit. For instance, if the range for longs is
127 * [-2147483648..2147483647] and the input base is 10,
128 * cutoff will be set to 214748364 and cutlim to either
129 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
130 * a value > 214748364, or equal but the next digit is > 7 (or 8),
131 * the number is too big, and we will return a range error.
133 * Set any if any `digits' consumed; make it negative to indicate
136 cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
137 cutlim = cutoff % (unsigned long)base;
138 cutoff /= (unsigned long)base;
139 for (acc = 0, any = 0;; c = *s++) {
143 c -= ISUPPER(c) ? 'A' - 10 : 'a' - 10;
148 if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
157 acc = neg ? LONG_MIN : LONG_MAX;
162 *endptr = (char *) (any ? s - 1 : nptr);