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 [rescinded 22 July 1999]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
38 The @code{strtol} function converts the string in @var{string} to a
39 long integer value according to the given @var{base}, which must be
40 between 2 and 36 inclusive, or be the special value 0. If @var{base}
41 is 0, @code{strtol} will look for the prefixes @code{0} and @code{0x}
42 to indicate bases 8 and 16, respectively, else default to base 10.
43 When 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
46 that 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
63 extern 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 */
89 long
90 strtol(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 }