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