1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * From: static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93";
33 *
34 * $FreeBSD: src/sys/libkern/strtol.c,v 1.5 1999/12/01 22:56:50 archie Exp $
35 */
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/ctype.h>
40 #include <machine/limits.h>
41
42 /*
43 * Convert a string to a long integer.
44 *
45 * Ignores `locale' stuff. Assumes that the upper and lower case
46 * alphabets and digits are each contiguous.
47 */
48 long
strtol(const char * nptr,char ** endptr,int base)49 strtol(const char *nptr, char **endptr, int base)
50 {
51 const char *s = nptr;
52 unsigned long acc;
53 unsigned char c;
54 unsigned long cutoff;
55 int neg = 0, any, cutlim;
56
57 /*
58 * Skip white space and pick up leading +/- sign if any.
59 * If base is 0, allow 0x for hex and 0 for octal, else
60 * assume decimal; if base is already 16, allow 0x.
61 */
62 do {
63 c = *s++;
64 } while (isspace(c));
65 if (c == '-') {
66 neg = 1;
67 c = *s++;
68 } else if (c == '+')
69 c = *s++;
70 if ((base == 0 || base == 16) &&
71 c == '0' && (*s == 'x' || *s == 'X')) {
72 c = s[1];
73 s += 2;
74 base = 16;
75 }
76 if (base == 0)
77 base = c == '0' ? 8 : 10;
78
79 /*
80 * Compute the cutoff value between legal numbers and illegal
81 * numbers. That is the largest legal value, divided by the
82 * base. An input number that is greater than this value, if
83 * followed by a legal input character, is too big. One that
84 * is equal to this value may be valid or not; the limit
85 * between valid and invalid numbers is then based on the last
86 * digit. For instance, if the range for longs is
87 * [-2147483648..2147483647] and the input base is 10,
88 * cutoff will be set to 214748364 and cutlim to either
89 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
90 * a value > 214748364, or equal but the next digit is > 7 (or 8),
91 * the number is too big, and we will return a range error.
92 *
93 * Set any if any `digits' consumed; make it negative to indicate
94 * overflow.
95 */
96 cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
97 cutlim = cutoff % (unsigned long)base;
98 cutoff /= (unsigned long)base;
99 for (acc = 0, any = 0;; c = *s++) {
100 if (!isascii(c))
101 break;
102 if (isdigit(c))
103 c -= '0';
104 else if (isalpha(c))
105 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
106 else
107 break;
108 if (c >= base)
109 break;
110 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
111 any = -1;
112 else {
113 any = 1;
114 acc *= base;
115 acc += c;
116 }
117 }
118 if (any < 0) {
119 acc = neg ? LONG_MIN : LONG_MAX;
120 } else if (neg)
121 acc = -acc;
122 if (endptr != NULL)
123 *((const char **)(void *)endptr) = any ? s - 1 : nptr;
124 return (acc);
125 }
126