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-rw-r--r--src/lib/libc/stdlib/strtol.c146
1 files changed, 146 insertions, 0 deletions
diff --git a/src/lib/libc/stdlib/strtol.c b/src/lib/libc/stdlib/strtol.c
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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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char *rcsid = "$OpenBSD: strtol.c,v 1.5 2003/06/02 20:18:38 millert Exp $";
32#endif /* LIBC_SCCS and not lint */
33
34#include <ctype.h>
35#include <errno.h>
36#include <limits.h>
37#include <stdlib.h>
38
39
40/*
41 * Convert a string to a long integer.
42 *
43 * Ignores `locale' stuff. Assumes that the upper and lower case
44 * alphabets and digits are each contiguous.
45 */
46long
47strtol(nptr, endptr, base)
48 const char *nptr;
49 char **endptr;
50 register int base;
51{
52 register const char *s;
53 register long acc, cutoff;
54 register int c;
55 register int neg, 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 s = nptr;
63 do {
64 c = (unsigned char) *s++;
65 } while (isspace(c));
66 if (c == '-') {
67 neg = 1;
68 c = *s++;
69 } else {
70 neg = 0;
71 if (c == '+')
72 c = *s++;
73 }
74 if ((base == 0 || base == 16) &&
75 c == '0' && (*s == 'x' || *s == 'X')) {
76 c = s[1];
77 s += 2;
78 base = 16;
79 }
80 if (base == 0)
81 base = c == '0' ? 8 : 10;
82
83 /*
84 * Compute the cutoff value between legal numbers and illegal
85 * numbers. That is the largest legal value, divided by the
86 * base. An input number that is greater than this value, if
87 * followed by a legal input character, is too big. One that
88 * is equal to this value may be valid or not; the limit
89 * between valid and invalid numbers is then based on the last
90 * digit. For instance, if the range for longs is
91 * [-2147483648..2147483647] and the input base is 10,
92 * cutoff will be set to 214748364 and cutlim to either
93 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
94 * a value > 214748364, or equal but the next digit is > 7 (or 8),
95 * the number is too big, and we will return a range error.
96 *
97 * Set any if any `digits' consumed; make it negative to indicate
98 * overflow.
99 */
100 cutoff = neg ? LONG_MIN : LONG_MAX;
101 cutlim = cutoff % base;
102 cutoff /= base;
103 if (neg) {
104 if (cutlim > 0) {
105 cutlim -= base;
106 cutoff += 1;
107 }
108 cutlim = -cutlim;
109 }
110 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
111 if (isdigit(c))
112 c -= '0';
113 else if (isalpha(c))
114 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
115 else
116 break;
117 if (c >= base)
118 break;
119 if (any < 0)
120 continue;
121 if (neg) {
122 if (acc < cutoff || acc == cutoff && c > cutlim) {
123 any = -1;
124 acc = LONG_MIN;
125 errno = ERANGE;
126 } else {
127 any = 1;
128 acc *= base;
129 acc -= c;
130 }
131 } else {
132 if (acc > cutoff || acc == cutoff && c > cutlim) {
133 any = -1;
134 acc = LONG_MAX;
135 errno = ERANGE;
136 } else {
137 any = 1;
138 acc *= base;
139 acc += c;
140 }
141 }
142 }
143 if (endptr != 0)
144 *endptr = (char *) (any ? s - 1 : nptr);
145 return (acc);
146}