1 /* $NetBSD: _strtol.h,v 1.2 2009/05/20 22:03:29 christos Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (c) 1990, 1993
7 * The Regents of the University of California. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * Original version ID:
34 * NetBSD: src/lib/libc/locale/_wcstol.h,v 1.2 2003/08/07 16:43:03 agc Exp
35 */
36
37 /*
38 * function template for strtol, strtoll and strtoimax.
39 *
40 * parameters:
41 * _FUNCNAME : function name
42 * __INT : return type
43 * __INT_MIN : lower limit of the return type
44 * __INT_MAX : upper limit of the return type
45 */
46
47 __INT
_FUNCNAME(const char * nptr,char ** endptr,int base)48 _FUNCNAME(const char *nptr, char **endptr, int base)
49 {
50 const char *s;
51 __INT acc, cutoff;
52 unsigned char c;
53 int any, cutlim, i, neg;
54
55 /* check base value */
56 if (base && (base < 2 || base > 36)) {
57 #if !defined(_KERNEL) && !defined(_STANDALONE)
58 errno = EINVAL;
59 if (endptr != NULL)
60 /* LINTED interface specification */
61 *endptr = __DECONST(void *, nptr);
62 return (0);
63 #else
64 panic("%s: invalid base %d", __func__, base);
65 #endif
66 }
67
68 /*
69 * Skip white space and pick up leading +/- sign if any.
70 * If base is 0, allow 0x for hex and 0 for octal, else
71 * assume decimal; if base is already 16, allow 0x.
72 */
73 s = nptr;
74 do {
75 c = *s++;
76 } while (isspace(c));
77 if (c == '-') {
78 neg = 1;
79 c = *s++;
80 } else {
81 neg = 0;
82 if (c == '+')
83 c = *s++;
84 }
85 if ((base == 0 || base == 16) &&
86 c == '0' && (*s == 'x' || *s == 'X') &&
87 ((s[1] >= '0' && s[1] <= '9') ||
88 (s[1] >= 'A' && s[1] <= 'F') ||
89 (s[1] >= 'a' && s[1] <= 'f'))) {
90 c = s[1];
91 s += 2;
92 base = 16;
93 }
94 if ((base == 0 || base == 2) &&
95 c == '0' && (*s == 'b' || *s == 'B') &&
96 (s[1] >= '0' && s[1] <= '1')) {
97 c = s[1];
98 s += 2;
99 base = 2;
100 }
101 if (base == 0)
102 base = (c == '0' ? 8 : 10);
103
104 /*
105 * Compute the cutoff value between legal numbers and illegal
106 * numbers. That is the largest legal value, divided by the
107 * base. An input number that is greater than this value, if
108 * followed by a legal input character, is too big. One that
109 * is equal to this value may be valid or not; the limit
110 * between valid and invalid numbers is then based on the last
111 * digit. For instance, if the range for longs is
112 * [-2147483648..2147483647] and the input base is 10,
113 * cutoff will be set to 214748364 and cutlim to either
114 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
115 * a value > 214748364, or equal but the next digit is > 7 (or 8),
116 * the number is too big, and we will return a range error.
117 *
118 * Set any if any `digits' consumed; make it negative to indicate
119 * overflow.
120 */
121 cutoff = (neg ? __INT_MIN : __INT_MAX);
122 cutlim = (int)(cutoff % base);
123 cutoff /= base;
124 if (neg) {
125 if (cutlim > 0) {
126 cutlim -= base;
127 cutoff += 1;
128 }
129 cutlim = -cutlim;
130 }
131 for (acc = 0, any = 0;; c = *s++) {
132 if (isdigit(c))
133 i = c - '0';
134 else if (isalpha(c))
135 i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
136 else
137 break;
138 if (i >= base)
139 break;
140 if (any < 0)
141 continue;
142 if (neg) {
143 if (acc < cutoff || (acc == cutoff && i > cutlim)) {
144 acc = __INT_MIN;
145 #if !defined(_KERNEL) && !defined(_STANDALONE)
146 any = -1;
147 errno = ERANGE;
148 #else
149 any = 0;
150 break;
151 #endif
152 } else {
153 any = 1;
154 acc *= base;
155 acc -= i;
156 }
157 } else {
158 if (acc > cutoff || (acc == cutoff && i > cutlim)) {
159 acc = __INT_MAX;
160 #if !defined(_KERNEL) && !defined(_STANDALONE)
161 any = -1;
162 errno = ERANGE;
163 #else
164 any = 0;
165 break;
166 #endif
167 } else {
168 any = 1;
169 acc *= base;
170 acc += i;
171 }
172 }
173 }
174 if (endptr != NULL)
175 /* LINTED interface specification */
176 *endptr = __DECONST(void *, any ? s - 1 : nptr);
177 return(acc);
178 }
179