1 /* $NetBSD: strtoimax.c,v 1.4 2005/11/29 03:12:00 christos Exp $ */
2
3 /*-
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31 #include <LibConfig.h>
32 #include <sys/EfiCdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "from: @(#)strtoq.c 8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: strtoimax.c,v 1.4 2005/11/29 03:12:00 christos Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40
41 #include "namespace.h"
42
43 #include <assert.h>
44 #include <ctype.h>
45 #include <errno.h>
46 #include <inttypes.h>
47 #include <stddef.h>
48
49 #ifdef __weak_alias
__weak_alias(strtoimax,_strtoimax)50 __weak_alias(strtoimax, _strtoimax)
51 #endif
52
53 /*
54 * Convert a string to an intmax_t.
55 *
56 * Ignores `locale' stuff. Assumes that the upper and lower case
57 * alphabets and digits are each contiguous.
58 */
59 intmax_t
60 _strtoimax(const char *nptr, char **endptr, int base)
61 {
62 const char *s;
63 intmax_t acc, cutoff;
64 int c;
65 int neg, any, cutlim;
66
67 _DIAGASSERT(nptr != NULL);
68 /* endptr may be NULL */
69
70 #ifdef __GNUC__
71 /* This outrageous construct just to shut up a GCC warning. */
72 (void) &acc; (void) &cutoff;
73 #endif
74
75 /*
76 * Skip white space and pick up leading +/- sign if any.
77 * If base is 0, allow 0x for hex and 0 for octal, else
78 * assume decimal; if base is already 16, allow 0x.
79 */
80 s = nptr;
81 do {
82 c = (unsigned char) *s++;
83 } while (isspace(c));
84 if (c == '-') {
85 neg = 1;
86 c = *s++;
87 } else {
88 neg = 0;
89 if (c == '+')
90 c = *s++;
91 }
92 if ((base == 0 || base == 16) &&
93 c == '0' && (*s == 'x' || *s == 'X')) {
94 c = s[1];
95 s += 2;
96 base = 16;
97 }
98 if (base == 0)
99 base = c == '0' ? 8 : 10;
100
101 /*
102 * Compute the cutoff value between legal numbers and illegal
103 * numbers. That is the largest legal value, divided by the
104 * base. An input number that is greater than this value, if
105 * followed by a legal input character, is too big. One that
106 * is equal to this value may be valid or not; the limit
107 * between valid and invalid numbers is then based on the last
108 * digit. For instance, if the range for intmax_t is
109 * [-9223372036854775808..9223372036854775807] and the input base
110 * is 10, cutoff will be set to 922337203685477580 and cutlim to
111 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
112 * accumulated a value > 922337203685477580, or equal but the
113 * next digit is > 7 (or 8), the number is too big, and we will
114 * return a range error.
115 *
116 * Set any if any `digits' consumed; make it negative to indicate
117 * overflow.
118 */
119 cutoff = neg ? INTMAX_MIN : INTMAX_MAX;
120 cutlim = (int)(cutoff % base);
121 cutoff /= base;
122 if (neg) {
123 if (cutlim > 0) {
124 cutlim -= base;
125 cutoff += 1;
126 }
127 cutlim = -cutlim;
128 }
129 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
130 if (isdigit(c))
131 c -= '0';
132 else if (isalpha(c))
133 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
134 else
135 break;
136 if (c >= base)
137 break;
138 if (any < 0)
139 continue;
140 if (neg) {
141 if (acc < cutoff || (acc == cutoff && c > cutlim)) {
142 any = -1;
143 acc = INTMAX_MIN;
144 errno = ERANGE;
145 } else {
146 any = 1;
147 acc *= base;
148 acc -= c;
149 }
150 } else {
151 if (acc > cutoff || (acc == cutoff && c > cutlim)) {
152 any = -1;
153 acc = INTMAX_MAX;
154 errno = ERANGE;
155 } else {
156 any = 1;
157 acc *= base;
158 acc += c;
159 }
160 }
161 }
162 if (endptr != 0)
163 *endptr = (char *)(any ? s - 1 : nptr);
164 //*endptr = __UNCONST(any ? s - 1 : nptr);
165 return (acc);
166 }
167