1 /* $OpenBSD: strtoumax.c,v 1.2 2014/09/13 20:10:12 schwarze Exp $ */
2 /*
3 * Copyright (c) 1992 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <ctype.h>
32 #include <errno.h>
33 #include <inttypes.h>
34
35 /*
36 * Convert a string to a uintmax_t.
37 *
38 * Ignores `locale' stuff. Assumes that the upper and lower case
39 * alphabets and digits are each contiguous.
40 */
41 uintmax_t
strtoumax(const char * nptr,char ** endptr,int base)42 strtoumax(const char *nptr, char **endptr, int base)
43 {
44 const char *s;
45 uintmax_t acc, cutoff;
46 int c;
47 int neg, any, cutlim;
48
49 /*
50 * See strtoimax for comments as to the logic used.
51 */
52 if (base < 0 || base == 1 || base > 36) {
53 if (endptr != 0)
54 *endptr = (char *)nptr;
55 errno = EINVAL;
56 return 0;
57 }
58
59 s = nptr;
60 do {
61 c = (unsigned char) *s++;
62 } while (isspace(c));
63 if (c == '-') {
64 neg = 1;
65 c = *s++;
66 } else {
67 neg = 0;
68 if (c == '+')
69 c = *s++;
70 }
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 cutoff = UINTMAX_MAX / (uintmax_t)base;
81 cutlim = UINTMAX_MAX % (uintmax_t)base;
82 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
83 if (isdigit(c))
84 c -= '0';
85 else if (isalpha(c))
86 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
87 else
88 break;
89 if (c >= base)
90 break;
91 if (any < 0)
92 continue;
93 if (acc > cutoff || (acc == cutoff && c > cutlim)) {
94 any = -1;
95 acc = UINTMAX_MAX;
96 errno = ERANGE;
97 } else {
98 any = 1;
99 acc *= (uintmax_t)base;
100 acc += c;
101 }
102 }
103 if (neg && any > 0)
104 acc = -acc;
105 if (endptr != 0)
106 *endptr = (char *) (any ? s - 1 : nptr);
107 return (acc);
108 }
109