1 /* $OpenBSD: strtoumax.c,v 1.1 2006/01/13 17:58:09 millert Exp $ */
2
3 /*-
4 * Copyright (c) 1992 The Regents of the University of California.
5 * 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
32 #include <ctype.h>
33 #include <errno.h>
34 #include <inttypes.h>
35
36 /*
37 * Convert a string to a uintmax_t.
38 *
39 * Ignores `locale' stuff. Assumes that the upper and lower case
40 * alphabets and digits are each contiguous.
41 */
42 uintmax_t
strtoumax(const char * nptr,char ** endptr,int base)43 strtoumax(const char *nptr, char **endptr, int base)
44 {
45 const char *s;
46 uintmax_t acc, cutoff;
47 int c;
48 int neg, any, cutlim;
49
50 /*
51 * See strtoq for comments as to the logic used.
52 */
53 s = nptr;
54 do {
55 c = (unsigned char) *s++;
56 } while (isspace(c));
57 if (c == '-') {
58 neg = 1;
59 c = *s++;
60 } else {
61 neg = 0;
62 if (c == '+')
63 c = *s++;
64 }
65 if ((base == 0 || base == 16) &&
66 c == '0' && (*s == 'x' || *s == 'X')) {
67 c = s[1];
68 s += 2;
69 base = 16;
70 }
71 if (base == 0)
72 base = c == '0' ? 8 : 10;
73
74 cutoff = UINTMAX_MAX / (uintmax_t)base;
75 cutlim = UINTMAX_MAX % (uintmax_t)base;
76 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
77 if (isdigit(c))
78 c -= '0';
79 else if (isalpha(c))
80 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
81 else
82 break;
83 if (c >= base)
84 break;
85 if (any < 0)
86 continue;
87 if (acc > cutoff || (acc == cutoff && c > cutlim)) {
88 any = -1;
89 acc = UINTMAX_MAX;
90 errno = ERANGE;
91 } else {
92 any = 1;
93 acc *= (uintmax_t)base;
94 acc += c;
95 }
96 }
97 if (neg && any > 0)
98 acc = -acc;
99 if (endptr != 0)
100 *endptr = (char *) (any ? s - 1 : nptr);
101 return (acc);
102 }
103