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git01.mediatek.com / filogic / atf / 5d8e64bf69a4ff3245de03d0345e56b22020b44e / . / lib / libc / strtoul.c
blob: b42fb141e43d3c6cee29149946b5ed2f920295ca [file] [log] [blame]
Madhukar Pappireddyc74cae42021-01-27 15:44:52 -0600[diff] [blame]1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Copyright (c) 2011 The FreeBSD Foundation
8 * All rights reserved.
9 * Portions of this software were developed by David Chisnall
10 * under sponsorship from the FreeBSD Foundation.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#include <errno.h>
38#include <limits.h>
39#include <stddef.h>
40#include <stdlib.h>
41
42/*
43 * Convert a string to an unsigned long integer.
44 *
45 * Assumes that the upper and lower case
46 * alphabets and digits are each contiguous.
47 */
48unsigned long strtoul(const char *nptr, char **endptr, int base)
49{
50 const char *s;
51 unsigned long acc;
52 char c;
53 unsigned long cutoff;
54 int neg, any, cutlim;
55
56 /*
57 * See strtol for comments as to the logic used.
58 */
59 s = nptr;
60 do {
61 c = *s++;
62 } while (isspace((unsigned char)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 ((s[1] >= '0' && s[1] <= '9') ||
74 (s[1] >= 'A' && s[1] <= 'F') ||
75 (s[1] >= 'a' && s[1] <= 'f'))) {
76 c = s[1];
77 s += 2;
78 base = 16;
79 }
80 if (base == 0)
81 base = c == '0' ? 8 : 10;
82 acc = any = 0;
83
84 cutoff = ULONG_MAX / base;
85 cutlim = ULONG_MAX % base;
86 for ( ; ; c = *s++) {
87 if (c >= '0' && c <= '9')
88 c -= '0';
89 else if (c >= 'A' && c <= 'Z')
90 c -= 'A' - 10;
91 else if (c >= 'a' && c <= 'z')
92 c -= 'a' - 10;
93 else
94 break;
95 if (c >= base)
96 break;
97 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
98 any = -1;
99 else {
100 any = 1;
101 acc *= base;
102 acc += c;
103 }
104 }
105 if (any < 0) {
106 acc = ULONG_MAX;
107 } else if (neg)
108 acc = -acc;
109 if (endptr != NULL)
110 *endptr = (char *)(any ? s - 1 : nptr);
111 return (acc);
112}