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 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/ctype.h>
38 #include <sys/limits.h>
39
40 /*
41 * Convert a string to a quad integer.
42 *
43 * Ignores `locale' stuff. Assumes that the upper and lower case
44 * alphabets and digits are each contiguous.
45 */
46 quad_t
strtoq(const char * nptr,char ** endptr,int base)47 strtoq(const char *nptr, char **endptr, int base)
48 {
49 const char *s;
50 u_quad_t acc;
51 unsigned char c;
52 u_quad_t qbase, cutoff;
53 int neg, any, cutlim;
54
55 /*
56 * Skip white space and pick up leading +/- sign if any.
57 * If base is 0, allow 0x for hex and 0 for octal, else
58 * assume decimal; if base is already 16, allow 0x.
59 */
60 s = nptr;
61 do {
62 c = *s++;
63 } while (isspace(c));
64 if (c == '-') {
65 neg = 1;
66 c = *s++;
67 } else {
68 neg = 0;
69 if (c == '+')
70 c = *s++;
71 }
72 if ((base == 0 || base == 16) &&
73 c == '0' && (*s == 'x' || *s == 'X')) {
74 c = s[1];
75 s += 2;
76 base = 16;
77 }
78 if (base == 0)
79 base = c == '0' ? 8 : 10;
80
81 /*
82 * Compute the cutoff value between legal numbers and illegal
83 * numbers. That is the largest legal value, divided by the
84 * base. An input number that is greater than this value, if
85 * followed by a legal input character, is too big. One that
86 * is equal to this value may be valid or not; the limit
87 * between valid and invalid numbers is then based on the last
88 * digit. For instance, if the range for quads is
89 * [-9223372036854775808..9223372036854775807] and the input base
90 * is 10, cutoff will be set to 922337203685477580 and cutlim to
91 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
92 * accumulated a value > 922337203685477580, or equal but the
93 * next digit is > 7 (or 8), the number is too big, and we will
94 * return a range error.
95 *
96 * Set any if any `digits' consumed; make it negative to indicate
97 * overflow.
98 */
99 qbase = (unsigned)base;
100 cutoff = neg ? (u_quad_t)-(QUAD_MIN + QUAD_MAX) + QUAD_MAX : QUAD_MAX;
101 cutlim = cutoff % qbase;
102 cutoff /= qbase;
103 for (acc = 0, any = 0;; c = *s++) {
104 if (!isascii(c))
105 break;
106 if (isdigit(c))
107 c -= '0';
108 else if (isalpha(c))
109 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
110 else
111 break;
112 if (c >= base)
113 break;
114 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
115 any = -1;
116 else {
117 any = 1;
118 acc *= qbase;
119 acc += c;
120 }
121 }
122 if (any < 0) {
123 acc = neg ? QUAD_MIN : QUAD_MAX;
124 } else if (neg)
125 acc = -acc;
126 if (endptr != NULL)
127 *endptr = __DECONST(char *, any ? s - 1 : nptr);
128 return (acc);
129 }
130