1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1992, 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 a long long integer.
44 *
45 * Assumes that the upper and lower case
46 * alphabets and digits are each contiguous.
47 */
strtoll(const char * nptr,char ** endptr,int base)48 long long strtoll(const char *nptr, char **endptr, int base)
49 {
50 const char *s;
51 unsigned long long acc;
52 char c;
53 unsigned long long cutoff;
54 int neg, any, cutlim;
55
56 /*
57 * Skip white space and pick up leading +/- sign if any.
58 * If base is 0, allow 0x for hex and 0 for octal, else
59 * assume decimal; if base is already 16, allow 0x.
60 */
61 s = nptr;
62 do {
63 c = *s++;
64 } while (isspace((unsigned char)c));
65 if (c == '-') {
66 neg = 1;
67 c = *s++;
68 } else {
69 neg = 0;
70 if (c == '+')
71 c = *s++;
72 }
73 if ((base == 0 || base == 16) &&
74 c == '0' && (*s == 'x' || *s == 'X') &&
75 ((s[1] >= '0' && s[1] <= '9') ||
76 (s[1] >= 'A' && s[1] <= 'F') ||
77 (s[1] >= 'a' && s[1] <= 'f'))) {
78 c = s[1];
79 s += 2;
80 base = 16;
81 }
82 if (base == 0)
83 base = c == '0' ? 8 : 10;
84 acc = any = 0;
85
86 /*
87 * Compute the cutoff value between legal numbers and illegal
88 * numbers. That is the largest legal value, divided by the
89 * base. An input number that is greater than this value, if
90 * followed by a legal input character, is too big. One that
91 * is equal to this value may be valid or not; the limit
92 * between valid and invalid numbers is then based on the last
93 * digit. For instance, if the range for quads is
94 * [-9223372036854775808..9223372036854775807] and the input base
95 * is 10, cutoff will be set to 922337203685477580 and cutlim to
96 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
97 * accumulated a value > 922337203685477580, or equal but the
98 * next digit is > 7 (or 8), the number is too big, and we will
99 * return a range error.
100 *
101 * Set 'any' if any `digits' consumed; make it negative to indicate
102 * overflow.
103 */
104 cutoff = neg ? (unsigned long long)-(LLONG_MIN + LLONG_MAX) + LLONG_MAX
105 : LLONG_MAX;
106 cutlim = cutoff % base;
107 cutoff /= base;
108 for ( ; ; c = *s++) {
109 if (c >= '0' && c <= '9')
110 c -= '0';
111 else if (c >= 'A' && c <= 'Z')
112 c -= 'A' - 10;
113 else if (c >= 'a' && c <= 'z')
114 c -= 'a' - 10;
115 else
116 break;
117 if (c >= base)
118 break;
119 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
120 any = -1;
121 else {
122 any = 1;
123 acc *= base;
124 acc += c;
125 }
126 }
127 if (any < 0) {
128 acc = neg ? LLONG_MIN : LLONG_MAX;
129 } else if (neg)
130 acc = -acc;
131 if (endptr != NULL)
132 *endptr = (char *)(any ? s - 1 : nptr);
133 return (acc);
134 }
135