1 /* $OpenBSD: strtoll.c,v 1.1 2006/09/18 21:12:57 mpf Exp $ */
2 /* Modified strtoll() from stdlib */
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 <sys/param.h>
33 #include "stand.h"
34
35 /*
36 * Convert a string to a long long.
37 *
38 * Ignores `locale' stuff. Assumes that the upper and lower case
39 * alphabets and digits are each contiguous.
40 */
41 long long
42 strtoll(const char *nptr, char **endptr, int base)
43 {
44 const char *s;
45 long long acc, cutoff;
46 int c;
47 int neg, any, cutlim;
48
49 /*
50 * Skip white space and pick up leading +/- sign if any.
51 * If base is 0, allow 0x for hex and 0 for octal, else
52 * assume decimal; if base is already 16, allow 0x.
53 */
54 s = nptr;
55 do {
56 c = (unsigned char) *s++;
57 } while (isspace(c));
58 if (c == '-') {
59 neg = 1;
60 c = *s++;
61 } else {
62 neg = 0;
63 if (c == '+')
64 c = *s++;
65 }
66 if ((base == 0 || base == 16) &&
67 c == '0' && (*s == 'x' || *s == 'X')) {
68 c = s[1];
69 s += 2;
70 base = 16;
71 }
72 if (base == 0)
73 base = c == '0' ? 8 : 10;
74
75 /*
76 * Compute the cutoff value between legal numbers and illegal
77 * numbers. That is the largest legal value, divided by the
78 * base. An input number that is greater than this value, if
79 * followed by a legal input character, is too big. One that
80 * is equal to this value may be valid or not; the limit
81 * between valid and invalid numbers is then based on the last
82 * digit. For instance, if the range for long longs is
83 * [-9223372036854775808..9223372036854775807] and the input base
84 * is 10, cutoff will be set to 922337203685477580 and cutlim to
85 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
86 * accumulated a value > 922337203685477580, or equal but the
87 * next digit is > 7 (or 8), the number is too big, and we will
88 * return a range error.
89 *
90 * Set any if any `digits' consumed; make it negative to indicate
91 * overflow.
92 */
93 cutoff = neg ? LLONG_MIN : LLONG_MAX;
94 cutlim = cutoff % base;
95 cutoff /= base;
96 if (neg) {
97 if (cutlim > 0) {
98 cutlim -= base;
99 cutoff += 1;
100 }
101 cutlim = -cutlim;
102 }
103 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
104 if (isdigit(c))
105 c -= '0';
106 else if (isalpha(c))
107 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
108 else
109 break;
110 if (c >= base)
111 break;
112 if (any < 0)
113 continue;
114 if (neg) {
115 if (acc < cutoff || (acc == cutoff && c > cutlim)) {
116 any = -1;
117 acc = LLONG_MIN;
118 } else {
119 any = 1;
120 acc *= base;
121 acc -= c;
122 }
123 } else {
124 if (acc > cutoff || (acc == cutoff && c > cutlim)) {
125 any = -1;
126 acc = LLONG_MAX;
127 } else {
128 any = 1;
129 acc *= base;
130 acc += c;
131 }
132 }
133 }
134 if (endptr != 0)
135 *endptr = (char *) (any ? s - 1 : nptr);
136 return (acc);
137 }