1 /* $OpenBSD: strtoll.c,v 1.7 2013/03/28 18:09:38 martynas Exp $ */
2 /*-
3 * Copyright (c) 1992 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/types.h>
32
33 #include <ctype.h>
34 #include <errno.h>
35 #include <limits.h>
36 #include <stdlib.h>
37
38 /*
39 * Convert a string to a long long.
40 *
41 * Ignores `locale' stuff. Assumes that the upper and lower case
42 * alphabets and digits are each contiguous.
43 */
44 long long
strtoll(const char * nptr,char ** endptr,int base)45 strtoll(const char *nptr, char **endptr, int base)
46 {
47 const char *s;
48 long long acc, cutoff;
49 int c;
50 int neg, any, cutlim;
51
52 /*
53 * Skip white space and pick up leading +/- sign if any.
54 * If base is 0, allow 0x for hex and 0 for octal, else
55 * assume decimal; if base is already 16, allow 0x.
56 */
57 s = nptr;
58 do {
59 c = (unsigned char) *s++;
60 } while (isspace(c));
61 if (c == '-') {
62 neg = 1;
63 c = *s++;
64 } else {
65 neg = 0;
66 if (c == '+')
67 c = *s++;
68 }
69 if ((base == 0 || base == 16) &&
70 c == '0' && (*s == 'x' || *s == 'X')) {
71 c = s[1];
72 s += 2;
73 base = 16;
74 }
75 if (base == 0)
76 base = c == '0' ? 8 : 10;
77
78 /*
79 * Compute the cutoff value between legal numbers and illegal
80 * numbers. That is the largest legal value, divided by the
81 * base. An input number that is greater than this value, if
82 * followed by a legal input character, is too big. One that
83 * is equal to this value may be valid or not; the limit
84 * between valid and invalid numbers is then based on the last
85 * digit. For instance, if the range for long longs is
86 * [-9223372036854775808..9223372036854775807] and the input base
87 * is 10, cutoff will be set to 922337203685477580 and cutlim to
88 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
89 * accumulated a value > 922337203685477580, or equal but the
90 * next digit is > 7 (or 8), the number is too big, and we will
91 * return a range error.
92 *
93 * Set any if any `digits' consumed; make it negative to indicate
94 * overflow.
95 */
96 cutoff = neg ? LLONG_MIN : LLONG_MAX;
97 cutlim = cutoff % base;
98 cutoff /= base;
99 if (neg) {
100 if (cutlim > 0) {
101 cutlim -= base;
102 cutoff += 1;
103 }
104 cutlim = -cutlim;
105 }
106 for (acc = 0, any = 0;; c = (unsigned char) *s++) {
107 if (isdigit(c))
108 c -= '0';
109 else if (isalpha(c))
110 c -= isupper(c) ? 'A' - 10 : 'a' - 10;
111 else
112 break;
113 if (c >= base)
114 break;
115 if (any < 0)
116 continue;
117 if (neg) {
118 if (acc < cutoff || (acc == cutoff && c > cutlim)) {
119 any = -1;
120 acc = LLONG_MIN;
121 errno = ERANGE;
122 } else {
123 any = 1;
124 acc *= base;
125 acc -= c;
126 }
127 } else {
128 if (acc > cutoff || (acc == cutoff && c > cutlim)) {
129 any = -1;
130 acc = LLONG_MAX;
131 errno = ERANGE;
132 } else {
133 any = 1;
134 acc *= base;
135 acc += c;
136 }
137 }
138 }
139 if (endptr != 0)
140 *endptr = (char *) (any ? s - 1 : nptr);
141 return (acc);
142 }
143
144 __strong_alias(strtoq, strtoll);
145