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strtoll.c (4486B)
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1 /*-
2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #include <limits.h>
35 #include <errno.h>
36 #include <ctype.h>
37 #include <stdlib.h>
38
39 /*
40 * Convert a string to a long long integer.
41 *
42 * Assumes that the upper and lower case
43 * alphabets and digits are each contiguous.
44 */
45 long long
46 strtoll(const char * __restrict nptr, char ** __restrict endptr, int base)
47 {
48 const char *s;
49 unsigned long long acc;
50 char c;
51 unsigned long long cutoff;
52 int neg, any, cutlim;
53
54 /*
55 * Skip white space and pick up leading +/- sign if any.
56 * If base is 0, allow 0x for hex and 0 for octal, else
57 * assume decimal; if base is already 16, allow 0x.
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 if (base < 2 || base > 36)
84 goto noconv;
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 errno = ERANGE;
130 } else if (!any) {
131 noconv:
132 errno = EINVAL;
133 } else if (neg)
134 acc = -acc;
135 if (endptr != NULL)
136 *endptr = (char *)(any ? s - 1 : nptr);
137 return (acc);
138 }