unctime.c revision 1.1.1.2 1 /*-
2 * Copyright (c) 1980, 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 #ifndef lint
35 static char sccsid[] = "@(#)unctime.c 8.1 (Berkeley) 6/5/93";
36 #endif /* not lint */
37
38 #include <sys/types.h>
39
40 #include <stdio.h>
41 #include <time.h>
42 #ifdef __STDC__
43 #include <stdlib.h>
44 #include <string.h>
45 #endif
46
47 #ifndef __P
48 #include <sys/cdefs.h>
49 #endif
50
51 /*
52 * Convert a ctime(3) format string into a system format date.
53 * Return the date thus calculated.
54 *
55 * Return -1 if the string is not in ctime format.
56 */
57
58 /*
59 * Offsets into the ctime string to various parts.
60 */
61
62 #define E_MONTH 4
63 #define E_DAY 8
64 #define E_HOUR 11
65 #define E_MINUTE 14
66 #define E_SECOND 17
67 #define E_YEAR 20
68
69 static int dcmp __P((struct tm *, struct tm *));
70 static time_t emitl __P((struct tm *));
71 static int lookup __P((char *));
72
73
74 time_t
75 unctime(str)
76 char *str;
77 {
78 struct tm then;
79 char dbuf[26];
80
81 (void) strncpy(dbuf, str, sizeof(dbuf) - 1);
82 dbuf[sizeof(dbuf) - 1] = '\0';
83 dbuf[E_MONTH+3] = '\0';
84 if ((then.tm_mon = lookup(&dbuf[E_MONTH])) < 0)
85 return (-1);
86 then.tm_mday = atoi(&dbuf[E_DAY]);
87 then.tm_hour = atoi(&dbuf[E_HOUR]);
88 then.tm_min = atoi(&dbuf[E_MINUTE]);
89 then.tm_sec = atoi(&dbuf[E_SECOND]);
90 then.tm_year = atoi(&dbuf[E_YEAR]) - 1900;
91 return(emitl(&then));
92 }
93
94 static char months[] =
95 "JanFebMarAprMayJunJulAugSepOctNovDec";
96
97 static int
98 lookup(str)
99 char *str;
100 {
101 register char *cp, *cp2;
102
103 for (cp = months, cp2 = str; *cp != '\0'; cp += 3)
104 if (strncmp(cp, cp2, 3) == 0)
105 return((cp-months) / 3);
106 return(-1);
107 }
108 /*
109 * Routine to convert a localtime(3) format date back into
110 * a system format date.
111 *
112 * Use a binary search.
113 */
114
115 static time_t
116 emitl(dp)
117 struct tm *dp;
118 {
119 time_t conv;
120 register int i, bit;
121 struct tm dcopy;
122
123 dcopy = *dp;
124 dp = &dcopy;
125 conv = 0;
126 for (i = 30; i >= 0; i--) {
127 bit = 1 << i;
128 conv |= bit;
129 if (dcmp(localtime(&conv), dp) > 0)
130 conv &= ~bit;
131 }
132 return(conv);
133 }
134
135 /*
136 * Compare two localtime dates, return result.
137 */
138
139 #define DECIDE(a) \
140 if (dp->a > dp2->a) \
141 return(1); \
142 if (dp->a < dp2->a) \
143 return(-1)
144
145 static int
146 dcmp(dp, dp2)
147 register struct tm *dp, *dp2;
148 {
149
150 DECIDE(tm_year);
151 DECIDE(tm_mon);
152 DECIDE(tm_mday);
153 DECIDE(tm_hour);
154 DECIDE(tm_min);
155 DECIDE(tm_sec);
156 return(0);
157 }
158