xref: /netbsd-src/sbin/dump/unctime.c (revision 811e6386f8c5e4a3521c7003da29ec8673e344fa)
1 /*-
2  * Copyright (c) 1980 The Regents of the University of California.
3  * 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	5.4 (Berkeley) 3/7/91";
36 static char rcsid[] = "$Header: /cvsroot/src/sbin/dump/unctime.c,v 1.3 1993/03/23 00:27:23 cgd Exp $";
37 #endif /* not lint */
38 
39 #include <sys/types.h>
40 #include <time.h>
41 #include <stdio.h>
42 #ifdef __STDC__
43 #include <stdlib.h>
44 #include <string.h>
45 #endif
46 
47 /*
48  * Convert a ctime(3) format string into a system format date.
49  * Return the date thus calculated.
50  *
51  * Return -1 if the string is not in ctime format.
52  */
53 
54 /*
55  * Offsets into the ctime string to various parts.
56  */
57 
58 #define	E_MONTH		4
59 #define	E_DAY		8
60 #define	E_HOUR		11
61 #define	E_MINUTE	14
62 #define	E_SECOND	17
63 #define	E_YEAR		20
64 
65 static int lookup();
66 
67 time_t
68 unctime(str)
69 	char *str;
70 {
71 	struct tm then;
72 	char dbuf[30];
73 	time_t emitl();
74 
75 	if (strlen(str) != 25)
76 		str[25] = 0;
77 	strcpy(dbuf, str);
78 	dbuf[E_MONTH+3] = 0;
79 	if ((then.tm_mon = lookup(&dbuf[E_MONTH])) < 0)
80 		return (-1);
81 	then.tm_mday = atoi(&dbuf[E_DAY]);
82 	then.tm_hour = atoi(&dbuf[E_HOUR]);
83 	then.tm_min = atoi(&dbuf[E_MINUTE]);
84 	then.tm_sec = atoi(&dbuf[E_SECOND]);
85 	then.tm_year = atoi(&dbuf[E_YEAR]) - 1900;
86 	return(emitl(&then));
87 }
88 
89 static char months[] =
90 	"JanFebMarAprMayJunJulAugSepOctNovDec";
91 
92 static int
93 lookup(str)
94 	char *str;
95 {
96 	register char *cp, *cp2;
97 
98 	for (cp = months, cp2 = str; *cp != 0; cp += 3)
99 		if (strncmp(cp, cp2, 3) == 0)
100 			return((cp-months) / 3);
101 	return(-1);
102 }
103 /*
104  * Routine to convert a localtime(3) format date back into
105  * a system format date.
106  *
107  *	Use a binary search.
108  */
109 
110 struct tm *localtime();
111 static int dcmp();
112 
113 time_t
114 emitl(dp)
115 	struct tm *dp;
116 {
117 	time_t conv;
118 	register int i, bit;
119 	struct tm dcopy;
120 
121 	dcopy = *dp;
122 	dp = &dcopy;
123 	conv = 0;
124 	for (i = 30; i >= 0; i--) {
125 		bit = 1 << i;
126 		conv |= bit;
127 		if (dcmp(localtime(&conv), dp) > 0)
128 			conv &= ~bit;
129 	}
130 	return(conv);
131 }
132 
133 /*
134  * Compare two localtime dates, return result.
135  */
136 
137 #define DECIDE(a) \
138 	if (dp->a > dp2->a) \
139 		return(1); \
140 	if (dp->a < dp2->a) \
141 		return(-1)
142 
143 static int
144 dcmp(dp, dp2)
145 	register struct tm *dp, *dp2;
146 {
147 
148 	DECIDE(tm_year);
149 	DECIDE(tm_mon);
150 	DECIDE(tm_mday);
151 	DECIDE(tm_hour);
152 	DECIDE(tm_min);
153 	DECIDE(tm_sec);
154 	return(0);
155 }
156