xref: /original-bsd/old/dump.4.1/unctime.c (revision 241757c4)
1 /*
2  * Copyright (c) 1980 Regents of the University of California.
3  * All rights reserved.  The Berkeley software License Agreement
4  * specifies the terms and conditions for redistribution.
5  */
6 
7 #ifndef lint
8 static char sccsid[] = "@(#)unctime.c	5.1 (Berkeley) 06/05/85";
9 #endif not lint
10 
11 #include "include.4.1/sys/types.h"
12 #include "include.4.1/time.h"
13 /*
14  * Convert a ctime(3) format string into a system format date.
15  * Return the date thus calculated.
16  *
17  * Return -1 if the string is not in ctime format.
18  */
19 
20 /*
21  * Offsets into the ctime string to various parts.
22  */
23 
24 #define	E_MONTH		4
25 #define	E_DAY		8
26 #define	E_HOUR		11
27 #define	E_MINUTE	14
28 #define	E_SECOND	17
29 #define	E_YEAR		20
30 
31 time_t unctime(str)
32 	char *str;
33 {
34 	struct tm then;
35 	char dbuf[30];
36 	time_t emitl();
37 
38 	if (strlen(str) != 25)
39 		str[25] = 0;
40 	strcpy(dbuf, str);
41 	dbuf[E_MONTH+3] = 0;
42 	if ( (then.tm_mon = lookup(&dbuf[E_MONTH])) < 0)
43 		return(-1);;
44 	then.tm_mday = atoi(&dbuf[E_DAY]);
45 	then.tm_hour = atoi(&dbuf[E_HOUR]);
46 	then.tm_min = atoi(&dbuf[E_MINUTE]);
47 	then.tm_sec = atoi(&dbuf[E_SECOND]);
48 	then.tm_year = atoi(&dbuf[E_YEAR]) - 1900;
49 	return(emitl(&then));
50 }
51 
52 static char months[] =
53 	"JanFebMarAprMayJunJulAugSepOctNovDec";
54 
55 static
56 lookup(str)
57 	char *str;
58 {
59 	register char *cp, *cp2;
60 
61 	for (cp = months, cp2 = str; *cp != 0; cp += 3)
62 		if (strncmp(cp, cp2, 3) == 0)
63 			return((cp-months) / 3);
64 	return(-1);
65 }
66 /*
67  * Routine to convert a localtime(3) format date back into
68  * a system format date.
69  *
70  *	Use a binary search.
71  */
72 
73 struct tm *localtime();
74 
75 time_t emitl(dp)
76 	struct tm *dp;
77 {
78 	time_t conv;
79 	register int i, bit;
80 	struct tm dcopy;
81 
82 	dcopy = *dp;
83 	dp = &dcopy;
84 	conv = 0;
85 	for (i = 31; i >= 0; i--) {
86 		bit = 1 << i;
87 		conv |= bit;
88 		if (dcmp(localtime(&conv), dp) > 0)
89 			conv &= ~bit;
90 	}
91 	return(conv);
92 }
93 
94 /*
95  * Compare two localtime dates, return result.
96  */
97 
98 #define DECIDE(a) \
99 	if (dp->a > dp2->a) \
100 		return(1); \
101 	if (dp->a < dp2->a) \
102 		return(-1)
103 
104 static
105 dcmp(dp, dp2)
106 	register struct tm *dp, *dp2;
107 {
108 
109 	DECIDE(tm_year);
110 	DECIDE(tm_mon);
111 	DECIDE(tm_mday);
112 	DECIDE(tm_hour);
113 	DECIDE(tm_min);
114 	DECIDE(tm_sec);
115 	return(0);
116 }
117