Migrating timing support routines over to SimGear.

2000-07-05 00:25:30 +00:00
parent a46163bcd7
commit 1b07b25ad2
9 changed files with 2417 additions and 0 deletions
@@ -0,0 +1,128 @@
+/* -*- Mode: C++ -*- *****************************************************
+ * lowleveltime.h
+ * Written by various people (I"ll look up the exact credits later)
+ * Modified by Durk Talsma, July 1999 for use in FlightGear
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ **************************************************************************/
+
+/********************************************************************
+ * This file redefines some low-level Unix-like time functions for  *
+ * use with FlightGear. Most notably, localtime() is adapted to use *
+ * a custom timezone, in order to get the 'local' time for a given  *
+ * aircraft's position, and not only for the current location of the*
+ * computer running the sim.                                        *
+ *                                                                  *
+ * Software adapted from glibc functions, by Durk Talsma. Started   *
+ * July, 17, 1999.                                                  *
+ ********************************************************************/
+
+#ifndef _LOWLEVELTIME_H_
+#define _LOWLEVELTIME_H_
+
+#include <time.h>
+
+/* adapted from zdump.c */
+void show (const char *zone, time_t t, int v);
+
+/* adapted from <time.h> */
+struct tm * fgLocaltime (const time_t *t, const char *tzName);
+
+/* Prototype for the internal function to get information based on TZ.  */
+extern struct tm *fgtz_convert (const time_t *t, int use_localtime,
+				     struct tm *tp, const char *tzName);
+
+/* This structure contains all the information about a
+   timezone given in the POSIX standard TZ envariable.  */
+typedef struct
+  {
+    const char *name;
+
+    /* When to change.  */
+    enum { J0, J1, M } type;	/* Interpretation of:  */
+    unsigned short int m, n, d;	/* Month, week, day.  */
+    unsigned int secs;		/* Time of day.  */
+
+    long int offset;		/* Seconds east of GMT (west if < 0).  */
+
+    /* We cache the computed time of change for a
+       given year so we don't have to recompute it.  */
+    time_t change;	/* When to change to this zone.  */
+    int computed_for;	/* Year above is computed for.  */
+  } fgtz_rule;
+
+struct tzhead {
+ 	char	tzh_magic[4];		/* TZ_MAGIC */
+	char	tzh_reserved[16];	/* reserved for future use */
+	char	tzh_ttisgmtcnt[4];	/* coded number of trans. time flags */
+	char	tzh_ttisstdcnt[4];	/* coded number of trans. time flags */
+	char	tzh_leapcnt[4];		/* coded number of leap seconds */
+	char	tzh_timecnt[4];		/* coded number of transition times */
+	char	tzh_typecnt[4];		/* coded number of local time types */
+	char	tzh_charcnt[4];		/* coded number of abbr. chars */
+};
+
+
+/* Defined in mktime.c.  */
+extern const unsigned short int mon_yday[2][13];
+
+#ifndef TZDIR
+#define TZDIR	"/usr/local/etc/zoneinfo" /* Time zone object file directory */
+#endif /* !defined TZDIR */
+
+
+
+#ifndef TZDEFAULT
+#define TZDEFAULT	"localtime"
+#endif /* !defined TZDEFAULT */
+
+#define SECSPERMIN	60
+#define MINSPERHOUR	60
+#define HOURSPERDAY	24
+#define DAYSPERWEEK	7
+#define DAYSPERNYEAR	365
+#define DAYSPERLYEAR	366
+#define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
+#define SECSPERDAY	((long) SECSPERHOUR * HOURSPERDAY)
+#define MONSPERYEAR	12
+
+#define TM_SUNDAY	0
+#define TM_MONDAY	1
+#define TM_TUESDAY	2
+#define TM_WEDNESDAY	3
+#define TM_THURSDAY	4
+#define TM_FRIDAY	5
+#define TM_SATURDAY	6
+
+#define TM_JANUARY	0
+#define TM_FEBRUARY	1
+#define TM_MARCH	2
+#define TM_APRIL	3
+#define TM_MAY		4
+#define TM_JUNE		5
+#define TM_JULY		6
+#define TM_AUGUST	7
+#define TM_SEPTEMBER	8
+#define TM_OCTOBER	9
+#define TM_NOVEMBER	10
+#define TM_DECEMBER	11
+
+#define TM_YEAR_BASE	1900
+
+#define EPOCH_YEAR	1970
+#define EPOCH_WDAY	TM_THURSDAY
+
+#endif