From 8c41081a5c0c272d8c2629f5308b6ab507eb2330 Mon Sep 17 00:00:00 2001
From: curt <curt>
Date: Sun, 10 Feb 2002 03:16:03 +0000
Subject: [PATCH] This code had been written to assume current clock time. 
 Added options to allow specifying an alternate clock time.

---
 simgear/timing/sg_time.cxx | 19 ++++++++++++++-----
 simgear/timing/sg_time.hxx | 14 ++++++++++----
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/simgear/timing/sg_time.cxx b/simgear/timing/sg_time.cxx
index f46d5da0..ba977646 100644
--- a/simgear/timing/sg_time.cxx
+++ b/simgear/timing/sg_time.cxx
@@ -70,13 +70,18 @@ static const double J2000   = 2451545.0 - MJD0;
 static const double SIDRATE = 0.9972695677;
 
 
-SGTime::SGTime( double lon, double lat, const string& root )
+SGTime::SGTime( double lon, double lat, const string& root, time_t init_time )
 {
     SG_LOG( SG_EVENT, SG_INFO, "Initializing Time" );
 
     gst_diff = -9999.0;
 
-    cur_time = time(NULL); 
+    if ( init_time ) {
+	cur_time = init_time;
+    } else {
+	cur_time = time(NULL); 
+    }
+
     cout << "Current greenwich mean time = " << asctime(gmtime(&cur_time))
          << endl;
     cout << "Current local time          = " 
@@ -190,7 +195,7 @@ static double sidereal_course( time_t cur_time, struct tm *gmt, double lng )
 
 
 // Update the time related variables
-void SGTime::update( double lon, double lat, long int warp ) {
+void SGTime::update( double lon, double lat, time_t ct, long int warp ) {
     double gst_precise, gst_course;
 
 #if defined(_MSC_VER) || defined(__MINGW32__)
@@ -201,7 +206,11 @@ void SGTime::update( double lon, double lat, long int warp ) {
 
     // get current Unix calendar time (in seconds)
     // warp += warp_delta;
-    cur_time = time(NULL) + warp;
+    if ( ct ) {
+	cur_time = ct + warp;
+    } else {
+	cur_time = time(NULL) + warp;
+    }
     SG_LOG( SG_EVENT, SG_DEBUG, 
 	    "  Current Unix calendar time = " << cur_time 
 	    << "  warp = " << warp );
@@ -359,7 +368,7 @@ double sgTimeCalcMJD(int mn, double dy, int yr) {
 
 // return the current modified Julian date (number of days elapsed
 // since 1900 jan 0.5), mjd.
-double sgTimeCurrentMJD( long int warp ) {
+double sgTimeCurrentMJD( time_t ct, long int warp ) {
 
 #if defined(_MSC_VER) || defined(__MINGW32__)
     struct tm m_gmt;    // copy of system gmtime(&time_t) structure
diff --git a/simgear/timing/sg_time.hxx b/simgear/timing/sg_time.hxx
index e8155c1d..800394de 100644
--- a/simgear/timing/sg_time.hxx
+++ b/simgear/timing/sg_time.hxx
@@ -122,8 +122,10 @@ public:
      * 0).
      * @param lon current longitude
      * @param lat current latitude
-     * @param root root path point to data file location (timezone, etc.)  */
-    SGTime( double lon, double lat, const string& root );
+     * @param root root path point to data file location (timezone, etc.)
+     * @param init_time provide an initialization time, 0 means use
+              current clock time */
+    SGTime( double lon, double lat, const string& root, time_t init_time = 0 );
 
     /**
      * Create an instance given a data file path.
@@ -143,9 +145,11 @@ public:
      * every frame.
      * @param lon current longitude
      * @param lat current latitude
+     * @param ct specify a unix time, otherwise specify 0 to use current
+              clock time
      * @param warp an optional time offset specified in seconds.  This
      *        allows us to advance or rewind "time" if we choose to.  */
-    void update( double lon, double lat, long int warp = 0 );
+    void update( double lon, double lat, time_t ct = 0, long int warp = 0 );
 
     /**
      * Given lon/lat, update timezone information and local_offset
@@ -235,10 +239,12 @@ double sgTimeCalcMJD(int mn, double dy, int yr);
  * \relates SGTime
  * Given an optional offset from current time calculate the current
  * modified julian date.
+ * @param ct specify a unix time, otherwise specify 0 to use current
+          clock time
  * @param warp number of seconds to offset from current time (0 if no offset)
  * @return current modified Julian date (number of days elapsed
  * since 1900 jan 0.5), mjd. */
-double sgTimeCurrentMJD( long int warp );
+double sgTimeCurrentMJD( time_t ct = 0, long int warp = 0 );
 
 /**
  * \relates SGTime
-- 
2.39.2