From 40518920665f96fec42f7dcd3ade0782ffd3838a Mon Sep 17 00:00:00 2001
From: tmj-fstate <dyvach@yahoo.com>
Date: Tue, 12 Mar 2019 18:49:06 +0100
Subject: [PATCH] maintenance: minor code tweaks

---
 DynObj.cpp         |  2 ++
 simulationtime.cpp | 16 +++++++++++-----
 simulationtime.h   |  3 +++
 sun.cpp            | 14 ++++----------
 4 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/DynObj.cpp b/DynObj.cpp
index 6ca495d3..5f17393f 100644
--- a/DynObj.cpp
+++ b/DynObj.cpp
@@ -2298,6 +2298,8 @@ void TDynamicObject::LoadExchange( int const Disembark, int const Embark, int co
         }
     }
 */
+    if( Platform == 0 ) { return; } // edge case, if there's no accessible platforms discard the request
+
     m_exchange.unload_count += Disembark;
     m_exchange.load_count += Embark;
     m_exchange.platforms = Platform;
diff --git a/simulationtime.cpp b/simulationtime.cpp
index b2574756..f1c5531e 100644
--- a/simulationtime.cpp
+++ b/simulationtime.cpp
@@ -121,7 +121,7 @@ scenario_time::update( double const Deltatime ) {
         }
         m_time.wHour -= 24;
     }
-    int leap { ( m_time.wYear % 4 == 0 ) && ( m_time.wYear % 100 != 0 ) || ( m_time.wYear % 400 == 0 ) };
+    int leap { is_leap( m_time.wYear ) };
     while( m_time.wDay > m_monthdaycounts[ leap ][ m_time.wMonth ] ) {
 
         m_time.wDay -= m_monthdaycounts[ leap ][ m_time.wMonth ];
@@ -130,7 +130,7 @@ scenario_time::update( double const Deltatime ) {
         if( m_time.wMonth > 12 ) {
 
             ++m_time.wYear;
-            leap = ( m_time.wYear % 4 == 0 ) && ( m_time.wYear % 100 != 0 ) || ( m_time.wYear % 400 == 0 );
+            leap = is_leap( m_time.wYear );
             m_time.wMonth -= 12;
         }
     }
@@ -144,7 +144,7 @@ scenario_time::year_day( int Day, const int Month, const int Year ) const {
         { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
     };
 
-    int const leap { ( Year % 4 == 0 ) && ( Year % 100 != 0 ) || ( Year % 400 == 0 ) };
+    int const leap { is_leap( Year ) };
     for( int i = 1; i < Month; ++i )
         Day += daytab[ leap ][ i ];
 
@@ -159,7 +159,7 @@ scenario_time::daymonth( WORD &Day, WORD &Month, WORD const Year, WORD const Yea
         { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
     };
 
-    int const leap { ( Year % 4 == 0 ) && ( Year % 100 != 0 ) || ( Year % 400 == 0 ) };
+    int const leap { is_leap( Year ) };
     WORD idx = 1;
     while( ( idx < 13 ) && ( Yearday >= daytab[ leap ][ idx ] ) ) {
 
@@ -222,7 +222,7 @@ scenario_time::day_of_month( int const Week, int const Weekday, int const Month,
             { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
             { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
         };
-        int const leap { ( Year % 4 == 0 ) && ( Year % 100 != 0 ) || ( Year % 400 == 0 ) };
+        int const leap { is_leap( Year ) };
 
         while( day > daytab[ leap ][ Month ] ) {
             day -= 7;
@@ -248,4 +248,10 @@ scenario_time::convert_transition_time( SYSTEMTIME &Time ) const {
     Time.wDay = day_of_month( Time.wDay, Time.wDayOfWeek + 1, Time.wMonth, m_time.wYear );
 }
 
+bool
+scenario_time::is_leap( int const Year ) const {
+
+    return ( ( Year % 4 == 0 ) && ( ( Year % 100 != 0 ) || ( Year % 400 == 0 ) ) );
+
+}
 //---------------------------------------------------------------------------
diff --git a/simulationtime.h b/simulationtime.h
index 45f4352e..58a8b317 100644
--- a/simulationtime.h
+++ b/simulationtime.h
@@ -61,6 +61,9 @@ private:
     // returns number of days between specified days of week
     int
         weekdays( int const First, int const Second ) const;
+    // returns true if specified year is a leap year, false otherwise
+    bool
+        is_leap( int const Year ) const;
 
     SYSTEMTIME m_time;
     double m_milliseconds{ 0.0 };
diff --git a/sun.cpp b/sun.cpp
index 0acf3864..b2cce6a6 100644
--- a/sun.cpp
+++ b/sun.cpp
@@ -185,17 +185,11 @@ void cSun::move() {
 
     m_body.rascen = clamp_circular( radtodeg * std::atan2( top, bottom ) );
 
-    // Greenwich mean sidereal time
-    m_observer.gmst = 6.697375 + 0.0657098242 * daynumber + m_observer.utime;
+    // Greenwich mean sidereal time (hours)
+    m_observer.gmst = clamp_circular( 6.697375 + 0.0657098242 * daynumber + m_observer.utime, 24.0 );
 
-    m_observer.gmst -= 24.0 * (int)( m_observer.gmst / 24.0 );
-    if( m_observer.gmst < 0.0 ) m_observer.gmst += 24.0;
-
-    // local mean sidereal time
-    m_observer.lmst = m_observer.gmst * 15.0 + m_observer.longitude;
-
-    m_observer.lmst -= 360.0 * (int)( m_observer.lmst / 360.0 );
-    if( m_observer.lmst < 0.0 ) m_observer.lmst += 360.0;
+    // local mean sidereal time (deg)
+    m_observer.lmst = clamp_circular( m_observer.gmst * 15.0 + m_observer.longitude );
 
     // hour angle
     m_body.hrang = m_observer.lmst - m_body.rascen;