From b74de43ce0d7cc6c8febc245b3c9163e77f15d88 Mon Sep 17 00:00:00 2001
From: Klaus Basan <klaus.basan@klausbasan.de>
Date: Tue, 10 Jul 2018 17:15:25 +0200
Subject: [PATCH] Ref T268, compare for CAltitude

---
 src/blackmisc/aviation/altitude.cpp | 14 ++++++++++++--
 src/blackmisc/aviation/altitude.h   |  9 ++++++---
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/blackmisc/aviation/altitude.cpp b/src/blackmisc/aviation/altitude.cpp
index dadccf21d..2d2083c73 100644
--- a/src/blackmisc/aviation/altitude.cpp
+++ b/src/blackmisc/aviation/altitude.cpp
@@ -8,11 +8,12 @@
  */
 
 #include "blackmisc/aviation/altitude.h"
-#include "blackmisc/iconlist.h"
-#include "blackmisc/icons.h"
 #include "blackmisc/pq/measurementunit.h"
 #include "blackmisc/pq/constants.h"
 #include "blackmisc/pq/pqstring.h"
+#include "blackmisc/comparefunctions.h"
+#include "blackmisc/iconlist.h"
+#include "blackmisc/icons.h"
 
 #include <Qt>
 #include <QtGlobal>
@@ -337,6 +338,15 @@ namespace BlackMisc
             return BlackMisc::CIcon::iconByIndex(CIcons::GeoPosition);
         }
 
+        int CAltitude::compare(const CAltitude &otherAltitude) const
+        {
+            if (this->getReferenceDatum() != otherAltitude.getReferenceDatum())
+            {
+                return Compare::compare(static_cast<int>(this->getReferenceDatum()), static_cast<int>(otherAltitude.getReferenceDatum()));
+            }
+            return CLength::compare(*this, otherAltitude);
+        }
+
         const CAltitude &CAltitude::null()
         {
             static const CAltitude null(0, CAltitude::MeanSeaLevel, CLengthUnit::nullUnit());
diff --git a/src/blackmisc/aviation/altitude.h b/src/blackmisc/aviation/altitude.h
index eff9db2c0..74ef7edf5 100644
--- a/src/blackmisc/aviation/altitude.h
+++ b/src/blackmisc/aviation/altitude.h
@@ -67,9 +67,9 @@ namespace BlackMisc
              */
             enum ReferenceDatum
             {
-                MeanSeaLevel = 0,   //!< MSL
-                AboveGround,        //!< AGL
-                FlightLevel         //!< Flight level
+                MeanSeaLevel = 0, //!< MSL
+                AboveGround,      //!< AGL
+                FlightLevel       //!< Flight level
             };
 
             //! Altitude type
@@ -185,6 +185,9 @@ namespace BlackMisc
             //! \copydoc BlackMisc::Mixin::Icon::toIcon
             BlackMisc::CIcon toIcon() const;
 
+            //! \copydoc PhysicalQuantities::CPhysicalQuantity::compare
+            int compare(const CAltitude &otherAltitude) const;
+
             //! Null altitude (MSL)
             static const CAltitude &null();