Check for half open interval in MathUtils::InRange

src/server.cpp

@@ -1382,7 +1382,8 @@ void CServer::SendChatTextToAllConChannels ( const int iSendingChanID, const QSt
 
 bool CServer::SendChatTextToConChannel ( const int iCurChanID, const QString& strChatText )
 {
-    if ( !MathUtils::InRange<int> ( iCurChanID, 0, iMaxNumChannels - 1 ) || !vecChannels[iCurChanID].IsConnected() )
+    // Check if iCurChanID is in range [0, iMaxNumChannels)
+    if ( !MathUtils::InRange<int> ( iCurChanID, 0, iMaxNumChannels ) || !vecChannels[iCurChanID].IsConnected() )
     {
         return false;
     }

src/util.h

@@ -1243,11 +1243,11 @@ class MathUtils
         }
     }
 
-    // return true if a value is within the lower and upper bounds (inclusively), otherwise false
+    // Returns true if value is in [lower, upper) (inclusive lower, exclusive upper).
     template<typename T>
-    static inline bool InRange ( T value, T lower, T upper )
+    static inline bool InRange ( T value, T lower /* inclusive */, T upper /* exclusive */ )
     {
-        return !( value < lower || value > upper );
+        return value >= lower && value < upper;
     }
 };