Time: Adjust the precision of the time name if necessary every time-step

This change guarantees that the precision of the time written to the log file,
all functionObject logs and the time directories is sufficient to be unique
irrespective of the change in the time-step or start time of the run.  If the
calculated time precision exceeds what can be represented by the floating point
resolution, e.g. by the time-step dropping to a VERY low value, the run stops.

src/OpenFOAM/db/Time/Time.C

@@ -1242,8 +1242,7 @@ Foam::Time& Foam::Time::operator++()
             writeOnce_ = false;
         }
 
-        // Adjust the precision of the time directory name if necessary
-        if (writeTime_)
+        // Adjust the precision of the time name if necessary
         {
             // User-time equivalent of deltaT
             const scalar userDeltaT =
@@ -1288,13 +1287,13 @@ Foam::Time& Foam::Time::operator++()
                     if (curPrecision_ == maxPrecision_)
                     {
                         // Reached maxPrecision limit
-                        WarningInFunction
+                        FatalErrorInFunction
                             << "Current time name " << dimensionedScalar::name()
                             << nl
                             << "    The maximum time precision has been reached"
                                " which might result in overwriting previous"
                                " results."
-                            << endl;
+                            << exit(FatalError);
                     }
 
                     // Check if round-off error caused time-reversal
@@ -1308,14 +1307,14 @@ Foam::Time& Foam::Time::operator++()
                         )
                     )
                     {
-                        WarningInFunction
+                        FatalErrorInFunction
                             << "Current time name " << dimensionedScalar::name()
                             << " is set to an instance prior to the "
                                "previous one "
                             << oldTimeName << nl
                             << "    This might result in temporal "
                                "discontinuities."
-                            << endl;
+                            << exit(FatalError);
                     }
                 }
             }