ENH: functionObjects improvements.

- readFields works seamlessly on-the-fly and as postprocessor
- new surfaceInterpolateFields to create interpolated field
- writeRegisteredObject only check upon writing, not upon startup
- add min,max to faceSource

src/postProcessing/functionObjects/field/fieldValues/faceSource/faceSource.C

@@ -49,13 +49,14 @@ namespace Foam
         fieldValues::faceSource::sourceTypeNames_;
 
     template<>
-    const char* NamedEnum<fieldValues::faceSource::operationType, 5>::
+    const char* NamedEnum<fieldValues::faceSource::operationType, 7>::
         names[] =
         {
-            "none", "sum", "areaAverage", "areaIntegrate", "weightedAverage"
+            "none", "sum", "areaAverage",
+            "areaIntegrate", "weightedAverage", "min", "max"
         };
 
-    const NamedEnum<fieldValues::faceSource::operationType, 5>
+    const NamedEnum<fieldValues::faceSource::operationType, 7>
         fieldValues::faceSource::operationTypeNames_;
 
 }

src/postProcessing/functionObjects/field/fieldValues/faceSource/faceSource.H

@@ -106,11 +106,13 @@ public:
             opSum,
             opAreaAverage,
             opAreaIntegrate,
-            opWeightedAverage
+            opWeightedAverage,
+            opMin,
+            opMax
         };
 
         //- Operation type names
-        static const NamedEnum<operationType, 5> operationTypeNames_;
+        static const NamedEnum<operationType, 7> operationTypeNames_;
 
 
 private:

src/postProcessing/functionObjects/field/fieldValues/faceSource/faceSourceTemplates.C

@@ -103,6 +103,16 @@ Type Foam::fieldValues::faceSource::processValues
             result = sum(values*weightField)/sum(weightField);
             break;
         }
+        case opMin:
+        {
+            result = min(values);
+            break;
+        }
+        case opMax:
+        {
+            result = max(values);
+            break;
+        }
         default:
         {
             // Do nothing