the begginning

utils/funcexp/func_isnull.cpp

@@ -0,0 +1,85 @@
+/* Copyright (C) 2014 InfiniDB, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; version 2 of
+   the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA. */
+
+/****************************************************************************
+* $Id: func_isnull.cpp 3648 2013-03-19 21:33:52Z dhall $
+*
+*
+****************************************************************************/
+
+#include <cstdlib>
+#include <string>
+#include <sstream>
+using namespace std;
+
+#include "functor_bool.h"
+#include "functioncolumn.h"
+#include "rowgroup.h"
+using namespace execplan;
+using namespace rowgroup;
+
+#include "dataconvert.h"
+
+namespace funcexp
+{
+
+CalpontSystemCatalog::ColType Func_isnull::operationType (FunctionParm& fp, 
+                       CalpontSystemCatalog::ColType& resultType)
+{
+	// operation type of idb_isnull should be the same as the argument type
+	assert (fp.size() == 1);
+	return fp[0]->data()->resultType();
+}
+
+/**
+ * getBoolVal API definition
+ *
+ * This would be the most commonly called API for idb_isnull function
+ */
+bool Func_isnull::getBoolVal(Row& row,
+							FunctionParm& parm,
+							bool& isNull,
+							CalpontSystemCatalog::ColType& op_ct)
+{
+	switch (op_ct.colDataType)
+	{
+		// For the purpose of this function, one does not need to get the value of
+		// the argument. One only need to know if the argument is NULL. The passed
+		// in parameter isNull will be set if the parameter is evaluated NULL. 
+		// Please note that before this function returns, isNull should be set to 
+		// false, otherwise the result of the function would be considered NULL,
+		// which is not possible for idb_isnull().
+        case CalpontSystemCatalog::DECIMAL:
+		case CalpontSystemCatalog::UDECIMAL:
+			parm[0]->data()->getDecimalVal(row, isNull);
+			break;
+		case CalpontSystemCatalog::CHAR:
+		case CalpontSystemCatalog::VARCHAR:
+			parm[0]->data()->getStrVal(row, isNull);
+			break;
+		default:
+			parm[0]->data()->getIntVal(row, isNull);
+	}
+	bool ret = isNull;
+	// It's important to reset isNull indicator.
+	isNull = false;
+	return (fIsNotNull? !ret : ret);
+}
+
+
+} // namespace funcexp
+// vim:ts=4 sw=4: