/* 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::TEXT:
        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: