mariadb-columnstore-engine/utils/funcexp/func_substring_index.cpp

/* 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_substring_index.cpp 2477 2011-04-01 16:07:35Z rdempsey $
*
*
****************************************************************************/

#include <string>
using namespace std;

#include "functor_str.h"
#include "functioncolumn.h"
using namespace execplan;

#include "rowgroup.h"
using namespace rowgroup;

#include "joblisttypes.h"
using namespace joblist;

#define STRCOLL_ENH__

namespace funcexp
{

CalpontSystemCatalog::ColType Func_substring_index::operationType(FunctionParm& fp, CalpontSystemCatalog::ColType& resultType)
{
    // operation type is not used by this functor
    return fp[0]->data()->resultType();
}


std::string Func_substring_index::getStrVal(rowgroup::Row& row,
        FunctionParm& fp,
        bool& isNull,
        execplan::CalpontSystemCatalog::ColType&)
{
    const string& str = fp[0]->data()->getStrVal(row, isNull);

    if (isNull)
        return "";

    const string& delim = fp[1]->data()->getStrVal(row, isNull);

    if (isNull)
        return "";

    int64_t count = fp[2]->data()->getIntVal(row, isNull);

    if (isNull)
        return "";

    if ( count == 0 )
        return "";

    size_t end = strlen(str.c_str());

    if ( count > (int64_t) end )
        return str;

    string value = str;

    if ( count > 0 )
    {
        int pointer = 0;

        for ( int i = 0 ; i < count ; i ++ )
        {
            string::size_type pos = str.find(delim, pointer);

            if (pos != string::npos)
                pointer = pos + 1;

            end = pos;
        }

        value = str.substr(0, end);
    }
    else
    {
        count = count * -1;
        size_t end = strlen(str.c_str());
        int pointer = end;
        int start = 0;

        for ( int i = 0 ; i < count ; i ++ )
        {
            string::size_type pos = str.rfind(delim, pointer);

            if (pos != string::npos)
            {
                if ( count > (int64_t) end )
                    return "";

                pointer = pos - 1;
                start = pos + 1;
            }
            else
                start = 0;
        }

        value = str.substr(start, end);
    }

    return value;
}


} // namespace funcexp
// vim:ts=4 sw=4: