ssq.cpp

/* Copyright (C) 2017 MariaDB Corporaton

   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. */

#include <sstream>
#include <cstring>
#include <typeinfo>
#include "ssq.h"
#include "bytestream.h"
#include "objectreader.h"

using namespace mcsv1sdk;
#define DATATYPE double

struct ssq_data
{
    uint64_t scale;
    DATATYPE	sumsq;
    ssq_data() : scale(0) {}
};

#define OUT_TYPE int64_t
mcsv1_UDAF::ReturnCode ssq::init(mcsv1Context* context,
                                 ColumnDatum* colTypes)
{
    if (context->getParameterCount() < 1)
    {
        // The error message will be prepended with
        // "The storage engine for the table doesn't support "
        context->setErrorMessage("ssq() with 0 arguments");
        return mcsv1_UDAF::ERROR;
    }

    if (context->getParameterCount() > 1)
    {
        context->setErrorMessage("ssq() with more than 1 argument");
        return mcsv1_UDAF::ERROR;
    }

    if (!(isNumeric(colTypes[0].dataType)))
    {
        // The error message will be prepended with
        // "The storage engine for the table doesn't support "
        context->setErrorMessage("ssq() with non-numeric argument");
        return mcsv1_UDAF::ERROR;
    }

    context->setUserDataSize(sizeof(ssq_data));
    context->setResultType(CalpontSystemCatalog::DOUBLE);
    context->setColWidth(8);
    context->setScale(context->getScale() * 2);
    context->setPrecision(19);
    context->setRunFlag(mcsv1sdk::UDAF_IGNORE_NULLS);
    return mcsv1_UDAF::SUCCESS;

}

mcsv1_UDAF::ReturnCode ssq::reset(mcsv1Context* context)
{
    struct ssq_data* data = (struct ssq_data*)context->getUserData()->data;

    if (data)
    {
        data->scale = 0;
        data->sumsq = 0;
    }

    return mcsv1_UDAF::SUCCESS;
}

mcsv1_UDAF::ReturnCode ssq::nextValue(mcsv1Context* context, ColumnDatum* valsIn)
{
    static_any::any& valIn = valsIn[0].columnData;
    struct ssq_data* data = (struct ssq_data*)context->getUserData()->data;

    if (context->isParamNull(0) || valIn.empty())
    {
        return mcsv1_UDAF::SUCCESS;
    }

    DATATYPE val = convertAnyTo<double>(valIn);

    // For decimal types, we need to move the decimal point.
    uint32_t scale = valsIn[0].scale;

    if (val != 0 && scale > 0)
    {
        val /= pow(10.0, (double)scale);
    }

    data->sumsq += val * val;
    return mcsv1_UDAF::SUCCESS;
}

mcsv1_UDAF::ReturnCode ssq::subEvaluate(mcsv1Context* context, const UserData* userDataIn)
{
    // If we turn off UDAF_IGNORE_NULLS in init(), then NULLS may be sent here in cases of Joins.
    // When a NULL value is sent here, userDataIn will be NULL, so check for NULLS.
    if (context->isParamNull(0))
    {
        return mcsv1_UDAF::SUCCESS;
    }

    struct ssq_data* outData = (struct ssq_data*)context->getUserData()->data;

    struct ssq_data* inData = (struct ssq_data*)userDataIn->data;

    outData->sumsq += inData->sumsq;

    return mcsv1_UDAF::SUCCESS;
}

mcsv1_UDAF::ReturnCode ssq::evaluate(mcsv1Context* context, static_any::any& valOut)
{
    struct ssq_data* data = (struct ssq_data*)context->getUserData()->data;
    valOut = data->sumsq;
    return mcsv1_UDAF::SUCCESS;
}

mcsv1_UDAF::ReturnCode ssq::dropValue(mcsv1Context* context, ColumnDatum* valsDropped)
{
    static_any::any& valIn = valsDropped[0].columnData;
    struct ssq_data* data = (struct ssq_data*)context->getUserData()->data;

    if (valIn.empty())
    {
        return mcsv1_UDAF::SUCCESS; // Ought not happen when UDAF_IGNORE_NULLS is on.
    }

    DATATYPE val = convertAnyTo<double>(valIn);

    // For decimal types, we need to move the decimal point.
    uint32_t scale = valsDropped[0].scale;

    if (val != 0 && scale > 0)
    {
        val /= pow(10.0, (double)scale);
    }

    data->sumsq -= val * val;
    return mcsv1_UDAF::SUCCESS;
}