aggregatefunctstddevsampexpression.cpp

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/*
 | Author: Michael Schmidt;
 |         Gunnar Jehl 
 |
 | ************************* SOFTWARE LICENSE AGREEMENT ***********************
 | This source code is published under the BSD License.
 |
 | See file 'LICENSE.txt' that comes with this distribution or
 | http://dbis.informatik.uni-freiburg.de/index.php?project=GCX/license.php
 | for the full license agreement.
 |
 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 | POSSIBILITY OF SUCH DAMAGE.
 | ****************************************************************************
*/

#include "aggregatefunctstddevsampexpression.h"

AggregateFunctStdDevSampExpression::AggregateFunctStdDevSampExpression(VarExpression * _var):
AggregateFunctExpression(et_aggregatefunctstddevsamp, _var) {
}

AggregateFunctStdDevSampExpression::AggregateFunctStdDevSampExpression(VarStepExpression * _varstep):
AggregateFunctExpression(et_aggregatefunctstddevsamp, _varstep) {
}

AggregateFunctStdDevSampExpression::~AggregateFunctStdDevSampExpression() {
}

void AggregateFunctStdDevSampExpression::eval(OutputStream & eos,
                                              Environment * env,
                                              unsigned modus) {

    switch (modus) {

        case EVAL_QUERY:
          {
              bool empty_sequence = true;
              long double stddevsamp_val =
                  calculateValue(eos, env, modus, empty_sequence);
              if (!empty_sequence) {
                  const char *stddevsamp_str =
                      MiscFunctions::getStringFromNumerical(stddevsamp_val);
                  eos << stddevsamp_str;
                  delete[]stddevsamp_str;
              } else {
                  eos << OUTPUT_STDDEVSAMP_ON_EMPTY_SEQUENCE;
              }
              break;
          }

        case EVAL_QUERY_SILENT:
          {
              bool empty_sequence = true;
              long double stddevsamp_val =
                  calculateValue(eos, env, modus, empty_sequence);
              if (!empty_sequence) {
                  cur_val.setNumVal(stddevsamp_val);
              } else {
                  const char *stddevsamp_empty_val =
                      new char[strlen(OUTPUT_STDDEVSAMP_ON_EMPTY_SEQUENCE) + 1];
                  strcpy((char *) stddevsamp_empty_val,
                         OUTPUT_STDDEVSAMP_ON_EMPTY_SEQUENCE);
                  cur_val.setStrVal(stddevsamp_empty_val);
              }
              break;
          }

        case EVAL_SIGNOFF:
            forexp->eval(eos, env, EVAL_SIGNOFF);
            break;

        default:
            throw
                RuntimeException
                ("AggregateFunctStdDevSampExpression: Illegal Evaluation Mode",
                 eid_runtime_illegalmode);
            break;
    }
}

long double AggregateFunctStdDevSampExpression::
calculateValue(OutputStream & eos, Environment * env, unsigned modus,
               bool & empty_sequence) {

    var ? bit->init(env->getNodeBinding(var->getId())) :
        bit->init(env->getNodeBinding(varstep->getId()));

    long double stddevsamp_ret = 0;
    long double result = 0;
    vector < long double >*pcds = new vector < long double >;
    const char *pcd = NULL;

    while (BufferNode * cur =
           bit->getNext(READ_UP_TO_CLOSE_CONTEXT, LOCK_CONTEXT_ALWAYS_CLEAR)) {

        empty_sequence = false;

        pcd = cur->getPCDataRepresentation();
        long double tmp = MiscFunctions::getNumericFromString(pcd);

        result = MiscFunctions::getSummationFrom(result, tmp);
        pcds->push_back(tmp);

        free((char *) pcd);

        forexp->evalSignOffForBinding(eos, env, cur);
    }
    bit->clear();

    if (!empty_sequence) {
        long double avg_val =
            MiscFunctions::getDivisionFrom(result, pcds->size());
        result = 0;
        for (unsigned i = 0; i < pcds->size(); i++) {
            result +=
                MiscFunctions::getPowerFrom(MiscFunctions::
                                            getSubtractionFrom((*pcds)[i],
                                                               avg_val), 2);
        }
        result =
            MiscFunctions::getRadicalFrom(MiscFunctions::
                                          getDivisionFrom(result,
                                                          pcds->size() - 1), 2);
        stddevsamp_ret = MiscFunctions::getRoundFrom(result);
    }
    delete pcds;

    return stddevsamp_ret;
}

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