aggregatefunctavgexpression.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 "aggregatefunctavgexpression.h"

AggregateFunctAvgExpression::AggregateFunctAvgExpression(VarExpression * _var):
AggregateFunctExpression(et_aggregatefunctavg, _var) {
}

AggregateFunctAvgExpression::AggregateFunctAvgExpression(VarStepExpression * _varstep):
AggregateFunctExpression(et_aggregatefunctavg, _varstep) {
}

AggregateFunctAvgExpression::~AggregateFunctAvgExpression() {
}

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

    switch (modus) {

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

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

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

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

long double AggregateFunctAvgExpression::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 avg_ret = 0;
    long double count = 0;
    long double result = 0;
    const char *pcd = NULL;

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

        empty_sequence = false;
        count++;

        pcd = cur->getPCDataRepresentation();
        result =
            MiscFunctions::getSummationFrom(result,
                                            MiscFunctions::
                                            getNumericFromString(pcd));

        free((char *) pcd);

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

    if (!empty_sequence) {
        avg_ret =
            MiscFunctions::getRoundFrom(MiscFunctions::
                                        getDivisionFrom(result, count));
    }

    return avg_ret;
}

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