qgsstringstatisticalsummary.h

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/***************************************************************************
  qgsstringstatisticalsummary.h
  -----------------------------
  Date                 : May 2016
  Copyright            : (C) 2016 by Nyall Dawson
  Email                : nyall dot dawson at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   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; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef QGSSTRINGSTATISTICALSUMMARY_H
#define QGSSTRINGSTATISTICALSUMMARY_H

#include <QSet>
#include <QVariantList>

#include "qgis_core.h"

/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in test_qgsstringstatisticalsummary.py.
 * See details in QEP #17
 ****************************************************************************/

class CORE_EXPORT QgsStringStatisticalSummary
{
  public:

    enum Statistic
    {
      Count = 1,  
      CountDistinct = 2,  
      CountMissing = 4,  
      Min = 8, 
      Max = 16, 
      MinimumLength = 32, 
      MaximumLength = 64, 
      MeanLength = 128, 
      All = Count | CountDistinct | CountMissing | Min | Max | MinimumLength | MaximumLength | MeanLength, 
    };
    Q_DECLARE_FLAGS( Statistics, Statistic )

    
    QgsStringStatisticalSummary( QgsStringStatisticalSummary::Statistics stats = QgsStringStatisticalSummary::All );

    Statistics statistics() const { return mStatistics; }

    void setStatistics( QgsStringStatisticalSummary::Statistics stats ) { mStatistics = stats; }

    void reset();

    void calculate( const QStringList &values );

    void calculateFromVariants( const QVariantList &values );

    void addString( const QString &string );

    void addValue( const QVariant &value );

    void finalize();

    QVariant statistic( QgsStringStatisticalSummary::Statistic stat ) const;

    int count() const { return mCount; }

    int countDistinct() const { return mValues.count(); }

    QSet< QString > distinctValues() const { return mValues; }

    int countMissing() const { return mCountMissing; }

    QString min() const { return mMin; }

    QString max() const { return mMax; }

    int minLength() const { return mMinLength; }

    int maxLength() const { return mMaxLength; }

    double meanLength() const { return mMeanLength; }

    static QString displayName( QgsStringStatisticalSummary::Statistic statistic );

  private:

    Statistics mStatistics;

    int mCount;
    QSet< QString > mValues;
    int mCountMissing;
    QString mMin;
    QString mMax;
    int mMinLength;
    int mMaxLength;
    long mSumLengths;
    double mMeanLength;

    void testString( const QString &string );
};

Q_DECLARE_OPERATORS_FOR_FLAGS( QgsStringStatisticalSummary::Statistics )

#endif // QGSSTRINGSTATISTICALSUMMARY_H