gameoflifemodel.cpp Example File

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 #include "gameoflifemodel.h"
 #include <QFile>
 #include <QTextStream>
 #include <QRect>

 GameOfLifeModel::GameOfLifeModel(QObject *parent)
     : QAbstractTableModel(parent)
 {
     clear();
 }

 int GameOfLifeModel::rowCount(const QModelIndex &parent) const
 {
     if (parent.isValid())
         return 0;

     return height;
 }

 int GameOfLifeModel::columnCount(const QModelIndex &parent) const
 {
     if (parent.isValid())
         return 0;

     return width;
 }

 QVariant GameOfLifeModel::data(const QModelIndex &index, int role) const
 {
     if (!index.isValid() || role != CellRole)
         return QVariant();

     return QVariant(m_currentState[cellIndex({index.column(), index.row()})]);
 }

 bool GameOfLifeModel::setData(const QModelIndex &index, const QVariant &value, int role)
 {
     if (role != CellRole || data(index, role) == value)
         return false;

     m_currentState[cellIndex({index.column(), index.row()})] = value.toBool();
     emit dataChanged(index, index, {role});

     return true;
 }

 Qt::ItemFlags GameOfLifeModel::flags(const QModelIndex &index) const
 {
     if (!index.isValid())
         return Qt::NoItemFlags;

     return Qt::ItemIsEditable;
 }

 void GameOfLifeModel::nextStep()
 {
     StateContainer newValues;

     for (std::size_t i = 0; i < size; ++i) {
         bool currentState = m_currentState[i];

         int cellNeighborsCount = this->cellNeighborsCount(cellCoordinatesFromIndex(static_cast<int>(i)));

         newValues[i] = currentState == true
                 ? cellNeighborsCount == 2 || cellNeighborsCount == 3
                 : cellNeighborsCount == 3;
     }

     m_currentState = std::move(newValues);

     emit dataChanged(index(0, 0), index(height - 1, width - 1), {CellRole});
 }

 bool GameOfLifeModel::loadFile(const QString &fileName)
 {
     QFile file(fileName);
     if (!file.open(QIODevice::ReadOnly))
         return false;

     QTextStream in(&file);
     loadPattern(in.readAll());

     return true;
 }

 void GameOfLifeModel::loadPattern(const QString &plainText)
 {
     clear();

     QStringList rows = plainText.split("\n");
     QSize patternSize(0, rows.count());
     for (QString row : rows) {
         if (row.size() > patternSize.width())
             patternSize.setWidth(row.size());
     }

     QPoint patternLocation((width - patternSize.width()) / 2, (height - patternSize.height()) / 2);

     for (int y = 0; y < patternSize.height(); ++y) {
         const QString line = rows[y];

         for (int x = 0; x < line.length(); ++x) {
             QPoint cellPosition(x + patternLocation.x(), y + patternLocation.y());
             m_currentState[cellIndex(cellPosition)] = line[x] == 'O';
         }
     }

     emit dataChanged(index(0, 0), index(height - 1, width - 1), {CellRole});
 }

 void GameOfLifeModel::clear()
 {
     m_currentState.fill(false);
     emit dataChanged(index(0, 0), index(height - 1, width - 1), {CellRole});
 }

 int GameOfLifeModel::cellNeighborsCount(const QPoint &cellCoordinates) const
 {
     int count = 0;

     for (int x = -1; x <= 1; ++x) {
         for (int y = -1; y <= 1; ++y) {
             if (x == 0 && y == 0)
                 continue;

             const QPoint neighborPosition { cellCoordinates.x() + x, cellCoordinates.y() + y };
             if (!areCellCoordinatesValid(neighborPosition))
                 continue;

             if (m_currentState[cellIndex(neighborPosition)])
                 ++count;

             if (count > 3)
                 return count;
         }
     }

     return count;
 }

 bool GameOfLifeModel::areCellCoordinatesValid(const QPoint &coordinates)
 {
     return QRect(0, 0, width, height).contains(coordinates);
 }

 QPoint GameOfLifeModel::cellCoordinatesFromIndex(int cellIndex)
 {
     return {cellIndex % width, cellIndex / width};
 }

 std::size_t GameOfLifeModel::cellIndex(const QPoint &coordinates)
 {
     return std::size_t(coordinates.y() * width + coordinates.x());
 }