diff options
Diffstat (limited to 'examples/corelib/tools/contiguouscache')
4 files changed, 226 insertions, 0 deletions
diff --git a/examples/corelib/tools/contiguouscache/contiguouscache.pro b/examples/corelib/tools/contiguouscache/contiguouscache.pro new file mode 100644 index 0000000000..fb2267fc64 --- /dev/null +++ b/examples/corelib/tools/contiguouscache/contiguouscache.pro @@ -0,0 +1,9 @@ +QT += widgets + +HEADERS = randomlistmodel.h +SOURCES = randomlistmodel.cpp \ + main.cpp + +# install +target.path = $$[QT_INSTALL_EXAMPLES]/corelib/tools/contiguouscache +INSTALLS += target diff --git a/examples/corelib/tools/contiguouscache/main.cpp b/examples/corelib/tools/contiguouscache/main.cpp new file mode 100644 index 0000000000..62fa8dcf42 --- /dev/null +++ b/examples/corelib/tools/contiguouscache/main.cpp @@ -0,0 +1,55 @@ +/**************************************************************************** +** +** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** This file is part of the examples of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names +** of its contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** +** 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." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "randomlistmodel.h" +#include <QListView> +#include <QApplication> + +int main(int c, char **v) +{ + QApplication a(c, v); + + QListView view; + view.setUniformItemSizes(true); + view.setModel(new RandomListModel(&view)); + view.show(); + + return a.exec(); +} diff --git a/examples/corelib/tools/contiguouscache/randomlistmodel.cpp b/examples/corelib/tools/contiguouscache/randomlistmodel.cpp new file mode 100644 index 0000000000..cd1a301dc7 --- /dev/null +++ b/examples/corelib/tools/contiguouscache/randomlistmodel.cpp @@ -0,0 +1,96 @@ +/**************************************************************************** +** +** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** This file is part of the examples of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names +** of its contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** +** 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." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ +#include "randomlistmodel.h" +#include <stdlib.h> + +static const int bufferSize(500); +static const int lookAhead(100); +static const int halfLookAhead(lookAhead/2); + +RandomListModel::RandomListModel(QObject *parent) +: QAbstractListModel(parent), m_rows(bufferSize), m_count(10000) +{ +} + +RandomListModel::~RandomListModel() +{ +} + +int RandomListModel::rowCount(const QModelIndex &) const +{ + return m_count; +} + +//! [0] +QVariant RandomListModel::data(const QModelIndex &index, int role) const +{ + if (role != Qt::DisplayRole) + return QVariant(); + + int row = index.row(); + + if (row > m_rows.lastIndex()) { + if (row - m_rows.lastIndex() > lookAhead) + cacheRows(row-halfLookAhead, qMin(m_count, row+halfLookAhead)); + else while (row > m_rows.lastIndex()) + m_rows.append(fetchRow(m_rows.lastIndex()+1)); + } else if (row < m_rows.firstIndex()) { + if (m_rows.firstIndex() - row > lookAhead) + cacheRows(qMax(0, row-halfLookAhead), row+halfLookAhead); + else while (row < m_rows.firstIndex()) + m_rows.prepend(fetchRow(m_rows.firstIndex()-1)); + } + + return m_rows.at(row); +} + +void RandomListModel::cacheRows(int from, int to) const +{ + for (int i = from; i <= to; ++i) + m_rows.insert(i, fetchRow(i)); +} +//![0] + +//![1] +QString RandomListModel::fetchRow(int position) const +{ + return QString::number(rand() % ++position); +} +//![1] diff --git a/examples/corelib/tools/contiguouscache/randomlistmodel.h b/examples/corelib/tools/contiguouscache/randomlistmodel.h new file mode 100644 index 0000000000..3acafc23ff --- /dev/null +++ b/examples/corelib/tools/contiguouscache/randomlistmodel.h @@ -0,0 +1,66 @@ +/**************************************************************************** +** +** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** This file is part of the examples of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names +** of its contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** +** 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." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ +#ifndef RANDOMLISTMODEL_H +#define RANDOMLISTMODEL_H + +#include <QContiguousCache> +#include <QAbstractListModel> + +QT_FORWARD_DECLARE_CLASS(QTimer) + +class RandomListModel : public QAbstractListModel +{ + Q_OBJECT +public: + RandomListModel(QObject *parent = 0); + ~RandomListModel(); + + int rowCount(const QModelIndex & = QModelIndex()) const Q_DECL_OVERRIDE; + QVariant data(const QModelIndex &, int) const Q_DECL_OVERRIDE; + +private: + void cacheRows(int, int) const; + QString fetchRow(int) const; + + mutable QContiguousCache<QString> m_rows; + const int m_count; +}; + +#endif |