Add set functions examples

set_functions/set_functions-examples.cpp

+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include <iterator>
+
+#include <QTextDocument>
+#include <QTextBlock>
+
+#include <vector>
+
+namespace Examples {
+
+class TextBlockIterator {
+public:
+    using iterator_category = std::forward_iterator_tag;
+    using value_type = QTextBlock;
+    using difference_type = int;
+    using pointer = QTextBlock*;
+    using reference = QTextBlock&;
+
+    TextBlockIterator(const QTextDocument *document, int blockNumber)
+        : m_document(document)
+        , m_blockNumber(blockNumber)
+    {}
+
+    TextBlockIterator(const QTextBlock &textBlock)
+        : m_document(textBlock.document())
+        , m_blockNumber(textBlock.blockNumber())
+    {}
+
+    QTextBlock operator*() { return m_document->findBlockByNumber(m_blockNumber); }
+
+    TextBlockIterator operator++()
+    {
+        ++m_blockNumber;
+        return *this;
+    }
+
+    friend bool operator==(TextBlockIterator first, TextBlockIterator second)
+    {
+        return first.m_document == second.m_document && first.m_blockNumber == second.m_blockNumber;
+    }
+
+    friend bool operator!=(TextBlockIterator first, TextBlockIterator second)
+    {
+        return !(first == second);
+    }
+
+private:
+    const QTextDocument *m_document;
+    int m_blockNumber;
+};
+
+class Range
+{
+public:
+    int start = 0;
+    int end = 0;
+
+    friend bool operator<(Range first, Range second)
+    {
+        return std::tie(first.start, first.end) < std::tie(second.start, second.end);
+    }
+};
+
+using Ranges = std::vector<Range>;
+
+void function()
+{
+    QTextDocument document;
+    Ranges ranges;
+
+    std::sort(ranges.begin(), ranges.end());
+
+    auto begin = TextBlockIterator(document.begin());
+    auto end = TextBlockIterator(document.end());
+
+    std::vector<QTextBlock> textBlockInsideRanges;
+    std::vector<QTextBlock> textBlockOutsideRanges;
+
+    class Compare
+    {
+    public:
+        bool operator()(QTextBlock first, Range second)
+        {
+            return first.blockNumber() < second.start;
+        }
+
+        bool operator()(Range first, QTextBlock second)
+        {
+            return first.end < second.blockNumber();
+        }
+    };
+
+    std::set_intersection(begin,
+                          end,
+                          ranges.begin(),
+                          ranges.end(),
+                          std::back_inserter(textBlockInsideRanges),
+                          Compare{});
+
+    std::set_difference(begin,
+                        end,
+                        ranges.begin(),
+                        ranges.end(),
+                        std::back_inserter(textBlockOutsideRanges),
+                        Compare{});
+}
+}

set_functions/set_functions.pro

@@ -3,5 +3,6 @@ include(../shared/benchmark.pri)
 TARGET = set_functions
 
 SOURCES += \
-    set_functions-benchmark.cpp
+    set_functions-benchmark.cpp \
+    set_functions-examples.cpp