Rename QRangeCollection to QPageRanges, make it a proper value type

The type is specific about printing, so give it a name in line with
QPageLayout and QPageSize.

As per API review comment, it's not clear why this type should not be a
regular, copyable and movable value type. It stores a list of intervals.
Give it value-type semantics, as an implicitly shared class.

Convert the parse method into a static factory function.

Add a Range type and use it instead of the semantic-free QPair.
Move QPrinter getter into QPagedPainteDevice, make it return a copy
rather than a pointer, and add a setter.

Extend test case to cover all members and more merge cases. Fix bugs
found that way.

Fixes: QTBUG-88113
Change-Id: If17ea4d410d49f16b097e88b7979db5d72add820
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

8 files changed, 459 insertions, 324 deletions

diff --git a/src/gui/painting/painting.pri b/src/gui/painting/painting.pri
index ccd67e12b3..1262b1775c 100644
--- a/src/gui/painting/painting.pri
+++ b/src/gui/painting/painting.pri
@@ -31,6 +31,8 @@ HEADERS += \
         painting/qpagedpaintdevice.h \
         painting/qpagedpaintdevice_p.h \
         painting/qpagelayout.h \
+        painting/qpageranges.h \
+        painting/qpageranges_p.h \
         painting/qpagesize.h \
         painting/qpaintdevice.h \
         painting/qpaintengine.h \
@@ -49,8 +51,6 @@ HEADERS += \
         painting/qpen.h \
         painting/qpixellayout_p.h \
         painting/qpolygon.h \
-        painting/qrangecollection.h \
-        painting/qrangecollection_p.h \
         painting/qrasterdefs_p.h \
         painting/qrasterizer_p.h \
         painting/qrbtree_p.h \
@@ -88,6 +88,7 @@ SOURCES += \
         painting/qoutlinemapper.cpp \
         painting/qpagedpaintdevice.cpp \
         painting/qpagelayout.cpp \
+        painting/qpageranges.cpp \
         painting/qpagesize.cpp \
         painting/qpaintdevice.cpp \
         painting/qpaintengine.cpp \
@@ -102,7 +103,6 @@ SOURCES += \
         painting/qpen.cpp \
         painting/qpixellayout.cpp \
         painting/qpolygon.cpp \
-        painting/qrangecollection.cpp \
         painting/qrasterizer.cpp \
         painting/qregion.cpp \
         painting/qstroker.cpp \
diff --git a/src/gui/painting/qpagedpaintdevice.cpp b/src/gui/painting/qpagedpaintdevice.cpp
index 9d09fb6f04..1e32f2c2bc 100644
--- a/src/gui/painting/qpagedpaintdevice.cpp
+++ b/src/gui/painting/qpagedpaintdevice.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtGui module of the Qt Toolkit.
@@ -42,10 +42,8 @@
 
 QT_BEGIN_NAMESPACE
 
-QPagedPaintDevicePrivate::~QPagedPaintDevicePrivate()
-{
-    delete rangeCollection;
-}
+
+QPagedPaintDevicePrivate::~QPagedPaintDevicePrivate() = default;
 
 /*!
     \class QPagedPaintDevice
@@ -213,4 +211,26 @@ QPageLayout QPagedPaintDevice::pageLayout() const
     return d->pageLayout();
 }
 
+/*!
+    \since 6.0
+
+    Returns the page ranges associated with this device.
+
+    \sa QPageRanges, QPrinter::fromPage(), QPrinter::toPage()
+*/
+QPageRanges QPagedPaintDevice::pageRanges() const
+{
+    return d->pageRanges;
+}
+
+/*!
+    \since 6.0
+
+    Sets the page ranges for this device to \a ranges.
+*/
+void QPagedPaintDevice::setPageRanges(const QPageRanges &ranges)
+{
+    d->pageRanges = ranges;
+}
+
 QT_END_NAMESPACE
diff --git a/src/gui/painting/qpagedpaintdevice.h b/src/gui/painting/qpagedpaintdevice.h
index ab304250c9..dedff446b8 100644
--- a/src/gui/painting/qpagedpaintdevice.h
+++ b/src/gui/painting/qpagedpaintdevice.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtGui module of the Qt Toolkit.
@@ -43,6 +43,7 @@
 #include <QtGui/qtguiglobal.h>
 #include <QtGui/qpaintdevice.h>
 #include <QtGui/qpagelayout.h>
+#include <QtGui/qpageranges.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -68,6 +69,9 @@ public:
     virtual bool setPageMargins(const QMarginsF &margins, QPageLayout::Unit units = QPageLayout::Millimeter);
     QPageLayout pageLayout() const;
 
+    virtual void setPageRanges(const QPageRanges &ranges);
+    QPageRanges pageRanges() const;
+
 protected:
     QPagedPaintDevice(QPagedPaintDevicePrivate *dd);
     QPagedPaintDevicePrivate *dd();
diff --git a/src/gui/painting/qpagedpaintdevice_p.h b/src/gui/painting/qpagedpaintdevice_p.h
index 1717727be4..4099846de5 100644
--- a/src/gui/painting/qpagedpaintdevice_p.h
+++ b/src/gui/painting/qpagedpaintdevice_p.h
@@ -53,7 +53,6 @@
 
 #include <QtGui/private/qtguiglobal_p.h>
 #include <qpagedpaintdevice.h>
-#include <qrangecollection.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -61,8 +60,7 @@ class Q_GUI_EXPORT QPagedPaintDevicePrivate
 {
 public:
     QPagedPaintDevicePrivate()
-        : rangeCollection(new QRangeCollection),
-          pageOrderAscending(true),
+        : pageOrderAscending(true),
           printSelectionOnly(false)
     {
     }
@@ -83,7 +81,7 @@ public:
     static inline QPagedPaintDevicePrivate *get(QPagedPaintDevice *pd) { return pd->d; }
 
     // These are currently required to keep QPrinter functionality working in QTextDocument::print()
-    QRangeCollection *rangeCollection;
+    QPageRanges pageRanges;
     bool pageOrderAscending;
     bool printSelectionOnly;
 };
diff --git a/src/gui/painting/qpageranges.cpp b/src/gui/painting/qpageranges.cpp
new file mode 100644
index 0000000000..0d66014d83
--- /dev/null
+++ b/src/gui/painting/qpageranges.cpp
@@ -0,0 +1,365 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** 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-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qpageranges.h"
+#include "qpageranges_p.h"
+
+#include <QtCore/qstack.h>
+#include <QtCore/qdebug.h>
+
+QT_BEGIN_NAMESPACE
+
+void QPageRangesPrivate::mergeIntervals()
+{
+    const int count = intervals.count();
+
+    if (count <= 1)
+        return;
+
+    std::sort(intervals.begin(), intervals.end());
+
+    QStack<QPageRanges::Range> stack;
+    stack.push(intervals[0]);
+
+    for (int i = 1; i < count; ++i) {
+        QPageRanges::Range &top = stack.top();
+
+        if (top.to < intervals[i].from - 1)
+            stack.push(intervals[i]);
+        else if (top.to < intervals[i].to)
+            top.to = intervals[i].to;
+    }
+
+    intervals = stack;
+}
+
+QT_DEFINE_QESDP_SPECIALIZATION_DTOR(QPageRangesPrivate)
+
+/*!
+    \class QPageRanges
+    \brief The QPageRanges class represents a collection of page ranges.
+    \inmodule QtGui
+    \ingroup painting
+    \ingroup printing
+    \ingroup shared
+    \since 6.0
+
+    Use QPagedPaintDevice::pageRanges() to access the collection of page ranges
+    associated with a paged device.
+*/
+
+/*!
+    Constructs an empty QPageRanges object.
+*/
+QPageRanges::QPageRanges() = default;
+
+/*!
+    Constructs a QPageRanges object by copying \a other.
+*/
+QPageRanges::QPageRanges(const QPageRanges &other) noexcept = default;
+
+/*!
+    \fn QPageRanges::QPageRanges(QPageRanges &&other)
+
+    Constructs a QPageRanges object by moving from \a other.
+*/
+
+/*!
+    Destroys the page ranges.
+*/
+QPageRanges::~QPageRanges() = default;
+
+/*!
+    Assigns \a other to this QPageRanges object.
+*/
+QPageRanges &QPageRanges::operator=(const QPageRanges &other) noexcept = default;
+
+/*!
+    \fn QPageRanges &QPageRanges::operator=(QPageRanges &&other)
+    Moves \a other into this QPageRanges object.
+*/
+
+/*!
+    Adds the single page \a pageNumber to the ranges.
+
+    \note Page numbers start with 1. Attempts to add page numbers
+    smaller than 1 will be ignored with a warning.
+*/
+void QPageRanges::addPage(int pageNumber)
+{
+    if (pageNumber <= 0) {
+        qWarning("QPageRanges::addPage: 'pageNumber' must be greater than 0");
+        return;
+    }
+
+    detach();
+    d->intervals.append({ pageNumber, pageNumber });
+    d->mergeIntervals();
+}
+
+/*!
+    Adds the range specified with \a from and \a to to the ranges.
+
+    \note Page numbers start with 1. Attempts to add page numbers
+    smaller than 1 will be ignored with a warning.
+*/
+void QPageRanges::addRange(int from, int to)
+{
+    if (from <= 0 || to <= 0) {
+        qWarning("QPageRanges::addRange: 'from' and 'to' must be greater than 0");
+        return;
+    }
+    if (to < from)
+        std::swap(from, to);
+
+    detach();
+    d->intervals.append({from, to});
+    d->mergeIntervals();
+}
+
+/*!
+    Returns a list with the values of the ranges.
+*/
+QList<QPageRanges::Range> QPageRanges::toRangeList() const
+{
+    if (d)
+        return d->intervals;
+    return QList<QPageRanges::Range>{};
+}
+
+/*!
+    Removes all page ranges.
+*/
+void QPageRanges::clear()
+{
+    d.reset();
+}
+
+/*!
+    Constructs and returns a QPageRanges object populated with the
+    \a ranges from the string representation.
+
+    \code
+    QPrinter printer;
+    QPageRanges ranges = QPageRanges::fromString("1-3,6-7");
+    printer.setPageRanges(ranges);
+    \endcode
+
+    In case of parsing error, returns an empty QPageRanges object.
+
+    \sa isEmpty()
+*/
+QPageRanges QPageRanges::fromString(const QString &ranges)
+{
+    QList<Range> intervals;
+    const QStringList items = ranges.split(u',');
+    for (const QString &item : items) {
+        if (item.isEmpty())
+            return QPageRanges();
+
+        if (item.contains(QLatin1Char('-'))) {
+            const QStringList rangeItems = item.split(u'-');
+            if (rangeItems.count() != 2)
+                return QPageRanges();
+
+            bool ok;
+            const int number1 = rangeItems[0].toInt(&ok);
+            if (!ok)
+                return QPageRanges();
+
+            const int number2 = rangeItems[1].toInt(&ok);
+            if (!ok)
+                return QPageRanges();
+
+            if (number1 < 1 || number2 < 1 || number2 < number1)
+                return QPageRanges();
+
+            intervals.append({number1, number2});
+
+        } else {
+            bool ok;
+            const int number = item.toInt(&ok);
+            if (!ok)
+                return QPageRanges();
+
+            if (number < 1)
+                return QPageRanges();
+
+            intervals.append({number, number});
+        }
+    }
+
+    QPageRanges newRanges;
+    newRanges.d.reset(new QPageRangesPrivate);
+    newRanges.d->intervals = intervals;
+    newRanges.d->mergeIntervals();
+    return newRanges;
+}
+
+/*!
+    Returns the string representation of the page ranges.
+*/
+QString QPageRanges::toString() const
+{
+    if (!d)
+        return QString();
+
+    QString result;
+    for (const Range &range : d->intervals) {
+        if (!result.isEmpty())
+            result += QLatin1Char(',');
+
+        if (range.from == range.to)
+            result += QString::number(range.from);
+        else
+            result += QStringLiteral("%1-%2").arg(range.from).arg(range.to);
+    }
+
+    return result;
+}
+
+/*!
+    \fn bool QPageRanges::contains(int pageNumber) const
+
+    Returns \c true if the ranges include the page \a pageNumber;
+    otherwise returns \c false.
+*/
+bool QPageRanges::contains(int pageNumber) const
+{
+    if (!d)
+        return false;
+
+    for (const Range &range : d->intervals) {
+        if (range.from <= pageNumber && range.to >= pageNumber)
+            return true;
+    }
+    return false;
+}
+
+/*!
+    Returns \c true if the ranges are empty; otherwise returns \c false.
+*/
+bool QPageRanges::isEmpty() const
+{
+    return !d || d->intervals.isEmpty();
+}
+
+/*!
+    Returns the index of the first page covered by the page ranges,
+    or 0 if the page ranges are empty.
+*/
+int QPageRanges::firstPage() const
+{
+    if (isEmpty())
+        return 0;
+    return d->intervals.first().from;
+}
+
+/*!
+    Returns the index of the last page covered by the page ranges,
+    or 0 if the page ranges are empty.
+*/
+int QPageRanges::lastPage() const
+{
+    if (isEmpty())
+        return 0;
+    return d->intervals.last().to;
+}
+
+/*!
+    \internal
+*/
+bool QPageRanges::isEqual(const QPageRanges &other) const noexcept
+{
+    if (d == other.d)
+        return true;
+    if (!d || !other.d)
+        return false;
+    return d->intervals == other.d->intervals;
+}
+
+/*!
+    \internal
+*/
+void QPageRanges::detach()
+{
+    if (d)
+        d.detach();
+    else
+        d.reset(new QPageRangesPrivate);
+}
+
+#ifndef QT_NO_DEBUG_STREAM
+QDebug operator<<(QDebug dbg, const QPageRanges &pageRanges)
+{
+    QDebugStateSaver saver(dbg);
+    dbg.nospace();
+    dbg.noquote();
+    dbg << "QPageRanges(" << pageRanges.toString() << ")";
+
+    return dbg;
+}
+#endif
+
+/*!
+    \struct QPageRanges::Range
+    \brief The QPageRanges::Range struct holds the \c from and \c to endpoints of a range.
+
+    \sa QPageRanges::toRangeList()
+*/
+
+/*!
+    \variable QPageRanges::Range::from
+    \brief the lower endpoint of the range
+*/
+
+/*!
+    \variable QPageRanges::Range::to
+    \brief the upper endpoint of the range
+*/
+
+/*!
+    \fn bool QPageRanges::Range::contains(int pageNumber) const
+
+    Returns \c true if \a pageNumber is within the interval \c{[from, to]};
+    otherwise returns \c false.
+*/
+
+
+QT_END_NAMESPACE
diff --git a/src/gui/painting/qrangecollection.h b/src/gui/painting/qpageranges.h
index b63ceb6b74..481fee109b 100644
--- a/src/gui/painting/qrangecollection.h
+++ b/src/gui/painting/qpageranges.h
@@ -37,42 +37,82 @@
 **
 ****************************************************************************/
 
-#ifndef QRANGECOLLECTION_H
-#define QRANGECOLLECTION_H
+#ifndef QPAGERANGES_H
+#define QPAGERANGES_H
 
 #include <QtGui/qtguiglobal.h>
+#include <QtCore/qstring.h>
 #include <QtCore/qlist.h>
-#include <QtCore/qpair.h>
-#include <QtCore/qscopedpointer.h>
+#include <QtCore/qshareddata.h>
+#include <QtCore/qmetatype.h>
 
 QT_BEGIN_NAMESPACE
 
-class QRangeCollectionPrivate;
+class QDebug;
+class QPageRangesPrivate;
+QT_DECLARE_QESDP_SPECIALIZATION_DTOR_WITH_EXPORT(QPageRangesPrivate, Q_GUI_EXPORT)
 
-class Q_GUI_EXPORT QRangeCollection
+class Q_GUI_EXPORT QPageRanges
 {
-    Q_DECLARE_PRIVATE(QRangeCollection)
 public:
-    explicit QRangeCollection();
-    ~QRangeCollection();
+    QPageRanges();
+    ~QPageRanges();
+
+    QPageRanges(const QPageRanges &other) noexcept;
+    QPageRanges &operator=(const QPageRanges &other) noexcept;
+
+    QPageRanges(QPageRanges &&other) noexcept = default;
+    QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_PURE_SWAP(QPageRanges)
+    void swap(QPageRanges &other) noexcept
+    { qSwap(d, other.d); }
+
+    friend bool operator==(const QPageRanges &lhs, const QPageRanges &rhs) noexcept
+    { return lhs.isEqual(rhs); }
+    friend bool operator!=(const QPageRanges &lhs, const QPageRanges &rhs) noexcept
+    { return !lhs.isEqual(rhs); }
+
+    struct Range {
+        int from = -1;
+        int to = -1;
+        bool contains(int pageNumber) const noexcept
+        { return from <= pageNumber && to >= pageNumber; }
+        friend bool operator==(Range lhs, Range rhs) noexcept
+        { return lhs.from == rhs.from && lhs.to == rhs.to; }
+        friend bool operator!=(Range lhs, Range rhs) noexcept
+        { return !(lhs == rhs); }
+        friend bool operator<(Range lhs, Range rhs) noexcept
+        { return lhs.from < rhs.from || (!(rhs.from < lhs.from) && lhs.to < rhs.to); }
+    };
 
     void addPage(int pageNumber);
     void addRange(int from, int to);
-    QList<QPair<int, int>> toList() const;
+    QList<Range> toRangeList() const;
     void clear();
 
-    bool parse(const QString &ranges);
     QString toString() const;
+    static QPageRanges fromString(const QString &ranges);
 
-    bool contains(const int pageNumber) const;
+    bool contains(int pageNumber) const;
     bool isEmpty() const;
     int firstPage() const;
     int lastPage() const;
 
 private:
-    QScopedPointer<QRangeCollectionPrivate> d_ptr;
+    bool isEqual(const QPageRanges &other) const noexcept;
+    void detach();
+
+    QExplicitlySharedDataPointer<QPageRangesPrivate> d;
 };
 
+#ifndef QT_NO_DEBUG_STREAM
+Q_GUI_EXPORT QDebug operator<<(QDebug dbg, const QPageRanges &pageRanges);
+#endif
+
+Q_DECLARE_SHARED(QPageRanges)
+Q_DECLARE_TYPEINFO(QPageRanges::Range, Q_MOVABLE_TYPE);
+
 QT_END_NAMESPACE
 
-#endif // QRANGECOLLECTION_H
+Q_DECLARE_METATYPE(QPageRanges)
+
+#endif // QPAGERANGES_H
diff --git a/src/gui/painting/qrangecollection_p.h b/src/gui/painting/qpageranges_p.h
index 39a52f2a6b..82b03224f3 100644
--- a/src/gui/painting/qrangecollection_p.h
+++ b/src/gui/painting/qpageranges_p.h
@@ -37,8 +37,8 @@
 **
 ****************************************************************************/
 
-#ifndef QRANGECOLLECTION_P_H
-#define QRANGECOLLECTION_P_H
+#ifndef QPAGERANGES_P_H
+#define QPAGERANGES_P_H
 
 //
 //  W A R N I N G
@@ -56,21 +56,14 @@
 
 QT_BEGIN_NAMESPACE
 
-class Q_GUI_EXPORT QRangeCollectionPrivate
+class QPageRangesPrivate : public QSharedData
 {
-    Q_DECLARE_PUBLIC(QRangeCollection)
 public:
-    QRangeCollectionPrivate(QRangeCollection *rangeCollection)
-        : q_ptr(rangeCollection)
-    {
-    }
-
     void mergeIntervals();
 
-    QList<QPair<int, int>> intervals;
-    QRangeCollection *q_ptr;
+    QList<QPageRanges::Range> intervals;
 };
 
 QT_END_NAMESPACE
 
-#endif // QRANGECOLLECTION_P_H
+#endif // QPAGERANGES_P_H
diff --git a/src/gui/painting/qrangecollection.cpp b/src/gui/painting/qrangecollection.cpp
deleted file mode 100644
index 8f212a1b08..0000000000
--- a/src/gui/painting/qrangecollection.cpp
+++ /dev/null
@@ -1,285 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2020 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtGui module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** 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 Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** 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-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#include "qrangecollection.h"
-#include "qrangecollection_p.h"
-
-#include <QtCore/qstack.h>
-
-QT_BEGIN_NAMESPACE
-
-void QRangeCollectionPrivate::mergeIntervals()
-{
-    const int count = intervals.count();
-
-    if (count <= 0)
-        return;
-
-    std::sort(intervals.begin(), intervals.end());
-
-    QStack<QPair<int, int>> stack;
-    stack.push(intervals[0]);
-
-    for (int i = 1; i < count; i++) {
-        QPair<int, int> &top = stack.top();
-
-        if (top.second < intervals[i].first)
-            stack.push(intervals[i]);
-        else if (top.second < intervals[i].second)
-            top.second = intervals[i].second;
-    }
-
-    std::sort(intervals.begin(), intervals.end());
-
-    intervals = stack;
-}
-
-/*!
-    \class QRangeCollection
-    \brief The QRangeCollection class represents a collection of decimal intervals.
-    \inmodule QtGui
-    \ingroup painting
-    \since 6.0
-
-    QRangeCollection manages a set of decimal intervals.
-
-    Use QPrinter::rangeCollection() to access the collection of page ranges
-    associated with a QPrinter.
-*/
-
-QRangeCollection::QRangeCollection()
-    : d_ptr(new QRangeCollectionPrivate(this))
-{
-}
-
-/*!
-    Destroys the collection.
-*/
-QRangeCollection::~QRangeCollection()
-{
-}
-
-/*!
-    Inserts a single number \a pageNumber into the collection.
- */
-void QRangeCollection::addPage(int pageNumber)
-{
-    Q_D(QRangeCollection);
-    if (pageNumber <= 0) {
-        qWarning("QRangeCollection::addPage: 'pageNumber' must be greater than 0");
-        return;
-    }
-    d->intervals.append(qMakePair(pageNumber, pageNumber));
-    d->mergeIntervals();
-}
-
-/*!
-    Inserts a range specified with \a from and \a to into the collection.
- */
-void QRangeCollection::addRange(int from, int to)
-{
-    Q_D(QRangeCollection);
-    if (from <= 0 || to <= 0) {
-        qWarning("QRangeCollection::addRange: 'from' and 'to' must be greater than 0");
-        return;
-    }
-    if (to < from) {
-        qWarning("QRangeCollection::addRange: 'from' must be less than or equal to 'to'");
-        std::swap(from, to);
-    }
-    d->intervals.append(qMakePair(from, to));
-    d->mergeIntervals();
-}
-
-/*!
-    Returns a list with the values of the ranges used in this collection.
- */
-QList<QPair<int, int>> QRangeCollection::toList() const
-{
-    Q_D(const QRangeCollection);
-    return d->intervals.toList();
-}
-
-/*!
- * Removes all ranges from this collection.
- */
-void QRangeCollection::clear()
-{
-    Q_D(QRangeCollection);
-    d->intervals.clear();
-}
-
-/*!
-    Constructs the range collection from a string representation of \a ranges.
-
-    \code
-    QPrinter printer;
-    printer->rangeCollection()->parse("1-3,6-7");
-    \endcode
-
-    Returns \c true on success.
- */
-bool QRangeCollection::parse(const QString &ranges)
-{
-    Q_D(QRangeCollection);
-    const QStringList items = ranges.split(u',');
-    for (const QString &item : items) {
-        if (item.isEmpty()) {
-            d->intervals.clear();
-            return false;
-        }
-
-        if (item.contains(QLatin1Char('-'))) {
-            const QStringList rangeItems = item.split(u'-');
-            if (rangeItems.count() != 2) {
-                d->intervals.clear();
-                return false;
-            }
-
-            bool ok;
-            const int number1 = rangeItems[0].toInt(&ok);
-            if (!ok) {
-                d->intervals.clear();
-                return false;
-            }
-
-            const int number2 = rangeItems[1].toInt(&ok);
-            if (!ok) {
-                d->intervals.clear();
-                return false;
-            }
-
-            if (number1 < 1 || number2 < 1 || number2 < number1) {
-                d->intervals.clear();
-                return false;
-            }
-
-            d->intervals.append(qMakePair(number1, number2));
-
-        } else {
-            bool ok;
-            const int number = item.toInt(&ok);
-            if (!ok) {
-                d->intervals.clear();
-                return false;
-            }
-
-            if (number < 1) {
-                d->intervals.clear();
-                return false;
-            }
-
-            d->intervals.append(qMakePair(number, number));
-        }
-    }
-
-    d->mergeIntervals();
-    return true;
-}
-
-/*!
-    Returns the string representation of the ranges in the collection.
- */
-QString QRangeCollection::toString() const
-{
-    Q_D(const QRangeCollection);
-    QString result;
-
-    for (const QPair<int, int> &pair : d->intervals) {
-        if (!result.isEmpty())
-            result += QLatin1Char(',');
-
-        if (pair.first == pair.second)
-            result += QString::number(pair.first);
-        else
-            result += QStringLiteral("%1-%2").arg(pair.first).arg(pair.second);
-    }
-
-    return result;
-}
-
-/*!
-    \fn bool QRangeCollection::contains(const int pageNumber) const
-
-    Returns \c true if the collection contains an occurrence
-    or a bounding range of \a pageNumber; otherwise returns
-    \c false.
- */
-bool QRangeCollection::contains(int pageNumber) const
-{
-    Q_D(const QRangeCollection);
-    for (const QPair<int, int> &pair : d->intervals) {
-        if (pair.first <= pageNumber && pair.second >= pageNumber)
-            return true;
-    }
-    return false;
-}
-
-/*!
-    Returns \c true if the collection is empty; otherwise returns \c false.
-*/
-bool QRangeCollection::isEmpty() const
-{
-    Q_D(const QRangeCollection);
-    return d->intervals.isEmpty();
-}
-
-/*!
-    Returns the index of the first page covered by the range collection.
-*/
-int QRangeCollection::firstPage() const
-{
-    Q_D(const QRangeCollection);
-    if (d->intervals.isEmpty())
-        return 0;
-    return d->intervals.first().first;
-}
-
-/*!
-    Returns the index of the last page covered by the range collection.
-*/
-int QRangeCollection::lastPage() const
-{
-    Q_D(const QRangeCollection);
-    if (d->intervals.isEmpty())
-        return 0;
-    return d->intervals.last().second;
-}
-
-QT_END_NAMESPACE