Add function QGlyphRun::setRawData()

To provide an optimized way of constructing QGlyphRun objects with no
copying or allocation, we add function setRawData() (naming inspired by
QByteArray::setRawData()). Data retrieved from QRawFont can be passed
directly into this. The logic is now that the data pointers in
QGlyphRunPrivate should always point to the current valid data and is
what will be used in comparisons and drawing calls. The vectors are
optimizations to avoid unnecessary copying if the user wants to use
the QVector based API (which makes it easier to manage the memory.)
This reflected in the functions that return QVectors, which will
return the stored vector if and only if it is identical to the
current pointer. Otherwise we will have to copy the memory.

The internal addition operators in QGlyphRun have been removed since
they really provide no real optimization and have an unclear definition
if the two glyph runs are based on different fonts.

Reviewed-by: Jiang Jiang
(cherry picked from commit 86d88c5b719fd3d50336d9d8e7127b8045ee82ae)

Change-Id: Id5bb55ee3d93afb32ffca850f53382e856df7b3e
Reviewed-on: http://codereview.qt.nokia.com/342
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>

4 files changed, 101 insertions, 46 deletions

diff --git a/src/gui/text/qglyphrun.cpp b/src/gui/text/qglyphrun.cpp
index 4a51e56805..18b6357863 100644
--- a/src/gui/text/qglyphrun.cpp
+++ b/src/gui/text/qglyphrun.cpp
@@ -132,13 +132,27 @@ QGlyphRun &QGlyphRun::operator=(const QGlyphRun &other)
 */
 bool QGlyphRun::operator==(const QGlyphRun &other) const
 {
-    return ((d == other.d)
-            || (d->glyphIndexes == other.d->glyphIndexes
-                && d->glyphPositions == other.d->glyphPositions
-                && d->overline == other.d->overline
-                && d->underline == other.d->underline
-                && d->strikeOut == other.d->strikeOut
-                && d->rawFont == other.d->rawFont));
+    if (d == other.d)
+        return true;
+
+    if ((d->glyphIndexDataSize != other.d->glyphIndexDataSize)
+     || (d->glyphPositionDataSize != other.d->glyphPositionDataSize)) {
+        return false;
+    }
+
+    for (int i=0; i<qMax(d->glyphIndexDataSize, d->glyphPositionDataSize); ++i) {
+        if (i < d->glyphIndexDataSize && d->glyphIndexData[i] != other.d->glyphIndexData[i])
+           return false;
+
+        if (i < d->glyphPositionDataSize && d->glyphPositionData[i] != other.d->glyphPositionData[i])
+           return false;
+    }
+
+
+    return (d->overline == other.d->overline
+            && d->underline == other.d->underline
+            && d->strikeOut == other.d->strikeOut
+            && d->rawFont == other.d->rawFont);
 }
 
 /*!
@@ -151,36 +165,6 @@ bool QGlyphRun::operator!=(const QGlyphRun &other) const
 }
 
 /*!
-    \internal
-
-    Adds together the lists of glyph indexes and positions in \a other and this QGlyphRun
-    object and returns the result. The font in the returned QGlyphRun will be the same as in
-    this QGlyphRun object.
-*/
-QGlyphRun QGlyphRun::operator+(const QGlyphRun &other) const
-{
-    QGlyphRun ret(*this);
-    ret += other;
-    return ret;
-}
-
-/*!
-    \internal
-
-    Appends the glyph indexes and positions in \a other to this QGlyphRun object and returns
-    a reference to the current object.
-*/
-QGlyphRun &QGlyphRun::operator+=(const QGlyphRun &other)
-{
-    detach();
-
-    d->glyphIndexes += other.d->glyphIndexes;
-    d->glyphPositions += other.d->glyphPositions;
-
-    return *this;
-}
-
-/*!
     Returns the font selected for this QGlyphRun object.
 
     \sa setRawFont()
@@ -208,7 +192,13 @@ void QGlyphRun::setRawFont(const QRawFont &rawFont)
 */
 QVector<quint32> QGlyphRun::glyphIndexes() const
 {
-    return d->glyphIndexes;
+    if (d->glyphIndexes.constData() == d->glyphIndexData) {
+        return d->glyphIndexes;
+    } else {
+        QVector<quint32> indexes(d->glyphIndexDataSize);
+        qMemCopy(indexes.data(), d->glyphIndexData, d->glyphIndexDataSize * sizeof(quint32));
+        return indexes;
+    }
 }
 
 /*!
@@ -218,7 +208,9 @@ QVector<quint32> QGlyphRun::glyphIndexes() const
 void QGlyphRun::setGlyphIndexes(const QVector<quint32> &glyphIndexes)
 {
     detach();
-    d->glyphIndexes = glyphIndexes;
+    d->glyphIndexes = glyphIndexes; // Keep a reference to the QVector to avoid copying
+    d->glyphIndexData = glyphIndexes.constData();
+    d->glyphIndexDataSize = glyphIndexes.size();
 }
 
 /*!
@@ -226,7 +218,14 @@ void QGlyphRun::setGlyphIndexes(const QVector<quint32> &glyphIndexes)
 */
 QVector<QPointF> QGlyphRun::positions() const
 {
-    return d->glyphPositions;
+    if (d->glyphPositions.constData() == d->glyphPositionData) {
+        return d->glyphPositions;
+    } else {
+        QVector<QPointF> glyphPositions(d->glyphPositionDataSize);
+        qMemCopy(glyphPositions.data(), d->glyphPositionData,
+                 d->glyphPositionDataSize * sizeof(QPointF));
+        return glyphPositions;
+    }
 }
 
 /*!
@@ -236,7 +235,9 @@ QVector<QPointF> QGlyphRun::positions() const
 void QGlyphRun::setPositions(const QVector<QPointF> &positions)
 {
     detach();
-    d->glyphPositions = positions;
+    d->glyphPositions = positions; // Keep a reference to the vector to avoid copying
+    d->glyphPositionData = positions.constData();
+    d->glyphPositionDataSize = positions.size();
 }
 
 /*!
@@ -245,12 +246,33 @@ void QGlyphRun::setPositions(const QVector<QPointF> &positions)
 void QGlyphRun::clear()
 {
     detach();
-    d->glyphPositions = QVector<QPointF>();
-    d->glyphIndexes = QVector<quint32>();
     d->rawFont = QRawFont();
     d->strikeOut = false;
     d->overline = false;
     d->underline = false;
+
+    setPositions(QVector<QPointF>());
+    setGlyphIndexes(QVector<quint32>());
+}
+
+/*!
+    Sets the glyph indexes and positions of this QGlyphRun to use the first \a size
+    elements in the arrays \a glyphIndexArray and \a glyphPositionArray. The data is
+    \e not copied. The caller must guarantee that the arrays are not deleted as long
+    as this QGlyphRun and any copies of it exists.
+
+    \sa setGlyphIndexes(), setPositions()
+*/
+void QGlyphRun::setRawData(const quint32 *glyphIndexArray, const QPointF *glyphPositionArray,
+                           int size)
+{
+    detach();
+    d->glyphIndexes.clear();
+    d->glyphPositions.clear();
+
+    d->glyphIndexData = glyphIndexArray;
+    d->glyphPositionData = glyphPositionArray;
+    d->glyphIndexDataSize = d->glyphPositionDataSize = size;
 }
 
 /*!
diff --git a/src/gui/text/qglyphrun.h b/src/gui/text/qglyphrun.h
index 99a1fc8593..b4f02f0d87 100644
--- a/src/gui/text/qglyphrun.h
+++ b/src/gui/text/qglyphrun.h
@@ -66,6 +66,10 @@ public:
     QRawFont rawFont() const;
     void setRawFont(const QRawFont &rawFont);
 
+    void setRawData(const quint32 *glyphIndexArray,
+                    const QPointF *glyphPositionArray,
+                    int size);
+
     QVector<quint32> glyphIndexes() const;
     void setGlyphIndexes(const QVector<quint32> &glyphIndexes);
 
diff --git a/src/gui/text/qglyphrun_p.h b/src/gui/text/qglyphrun_p.h
index 533679d96a..1cb63b2403 100644
--- a/src/gui/text/qglyphrun_p.h
+++ b/src/gui/text/qglyphrun_p.h
@@ -71,6 +71,10 @@ public:
         : overline(false)
         , underline(false)
         , strikeOut(false)
+        , glyphIndexData(glyphIndexes.constData())
+        , glyphIndexDataSize(0)
+        , glyphPositionData(glyphPositions.constData())
+        , glyphPositionDataSize(0)
     {
     }
 
@@ -82,6 +86,10 @@ public:
       , overline(other.overline)
       , underline(other.underline)
       , strikeOut(other.strikeOut)
+      , glyphIndexData(other.glyphIndexData)
+      , glyphIndexDataSize(other.glyphIndexDataSize)
+      , glyphPositionData(other.glyphPositionData)
+      , glyphPositionDataSize(other.glyphPositionDataSize)
     {
     }
 
@@ -89,6 +97,17 @@ public:
     QVector<QPointF> glyphPositions;
     QRawFont rawFont;
 
+    const quint32 *glyphIndexData;
+    int glyphIndexDataSize;
+
+    const QPointF *glyphPositionData;
+    int glyphPositionDataSize;
+
+    static QGlyphRunPrivate *get(const QGlyphRun &glyphRun)
+    {
+        return glyphRun.d.data();
+    }
+
     uint overline  : 1;
     uint underline : 1;
     uint strikeOut : 1;
diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index add25cdad9..781dd23a58 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -2282,10 +2282,20 @@ QList<QGlyphRun> QTextLine::glyphRuns(int from, int length) const
             glyphIndexes.setRawFont(font);
 
             QPair<QFontEngine *, int> key(fontEngine, int(flags));
-            if (!glyphsHash.contains(key))
+            if (!glyphsHash.contains(key)) {
                 glyphsHash.insert(key, glyphIndexes);
-            else
-                glyphsHash[key] += glyphIndexes;
+            } else {
+                QGlyphRun &glyphRun = glyphsHash[key];
+
+                QVector<quint32> indexes = glyphRun.glyphIndexes();
+                QVector<QPointF> positions = glyphRun.positions();
+
+                indexes += glyphIndexes.glyphIndexes();
+                positions += glyphIndexes.positions();
+
+                glyphRun.setGlyphIndexes(indexes);
+                glyphRun.setPositions(positions);
+            }
         }
     }