gui: Add several QList::reserve() calls.

Reduces reallocations.

Change-Id: I0db16726f413a67b76a73fabd013f910ab5f5109
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

src/gui/image/qpicture.cpp

@@ -1216,7 +1216,9 @@ QList<QByteArray> QPicture::inputFormats()
 static QStringList qToStringList(const QList<QByteArray> &arr)
 {
     QStringList list;
-    for (int i = 0; i < arr.count(); ++i)
+    const int count = arr.count();
+    list.reserve(count);
+    for (int i = 0; i < count; ++i)
         list.append(QString::fromLatin1(arr.at(i)));
     return list;
 }

src/gui/itemmodels/qstandarditemmodel.cpp

@@ -1803,6 +1803,7 @@ QList<QStandardItem*> QStandardItem::takeRow(int row)
     int index = d->childIndex(row, 0);  // Will return -1 if there are no columns
     if (index != -1) {
         int col_count = d->columnCount();
+        items.reserve(col_count);
         for (int column = 0; column < col_count; ++column) {
             QStandardItem *ch = d->children.at(index + column);
             if (ch)
@@ -2518,7 +2519,9 @@ QList<QStandardItem*> QStandardItemModel::findItems(const QString &text,
     QModelIndexList indexes = match(index(0, column, QModelIndex()),
                                     Qt::DisplayRole, text, -1, flags);
     QList<QStandardItem*> items;
-    for (int i = 0; i < indexes.size(); ++i)
+    const int numIndexes = indexes.size();
+    items.reserve(numIndexes);
+    for (int i = 0; i < numIndexes; ++i)
         items.append(itemFromIndex(indexes.at(i)));
     return items;
 }

src/gui/kernel/qdnd.cpp

@@ -147,7 +147,9 @@ static QStringList imageReadMimeFormats()
 {
     QStringList formats;
     QList<QByteArray> imageFormats = QImageReader::supportedImageFormats();
-    for (int i = 0; i < imageFormats.size(); ++i) {
+    const int numImageFormats = imageFormats.size();
+    formats.reserve(numImageFormats);
+    for (int i = 0; i < numImageFormats; ++i) {
         QString format = QLatin1String("image/");
         format += QString::fromLatin1(imageFormats.at(i).toLower());
         formats.append(format);
@@ -166,7 +168,9 @@ static QStringList imageWriteMimeFormats()
 {
     QStringList formats;
     QList<QByteArray> imageFormats = QImageWriter::supportedImageFormats();
-    for (int i = 0; i < imageFormats.size(); ++i) {
+    const int numImageFormats = imageFormats.size();
+    formats.reserve(numImageFormats);
+    for (int i = 0; i < numImageFormats; ++i) {
         QString format = QLatin1String("image/");
         format += QString::fromLatin1(imageFormats.at(i).toLower());
         formats.append(format);

src/gui/kernel/qkeysequence.cpp

@@ -1534,6 +1534,7 @@ QList<QKeySequence> QKeySequence::listFromString(const QString &str, SequenceFor
     QList<QKeySequence> result;
 
     QStringList strings = str.split(QLatin1String("; "));
+    result.reserve(strings.count());
     foreach (const QString &string, strings) {
         result << fromString(string, format);
     }

src/gui/kernel/qscreen.cpp

@@ -329,6 +329,7 @@ QList<QScreen *> QScreen::virtualSiblings() const
     Q_D(const QScreen);
     QList<QPlatformScreen *> platformScreens = d->platformScreen->virtualSiblings();
     QList<QScreen *> screens;
+    screens.reserve(platformScreens.count());
     foreach (QPlatformScreen *platformScreen, platformScreens)
         screens << platformScreen->screen();
     return screens;

src/gui/kernel/qwindowsysteminterface.cpp

@@ -455,6 +455,7 @@ QList<QTouchEvent::TouchPoint> QWindowSystemInterfacePrivate::convertTouchPoints
     Qt::TouchPointStates states;
     QTouchEvent::TouchPoint p;
 
+    touchPoints.reserve(points.count());
     QList<QWindowSystemInterface::TouchPoint>::const_iterator point = points.constBegin();
     QList<QWindowSystemInterface::TouchPoint>::const_iterator end = points.constEnd();
     while (point != end) {

src/gui/painting/qbrush.cpp

@@ -1163,6 +1163,7 @@ QDataStream &operator>>(QDataStream &s, QBrush &b)
             QColor c;
 
             s >> numStops;
+            stops.reserve(numStops);
             for (quint32 i = 0; i < numStops; ++i) {
                 s >> n >> c;
                 stops << QPair<qreal, QColor>(n, c);

src/gui/painting/qpainter.cpp

@@ -7497,6 +7497,7 @@ start_lengthVariant:
 
     if (engine.option.tabs().isEmpty() && ta) {
         QList<qreal> tabs;
+        tabs.reserve(tabarraylen);
         for (int i = 0; i < tabarraylen; i++)
             tabs.append(qreal(ta[i]));
         engine.option.setTabArray(tabs);

src/gui/painting/qpdf.cpp

@@ -1952,7 +1952,9 @@ int QPdfEnginePrivate::createShadingFunction(const QGradient *gradient, int from
         stops.append(QGradientStop(1, stops.at(stops.size() - 1).second));
 
     QVector<int> functions;
-    for (int i = 0; i < stops.size() - 1; ++i) {
+    const int numStops = stops.size();
+    functions.reserve(numStops - 1);
+    for (int i = 0; i < numStops - 1; ++i) {
         int f = addXrefEntry(-1);
         QByteArray data;
         QPdf::ByteStream s(&data);

src/gui/painting/qpen.cpp

@@ -980,6 +980,7 @@ QDataStream &operator>>(QDataStream &s, QPen &p)
             quint32 numDashes;
             s >> numDashes;
             double dash;
+            dashPattern.reserve(numDashes);
             for (quint32 i = 0; i < numDashes; ++i) {
                 s >> dash;
                 dashPattern << dash;

src/gui/text/qcssparser.cpp

@@ -461,6 +461,7 @@ void ValueExtractor::lengthValues(const Declaration &decl, int *m)
     }
 
     QList<QVariant> v;
+    v.reserve(4);
     for (i = 0; i < 4; i++) {
         v += QVariant::fromValue<LengthData>(datas[i]);
         m[i] = lengthValueFromData(datas[i], f);

src/gui/text/qfont.cpp

@@ -1860,14 +1860,9 @@ void QFont::removeSubstitutions(const QString &familyName)
 */
 QStringList QFont::substitutions()
 {
-    typedef QFontSubst::const_iterator QFontSubstConstIterator;
-
     QFontSubst *fontSubst = globalFontSubst();
     Q_ASSERT(fontSubst != 0);
-    QStringList ret;
-    const QFontSubstConstIterator cend = fontSubst->constEnd();
-    for (QFontSubstConstIterator it = fontSubst->constBegin(); it != cend; ++it)
-        ret.append(it.key());
+    QStringList ret = fontSubst->keys();
 
     ret.sort();
     return ret;

src/gui/text/qtextdocumentlayout.cpp

@@ -1071,7 +1071,9 @@ void QTextDocumentLayoutPrivate::drawFrame(const QPointF &offset, QPainter *pain
             it = frameIteratorForYPosition(QFixed::fromReal(context.clip.top()));
 
         QList<QTextFrame *> floats;
-        for (int i = 0; i < fd->floats.count(); ++i)
+        const int numFloats = fd->floats.count();
+        floats.reserve(numFloats);
+        for (int i = 0; i < numFloats; ++i)
             floats.append(fd->floats.at(i));
 
         drawFlow(off, painter, context, it, floats, &cursorBlockNeedingRepaint);

src/gui/text/qtextengine.cpp

@@ -2863,6 +2863,7 @@ QFixed QTextEngine::calculateTabWidth(int item, QFixed x) const
     if (!tabArray.isEmpty()) {
         if (isRightToLeft()) { // rebase the tabArray positions.
             QList<QTextOption::Tab> newTabs;
+            newTabs.reserve(tabArray.count());
             QList<QTextOption::Tab>::Iterator iter = tabArray.begin();
             while(iter != tabArray.end()) {
                 QTextOption::Tab tab = *iter;

src/gui/text/qtextformat.cpp

@@ -1115,7 +1115,9 @@ void QTextFormat::setProperty(int propertyId, const QVector<QTextLength> &value)
     if (!d)
         d = new QTextFormatPrivate;
     QVariantList list;
-    for (int i=0; i<value.size(); ++i)
+    const int numValues = value.size();
+    list.reserve(numValues);
+    for (int i = 0; i < numValues; ++i)
         list << value.at(i);
     d->insertProperty(propertyId, list);
 }
@@ -2041,6 +2043,7 @@ QTextBlockFormat::QTextBlockFormat(const QTextFormat &fmt)
 void QTextBlockFormat::setTabPositions(const QList<QTextOption::Tab> &tabs)
 {
     QList<QVariant> list;
+    list.reserve(tabs.count());
     QList<QTextOption::Tab>::ConstIterator iter = tabs.constBegin();
     while (iter != tabs.constEnd()) {
         QVariant v;
@@ -2065,6 +2068,7 @@ QList<QTextOption::Tab> QTextBlockFormat::tabPositions() const
     QList<QTextOption::Tab> answer;
     QList<QVariant> variantsList = qvariant_cast<QList<QVariant> >(variant);
     QList<QVariant>::Iterator iter = variantsList.begin();
+    answer.reserve(variantsList.count());
     while(iter != variantsList.end()) {
         answer.append( qvariant_cast<QTextOption::Tab>(*iter));
         ++iter;

src/gui/text/qtextoption.cpp

@@ -146,6 +146,7 @@ void QTextOption::setTabArray(const QList<qreal> &tabStops)
         d = new QTextOptionPrivate;
     QList<QTextOption::Tab> tabs;
     QTextOption::Tab tab;
+    tabs.reserve(tabStops.count());
     foreach (qreal pos, tabStops) {
         tab.position = pos;
         tabs.append(tab);
@@ -174,10 +175,11 @@ void QTextOption::setTabs(const QList<QTextOption::Tab> &tabStops)
 */
 QList<qreal> QTextOption::tabArray() const
 {
-    if (!d)
-        return QList<qreal>();
-
     QList<qreal> answer;
+    if (!d)
+        return answer;
+
+    answer.reserve(d->tabStops.count());
     QList<QTextOption::Tab>::ConstIterator iter = d->tabStops.constBegin();
     while(iter != d->tabStops.constEnd()) {
         answer.append( (*iter).position);

src/gui/text/qzip.cpp

@@ -916,7 +916,9 @@ QList<QZipReader::FileInfo> QZipReader::fileInfoList() const
 {
     d->scanFiles();
     QList<QZipReader::FileInfo> files;
-    for (int i = 0; i < d->fileHeaders.size(); ++i) {
+    const int numFileHeaders = d->fileHeaders.size();
+    files.reserve(numFileHeaders);
+    for (int i = 0; i < numFileHeaders; ++i) {
         QZipReader::FileInfo fi;
         d->fillFileInfo(i, fi);
         files.append(fi);