diff options
| author | Thorbjørn Lund Martsum <tmartsum@gmail.com> | 2012-02-20 16:11:31 +0100 |
|---|---|---|
| committer | Qt by Nokia <qt-info@nokia.com> | 2012-02-21 12:52:00 +0100 |
| commit | 13f3346d34c007727f60f9ee73805bcc0aa1c04b (patch) | |
| tree | 2eac92376eedb198e491d221ebc1cfef93470f75 | |
| parent | a4e4c3100780be27070c8916d25a9f7c461d1e11 (diff) | |
QHeaderView - create a union to save some space.
Beside saving some space it also ensures a bit faster vector operations
(remove and insert memcpy) - and lower the risk for a cache-miss.
(Many operations seems to be about 5-10% faster in the benchmark).
Change-Id: If8109e2146c25f642015906375dfbb449706ce8e
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
| -rw-r--r-- | src/widgets/itemviews/qheaderview_p.h | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/widgets/itemviews/qheaderview_p.h b/src/widgets/itemviews/qheaderview_p.h index 4d1f4ba5a0..2c657221dd 100644 --- a/src/widgets/itemviews/qheaderview_p.h +++ b/src/widgets/itemviews/qheaderview_p.h @@ -287,8 +287,11 @@ public: struct SectionSpan { int size; - mutable int calculated_startpos; - mutable int tmpLogIdx; + union { // This union is made in order to save space and ensure good vector performance (on remove) + mutable int calculated_startpos; // <- this is the primary used member. + mutable int tmpLogIdx; // When one of these 'tmp'-members has been used we call + int tmpDataStreamSectionCount; // recalcSectionStartPos() or set sectionStartposRecalc to true + }; // to ensure that calculated_startpos will be calculated afterwards. QHeaderView::ResizeMode resizeMode; inline SectionSpan() : size(0), resizeMode(QHeaderView::Interactive) {} inline SectionSpan(int length, QHeaderView::ResizeMode mode) @@ -296,7 +299,6 @@ public: inline int sectionSize() const { return size; } inline int calculatedEndPos() const { return calculated_startpos + size; } #ifndef QT_NO_DATASTREAM - int tmpDataStreamSectionCount; inline void write(QDataStream &out) const { out << size; out << 1; out << (int)resizeMode; } inline void read(QDataStream &in) |