Make QGlyphLayout consume one byte less per glyph

Change-Id: Iddcc2e1f284dcf13ae98b57ea2d5854e57c83530
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

2 files changed, 23 insertions, 18 deletions

diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index e2c45f9bab..45894d27b6 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -1206,7 +1206,6 @@ QT_BEGIN_INCLUDE_NAMESPACE
 QT_END_INCLUDE_NAMESPACE
 
 Q_STATIC_ASSERT(sizeof(HB_Glyph) == sizeof(glyph_t));
-Q_STATIC_ASSERT(sizeof(HB_GlyphAttributes) == sizeof(QGlyphAttributes));
 Q_STATIC_ASSERT(sizeof(HB_Fixed) == sizeof(QFixed));
 Q_STATIC_ASSERT(sizeof(HB_FixedPoint) == sizeof(QFixedPoint));
 
@@ -1272,18 +1271,23 @@ int QTextEngine::shapeTextWithHarfbuzz(const QScriptItem &si, const ushort *stri
 
         remaining_glyphs -= shaper_item.initialGlyphCount;
 
+        QVarLengthArray<HB_GlyphAttributes, 128> hbGlyphAttributes;
         do {
             if (!ensureSpace(glyph_pos + shaper_item.num_glyphs + remaining_glyphs))
                 return 0;
+            if (hbGlyphAttributes.size() < int(shaper_item.num_glyphs)) {
+                hbGlyphAttributes.resize(shaper_item.num_glyphs);
+                memset(hbGlyphAttributes.data(), 0, hbGlyphAttributes.size() * sizeof(HB_GlyphAttributes));
+            }
 
             const QGlyphLayout g = availableGlyphs(&si).mid(glyph_pos);
             if (fontEngine->type() == QFontEngine::Multi && shaper_item.num_glyphs > shaper_item.item.length)
                 moveGlyphData(g.mid(shaper_item.num_glyphs), g.mid(shaper_item.initialGlyphCount), remaining_glyphs);
 
             shaper_item.glyphs = reinterpret_cast<HB_Glyph *>(g.glyphs);
-            shaper_item.attributes = reinterpret_cast<HB_GlyphAttributes *>(g.attributes);
             shaper_item.advances = reinterpret_cast<HB_Fixed *>(g.advances);
             shaper_item.offsets = reinterpret_cast<HB_FixedPoint *>(g.offsets);
+            shaper_item.attributes = hbGlyphAttributes.data();
 
             if (engineIdx != 0 && shaper_item.glyphIndicesPresent) {
                 for (quint32 i = 0; i < shaper_item.initialGlyphCount; ++i)
@@ -1297,6 +1301,14 @@ int QTextEngine::shapeTextWithHarfbuzz(const QScriptItem &si, const ushort *stri
         if (fontEngine->type() == QFontEngine::Multi)
             moveGlyphData(g.mid(shaper_item.num_glyphs), g.mid(shaper_item.initialGlyphCount), remaining_glyphs);
 
+        for (quint32 i = 0; i < shaper_item.num_glyphs; ++i) {
+            HB_GlyphAttributes hbAttrs = hbGlyphAttributes.at(i);
+            QGlyphAttributes &attrs = g.attributes[i];
+            attrs.clusterStart = hbAttrs.clusterStart;
+            attrs.dontPrint = hbAttrs.dontPrint;
+            attrs.justification = hbAttrs.justification;
+        }
+
         for (quint32 i = 0; i < shaper_item.item.length; ++i)
             shaper_item.log_clusters[i] += glyph_pos;
 
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index 06075eb992..342a94de66 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -89,21 +89,6 @@ class QAbstractTextDocumentLayout;
 
 typedef quint32 glyph_t;
 
-#ifdef  __xlC__
-typedef unsigned q_hb_bitfield;
-#else
-typedef quint8 q_hb_bitfield;
-#endif
-
-struct QGlyphAttributes {
-    q_hb_bitfield justification   :4;
-    q_hb_bitfield clusterStart    :1;
-    q_hb_bitfield unused1         :1;
-    q_hb_bitfield unused2         :1;
-    q_hb_bitfield dontPrint       :1;
-    q_hb_bitfield unused3         :8;
-};
-
 // this uses the same coordinate system as Qt, but a different one to freetype.
 // * y is usually negative, and is equal to the ascent.
 // * negative yoff means the following stuff is drawn higher up.
@@ -174,6 +159,14 @@ struct QGlyphJustification
 };
 Q_DECLARE_TYPEINFO(QGlyphJustification, Q_PRIMITIVE_TYPE);
 
+struct QGlyphAttributes {
+    uchar clusterStart  : 1;
+    uchar dontPrint     : 1;
+    uchar justification : 4;
+    uchar reserved      : 2;
+};
+Q_STATIC_ASSERT(sizeof(QGlyphAttributes) == 1);
+
 struct QGlyphLayout
 {
     enum {
@@ -186,7 +179,7 @@ struct QGlyphLayout
     glyph_t *glyphs; // 4 bytes per element
     QFixed *advances; // 4 bytes per element
     QGlyphJustification *justifications; // 4 bytes per element
-    QGlyphAttributes *attributes; // 2 bytes per element
+    QGlyphAttributes *attributes; // 1 byte per element
 
     int numGlyphs;