Fix QString::isRightToLeft() to conform with Unicode Bidi algorithm

Rules P2 and P3 demand us to ignore the LRE/LRO/RLE/RLO
characters for determining the paragraph direction.

Task-Number: Part of QT-3292

2 files changed, 12 insertions, 10 deletions

diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index 1172a7b..1d5fab3 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -6916,20 +6916,23 @@ void QString::updateProperties() const
         p++;
     }
 
-    p = d->data;
-    d->righttoleft = false;
+    d->righttoleft = isRightToLeft();
+    d->clean = true;
+}
+
+bool QString::isRightToLeft() const
+{
+    ushort *p = d->data;
+    const ushort * const end = p + d->size;
+    bool righttoleft = false;
     while (p < end) {
         switch(QChar::direction(*p))
         {
         case QChar::DirL:
-        case QChar::DirLRO:
-        case QChar::DirLRE:
             goto end;
         case QChar::DirR:
         case QChar::DirAL:
-        case QChar::DirRLO:
-        case QChar::DirRLE:
-            d->righttoleft = true;
+            righttoleft = true;
             goto end;
         default:
             break;
@@ -6937,8 +6940,7 @@ void QString::updateProperties() const
         ++p;
     }
  end:
-    d->clean = true;
-    return;
+    return righttoleft;
 }
 
 /*! \fn bool QString::isSimpleText() const
diff --git a/src/corelib/tools/qstring.h b/src/corelib/tools/qstring.h
index a1c4e77..e52f59f 100644
--- a/src/corelib/tools/qstring.h
+++ b/src/corelib/tools/qstring.h
@@ -590,7 +590,7 @@ public:
 #endif
 
     bool isSimpleText() const { if (!d->clean) updateProperties(); return d->simpletext; }
-    bool isRightToLeft() const { if (!d->clean) updateProperties(); return d->righttoleft; }
+    bool isRightToLeft() const;
 
     QString(int size, Qt::Initialization);