Cut away 2/3 of the startup time on Linux

Optimize the parser of the X11 compose tables. Parsing these was
responsible for over 90% of the startup time in Qt 5.1.

Change-Id: Ifddc3f30828791e51a755f92791c26ffe43a9cd3
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp b/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp
index 433c9eec37..611b9fdd9b 100644
--- a/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp
+++ b/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp
@@ -169,11 +169,11 @@ static bool isDuplicate(const QComposeTableElement &lhs, const QComposeTableElem
 
 bool QComposeInputContext::checkComposeTable()
 {
-    QList<QComposeTableElement>::iterator it =
-            qLowerBound(m_composeTable.begin(), m_composeTable.end(), m_composeBuffer, Compare());
+    QVector<QComposeTableElement>::const_iterator it =
+            qLowerBound(m_composeTable.constBegin(), m_composeTable.constEnd(), m_composeBuffer, Compare());
 
     // prevent dereferencing an 'end' iterator, which would result in a crash
-    if (it == m_composeTable.end())
+    if (it == m_composeTable.constEnd())
         it -= 1;
 
     QComposeTableElement elem = *it;