From 2b31356ac9faaa3ad9522d3e8b0dd00d90877476 Mon Sep 17 00:00:00 2001
From: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Date: Thu, 13 Nov 2014 18:02:02 +0100
Subject: [PATCH] optimize filePrefixRoot()

more efficient use of string functions.

Change-Id: I3d95d6379eaab025b18449b706f93631a2132aad
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>
---
 qmake/generators/makefile.cpp | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/qmake/generators/makefile.cpp b/qmake/generators/makefile.cpp
index d2b11aaa017..5d9ce7af084 100644
--- a/qmake/generators/makefile.cpp
+++ b/qmake/generators/makefile.cpp
@@ -1190,11 +1190,13 @@ MakefileGenerator::writeObj(QTextStream &t, const char *src)
 QString
 MakefileGenerator::filePrefixRoot(const QString &root, const QString &path)
 {
-    QString ret(root + path);
+    QString ret(path);
     if(path.length() > 2 && path[1] == ':') //c:\foo
-        ret = QString(path.mid(0, 2) + root + path.mid(2));
-    while(ret.endsWith("\\"))
-        ret = ret.left(ret.length()-1);
+        ret.insert(2, root);
+    else
+        ret.prepend(root);
+    while (ret.endsWith('\\'))
+        ret.chop(1);
     return ret;
 }