From a87b549edfb66b3c3bc14466455792aea6e80c84 Mon Sep 17 00:00:00 2001
From: Joni Poikelin <joni.poikelin@qt.io>
Date: Wed, 17 Jan 2018 11:01:28 +0200
Subject: Fix compilation with -no-feature-regularexpression

Change-Id: I4d213a266034d388af723337deeeb4cdd1f5cbdb
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
---
 .../platforms/windows/qwindowsdialoghelpers.cpp    | 27 ++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp b/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
index 6b978a38fe..bdae764025 100644
--- a/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
+++ b/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
@@ -65,7 +65,6 @@
 #include <QtCore/QMutex>
 #include <QtCore/QMutexLocker>
 #include <QtCore/QUuid>
-#include <QtCore/QRegularExpression>
 #include <QtCore/QTemporaryFile>
 #include <QtCore/private/qsystemlibrary_p.h>
 
@@ -1153,12 +1152,32 @@ void QWindowsNativeFileDialogBase::setLabelText(QFileDialogOptions::DialogLabel
     }
 }
 
+static bool isHexRange(const QString& s, int start, int end)
+{
+    for (;start < end; ++start) {
+        QChar ch = s.at(start);
+        if (!(ch.isDigit()
+              || (ch >= QLatin1Char('a') && ch <= QLatin1Char('f'))
+              || (ch >= QLatin1Char('A') && ch <= QLatin1Char('F'))))
+            return false;
+    }
+    return true;
+}
+
 static inline bool isClsid(const QString &s)
 {
     // detect "374DE290-123F-4565-9164-39C4925E467B".
-   static const QRegularExpression pattern(QLatin1String("\\A[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{4}-[0-9A-Fa-f]{12}\\z"));
-   Q_ASSERT(pattern.isValid());
-   return pattern.match(s).hasMatch();
+    const QChar dash(QLatin1Char('-'));
+    return s.size() == 36
+            && isHexRange(s, 0, 8)
+            && s.at(8) == dash
+            && isHexRange(s, 9, 13)
+            && s.at(13) == dash
+            && isHexRange(s, 14, 18)
+            && s.at(18) == dash
+            && isHexRange(s, 19, 23)
+            && s.at(23) == dash
+            && isHexRange(s, 24, 36);
 }
 
 void QWindowsNativeFileDialogBase::selectFile(const QString &fileName) const
-- 
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