From d826a08add652314bb22bee44e0d43bbd672f272 Mon Sep 17 00:00:00 2001
From: Leonardo Sobral Cunha <leo.cunha@nokia.com>
Date: Tue, 9 Jun 2009 12:02:59 +0200
Subject: Fix floating point exception in QImageReader::setScaledSize(QSize(0,
 0))

Avoid a division by 0 when doing QImageReader::setScaledSize(QSize(0, 0))
for jpeg formats.

Reviewed-by: thierry
Task-number: 255627
---
 src/plugins/imageformats/jpeg/qjpeghandler.cpp |  3 ++-
 tests/auto/qimagereader/tst_qimagereader.cpp   | 26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/plugins/imageformats/jpeg/qjpeghandler.cpp b/src/plugins/imageformats/jpeg/qjpeghandler.cpp
index 6d0bc1f..088ef97 100644
--- a/src/plugins/imageformats/jpeg/qjpeghandler.cpp
+++ b/src/plugins/imageformats/jpeg/qjpeghandler.cpp
@@ -781,7 +781,8 @@ static bool read_jpeg_image(QIODevice *device, QImage *outImage,
 
 #ifndef QT_NO_IMAGE_SMOOTHSCALE
         // If high quality not required, shrink image during decompression
-        if (scaledSize.isValid() && quality < HIGH_QUALITY_THRESHOLD && !params.contains(QLatin1String("GetHeaderInformation")) ) {
+        if (scaledSize.isValid() && !scaledSize.isEmpty() && quality < HIGH_QUALITY_THRESHOLD
+            && !params.contains(QLatin1String("GetHeaderInformation")) ) {
             cinfo.scale_denom = qMin(cinfo.image_width / scaledSize.width(),
                                      cinfo.image_width / scaledSize.height());
             if (cinfo.scale_denom < 2) {
diff --git a/tests/auto/qimagereader/tst_qimagereader.cpp b/tests/auto/qimagereader/tst_qimagereader.cpp
index f5313eb..0b32f0a 100644
--- a/tests/auto/qimagereader/tst_qimagereader.cpp
+++ b/tests/auto/qimagereader/tst_qimagereader.cpp
@@ -156,6 +156,9 @@ private slots:
 
     void pixelCompareWithBaseline_data();
     void pixelCompareWithBaseline();
+
+    void task255627_setNullScaledSize_data();
+    void task255627_setNullScaledSize();
 };
 
 static const QLatin1String prefix(SRCDIR "/images/");
@@ -333,6 +336,29 @@ void tst_QImageReader::setScaledSize()
     QCOMPARE(image.size(), newSize);
 }
 
+void tst_QImageReader::task255627_setNullScaledSize_data()
+{
+    setScaledSize_data();
+}
+
+void tst_QImageReader::task255627_setNullScaledSize()
+{
+    QFETCH(QString, fileName);
+    QFETCH(QByteArray, format);
+
+    if (!format.isEmpty() && !QImageReader::supportedImageFormats().contains(format))
+        QSKIP("Qt does not support reading the \"" + format + "\" format", SkipSingle);
+
+    QImageReader reader(prefix + fileName);
+
+    // set a null size
+    reader.setScaledSize(QSize(0, 0));
+    reader.setQuality(0);
+    QImage image = reader.read();
+    QVERIFY(image.isNull());
+    QCOMPARE(image.size(), QSize(0, 0));
+}
+
 void tst_QImageReader::setClipRect_data()
 {
     QTest::addColumn<QString>("fileName");
-- 
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