Avoid wrong warning message on private pixel data.

Made sure that a warning message on compressed private pixel data is
only reported if the element length is really undefined.

Thanks to Mathieu Malaterre <[email protected]> for the
original report.

Author: jriesmeier

dcmdata/libsrc/dcitem.cc

@@ -4950,8 +4950,11 @@ OFCondition DcmItem::newDicomElement(DcmElement *&newElement,
                 // special handling for private pixel data (compressed or uncompressed)
                 if (newTag.getEVR() == EVR_px)
                 {
-                    DCMDATA_WARN("DcmItem: Found private element " << tag << " with VR=" << tag.getVRName()
-                        << " and undefined length, reading a pixel sequence according to data dictionary");
+                    if (length == DCM_UndefinedLength)
+                    {
+                        DCMDATA_WARN("DcmItem: Found private element " << tag << " with VR=" << tag.getVRName()
+                            << " and undefined length, reading a pixel sequence according to data dictionary");
+                    }
                     newElement = new DcmPixelData(tag, length);
                 }
             }