tdf#96326 RTF import: handle checkbox form field undefined result

The RTF spec is quite terse on how the form filed result should be
interpreted, but the binary equivalent documents properly that
checkboxes have 3 valid states: 0, 1 and 25, the later meaning
undefined. Use the default value in that case.

Change-Id: I672bf8d1f63d7880227b7fa7b5c81f91e1877b2a

sw/qa/extras/rtfimport/data/tdf96326.rtf

+{\rtf1\adeflang1025\ansi\ansicpg1252\uc1\adeff1\deff0\stshfdbch0\stshfloch0\stshfhich0\stshfbi0\deflang1033\deflangfe1033\themelang1035\themelangfe0\themelangcs0
+\pard\plain
+This is not checked:
+{\field\flddirty\fldpriv
+{\*\fldinst
+ FORMCHECKBOX
+{\*\formfield
+{\fftype1\ffres25\fftypetxt0\ffhps20
+\ffdefres0}
+}
+}
+{\fldrslt }
+}
+\par
+This is checked:
+{\field\fldpriv
+{\*\fldinst
+ FORMCHECKBOX
+{\*\formfield
+{\fftype1\ffres25\fftypetxt0\ffhps20
+\ffdefres1}
+}
+}
+{\fldrslt }
+}
+\par
+}

sw/qa/extras/rtfimport/rtfimport.cxx

@@ -49,6 +49,7 @@
 #include <com/sun/star/text/WritingMode2.hpp>
 #include <com/sun/star/util/XNumberFormatsSupplier.hpp>
 #include <com/sun/star/graphic/XGraphic.hpp>
+#include <com/sun/star/text/XFormField.hpp>
 
 #include <rtl/ustring.hxx>
 #include <vcl/outdev.hxx>
@@ -1283,6 +1284,20 @@ DECLARE_RTFIMPORT_TEST(testPoshPosv, "posh-posv.rtf")
     CPPUNIT_ASSERT_EQUAL(true, getProperty<bool>(getShape(1), "FrameIsAutomaticHeight"));
 }
 
+DECLARE_RTFIMPORT_TEST(testTdf96326, "tdf96326.rtf")
+{
+    // Make sure this is not checked.
+    auto xFormField = getProperty< uno::Reference<text::XFormField> >(getRun(getParagraph(1), 2), "Bookmark");
+    uno::Reference<container::XNameContainer> xParameters = xFormField->getParameters();
+    // This was true, ffres=25 was interpreted as checked.
+    CPPUNIT_ASSERT_EQUAL(false, bool(xParameters->hasElements()));
+
+    // And this is checked.
+    xFormField = getProperty< uno::Reference<text::XFormField> >(getRun(getParagraph(2), 2), "Bookmark");
+    xParameters = xFormField->getParameters();
+    CPPUNIT_ASSERT_EQUAL(true, xParameters->getByName("Checkbox_Checked").get<bool>());
+}
+
 DECLARE_RTFIMPORT_TEST(testN825305, "n825305.rtf")
 {
     // The problem was that the textbox wasn't transparent, due to unimplemented fFilled == 0.

writerfilter/source/rtftok/rtfdocumentimpl.cxx

@@ -4462,7 +4462,8 @@ RTFError RTFDocumentImpl::dispatchValue(RTFKeyword nKeyword, int nParam)
             m_aFormfieldSprms.set(NS_ooxml::LN_CT_FFDDList_default, pIntValue);
         break;
     case RTF_FFRES:
-        if (m_nFormFieldType == RTFFormFieldType::CHECKBOX)
+        // 25 means undefined, see [MS-DOC] 2.9.79, FFDataBits.
+        if (m_nFormFieldType == RTFFormFieldType::CHECKBOX && nParam != 25)
             m_aFormfieldSprms.set(NS_ooxml::LN_CT_FFCheckBox_checked, pIntValue);
         else if (m_nFormFieldType == RTFFormFieldType::LIST)
             m_aFormfieldSprms.set(NS_ooxml::LN_CT_FFDDList_result, pIntValue);