BUG: fix writing a corrupt meta image header from unknow metadata

If an entry in the metadata dictionary which had a type that the
MetaImagIO did not know about then an empty string in the written out
for the value. This is not readable by the metaIO library. So these
unknow or empty metadata entries, are not written.

Change-Id: I322676fdc63ba3b76e21968f986e1e841c0b8e38

Modules/IO/Meta/src/itkMetaImageIO.cxx

@@ -625,14 +625,22 @@ ::WriteImageInformation(void)
       {
       strs << bval;
       }
-    else
+
+    value = strs.str();
+
+    if (value == "" )
       {
-      itkWarningMacro("Unsupported metaData item "
-        << *keyIt << " of type "
-        << metaDict[*keyIt]->GetMetaDataObjectTypeName()
-        << "found, won't be written to image file");
+      // if the value is an empty string then the resulting entry in
+      // the header will not be able to be read the the metaIO
+      // library, which results is a unreadable/corrupt file.
+      itkWarningMacro("Unsupported or empty metaData item "
+                      << *keyIt << " of type "
+                      << metaDict[*keyIt]->GetMetaDataObjectTypeName()
+                      << "found, won't be written to image file");
+
+      // so this entry should be skipped.
+      continue;
       }
-    value = strs.str();
 
     // Rolling this back out so that the tests pass.
     // The meta image AddUserField requires control of the memory space.

Modules/IO/Meta/test/CMakeLists.txt

@@ -3,6 +3,7 @@ set(ITKIOMetaTests
 itkMetaImageIOMetaDataTest.cxx
 itkMetaImageIOGzTest.cxx
 itkMetaImageIOTest.cxx
+itkMetaImageIOTest2.cxx
 itkLargeMetaImageWriteReadTest.cxx
 testMetaArray.cxx
 testMetaBlob.cxx
@@ -34,6 +35,9 @@ itk_add_test(NAME itkMetaImageIOTest
     --compare DATA{${ITK_DATA_ROOT}/Baseline/IO/HeadMRVolume.mhd,HeadMRVolume.raw}
               ${ITK_TEST_OUTPUT_DIR}/HeadMRVolume.mhd
     itkMetaImageIOTest DATA{${ITK_DATA_ROOT}/Input/HeadMRVolume.mhd,HeadMRVolume.raw} ${ITK_TEST_OUTPUT_DIR}/HeadMRVolume.mhd)
+itk_add_test(NAME itkMetaImageIOTest2
+      COMMAND ITKIOMetaTestDriver itkMetaImageIOTest2
+      ${ITK_TEST_OUTPUT_DIR}/itkMetaImageIOTest2.mha)
 itk_add_test(NAME itkMetaImageIOShouldFailTest
       COMMAND ITKIOMetaTestDriver itkMetaImageIOTest
               DATA{${ITK_DATA_ROOT}/Input/MetaImageError.mhd} 1)

Modules/IO/Meta/test/itkMetaImageIOTest2.cxx

@@ -0,0 +1,113 @@
+/*=========================================================================
+ *
+ *  Copyright Insight Software Consortium
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0.txt
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *=========================================================================*/
+
+#include <fstream>
+#include "itkImageFileReader.h"
+#include "itkImageFileWriter.h"
+#include "itkMetaDataObject.h"
+#include "itkMetaImageIO.h"
+#include "itkTestingHashImageFilter.h"
+#include "itkTestingMacros.h"
+
+
+#define SPECIFIC_IMAGEIO_MODULE_TEST
+
+namespace
+{
+
+int TestUnknowMetaDataBug( const std::string &fname )
+{
+
+  std::cout << "Testing for unknow meta data entry bug." << std::endl;
+
+  try
+    {
+
+    typedef unsigned short           PixelType;
+    typedef itk::Image<PixelType, 2> ImageType;
+
+    ImageType::RegionType region;
+    ImageType::SizeType size = {{32,32}};
+    region.SetSize( size );
+
+    ImageType::Pointer image = ImageType::New();
+    image->SetRegions( region );
+    image->Allocate();
+    image->FillBuffer( 0 );
+
+    itk::MetaDataDictionary &dict = image->GetMetaDataDictionary();
+
+    itk::EncapsulateMetaData<float>(dict,"ASimpleFloatInitalized",static_cast<float>(1.234560F));
+    itk::EncapsulateMetaData<std::complex<float> >(dict,"AnUnsuportedComplexInitalized",std::complex<float>(1.234560F));
+
+    typedef itk::Testing::HashImageFilter<ImageType> Hasher;
+    Hasher::Pointer hasher = Hasher::New();
+    hasher->SetInput( image );
+    hasher->InPlaceOff();
+    hasher->Update();
+
+    std::string originalHash = hasher->GetHash();
+    std::cout << "\tOriginal image hash: " << originalHash << std::endl;
+
+
+    // Write image out
+    itk::ImageFileWriter<ImageType>::Pointer writer;
+    writer = itk::ImageFileWriter<ImageType>::New();
+    writer->SetInput( image );
+    writer->SetFileName( fname );
+    writer->Update();
+
+    itk::ImageFileReader<ImageType>::Pointer reader;
+    reader = itk::ImageFileReader<ImageType>::New();
+    reader->SetFileName( fname );
+
+    hasher->SetInput( reader->GetOutput() );
+    hasher->Update();
+
+    std::string readHash = hasher->GetHash();
+    std::cout << "\tRead hash: " << readHash << std::endl;
+
+    TEST_EXPECT_EQUAL( originalHash, readHash );
+
+    }
+  catch ( std::exception &e )
+    {
+    std::cerr << "Exception: " << e.what() << std::endl;
+    return EXIT_FAILURE;
+    }
+
+
+  return EXIT_SUCCESS;
+}
+
+}
+
+int itkMetaImageIOTest2(int argc, char* argv[])
+{
+  if(argc < 2)
+    {
+    std::cerr << "Usage: " << argv[0] << " Output\n";
+    return EXIT_FAILURE;
+    }
+
+  bool pass = true;
+
+  pass = ( TestUnknowMetaDataBug( argv[1] ) == EXIT_SUCCESS );
+
+  return EXIT_SUCCESS;
+}