I have tried numerous ways and followed some of the examples that are scattered around the web on how to write a jagged array (an array of arrays that may be of differing lengths) in HDF5.
Most of the examples are in C and rather low-level. Anyhow I can't seem to get it working and I just looked at the C-source code and it pretty much says that any variable-length datatypes that are not strings are not supported (if I understood correctly).
My miserable dysfunctional code (as is):
public void WIP_createVLenFloatDataSet( List<? extends Number> floats ) throws Exception
{
String group = "/test";
long groupId = createGroupIfNotExist( group );
MDataQualifier qualifier = new MDataQualifierImpl( group, "float", "0.0.0" );
long datasetId = openDataSet( qualifier );
long heapType = H5.H5Tcopy( MDataType.FLOAT_ARRAY.getHDFType() );
heapType = H5.H5Tvlen_create( heapType );
// heapType = H5.H5Tarray_create( heapType, 1, new long[]{1} );
if( !exists( datasetId ) )
{
long[] maxDims = new long[]{ HDF5Constants.H5S_UNLIMITED };
long dataspaceId = H5.H5Screate_simple( 1, new long[]{ 1 }, null );
// Create the dataset.
long datasetId1 = -1;
try
{
if( exists( m_fileId ) && exists( dataspaceId ) && exists( heapType ) )
{
long creationProperties = H5.H5Pcreate( HDF5Constants.H5P_DATASET_CREATE );
H5.H5Pset_chunk( creationProperties, /*ndims*/1, new long[]{ 1 } );
datasetId1 = H5.H5Dcreate( groupId, qualifier.getVersionedName(), heapType, dataspaceId, H5P_DEFAULT, creationProperties, H5P_DEFAULT );
// H5.H5Pclose( creationProperties );
}
}
catch( Exception e )
{
LOG.error( "Problems creating the dataset: " + e.getMessage(), e );
}
datasetId = datasetId1;
if( exists( datasetId ) )
{
// flushIfNecessary();
LOG.trace( "Wrote empty dataset {}", qualifier.getVersionedName() );
}
}
List<? extends Number> data = ( List<? extends Number> )floats;
// H5.H5Dwrite( datasetId, heapType, dataspaceId, memSpaceId, HDF5Constants.H5P_DEFAULT, Floats.toArray( data) );
ByteBuffer bb = ByteBuffer.allocate( data.size() * 4 );
floats.forEach( f -> bb.putFloat( f.floatValue() ) );
// H5.H5Dwrite( datasetId, heapType, H5S_ALL, H5S_ALL, H5P_DEFAULT, Floats.toArray( data ) );
H5.H5Dwrite( datasetId, heapType, H5S_ALL, H5S_ALL, H5P_DEFAULT, bb.array() );
}
Has anyone done this before and can at least confirm that it's not possible? The most I can get out of HDF5 is the message "buf does not support variable length type".
