Class: HDF5::AttributeManager

Inherits:
Object
  • Object
show all
Defined in:
lib/hdf5/attribute.rb

Instance Method Summary collapse

Constructor Details

#initialize(dataset_id) ⇒ AttributeManager

Returns a new instance of AttributeManager.



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# File 'lib/hdf5/attribute.rb', line 55

def initialize(dataset_id)
  @dataset_id = dataset_id
end

Instance Method Details

#[](attr_name) ⇒ Object 



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# File 'lib/hdf5/attribute.rb', line 59

def [](attr_name)
  attr = Attribute.new(@dataset_id, attr_name)
  attr.read
ensure
  attr.close if attr
end

#[]=(attr_name, value) ⇒ Object 



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# File 'lib/hdf5/attribute.rb', line 66

def []=(attr_name, value)
  write(attr_name, value)
end

#write(attr_name, value) ⇒ Object 



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# File 'lib/hdf5/attribute.rb', line 70

def write(attr_name, value)
  values = normalize_data(value)
  datatype_id = datatype_id_for(values)

  exists = HDF5::FFI.H5Aexists(@dataset_id, attr_name)
  raise HDF5::Error, "Failed to check attribute existence: #{attr_name}" if exists.negative?

  if exists.positive?
    status = HDF5::FFI.H5Adelete(@dataset_id, attr_name)
    raise HDF5::Error, "Failed to replace attribute: #{attr_name}" if status < 0
  end

  dims = ::FFI::MemoryPointer.new(:ulong_long, 1)
  dims.write_array_of_ulong_long([values.length])
  dataspace_id = HDF5::FFI.H5Screate_simple(1, dims, nil)
  raise HDF5::Error, 'Failed to create attribute dataspace' if dataspace_id < 0

  attr_id = HDF5::FFI.H5Acreate2(
    @dataset_id,
    attr_name,
    datatype_id,
    dataspace_id,
    HDF5::DEFAULT_PROPERTY_LIST,
    HDF5::DEFAULT_PROPERTY_LIST
  )
  raise HDF5::Error, "Failed to create attribute: #{attr_name}" if attr_id < 0

  buffer = buffer_for(values)
  status = HDF5::FFI.H5Awrite(attr_id, datatype_id, buffer)
  raise HDF5::Error, "Failed to write attribute: #{attr_name}" if status < 0

  value
ensure
  HDF5::FFI.H5Aclose(attr_id) if attr_id && attr_id >= 0
  HDF5::FFI.H5Sclose(dataspace_id) if dataspace_id && dataspace_id >= 0
end