Class: Cicada::Serialization

Inherits:
Object
  • Object
show all
Defined in:
lib/cicada/file_interaction.rb

Overview

Handles the serialization of the ImageObjects for storing them in a file.

The serialized output will consist of an XML file describing the objects in human-readable form and including a binary data sectiobn containing the serialized object. This binary section is the only thing read back in, so changing the XML human-readable portion of the file manually will not affect the data read back in.

Class Method Summary collapse

Class Method Details

.image_object_from_bytes(bin_data) ⇒ ImageObject

Restores an image object from a byte string.

Parameters:

  • bin_data (String) —

    the bytes representing the image object. This should be a standard byte string. The XML files use base64 encoding, and the data should already be unencoded.

Returns:

  • (ImageObject) —

    the encoded ImageObject



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# File 'lib/cicada/file_interaction.rb', line 81

def self.image_object_from_bytes(bin_data)
  Marshal.load(bin_data)
end

.serialize_image_objects(image_objects) ⇒ String

Converts an array of ImageObjects to an XML-formatted string containing the serialized data.

Parameters:

  • image_objects (Enumerable<ImageObject>) —

    an Enumerable list of image objects

Returns:

  • (String) —

    a string containing formatted XML and binary representations of the image objects.



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# File 'lib/cicada/file_interaction.rb', line 57

def self.serialize_image_objects(image_objects)
  doc = REXML::Document.new
  doc.add_element "root"

  image_objects.each do |iobj|
    in_doc = REXML::Document.new iobj.writeToXMLString
    in_doc.root.elements[1, "serialized_form"].text = Base64.encode64(Marshal.dump(iobj))
    doc.root.add in_doc.elements[1,"image_object"]
  end

  output = ""
  doc.write(output, 2)
  output
end

.unserialize_image_objects(data) ⇒ Array<ImageObject>

Restores image objects from an XML string containing their serialized representation. (This uses the base64 encoded binary information in the XML file, not the human readable portion.)

Parameters:

  • data (String) —

    the XML string

Returns:

  • (Array<ImageObject>) —

    the image objects encoded in the string



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# File 'lib/cicada/file_interaction.rb', line 93

def self.unserialize_image_objects(data)
  objs = []
  doc = REXML::Document.new data

  doc.elements.each("*/image_object/serialized_form") do |el|
    bin_data = Base64.decode64(el.text)
    objs << image_object_from_bytes(bin_data)
  end

  objs
end