Method: Origami::PDF#get_object

Defined in:
lib/origami/pdf.rb

#get_object(no, generation = 0, use_xrefstm: true) ⇒ Object Also known as: []

Search for an indirect object in the document.

no

Reference or number of the object.

generation

Object generation.



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# File 'lib/origami/pdf.rb', line 495

def get_object(no, generation = 0, use_xrefstm: true) #:nodoc:
    case no
    when Reference
        target = no
    when ::Integer
        target = Reference.new(no, generation)
    when Origami::Object
        return no
    else
        raise TypeError, "Invalid parameter type : #{no.class}"
    end

    #
    # Search through accessible indirect objects.
    #
    @revisions.reverse_each do |rev|
        return rev.body[target] if rev.body.include?(target)
    end

    #
    # Search through xref sections.
    #
    @revisions.reverse_each do |rev|
        next unless rev.has_xreftable?

        xref = rev.xreftable.find(target.refno)
        next if xref.nil? or xref.free?

        # Try loading the object if it is not present.
        object = load_object_at_offset(rev, xref.offset)
        return object unless object.nil?
    end

    return nil unless use_xrefstm

    # Search through xref streams.
    @revisions.reverse_each do |rev|
        next unless rev.has_xrefstm?

        xrefstm = rev.xrefstm

        xref = xrefstm.find(target.refno)
        next if xref.nil?

        #
        # We found a matching XRef.
        #
        if xref.is_a?(XRefToCompressedObj)
            objstm = get_object(xref.objstmno, 0, use_xrefstm: use_xrefstm)

            object = objstm.extract_by_index(xref.index)
            if object.is_a?(Origami::Object) and object.no == target.refno
                return object
            else
                return objstm.extract(target.refno)
            end
        elsif xref.is_a?(XRef)
            object = load_object_at_offset(rev, xref.offset)
            return object unless object.nil?
        end
    end

    #
    # Lastly search directly into Object streams (might be very slow).
    #
    @revisions.reverse_each do |rev|
        stream = rev.objects.find{|obj| obj.is_a?(ObjectStream) and obj.include?(target.refno)}
        return stream.extract(target.refno) unless stream.nil?
    end

    nil
end