Method: Origami::Filter::RunLength#encode

Defined in:
lib/origami/filters/runlength.rb

#encode(stream) ⇒ Object

Encodes data using RLE compression method.

stream

The data to encode.



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# File 'lib/origami/filters/runlength.rb', line 40

def encode(stream)
    result = "".b
    i = 0

    while i < stream.size

        # How many identical bytes coming?
        length = compute_run_length(stream, i)

        # If more than 1, then compress them.
        if length > 1
            result << (257 - length).chr << stream[i]
            i += length

        # Otherwise how many different bytes to copy?
        else
            next_pos = find_next_run(stream, i)
            length = next_pos - i

            result << (length - 1).chr << stream[i, length]

            i += length
        end
    end

    result << EOD.chr
end