Method: OpenC3::BufferedFile#read

Defined in:
lib/openc3/io/buffered_file.rb,
ext/openc3/ext/buffered_file/buffered_file.c

#read(arg_length) ⇒ Object

Read using an internal buffer to avoid system calls



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# File 'lib/openc3/io/buffered_file.rb', line 35

def read(read_length)
  if read_length <= (@buffer.length - @buffer_index)
    # Return part of the buffer without having to go to the OS
    result = @buffer[@buffer_index, read_length]
    @buffer_index += read_length
    return result
  elsif read_length > BUFFER_SIZE
    # Reading more than our buffer
    if @buffer.length > 0
      if @buffer_index > 0
        @buffer.slice!(0..(@buffer_index - 1))
        @buffer_index = 0
      end
      @buffer << super(read_length - @buffer.length).to_s
      return @buffer.slice!(0..-1)
    else
      return super(read_length)
    end
  else
    # Read into the buffer
    if @buffer_index > 0
      @buffer.slice!(0..(@buffer_index - 1))
      @buffer_index = 0
    end
    @buffer << super(BUFFER_SIZE - @buffer.length).to_s
    if @buffer.length <= 0
      return nil
    end

    if read_length <= @buffer.length
      result = @buffer[@buffer_index, read_length]
      @buffer_index += read_length
      return result
    else
      return @buffer.slice!(0..-1)
    end
  end
end