read_pcd.rb

#!/usr/bin/env ruby

class PCD
  # PCD file must have fields precisely in this order
  DATA_FIELDS = %w(
VERSION
FIELDS
SIZE
TYPE
COUNT
WIDTH
HEIGHT
VIEWPOINT
POINTS
DATA
  ).freeze

  def initialize(opts)
    DATA_FIELDS.each do |field_name|
      method_name = field_name.upcase

      # Define readers for each field
      self.class.class_eval do
        attr_reader method_name.to_sym
        alias_method method_name.to_sym, method_name.to_sym
      end

      val = opts[method_name.to_sym] || opts[method_name.downcase.to_sym]
      self.instance_variable_set("@#{method_name}", val)
    end
  end
end

opts = {
  VERSION: 0.7,
  FIELDS: %w(rgb x y z _),
  SIZE: %w(4 4 4 4 1),
  TYPE: %w(F F F F U),
  COUNT: %w(1 1 1 1 4),
  WIDTH: 4728,
  HEIGHT: 1,
  VIEWPOINT: %w(0 0 0 1 0 0 0),
  POINTS: 4728,
  DATA: 'binary'
}

pcd = PCD.new(opts)
puts pcd.inspect