#!/usr/bin/env ruby
#require 'rubygems'
#require 'pry'
#require 'pp'

# This scripts returns a list of MAC addresses.
# Usage:
# ./$0 LIMIT START END
# ./genmac.rb 5 00:50:56:00:00:00 00:50:56:3F:FF:FF
#
# With limit you can set how many MAC addresses you want to have returned. Use 0 for unlimited results
# Start and end are obvious, end ist optional.

class String
  def to_mac
      MacAddress.new(self).to_s
  end
end

class MacAddress
  def initialize(str)
    raise ArgumentError.new("Nil? Really?")  if str.nil?
    if str.is_a?(String)
      @mac_str = str.strip
      n = @mac_str.index(':')
      if not n.nil? and n >= 12
        @mac_str = @mac_str.split(':')[0]
      end
      @mac_str = @mac_str.downcase.gsub(/^0[xX]/,'').gsub(/[^0-9a-f]/,'')
      raise ArgumentError.new("Invalid MAC address: #{str}") if @mac_str.length != 12
    elsif str.is_a?(Fixnum) or str.is_a?(Integer)
      @mac_str = str.to_s(16)
      (12 - @mac_str.size).times {|x| @mac_str = '0' + @mac_str }
    else
      ArgumentError.new("Don't know what #{str} is.")
    end
  end

  def to_i
    @mac_str.hex
  end

  def to_s
    arr = @mac_str.scan(/../)
    arr.join(":")
  end

  def mac
    @mac_str
  end
end

begin
  limit = ARGV[0].to_i unless ARGV[0].nil?
  start = MacAddress.new(ARGV[1])
  stop = MacAddress.new(ARGV[2])
rescue
end

start ||= MacAddress.new("00:50:56:00:00:00")
stop ||= MacAddress.new("FF:FF:FF:FF:FF:FF")
limit ||= -1

start.to_i.upto(stop.to_i).each do |x|
  puts MacAddress.new(x).to_s

  break if limit == 1
  limit = limit - 1 unless limit == -1
end