module Net; module SSH
  # A class for describing the current version of a library. The version
  # consists of three parts: the +major+ number, the +minor+ number, and the
  # +tiny+ (or +patch+) number.
  #
  # Two Version instances may be compared, so that you can test that a version
  # of a library is what you require:
  #
  #   require 'net/ssh/version'
  #
  #   if Net::SSH::Version::CURRENT < Net::SSH::Version[2,1,0]
  #     abort "your software is too old!"
  #   end
  class Version
    include Comparable

    # A convenience method for instantiating a new Version instance with the
    # given +major+, +minor+, and +tiny+ components.
    def self.[](major, minor, tiny, pre = nil)
      new(major, minor, tiny, pre)
    end

    attr_reader :major, :minor, :tiny

    # Create a new Version object with the given components.
    def initialize(major, minor, tiny, pre = nil)
      @major, @minor, @tiny, @pre = major, minor, tiny, pre
    end

    # Compare this version to the given +version+ object.
    def <=>(version)
      to_i <=> version.to_i
    end

    # Converts this version object to a string, where each of the three
    # version components are joined by the '.' character. E.g., 2.0.0.
    def to_s
      @to_s ||= [@major, @minor, @tiny, @pre].compact.join(".")
    end

    # Converts this version to a canonical integer that may be compared
    # against other version objects.
    def to_i
      @to_i ||= @major * 1_000_000 + @minor * 1_000 + @tiny
    end

    # The major component of this version of the Net::SSH library
    MAJOR = 3

    # The minor component of this version of the Net::SSH library
    MINOR = 0

    # The tiny component of this version of the Net::SSH library
    TINY  = 1

    # The prerelease component of this version of the Net::SSH library 
    # nil allowed
    PRE   = nil

    # The current version of the Net::SSH library as a Version instance
    CURRENT = new(*[MAJOR, MINOR, TINY, PRE].compact)

    # The current version of the Net::SSH library as a String
    STRING = CURRENT.to_s
  end
end; end
