#--
# ByteOrder
#
# Copyright (c) 2003 Michael Neumann
#
# ==========================================================================
# Revision History ::
# --------------------------------------------------------------------------
#  2005.04.28  TO   * Minor modifications to documentation.
# ==========================================================================
#
# :NOTE: This seems like a little much for what's really a single method.
#        In the future this should be reduced and moved to Nano Methods.
#        Only reason I haven't done so yet, is b/c BinaryReader
#        depends on it.
#
#++

#:title: ByteOrder
#
# ByteOrder module makes it possible to determine your systems
# byte order, either big or little endian.
#
# == Usage
#
#   ByteOrder.byteorder => :LittleEndian
#
# == Author(s)
#
# * Michael Neumann
#
#
module ByteOrder

  Native = :Native
  BigEndian = Big = Network = :BigEndian
  LittleEndian = Little = :LittleEndian

  # examines the byte order of the underlying machine
  def byte_order
    if [0x12345678].pack("L") == "\x12\x34\x56\x78"
      BigEndian
    else
      LittleEndian
    end
  end

  alias_method :byteorder, :byte_order

  def little_endian?
    byte_order == LittleEndian
  end

  def big_endian?
    byte_order == BigEndian
  end

  alias little? little_endian?
  alias big? big_endian?
  alias network? big_endian?

  module_function :byte_order, :byteorder
  module_function :little_endian?, :little?
  module_function :big_endian?, :big?, :network?

end



#  _____         _
# |_   _|__  ___| |_
#   | |/ _ \/ __| __|
#   | |  __/\__ \ |_
#   |_|\___||___/\__|
#

=begin testing

  # By Michael Neumann

  require 'test/unit'

  class TC_ByteOrder < Test::Unit::TestCase

    def test_equal
      assert_equal ByteOrder.little?, ByteOrder.little_endian?
      assert_equal ByteOrder.big?, ByteOrder.big_endian?
      assert_equal ByteOrder.network?, ByteOrder.big_endian?
      assert_equal ByteOrder.byte_order, ByteOrder.byteorder

      assert_equal ByteOrder::Big, ByteOrder::BigEndian
      assert_equal ByteOrder::Network, ByteOrder::BigEndian
      assert_equal ByteOrder::Little, ByteOrder::LittleEndian

      assert_equal ByteOrder.byte_order, ByteOrder::LittleEndian if ByteOrder.little?
      assert_equal ByteOrder.byte_order, ByteOrder::BigEndian if ByteOrder.big?
    end

    def test_uname_byteorder
      assert_equal(ByteOrder.little?, true) if `uname -m` =~ /i386/
    end

    def test_byteorder
      if ByteOrder.little?
        assert_equal "\x12\x34\x56\x78".unpack("L").first, 0x78563412
        assert_equal "\x78\x56\x34\x12".unpack("L").first, 0x12345678
        assert_equal [0x12345678].pack("L"), "\x78\x56\x34\x12"
        assert_equal [0x78563412].pack("L"), "\x12\x34\x56\x78"
      else
        assert_equal "\x12\x34\x56\x78".unpack("L").first, 0x12345678
        assert_equal "\x78\x56\x34\x12".unpack("L").first, 0x78563412 
        assert_equal [0x12345678].pack("L"), "\x12\x34\x56\x78"
        assert_equal [0x78563412].pack("L"), "\x78\x56\x34\x12"
      end
    end

  end

=end