UUID

uuid.rb

class UUID
  def initialize
    @timestamp = timestamp
    @clockseq = clockseq
    @node = node
  end

  def to_s
    t = @timestamp
    sprintf("%08x-%04x-%04x-%04x-%012x", t[0], t[1], t[2] | version, @clockseq | variant, @node)
  end

  def timestamp
    # 60-bit value                                                                                                           
    now = Time.now
    usec = (now.tv_sec * 1000 * 1000) + now.tv_usec
    hsec = usec * 10   # 100-nanosecond intervals                                                                            

    time_low = hsec & 0x0000000ffffffff
    time_mid = (hsec & 0x000ffff00000000) >> 32
    time_hi  = (hsec & 0xfff000000000000) >> 48

    [ time_low, time_mid, time_hi ]
  end

  def version
    0b0001 << 12
  end

  def clockseq
    # 14-bit value                                                                                                           
    rand(0x10000) & ~0xc0000
  end

  def variant
    0x8000
  end

  def node
    rand(0x1000000000000) | 0x010000000000
  end
end