text: # Copyright (c) Twisted Matrix Laboratories.
  # See LICENSE for details.
  
  #
  """Logictech MouseMan serial protocol.
  
  http://www.softnco.demon.co.uk/SerialMouse.txt
  """
  
  from twisted.internet import protocol
  
  class MouseMan(protocol.Protocol):
      """
  
      Parser for Logitech MouseMan serial mouse protocol (compatible
      with Microsoft Serial Mouse).
  
      """
  
      state = 'initial'
  
      leftbutton=None
      rightbutton=None
      middlebutton=None
  
      leftold=None
      rightold=None
      middleold=None
  
      horiz=None
      vert=None
      horizold=None
      vertold=None
  
      def down_left(self):
          pass
  
      def up_left(self):
          pass
  
      def down_middle(self):
          pass
  
      def up_middle(self):
          pass
  
      def down_right(self):
          pass
  
      def up_right(self):
          pass
  
      def move(self, x, y):
          pass
  
      horiz=None
      vert=None
  
      def state_initial(self, byte):
          if byte & 1<<6:
              self.word1=byte
              self.leftbutton = byte & 1<<5
              self.rightbutton = byte & 1<<4
              return 'horiz'
          else:
              return 'initial'
  
      def state_horiz(self, byte):
          if byte & 1<<6:
              return self.state_initial(byte)
          else:
              x=(self.word1 & 0x03)<<6 | (byte & 0x3f)
              if x>=128:
                  x=-256+x
              self.horiz = x
              return 'vert'
  
      def state_vert(self, byte):
          if byte & 1<<6:
              # short packet
              return self.state_initial(byte)
          else:
              x = (self.word1 & 0x0c)<<4 | (byte & 0x3f)
              if x>=128:
                  x=-256+x
              self.vert = x
              self.snapshot()
              return 'maybemiddle'
  
      def state_maybemiddle(self, byte):
          if byte & 1<<6:
              self.snapshot()
              return self.state_initial(byte)
          else:
              self.middlebutton=byte & 1<<5
              self.snapshot()
              return 'initial'
  
      def snapshot(self):
          if self.leftbutton and not self.leftold:
              self.down_left()
              self.leftold=1
          if not self.leftbutton and self.leftold:
              self.up_left()
              self.leftold=0
  
          if self.middlebutton and not self.middleold:
              self.down_middle()
              self.middleold=1
          if not self.middlebutton and self.middleold:
              self.up_middle()
              self.middleold=0
  
          if self.rightbutton and not self.rightold:
              self.down_right()
              self.rightold=1
          if not self.rightbutton and self.rightold:
              self.up_right()
              self.rightold=0
  
          if self.horiz or self.vert:
              self.move(self.horiz, self.vert)
  
      def dataReceived(self, data):
          for c in data:
              byte = ord(c)
              self.state = getattr(self, 'state_'+self.state)(byte)
  