INTEGER FUNCTION istring2integer(c4)
  CHARACTER(4) :: c4
  j0001=1
  j0010=256
  j0100=256*256
  j1000=256*256*256
  i1000=ichar(c4(1:1))
  i0100=ichar(c4(2:2))
  i0010=ichar(c4(3:3))
  i0001=ichar(c4(4:4))
  i4=i1000*j1000+i0100*j0100+i0010*j0010+i0001*j0001
  istring2integer=i4 
  RETURN
  END FUNCTION istring2integer