basis-library/posix/flags.sml

   1 (* Copyright (C) 1999-2006 Henry Cejtin, Matthew Fluet, Suresh
   2  *    Jagannathan, and Stephen Weeks.
   3  * Copyright (C) 1997-2000 NEC Research Institute.
   4  *
   5  * MLton is released under a BSD-style license.
   6  * See the file MLton-LICENSE for details.
   7  *)
   8
   9 functor BitFlags(structure S : sig
  10                     eqtype t
  11                     val castToSysWord: t -> SysWord.word
  12                     val castFromSysWord: SysWord.word -> t
  13                     val andb: t * t -> t
  14                     val notb: t -> t
  15                     val orb: t * t -> t
  16                  end): BIT_FLAGS_EXTRA =
  17    struct
  18       type flags = S.t
  19
  20       val all: flags = S.castFromSysWord (SysWord.~ 0w1)
  21       val empty: flags = S.castFromSysWord 0w0
  22
  23       fun toWord f = S.castToSysWord f
  24       fun fromWord w = S.castFromSysWord (SysWord.andb (w, toWord all))
  25
  26       val flags: flags list -> flags = List.foldl S.orb empty
  27
  28       val intersect: flags list -> flags = List.foldl S.andb all
  29
  30       fun clear (f, f') = S.andb (S.notb f, f')
  31
  32       fun allSet (f, f') = S.andb (f, f') = f'
  33
  34       fun anySet (f, f') = S.andb (f, f') <> empty
  35    end