regress/sys/uvm/pdsim/lfu.hs

   1 {-
   2 /*      $NetBSD: lfu.hs,v 1.1 2006/09/30 08:50:32 yamt Exp $    */
   3
   4 /*-
   5  * Copyright (c)2005 YAMAMOTO Takashi,
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29 -}
  30
  31 import System.Environment
  32 import System.IO
  33 import List
  34 import Maybe
  35 import Monad
  36
  37 pgmatch idx pg = idx == fst pg
  38
  39 pglookup :: Eq a => a -> [(a,b)] -> Maybe (a,b)
  40 pglookup x = find (pgmatch x)
  41
  42 pgdequeue :: Eq a => a -> [a] -> [a]
  43 pgdequeue = delete
  44
  45 victim :: Ord b => [(a,b)] -> (a,b)
  46 victim = minimumBy p where
  47         p x y = compare (snd x) (snd y)
  48
  49 do_lfu1 npg n q qlen [] = (reverse n, q)
  50 do_lfu1 npg n q qlen rs@(r:rs2) =
  51         let
  52                 p = pglookup r q
  53         in
  54         if isJust p then
  55                 let
  56                         opg = fromJust p
  57                         nq = pgdequeue opg q
  58                         pg = (fst opg, snd opg + 1)
  59                 in
  60                 do_lfu1 npg n (pg:nq) qlen rs2
  61         else if qlen < npg then
  62                 do_lfu1 npg (r:n) ((r,1):q) (qlen+1) rs2
  63         else
  64                 let
  65                         opg = victim q
  66                         nq = pgdequeue opg q
  67                 in
  68                 do_lfu1 npg (r:n) ((r,1):nq) qlen rs2
  69
  70 do_lfu npg rs = fst $ do_lfu1 npg [] [] 0 rs
  71
  72 main = do
  73         xs <- getContents
  74         args <- getArgs
  75         let
  76                 ls = lines xs
  77                 npgs::Int
  78                 npgs = read $ args !! 0
  79                 pgs::[Int]
  80                 pgs = map read ls
  81         mapM_ print $ do_lfu npgs pgs