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ribtoks/build.sh

Last active Aug 20, 2017
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Solution of the Santa Claus problem in Ocaml
#!/bin/bash
rm santa_problem &> /dev/null
rm *.cmo &> /dev/null
rm *.cmi &> /dev/null
rm *.mli &> /dev/null
THREAD_PARAMS="-thread unix.cma threads.cma"
OCAML_COMMAND="ocamlc $THREAD_PARAMS"
$OCAML_COMMAND -i semaphore.ml > semaphore.mli
$OCAML_COMMAND -c semaphore.mli
$OCAML_COMMAND -c semaphore.ml
$OCAML_COMMAND semaphore.mli -i santa_problem.ml > santa_problem.mli
$OCAML_COMMAND semaphore.mli -c santa_problem.mli
$OCAML_COMMAND semaphore.mli -c santa_problem.ml
$OCAML_COMMAND -o santa_problem semaphore.cmo santa_problem.cmo
open Semaphore;;
let stdout_sem = new Semaphore.semaphore 1 "stdout_sem";;
let puts s =
stdout_sem#wait;
Printf.printf "%s\n" s;
flush stdout;
stdout_sem#signal ();;
type santa_counters = { mutable elves : int;
mutable reindeer : int;
santa_sem : Semaphore.semaphore;
reindeer_sem : Semaphore.semaphore;
elf_sem : Semaphore.semaphore;
elf_mutex : Semaphore.semaphore;
mutex : Semaphore.semaphore };;
let new_santa_counters () = { elves = 0;
reindeer = 0;
santa_sem = new Semaphore.semaphore 0 "santa_sem";
reindeer_sem = new Semaphore.semaphore 0 "reindeer_sem";
elf_sem = new Semaphore.semaphore 0 "elf_sem";
elf_mutex = new Semaphore.semaphore 1 "elf_mutex";
mutex = new Semaphore.semaphore 1 "mutex" };;
let prepare_sleigh () = puts "Prepare sleigh";;
let help_elves () = puts "Help Elves";;
let get_hitched () = puts "Get Hitched";;
let get_help () = puts "Get Help";;
let santa_role_func c =
c.santa_sem#wait;
c.mutex#wait;
if c.reindeer = 9 then (
prepare_sleigh ();
c.reindeer_sem#signal ~n:9 ();
c.reindeer <- 0;
)
else if c.elves = 3 then (
help_elves ();
c.elf_sem#signal ~n:3 ()
);
c.mutex#signal ();;
let reindeer_role_func (c, i) =
Thread.delay 0.5;
let s = Printf.sprintf "Starting reindeer (%d)" i in
puts s;
c.mutex#wait;
c.reindeer <- c.reindeer + 1;
if c.reindeer = 9 then c.santa_sem#signal ();
c.mutex#signal ();
c.reindeer_sem#wait;
get_hitched ();;
let elves_role_func (c, i) =
Thread.delay 0.5;
let s = Printf.sprintf "Starting elf [%d]" i in
puts s;
c.elf_mutex#wait;
c.mutex#wait;
c.elves <- c.elves + 1;
if c.elves = 3 then
c.santa_sem#signal ()
else
c.elf_mutex#signal ();
c.mutex#signal ();
c.elf_sem#wait;
get_help ();
c.mutex#wait;
c.elves <- c.elves - 1;
if c.elves = 0 then c.elf_mutex#signal ();
c.mutex#signal ();;
let c = new_santa_counters () in
let santa_loop () =
puts "Starting Santa loop";
while true do
santa_role_func c;
done
in
let santa_array = [| Thread.create santa_loop () |]
and
reindeer_array = Array.init 9 (fun i -> Thread.create reindeer_role_func (c, i))
and
elf_array = Array.init 20 (fun i -> Thread.create elves_role_func (c, i))
in
Array.iter Thread.join (Array.concat [santa_array; reindeer_array; elf_array]);;
flush_all ()
module Semaphore = struct
class semaphore initial_count initial_name =
object (self)
val mutable count = initial_count
val name = initial_name
val sync = Mutex.create()
val cond = Condition.create()
method inc n = count <- count + n
method dec n = count <- count - n
method signal ?(n=1) () =
Mutex.lock sync;
self#inc n;
for i = 1 to n do
Condition.signal cond
done;
Mutex.unlock sync
method wait =
Mutex.lock sync;
while count = 0 do
Condition.wait cond sync
done;
self#dec 1;
Mutex.unlock sync
end
end;;
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