1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT LIBRARY COMPONENTS                          --
4--                                                                          --
5--                      G N A T . S E M A P H O R E S                       --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--              Copyright (C) 2003 Ada Core Technologies, Inc.              --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 2,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
19-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
20-- MA 02111-1307, USA.                                                      --
21--                                                                          --
22-- As a special exception,  if other files  instantiate  generics from this --
23-- unit, or you link  this unit with other files  to produce an executable, --
24-- this  unit  does not  by itself cause  the resulting  executable  to  be --
25-- covered  by the  GNU  General  Public  License.  This exception does not --
26-- however invalidate  any other reasons why  the executable file  might be --
27-- covered by the  GNU Public License.                                      --
28--                                                                          --
29-- GNAT was originally developed  by the GNAT team at  New York University. --
30-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
31--                                                                          --
32------------------------------------------------------------------------------
33
34package body GNAT.Semaphores is
35
36   ------------------------
37   -- Counting_Semaphore --
38   ------------------------
39
40   protected body Counting_Semaphore is
41
42      -----------
43      -- Seize --
44      -----------
45
46      entry Seize when Count > 0 is
47      begin
48         Count := Count - 1;
49      end Seize;
50
51      -------------
52      -- Release --
53      -------------
54
55      procedure Release is
56      begin
57         Count := Count + 1;
58      end Release;
59   end Counting_Semaphore;
60
61   ----------------------
62   -- Binary_Semaphore --
63   ----------------------
64
65   protected body Binary_Semaphore is
66
67      -----------
68      -- Seize --
69      -----------
70
71      entry Seize when Available is
72      begin
73         Available := False;
74      end Seize;
75
76      -------------
77      -- Release --
78      -------------
79
80      procedure Release is
81      begin
82         Available := True;
83      end Release;
84   end Binary_Semaphore;
85
86end GNAT.Semaphores;
87