gcc/ada/libgnarl/g-semaph.adb

   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) 2003-2017, AdaCore                     --
  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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 package body GNAT.Semaphores is
  33
  34    ------------------------
  35    -- Counting_Semaphore --
  36    ------------------------
  37
  38    protected body Counting_Semaphore is
  39
  40       -----------
  41       -- Seize --
  42       -----------
  43
  44       entry Seize when Count > 0 is
  45       begin
  46          Count := Count - 1;
  47       end Seize;
  48
  49       -------------
  50       -- Release --
  51       -------------
  52
  53       procedure Release is
  54       begin
  55          Count := Count + 1;
  56       end Release;
  57    end Counting_Semaphore;
  58
  59    ----------------------
  60    -- Binary_Semaphore --
  61    ----------------------
  62
  63    protected body Binary_Semaphore is
  64
  65       -----------
  66       -- Seize --
  67       -----------
  68
  69       entry Seize when Available is
  70       begin
  71          Available := False;
  72       end Seize;
  73
  74       -------------
  75       -- Release --
  76       -------------
  77
  78       procedure Release is
  79       begin
  80          Available := True;
  81       end Release;
  82    end Binary_Semaphore;
  83
  84 end GNAT.Semaphores;