gcc/ada/a-cbsyqu.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT LIBRARY COMPONENTS                          --
   4 --                                                                          --
   5 --                ADA.CONTAINERS.BOUNDED_SYNCHRONIZED_QUEUES                --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --            Copyright (C) 2011-2014, Free Software Foundation, 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 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 -- This unit was originally developed by Matthew J Heaney.                  --
  28 ------------------------------------------------------------------------------
  29
  30 package body Ada.Containers.Bounded_Synchronized_Queues is
  31
  32    pragma Annotate (CodePeer, Skip_Analysis);
  33
  34    package body Implementation is
  35
  36       -------------
  37       -- Dequeue --
  38       -------------
  39
  40       procedure Dequeue
  41         (List    : in out List_Type;
  42          Element : out Queue_Interfaces.Element_Type)
  43       is
  44          EE : Element_Array renames List.Elements;
  45
  46       begin
  47          Element := EE (List.First);
  48          List.Length := List.Length - 1;
  49
  50          if List.Length = 0 then
  51             List.First := 0;
  52             List.Last := 0;
  53
  54          elsif List.First <= List.Last then
  55             List.First := List.First + 1;
  56
  57          else
  58             List.First := List.First + 1;
  59
  60             if List.First > List.Capacity then
  61                List.First := 1;
  62             end if;
  63          end if;
  64       end Dequeue;
  65
  66       -------------
  67       -- Enqueue --
  68       -------------
  69
  70       procedure Enqueue
  71         (List     : in out List_Type;
  72          New_Item : Queue_Interfaces.Element_Type)
  73       is
  74       begin
  75          if List.Length >= List.Capacity then
  76             raise Capacity_Error with "No capacity for insertion";
  77          end if;
  78
  79          if List.Length = 0 then
  80             List.Elements (1) := New_Item;
  81             List.First := 1;
  82             List.Last := 1;
  83
  84          elsif List.First <= List.Last then
  85             if List.Last < List.Capacity then
  86                List.Elements (List.Last + 1) := New_Item;
  87                List.Last := List.Last + 1;
  88
  89             else
  90                List.Elements (1) := New_Item;
  91                List.Last := 1;
  92             end if;
  93
  94          else
  95             List.Elements (List.Last + 1) := New_Item;
  96             List.Last := List.Last + 1;
  97          end if;
  98
  99          List.Length := List.Length + 1;
 100
 101          if List.Length > List.Max_Length then
 102             List.Max_Length := List.Length;
 103          end if;
 104       end Enqueue;
 105
 106       ------------
 107       -- Length --
 108       ------------
 109
 110       function Length (List : List_Type) return Count_Type is
 111       begin
 112          return List.Length;
 113       end Length;
 114
 115       ----------------
 116       -- Max_Length --
 117       ----------------
 118
 119       function Max_Length (List : List_Type) return Count_Type is
 120       begin
 121          return List.Max_Length;
 122       end Max_Length;
 123
 124    end Implementation;
 125
 126    protected body Queue is
 127
 128       -----------------
 129       -- Current_Use --
 130       -----------------
 131
 132       function Current_Use return Count_Type is
 133       begin
 134          return List.Length;
 135       end Current_Use;
 136
 137       -------------
 138       -- Dequeue --
 139       -------------
 140
 141       entry Dequeue (Element : out Queue_Interfaces.Element_Type)
 142         when List.Length > 0
 143       is
 144       begin
 145          List.Dequeue (Element);
 146       end Dequeue;
 147
 148       -------------
 149       -- Enqueue --
 150       -------------
 151
 152       entry Enqueue (New_Item : Queue_Interfaces.Element_Type)
 153         when List.Length < Capacity
 154       is
 155       begin
 156          List.Enqueue (New_Item);
 157       end Enqueue;
 158
 159       --------------
 160       -- Peak_Use --
 161       --------------
 162
 163       function Peak_Use return Count_Type is
 164       begin
 165          return List.Max_Length;
 166       end Peak_Use;
 167
 168    end Queue;
 169
 170 end Ada.Containers.Bounded_Synchronized_Queues;