File : 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) 2011-2015, 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 -- --
19 -- --
20 -- --
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 package body Implementation is
33
34 -------------
35 -- Dequeue --
36 -------------
37
38 procedure Dequeue
39 (List : in out List_Type;
40 Element : out Queue_Interfaces.Element_Type)
41 is
42 EE : Element_Array renames List.Elements;
43
44 begin
45 Element := EE (List.First);
46 List.Length := List.Length - 1;
47
48 if List.Length = 0 then
49 List.First := 0;
50 List.Last := 0;
51
52 elsif List.First <= List.Last then
53 List.First := List.First + 1;
54
55 else
56 List.First := List.First + 1;
57
58 if List.First > List.Capacity then
59 List.First := 1;
60 end if;
61 end if;
62 end Dequeue;
63
64 -------------
65 -- Enqueue --
66 -------------
67
68 procedure Enqueue
69 (List : in out List_Type;
70 New_Item : Queue_Interfaces.Element_Type)
71 is
72 begin
73 if List.Length >= List.Capacity then
74 raise Capacity_Error with "No capacity for insertion";
75 end if;
76
77 if List.Length = 0 then
78 List.Elements (1) := New_Item;
79 List.First := 1;
80 List.Last := 1;
81
82 elsif List.First <= List.Last then
83 if List.Last < List.Capacity then
84 List.Elements (List.Last + 1) := New_Item;
85 List.Last := List.Last + 1;
86
87 else
88 List.Elements (1) := New_Item;
89 List.Last := 1;
90 end if;
91
92 else
93 List.Elements (List.Last + 1) := New_Item;
94 List.Last := List.Last + 1;
95 end if;
96
97 List.Length := List.Length + 1;
98
99 if List.Length > List.Max_Length then
100 List.Max_Length := List.Length;
101 end if;
102 end Enqueue;
103
104 ------------
105 -- Length --
106 ------------
107
108 function Length (List : List_Type) return Count_Type is
109 begin
110 return List.Length;
111 end Length;
112
113 ----------------
114 -- Max_Length --
115 ----------------
116
117 function Max_Length (List : List_Type) return Count_Type is
118 begin
119 return List.Max_Length;
120 end Max_Length;
121
122 end Implementation;
123
124 protected body Queue is
125
126 -----------------
127 -- Current_Use --
128 -----------------
129
130 function Current_Use return Count_Type is
131 begin
132 return List.Length;
133 end Current_Use;
134
135 -------------
136 -- Dequeue --
137 -------------
138
139 entry Dequeue (Element : out Queue_Interfaces.Element_Type)
140 when List.Length > 0
141 is
142 begin
143 List.Dequeue (Element);
144 end Dequeue;
145
146 -------------
147 -- Enqueue --
148 -------------
149
150 entry Enqueue (New_Item : Queue_Interfaces.Element_Type)
151 when List.Length < Capacity
152 is
153 begin
154 List.Enqueue (New_Item);
155 end Enqueue;
156
157 --------------
158 -- Peak_Use --
159 --------------
160
161 function Peak_Use return Count_Type is
162 begin
163 return List.Max_Length;
164 end Peak_Use;
165
166 end Queue;
167
168 end Ada.Containers.Bounded_Synchronized_Queues;