tpsystools_4.04/source/StDque.pas

// Upgraded to Delphi 2009: Sebastian Zierer

(* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is TurboPower SysTools
 *
 * The Initial Developer of the Original Code is
 * TurboPower Software
 *
 * Portions created by the Initial Developer are Copyright (C) 1996-2002
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * ***** END LICENSE BLOCK ***** *)

{*********************************************************}
{* SysTools: StDQue.pas 4.04                             *}
{*********************************************************}
{* SysTools: DEQue class                                 *}
{*********************************************************}

{$I StDefine.inc}

{Notes:
   This class is derived from TStList and allows all of
   the inherited list methods to be used.

   The "head" of the queue is element 0 in the list. The "tail" of the
   queue is the last element in the list.

   The dequeue can be used as a LIFO stack by calling PushTail and
   PopTail, or as a FIFO queue by calling PushTail and PopHead.
}

unit StDQue;

interface

uses
  Windows,
  STConst, StBase, StList;

type
  TStDQue = class(TStList)
    public
      procedure PushTail(Data : Pointer);
        {-Add element at tail of queue}
      procedure PopTail;
        {-Delete element at tail of queue, destroys its data}
      procedure PeekTail(var Data : Pointer);
        {-Return data at tail of queue}

      procedure PushHead(Data : Pointer);
        {-Add element at head of queue}
      procedure PopHead;
        {-Delete element at head of queue, destroys its data}
      procedure PeekHead(var Data : Pointer);
        {-Return data at head of queue}
  end;

{======================================================================}

implementation


procedure TStDQue.PeekHead(var Data : Pointer);
begin
{$IFDEF ThreadSafe}
  EnterCS;
  try
{$ENDIF}
    if Count = 0 then
      Data := nil
    else
      Data := Head.Data;
{$IFDEF ThreadSafe}
  finally
    LeaveCS;
  end;
{$ENDIF}
end;

procedure TStDQue.PeekTail(var Data : Pointer);
begin
{$IFDEF ThreadSafe}
  EnterCS;
  try
{$ENDIF}
    if Count = 0 then
      Data := nil
    else
      Data := Tail.Data;
{$IFDEF ThreadSafe}
  finally
    LeaveCS;
  end;
{$ENDIF}
end;

procedure TStDQue.PopHead;
begin
{$IFDEF ThreadSafe}
  EnterCS;
  try
{$ENDIF}
    if Count > 0 then
      Delete(Head);
{$IFDEF ThreadSafe}
  finally
    LeaveCS;
  end;
{$ENDIF}
end;

procedure TStDQue.PopTail;
begin
{$IFDEF ThreadSafe}
  EnterCS;
  try
{$ENDIF}
    if Count > 0 then
      Delete(Tail);
{$IFDEF ThreadSafe}
  finally
    LeaveCS;
  end;
{$ENDIF}
end;

procedure TStDQue.PushHead(Data : Pointer);
begin
{$IFDEF ThreadSafe}
  EnterCS;
  try
{$ENDIF}
    Insert(Data);
{$IFDEF ThreadSafe}
  finally
    LeaveCS;
  end;
{$ENDIF}
end;

procedure TStDQue.PushTail(Data : Pointer);
begin
{$IFDEF ThreadSafe}
  EnterCS;
  try
{$ENDIF}
    Append(Data);
{$IFDEF ThreadSafe}
  finally
    LeaveCS;
  end;
{$ENDIF}
end;


end.
1	// Upgraded to Delphi 2009: Sebastian Zierer
2
3	(* *** BEGIN LICENSE BLOCK ***
4	* Version: MPL 1.1
5	*
6	* The contents of this file are subject to the Mozilla Public License Version
7	* 1.1 (the "License"); you may not use this file except in compliance with
8	* the License. You may obtain a copy of the License at
9	* http://www.mozilla.org/MPL/
10	*
11	* Software distributed under the License is distributed on an "AS IS" basis,
12	* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13	* for the specific language governing rights and limitations under the
14	* License.
15	*
16	* The Original Code is TurboPower SysTools
17	*
18	* The Initial Developer of the Original Code is
19	* TurboPower Software
20	*
21	* Portions created by the Initial Developer are Copyright (C) 1996-2002
22	* the Initial Developer. All Rights Reserved.
23	*
24	* Contributor(s):
25	*
26	* *** END LICENSE BLOCK *** *)
27
28	{*********************************************************}
29	{* SysTools: StDQue.pas 4.04 *}
30	{*********************************************************}
31	{* SysTools: DEQue class *}
32	{*********************************************************}
33
34	{$I StDefine.inc}
35
36	{Notes:
37	This class is derived from TStList and allows all of
38	the inherited list methods to be used.
39
40	The "head" of the queue is element 0 in the list. The "tail" of the
41	queue is the last element in the list.
42
43	The dequeue can be used as a LIFO stack by calling PushTail and
44	PopTail, or as a FIFO queue by calling PushTail and PopHead.
45	}
46
47	unit StDQue;
48
49	interface
50
51	uses
52	Windows,
53	STConst, StBase, StList;
54
55	type
56	TStDQue = class(TStList)
57	public
58	procedure PushTail(Data : Pointer);
59	{-Add element at tail of queue}
60	procedure PopTail;
61	{-Delete element at tail of queue, destroys its data}
62	procedure PeekTail(var Data : Pointer);
63	{-Return data at tail of queue}
64
65	procedure PushHead(Data : Pointer);
66	{-Add element at head of queue}
67	procedure PopHead;
68	{-Delete element at head of queue, destroys its data}
69	procedure PeekHead(var Data : Pointer);
70	{-Return data at head of queue}
71	end;
72
73	{======================================================================}
74
75	implementation
76
77
78
79	procedure TStDQue.PeekHead(var Data : Pointer);
80	begin
81	{$IFDEF ThreadSafe}
82	EnterCS;
83	try
84	{$ENDIF}
85	if Count = 0 then
86	Data := nil
87	else
88	Data := Head.Data;
89	{$IFDEF ThreadSafe}
90	finally
91	LeaveCS;
92	end;
93	{$ENDIF}
94	end;
95
96	procedure TStDQue.PeekTail(var Data : Pointer);
97	begin
98	{$IFDEF ThreadSafe}
99	EnterCS;
100	try
101	{$ENDIF}
102	if Count = 0 then
103	Data := nil
104	else
105	Data := Tail.Data;
106	{$IFDEF ThreadSafe}
107	finally
108	LeaveCS;
109	end;
110	{$ENDIF}
111	end;
112
113	procedure TStDQue.PopHead;
114	begin
115	{$IFDEF ThreadSafe}
116	EnterCS;
117	try
118	{$ENDIF}
119	if Count > 0 then
120	Delete(Head);
121	{$IFDEF ThreadSafe}
122	finally
123	LeaveCS;
124	end;
125	{$ENDIF}
126	end;
127
128	procedure TStDQue.PopTail;
129	begin
130	{$IFDEF ThreadSafe}
131	EnterCS;
132	try
133	{$ENDIF}
134	if Count > 0 then
135	Delete(Tail);
136	{$IFDEF ThreadSafe}
137	finally
138	LeaveCS;
139	end;
140	{$ENDIF}
141	end;
142
143	procedure TStDQue.PushHead(Data : Pointer);
144	begin
145	{$IFDEF ThreadSafe}
146	EnterCS;
147	try
148	{$ENDIF}
149	Insert(Data);
150	{$IFDEF ThreadSafe}
151	finally
152	LeaveCS;
153	end;
154	{$ENDIF}
155	end;
156
157	procedure TStDQue.PushTail(Data : Pointer);
158	begin
159	{$IFDEF ThreadSafe}
160	EnterCS;
161	try
162	{$ENDIF}
163	Append(Data);
164	{$IFDEF ThreadSafe}
165	finally
166	LeaveCS;
167	end;
168	{$ENDIF}
169	end;
170
171
172	end.