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	torben	2671	// 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.