543cdf06d9
git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@6159 8e941d3f-bd1b-0410-a28a-d453659cc2b4
177 lines
3.5 KiB
ObjectPascal
177 lines
3.5 KiB
ObjectPascal
// Upgraded to Delphi 2009: Sebastian Zierer
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(* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is TurboPower SysTools
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*
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* The Initial Developer of the Original Code is
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* TurboPower Software
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*
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* Portions created by the Initial Developer are Copyright (C) 1996-2002
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* ***** END LICENSE BLOCK ***** *)
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{*********************************************************}
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{* SysTools: StDQue.pas 4.04 *}
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{*********************************************************}
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{* SysTools: DEQue class *}
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{*********************************************************}
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{$IFDEF FPC}
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{$mode DELPHI}
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{$ENDIF}
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//{$I StDefine.inc}
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{Notes:
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This class is derived from TStList and allows all of
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the inherited list methods to be used.
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The "head" of the queue is element 0 in the list. The "tail" of the
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queue is the last element in the list.
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The dequeue can be used as a LIFO stack by calling PushTail and
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PopTail, or as a FIFO queue by calling PushTail and PopHead.
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}
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unit StDQue;
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interface
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uses
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Windows,
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STConst, StBase, StList;
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type
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TStDQue = class(TStList)
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public
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procedure PushTail(Data : Pointer);
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{-Add element at tail of queue}
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procedure PopTail;
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{-Delete element at tail of queue, destroys its data}
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procedure PeekTail(var Data : Pointer);
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{-Return data at tail of queue}
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procedure PushHead(Data : Pointer);
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{-Add element at head of queue}
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procedure PopHead;
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{-Delete element at head of queue, destroys its data}
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procedure PeekHead(var Data : Pointer);
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{-Return data at head of queue}
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end;
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{======================================================================}
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implementation
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procedure TStDQue.PeekHead(var Data : Pointer);
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begin
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{$IFDEF ThreadSafe}
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EnterCS;
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try
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{$ENDIF}
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if Count = 0 then
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Data := nil
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else
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Data := Head.Data;
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{$IFDEF ThreadSafe}
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finally
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LeaveCS;
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end;
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{$ENDIF}
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end;
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procedure TStDQue.PeekTail(var Data : Pointer);
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begin
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{$IFDEF ThreadSafe}
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EnterCS;
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try
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{$ENDIF}
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if Count = 0 then
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Data := nil
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else
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Data := Tail.Data;
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{$IFDEF ThreadSafe}
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finally
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LeaveCS;
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end;
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{$ENDIF}
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end;
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procedure TStDQue.PopHead;
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begin
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{$IFDEF ThreadSafe}
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EnterCS;
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try
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{$ENDIF}
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if Count > 0 then
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Delete(Head);
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{$IFDEF ThreadSafe}
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finally
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LeaveCS;
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end;
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{$ENDIF}
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end;
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procedure TStDQue.PopTail;
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begin
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{$IFDEF ThreadSafe}
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EnterCS;
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try
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{$ENDIF}
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if Count > 0 then
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Delete(Tail);
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{$IFDEF ThreadSafe}
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finally
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LeaveCS;
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end;
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{$ENDIF}
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end;
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procedure TStDQue.PushHead(Data : Pointer);
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begin
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{$IFDEF ThreadSafe}
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EnterCS;
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try
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{$ENDIF}
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Insert(Data);
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{$IFDEF ThreadSafe}
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finally
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LeaveCS;
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end;
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{$ENDIF}
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end;
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procedure TStDQue.PushTail(Data : Pointer);
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begin
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{$IFDEF ThreadSafe}
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EnterCS;
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try
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{$ENDIF}
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Append(Data);
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{$IFDEF ThreadSafe}
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finally
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LeaveCS;
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end;
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{$ENDIF}
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end;
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end.
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