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{
Free Pascal port of the OpenPTC C++ library.
Copyright (C) 2001-2003 Nikolay Nikolov (nickysn@users.sourceforge.net)
Original C++ version by Glenn Fiedler (ptc@gaffer.org)
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
}
{Function TPTCExposeEvent.GetType : TPTCEventType;
Begin
Result := PTCExposeEvent;
End;}
Type
PEventLinkedList = ^TEventLinkedList;
TEventLinkedList = Record
Event : TPTCEvent;
Next : PEventLinkedList;
End;
TEventQueue = Class(TObject)
Private
FHead, FTail : PEventLinkedList;
Public
Constructor Create;
Destructor Destroy; Override;
Procedure AddEvent(event : TPTCEvent);
Function PeekEvent(Const EventMask : TPTCEventMask) : TPTCEvent;
Function NextEvent(Const EventMask : TPTCEventMask) : TPTCEvent;
End;
Constructor TEventQueue.Create;
Begin
FHead := Nil;
FTail := Nil;
End;
Destructor TEventQueue.Destroy;
Var
p, pnext : PEventLinkedList;
Begin
p := FHead;
While p <> Nil Do
Begin
FreeAndNil(p^.Event);
pnext := p^.Next;
Dispose(p);
p := pnext;
End;
Inherited Destroy;
End;
Procedure TEventQueue.AddEvent(event : TPTCEvent);
Var
tmp : PEventLinkedList;
Begin
New(tmp);
FillChar(tmp^, SizeOf(tmp^), 0);
tmp^.Next := Nil;
tmp^.Event := event;
If FTail <> Nil Then
Begin
FTail^.Next := tmp;
FTail := tmp;
End
Else
Begin { FTail = Nil }
FHead := tmp;
FTail := tmp;
End;
End;
Function TEventQueue.PeekEvent(Const EventMask : TPTCEventMask) : TPTCEvent;
Var
p : PEventLinkedList;
Begin
p := FHead;
While p <> Nil Do
Begin
If p^.Event.EventType In EventMask Then
Begin
Result := p^.Event;
Exit;
End;
p := p^.Next;
End;
Result := Nil;
End;
Function TEventQueue.NextEvent(Const EventMask : TPTCEventMask) : TPTCEvent;
Var
prev, p : PEventLinkedList;
Begin
prev := Nil;
p := FHead;
While p <> Nil Do
Begin
If p^.Event.EventType In EventMask Then
Begin
Result := p^.Event;
{ delete the element from the linked list }
If prev <> Nil Then
prev^.Next := p^.Next
Else
FHead := p^.Next;
If p^.Next = Nil Then
FTail := prev;
Dispose(p);
Exit;
End;
prev := p;
p := p^.Next;
End;
Result := Nil;
End;
|
