129 lines
4.2 KiB
C++
129 lines
4.2 KiB
C++
//------------------------------------------------------------------------------
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// File: Schedule.h
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//
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// Desc: DirectShow base classes.
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//
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// Copyright (c) 1996-2001 Microsoft Corporation. All rights reserved.
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//------------------------------------------------------------------------------
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#ifndef __CAMSchedule__
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#define __CAMSchedule__
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class CAMSchedule : private CBaseObject
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{
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public:
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virtual ~CAMSchedule();
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// ev is the event we should fire if the advise time needs re-evaluating
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CAMSchedule( HANDLE ev );
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DWORD GetAdviseCount();
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REFERENCE_TIME GetNextAdviseTime();
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// We need a method for derived classes to add advise packets, we return the cookie
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DWORD_PTR AddAdvisePacket( const REFERENCE_TIME & time1, const REFERENCE_TIME & time2, HANDLE h, BOOL periodic );
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// And a way to cancel
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HRESULT Unadvise(DWORD_PTR dwAdviseCookie);
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// Tell us the time please, and we'll dispatch the expired events. We return the time of the next event.
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// NB: The time returned will be "useless" if you start adding extra Advises. But that's the problem of
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// whoever is using this helper class (typically a clock).
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REFERENCE_TIME Advise( const REFERENCE_TIME & rtTime );
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// Get the event handle which will be set if advise time requires re-evaluation.
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HANDLE GetEvent() const { return m_ev; }
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private:
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// We define the nodes that will be used in our singly linked list
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// of advise packets. The list is ordered by time, with the
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// elements that will expire first at the front.
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class CAdvisePacket
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{
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public:
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CAdvisePacket()
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{}
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CAdvisePacket * m_next;
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DWORD_PTR m_dwAdviseCookie;
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REFERENCE_TIME m_rtEventTime; // Time at which event should be set
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REFERENCE_TIME m_rtPeriod; // Periodic time
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HANDLE m_hNotify; // Handle to event or semephore
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BOOL m_bPeriodic; // TRUE => Periodic event
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CAdvisePacket( __inout_opt CAdvisePacket * next, LONGLONG time ) : m_next(next), m_rtEventTime(time)
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{}
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void InsertAfter( __inout CAdvisePacket * p )
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{
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p->m_next = m_next;
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m_next = p;
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}
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int IsZ() const // That is, is it the node that represents the end of the list
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{ return m_next == 0; }
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CAdvisePacket * RemoveNext()
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{
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CAdvisePacket *const next = m_next;
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CAdvisePacket *const new_next = next->m_next;
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m_next = new_next;
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return next;
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}
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void DeleteNext()
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{
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delete RemoveNext();
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}
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CAdvisePacket * Next() const
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{
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CAdvisePacket * result = m_next;
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if (result->IsZ()) result = 0;
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return result;
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}
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DWORD_PTR Cookie() const
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{ return m_dwAdviseCookie; }
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};
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// Structure is:
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// _head -> elmt1 -> elmt2 -> z -> null
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// So an empty list is: _head -> z -> null
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// Having _head & z as links makes insertaion,
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// deletion and shunting much easier.
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CAdvisePacket head, z; // z is both a _tail and a sentry
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volatile DWORD_PTR m_dwNextCookie; // Strictly increasing
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volatile DWORD m_dwAdviseCount; // Number of elements on list
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CCritSec m_Serialize;
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// AddAdvisePacket: adds the packet, returns the cookie (0 if failed)
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DWORD_PTR AddAdvisePacket( __inout CAdvisePacket * pPacket );
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// Event that we should set if the packed added above will be the next to fire.
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const HANDLE m_ev;
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// A Shunt is where we have changed the first element in the
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// list and want it re-evaluating (i.e. repositioned) in
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// the list.
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void ShuntHead();
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// Rather than delete advise packets, we cache them for future use
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CAdvisePacket * m_pAdviseCache;
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DWORD m_dwCacheCount;
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enum { dwCacheMax = 5 }; // Don't bother caching more than five
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void Delete( __inout CAdvisePacket * pLink );// This "Delete" will cache the Link
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// Attributes and methods for debugging
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public:
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#ifdef DEBUG
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void DumpLinkedList();
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#else
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void DumpLinkedList() {}
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#endif
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};
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#endif // __CAMSchedule__
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