queue

queue를 만들어 쓰다가 동작이 불안하여 검색 결과

directshow에서 제공하는 CQueue class를 알게되었다.

"DirectShowBaseClasseswxutil.h "  에 포함 되어 있다.

사용법은  Streams.h 헤더파일을 포함 식키고 타입 캐스팅 하면 된다.

#include <Streams.h>

CQueue <VInputPacket*> m_queue_video;

// put queue
VInputPacket *pkt = new VInputPacket();
m_queue_video.PutQueueObject(pkt);

// get queue
VInputPacket *pkt = m_queue_video.GetQueueObject ();

다음은 CQueue 소스

[cpp]

// CQueue

//

// Implements a simple Queue ADT.  The queue contains a finite number of

// objects, access to which is controlled by a semaphore.  The semaphore

// is created with an initial count (N).  Each time an object is added

// a call to WaitForSingleObject is made on the semaphore's handle.  When

// this function returns a slot has been reserved in the queue for the new

// object.  If no slots are available the function blocks until one becomes

// available.  Each time an object is removed from the queue ReleaseSemaphore

// is called on the semaphore's handle, thus freeing a slot in the queue.

// If no objects are present in the queue the function blocks until an

// object has been added.

#define DEFAULT_QUEUESIZE   2

template <class T> class CQueue {

private:

HANDLE          hSemPut;        // Semaphore controlling queue "putting"

HANDLE          hSemGet;        // Semaphore controlling queue "getting"

CRITICAL_SECTION CritSect;      // Thread seriallization

int             nMax;           // Max objects allowed in queue

int             iNextPut;       // Array index of next "PutMsg"

int             iNextGet;       // Array index of next "GetMsg"

T              *QueueObjects;   // Array of objects (ptr's to void)

void Initialize(int n) {

iNextPut = iNextGet = 0;

nMax = n;

InitializeCriticalSection(&CritSect);

hSemPut = CreateSemaphore(NULL, n, n, NULL);

hSemGet = CreateSemaphore(NULL, 0, n, NULL);

QueueObjects = new T[n];

}

public:

CQueue(int n) {

Initialize(n);

}

CQueue() {

Initialize(DEFAULT_QUEUESIZE);

}

~CQueue() {

delete [] QueueObjects;

DeleteCriticalSection(&CritSect);

CloseHandle(hSemPut);

CloseHandle(hSemGet);

}

T GetQueueObject() {

int iSlot;

T Object;

LONG lPrevious;

// Wait for someone to put something on our queue, returns straight

// away is there is already an object on the queue.

//

WaitForSingleObject(hSemGet, INFINITE);

EnterCriticalSection(&CritSect);

iSlot = iNextGet++ % nMax;

Object = QueueObjects[iSlot];

LeaveCriticalSection(&CritSect);

// Release anyone waiting to put an object onto our queue as there

// is now space available in the queue.

//

ReleaseSemaphore(hSemPut, 1L, &lPrevious);

return Object;

}

void PutQueueObject(T Object) {

int iSlot;

LONG lPrevious;

// Wait for someone to get something from our queue, returns straight

// away is there is already an empty slot on the queue.

//

WaitForSingleObject(hSemPut, INFINITE);

EnterCriticalSection(&CritSect);

iSlot = iNextPut++ % nMax;

QueueObjects[iSlot] = Object;

LeaveCriticalSection(&CritSect);

// Release anyone waiting to remove an object from our queue as there

// is now an object available to be removed.

//

ReleaseSemaphore(hSemGet, 1L, &lPrevious);

}

};

[/cpp]