/********************************************************************************
* *
* S e m a p h o r e Q u e u e *
* *
*********************************************************************************
* Copyright (C) 2006,2024 by Jeroen van der Zijp. All Rights Reserved. *
*********************************************************************************
* 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 3 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 program. If not, see *
********************************************************************************/
#ifndef FXSEMAQUEUE_H
#define FXSEMAQUEUE_H
namespace FX {
/**
* Semaphore protected queue for a single producer and
* a single consumer thread.
* Producer thread will only block in push() when the queue
* is full; likewise, consumer will only block in pop() if
* the queue is empty.
* To avoid blocking the producer, call trypush() instead.
* Without timeout parameter, trypush() will return immediately
* if no space is available.
* When the timeout parameter is passed, the producer will wait
* a finite amount of time before giving up.
* Similarly, to avoid blocking the consumer, call trypop().
* Without the timeout parameter, trypop() will return immediately
* if no items are available.
* When the timeout parameter is passed, the consumer will wait
* a finite amount of time before giving up.
*/
class FXAPI FXSemaQueue {
private:
FXPtrQueue queue; // Queue
FXSemaphore free; // Free cells
FXSemaphore used; // Used cells
private:
FXSemaQueue(const FXSemaQueue&);
FXSemaQueue &operator=(const FXSemaQueue&);
public:
/// Create initially empty queue of given size sz
FXSemaQueue(FXival sz=32);
/// Return size
FXival getSize() const { return queue.getSize(); }
/// Add item to queue, return true if success
FXbool push(FXptr ptr);
/// Try push object into queue
FXbool trypush(FXptr obj);
/// Try push object into queue, waiting up
/// to nsec for space to become available.
FXbool trypush(FXptr obj,FXTime nsec);
/// Remove item from queue, return true if success
FXbool pop(FXptr& ptr);
/// Try pop object from queue
FXbool trypop(FXptr& obj);
/// Try pop object from queue, waiting up
/// to nsec for object to become available.
FXbool trypop(FXptr& obj,FXTime nsec);
/// Drop item from queue, return true if success
FXbool pop();
/// Destroy queue
~FXSemaQueue();
};
// Specialize to pointers to TYPE
template
class FXSemaQueueOf : public FXSemaQueue {
public:
/// Create initially empty queue of given size sz
FXSemaQueueOf(FXival sz=32):FXSemaQueue(sz){}
/// Add item to queue, return true if success
FXbool push(TYPE* obj){ return FXSemaQueue::push((FXptr)obj); }
/// Try push object into queue, return true if success
FXbool trypush(TYPE* obj){ return FXSemaQueue::trypush((FXptr)obj); }
/// Try push object into queue, return true if success
FXbool trypush(TYPE* obj,FXTime nsec){ return FXSemaQueue::trypush((FXptr)obj,nsec); }
/// Drop item from queue, return true if success
FXbool pop(TYPE*& obj){ return FXSemaQueue::pop((FXptr&)obj); }
/// Try pop object from queue, return true if success
FXbool trypop(TYPE*& obj){ return FXSemaQueue::trypop((FXptr&)obj); }
/// Try pop object from queue, return true if success
FXbool trypop(TYPE*& obj,FXTime nsec){ return FXSemaQueue::trypop((FXptr&)obj,nsec); }
};
}
#endif