Synchronized queue C++17

Complete the provided template so that the SBuffer class is an implementation of a synchronized queue. The queue should additionally manage a pool of objects of type ItemType. The constructor of the SBuffer class should create N objects of type ItemType. Only pointers to these objects can be returned by the implemented methods. It can also be assumed that all pointers passed as arguments have been previously returned by other methods of this same object.

Method specifications:

• int enqueue(ItemType* item) — adds the object pointed to by item to the end of the queue and returns 1. If stop() has been called previously, does nothing and returns 0.

• ItemType* dequeue() — removes the object from the beginning of the queue and returns a pointer to it. If the queue is empty, suspends thread execution until an accessible object appears or the stop method is called for the queue object.

• ItemType* allocItem() — returns any object of type ItemType from the pool of currently unused objects. If all objects are currently busy, suspends thread execution until some object is freed or stop is called.

• void freeItem(ItemType* item) — marks the resource as freed by the thread. The passed object *item should return to the pool of unused objects.

• void stop() — from the moment stop is called on the queue object, the allocItem method always returns nullptr, and the dequeue method returns objects until the queue is empty; after that, it also always returns nullptr.

The queue must operate according to the specification during use by multiple threads. Solutions based on active waiting are not allowed.

Conditions:

1. **Prohibition of LLM-generation:** code will be strictly checked for plagiarism from publicly available AI models — it is strictly forbidden to refer to public LLMs for code writing.

2. **Evaluation:** your file will be uploaded to an automated testing system. To be accepted, it must pass all tests without errors.

Solution template

You should submit only the header file sbuffer.h. For thread synchronization, please use the capabilities of the C++17 standard library.