queue.h

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#ifndef UTILS_QUEUE
#define UTILS_QUEUE
 
#include <array>
#include <cstddef>
#include <cstdint>
 
namespace lampda {
namespace utils {
 
template<typename T, size_t MaxElements = 10> struct Queue
{
  static_assert(MaxElements > 1, "Queue: cannot define a one or less elements queue");
 
  struct Element
  {
    uint32_t raisedTime;
    T _data;
  };
 
  bool has_elements() const { return currentStoredEvents > 0; }
 
  bool enqueue(const T& element)
  {
    if (currentStoredEvents >= MaxElements)
      return false;
 
    Element e;
    e._data = element;
    _queueData[currentStoredEvents] = e;
 
    currentStoredEvents++;
    return true;
  }
 
  struct Optional
  {
    Optional() : _hasValue(false) {}
    Optional(T val) : _hasValue(true), _value(val) {}
    bool has_value() const { return _hasValue; }
    T value() const { return _hasValue ? _value : T(); }
 
  private:
    bool _hasValue = false;
    T _value;
  };
 
  Optional dequeue()
  {
    if (currentStoredEvents <= 0)
      return Optional();
 
    // store first element
    const Element toReturn = _queueData[0];
 
    // move all other elements toward the front
    for (size_t i = 1; i < currentStoredEvents; i++)
    {
      _queueData[i - 1] = _queueData[i];
    }
    // remove the element
    currentStoredEvents -= 1;
    return Optional(toReturn._data);
  }
 
private:
  size_t currentStoredEvents = 0;
  std::array<Element, MaxElements> _queueData;
};
 
} // namespace utils
} // namespace lampda
 
#endif