New class to manage subscribers and give IDs.

src/observersmanager.hpp

@@ -0,0 +1,129 @@
+#ifndef idF5E41734950640CDA3C949E0D3A9A30D
+#define idF5E41734950640CDA3C949E0D3A9A30D
+
+#include <cassert>
+#include <vector>
+#include <algorithm>
+#include <iterator>
+#include <ciso646>
+
+namespace cloonel {
+	namespace implem {
+		template <typename T>
+		class Iterator {
+		public:
+			Iterator ( const std::vector<bool>& parOccupied, std::vector<T>& parItems, bool parEnd ) :
+				m_occupied(parOccupied),
+				m_items(parItems),
+				m_pos(parEnd ? m_occupied.size() : 0)
+			{
+				assert(m_occupied.size() == m_items.size());
+			}
+			Iterator ( const Iterator& parOther ) :
+				m_occupied(parOther.m_occupied),
+				m_items(parOther.m_items),
+				m_pos(parOther.m_pos)
+			{
+			}
+			~Iterator ( void ) noexcept = default;
+
+			T operator-> ( void ) {
+				assert(m_pos < m_occupied.size());
+				assert(m_occupied[m_pos]);
+				return m_items[m_pos];
+			}
+			T operator* ( void ) {
+				assert(m_pos < m_occupied.size());
+				assert(m_occupied[m_pos]);
+				return m_items[m_pos];
+			}
+
+			Iterator& operator++ ( void ) {
+				if (m_occupied.size() == m_pos)
+					return *this;
+				auto itNext = std::find(m_occupied.begin() + m_pos + 1, m_occupied.end(), true);
+				if (m_occupied.end() != itNext)
+					m_pos = itNext - m_occupied.begin();
+				else
+					m_pos = m_occupied.size();
+				return *this;
+			}
+			Iterator operator++ ( int ) {
+				Iterator prevState(*this);
+				++(*this);
+				return prevState;
+			}
+
+			bool operator== ( const Iterator& parOther ) const {
+				return m_pos == parOther.m_pos and &m_items == &parOther.m_items;
+			}
+			bool operator!= ( const Iterator& parOther ) const { return not this->operator==(parOther); }
+
+		private:
+			const std::vector<bool>& m_occupied;
+			std::vector<T>& m_items;
+			std::size_t m_pos;
+		};
+	} //namespace implem
+
+	template <typename T>
+	class ObserversManager {
+	public:
+		typedef size_t TicketType;
+		typedef implem::Iterator<T> iterator;
+
+		ObserversManager ( void );
+		~ObserversManager ( void ) noexcept = default;
+
+		TicketType Add ( T parObserver );
+		void Remove ( TicketType parTicket ) noexcept;
+		std::size_t size ( void ) const { return m_usedCount; }
+		iterator begin ( void ) { return iterator(m_occupied, m_list, false); }
+		iterator end ( void ) { return iterator(m_occupied, m_list, true); }
+
+	private:
+		std::vector<T> m_list;
+		std::vector<bool> m_occupied;
+		std::size_t m_usedCount;
+	};
+
+	///--------------------------------------------------------------------------
+	///--------------------------------------------------------------------------
+	template <typename T>
+	ObserversManager<T>::ObserversManager() :
+		m_usedCount(0)
+	{
+	}
+
+	///--------------------------------------------------------------------------
+	///--------------------------------------------------------------------------
+	template <typename T>
+	typename ObserversManager<T>::TicketType ObserversManager<T>::Add (T parObserver) {
+		m_list.push_back(parObserver);
+		m_occupied.push_back(true);
+		++m_usedCount;
+		return static_cast<TicketType>(m_list.size());
+	}
+
+	///--------------------------------------------------------------------------
+	///--------------------------------------------------------------------------
+	template <typename T>
+	void ObserversManager<T>::Remove (TicketType parTicket) noexcept {
+		assert(static_cast<std::size_t>(parTicket) <= m_list.size());
+		assert(m_occupied[parTicket - 1]);
+		assert(m_usedCount > 0);
+		assert(m_list.size() == m_occupied.size());
+
+		m_occupied[parTicket - 1] = false;
+		--m_usedCount;
+
+		auto lastNull = std::find(m_occupied.rbegin(), m_occupied.rend(), false);
+		if (m_occupied.rend() != lastNull) {
+			const std::size_t newSize = m_occupied.size() - (lastNull - m_occupied.rbegin()) + 1;
+			m_occupied.resize(newSize);
+			m_list.resize(newSize);
+		}
+	}
+} //namespace cloonel
+
+#endif