Merge branch 'master' into jgrpp

# Conflicts:
#	config.lib
#	projects/openttd_vs140.vcxproj
#	projects/openttd_vs140.vcxproj.filters
#	projects/openttd_vs141.vcxproj
#	projects/openttd_vs141.vcxproj.filters
#	projects/openttd_vs142.vcxproj
#	projects/openttd_vs142.vcxproj.filters
#	src/aircraft_cmd.cpp
#	src/base_station_base.h
#	src/core/pool_type.hpp
#	src/disaster_vehicle.cpp
#	src/economy.cpp
#	src/engine.cpp
#	src/group.h
#	src/group_cmd.cpp
#	src/group_gui.cpp
#	src/lang/english.txt
#	src/lang/german.txt
#	src/linkgraph/linkgraph_gui.cpp
#	src/network/network_command.cpp
#	src/network/network_server.cpp
#	src/openttd.cpp
#	src/order_cmd.cpp
#	src/road_cmd.cpp
#	src/saveload/afterload.cpp
#	src/saveload/cargopacket_sl.cpp
#	src/saveload/linkgraph_sl.cpp
#	src/saveload/order_sl.cpp
#	src/saveload/station_sl.cpp
#	src/saveload/town_sl.cpp
#	src/saveload/vehicle_sl.cpp
#	src/screenshot.cpp
#	src/screenshot.h
#	src/settings_gui.cpp
#	src/settings_type.h
#	src/smallmap_gui.cpp
#	src/station.cpp
#	src/station_cmd.cpp
#	src/table/settings.ini
#	src/toolbar_gui.cpp
#	src/town_cmd.cpp
#	src/train.h
#	src/train_cmd.cpp
#	src/train_gui.cpp
#	src/vehicle.cpp
#	src/vehicle_base.h
#	src/vehiclelist.cpp
#	src/window_type.h

src/core/pool_type.hpp

@@ -12,6 +12,7 @@
 
 #include "smallvec_type.hpp"
 #include "enum_type.hpp"
+#include <functional>
 
 /** Various types of a pool. */
 enum PoolType {
@@ -137,6 +138,49 @@ struct Pool : PoolBase {
 		return ret;
 	}
 
+	/**
+	 * Iterator to iterate all valid T of a pool
+	 * @tparam T Type of the class/struct that is going to be iterated
+	 */
+	template <class T>
+	struct PoolIterator {
+		typedef T value_type;
+		typedef T* pointer;
+		typedef T& reference;
+		typedef size_t difference_type;
+		typedef std::forward_iterator_tag iterator_category;
+
+		explicit PoolIterator(size_t index, std::function<bool(size_t)> filter = nullptr) : index(index), filter(filter)
+		{
+			if (this->filter == nullptr) this->filter = [](size_t) { return true; };
+			this->ValidateIndex();
+		};
+
+		bool operator==(const PoolIterator &other) const { return this->index == other.index; }
+		bool operator!=(const PoolIterator &other) const { return !(*this == other); }
+		T * operator*() const { return T::Get(this->index); }
+		PoolIterator & operator++() { this->index++; this->ValidateIndex(); return *this; }
+
+	private:
+		size_t index;
+		std::function<bool(size_t)> filter;
+		void ValidateIndex() { while (this->index < T::GetPoolSize() && !(T::IsValidID(this->index) && this->filter(this->index))) this->index++; }
+	};
+
+	/*
+	 * Iterable ensemble of all valid T
+	 * @tparam T Type of the class/struct that is going to be iterated
+	 */
+	template <class T>
+	struct IterateWrapper {
+		size_t from;
+		std::function<bool(size_t)> filter;
+		IterateWrapper(size_t from = 0, std::function<bool(size_t)> filter = nullptr) : from(from), filter(filter) {}
+		PoolIterator<T> begin() { return PoolIterator<T>(this->from, this->filter); }
+		PoolIterator<T> end() { return PoolIterator<T>(T::GetPoolSize()); }
+		bool empty() { return this->begin() == this->end(); }
+	};
+
 	/**
 	 * Base class for all PoolItems
 	 * @tparam Tpool The pool this item is going to be part of
@@ -145,6 +189,9 @@ struct Pool : PoolBase {
 	struct PoolItem {
 		Tindex index; ///< Index of this pool item
 
+		/** Type of the pool this item is going to be part of */
+		typedef struct Pool<Titem, Tindex, Tgrowth_step, Tmax_size, Tpool_type, Tcache, Tzero> Pool;
+
 		/**
 		 * Allocates space for new Titem
 		 * @param size size of Titem
@@ -292,6 +339,13 @@ struct Pool : PoolBase {
 		 * @note it's called only when CleaningPool()
 		 */
 		static inline void PreCleanPool() { }
+
+		/**
+		 * Returns an iterable ensemble of all valid Titem
+		 * @param from index of the first Titem to consider
+		 * @return an iterable ensemble of all valid Titem
+		 */
+		static Pool::IterateWrapper<Titem> Iterate(size_t from = 0) { return Pool::IterateWrapper<Titem>(from); }
 	};
 
 private:
@@ -319,10 +373,4 @@ private:
 	void FreeItem(size_t index);
 };
 
-#define FOR_ALL_ITEMS_FROM(type, iter, var, start) \
-	for (size_t iter = start; var = nullptr, iter < type::GetPoolSize(); iter++) \
-		if ((var = type::Get(iter)) != nullptr)
-
-#define FOR_ALL_ITEMS(type, iter, var) FOR_ALL_ITEMS_FROM(type, iter, var, 0)
-
 #endif /* POOL_TYPE_HPP */