Specialize std::back_insert_iterator

morzhovets · Dec 25, 2024 · 62d1cae · 62d1cae
1 parent 51a4496
commit 62d1cae
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Showing 5 changed files with 110 additions and 8 deletions.
diff --git a/include/momo/Array.h b/include/momo/Array.h
@@ -1112,3 +1112,18 @@ namespace internal
 }
 
 } // namespace momo
+
+namespace std
+{
+	template<typename... Params>
+	class back_insert_iterator<momo::Array<Params...>>
+		: public momo::internal::BackAddIterator<momo::Array<Params...>>
+	{
+	public:
+		typedef momo::Array<Params...> container_type;
+
+	public:
+		using momo::internal::BackAddIterator<container_type>::BackAddIterator;
+		using momo::internal::BackAddIterator<container_type>::operator=;
+	};
+} // namespace std
diff --git a/include/momo/ArrayUtility.h b/include/momo/ArrayUtility.h
@@ -275,6 +275,55 @@ namespace internal
 			return remCount;
 		}
 	};
+
+	template<typename TContainer>
+	class BackAddIterator
+	{
+	public:
+		typedef TContainer Container;
+		typedef typename Container::Item Item;
+
+	public:
+		explicit BackAddIterator(Container& cont) noexcept
+			: container(&cont)
+		{
+		}
+
+		template<typename Iterator>
+		Iterator& operator=(this Iterator& iter, Item&& item)
+		{
+			iter.container->AddBack(std::move(item));
+			return iter;
+		}
+
+		template<typename Iterator>
+		Iterator& operator=(this Iterator& iter, const Item& item)
+		{
+			iter.container->AddBack(item);
+			return iter;
+		}
+
+		template<typename Iterator>
+		Iterator& operator*(this Iterator& iter) noexcept
+		{
+			return iter;
+		}
+
+		template<typename Iterator>
+		Iterator& operator++(this Iterator& iter) noexcept
+		{
+			return iter;
+		}
+
+		template<typename Iterator>
+		Iterator operator++(this Iterator& iter, int) noexcept
+		{
+			return iter;
+		}
+
+	protected:
+		Container* container;
+	};
 }
 
 } // namespace momo
@@ -295,4 +344,14 @@ namespace std
 			random_access_iterator_tag, contiguous_iterator_tag>
 	{
 	};
+
+	template<typename C>
+	struct iterator_traits<momo::internal::BackAddIterator<C>>
+	{
+		typedef std::output_iterator_tag iterator_category;
+		typedef ptrdiff_t difference_type;
+		typedef void pointer;
+		typedef void reference;
+		typedef void value_type;
+	};
 } // namespace std
diff --git a/include/momo/MergeArray.h b/include/momo/MergeArray.h
@@ -833,3 +833,18 @@ class MergeArray
 };
 
 } // namespace momo
+
+namespace std
+{
+	template<typename... Params>
+	class back_insert_iterator<momo::MergeArray<Params...>>
+		: public momo::internal::BackAddIterator<momo::MergeArray<Params...>>
+	{
+	public:
+		typedef momo::MergeArray<Params...> container_type;
+
+	public:
+		using momo::internal::BackAddIterator<container_type>::BackAddIterator;
+		using momo::internal::BackAddIterator<container_type>::operator=;
+	};
+} // namespace std
diff --git a/include/momo/SegmentedArray.h b/include/momo/SegmentedArray.h
@@ -788,3 +788,18 @@ using SegmentedArraySqrt = SegmentedArray<TItem, TMemManager, TItemTraits,
 	SegmentedArraySettings<SegmentedArrayItemCountFunc::sqrt>>;
 
 } // namespace momo
+
+namespace std
+{
+	template<typename... Params>
+	class back_insert_iterator<momo::SegmentedArray<Params...>>
+		: public momo::internal::BackAddIterator<momo::SegmentedArray<Params...>>
+	{
+	public:
+		typedef momo::SegmentedArray<Params...> container_type;
+
+	public:
+		using momo::internal::BackAddIterator<container_type>::BackAddIterator;
+		using momo::internal::BackAddIterator<container_type>::operator=;
+	};
+} // namespace std
diff --git a/test/sources/SimpleArrayTester.cpp b/test/sources/SimpleArrayTester.cpp
@@ -46,14 +46,11 @@ class SimpleArrayTester
 
 		~TemplItem() noexcept = default;
 
-		TemplItem& operator=(TemplItem&& item) noexcept = default;
+		TemplItem& operator=(TemplItem&&) noexcept = default;
 
-		TemplItem& operator=(const TemplItem& item) noexcept = default;
+		TemplItem& operator=(const TemplItem&) noexcept = default;
 
-		bool operator==(const TemplItem& item) const noexcept
-		{
-			return mValue == item.mValue;
-		}
+		bool operator==(const TemplItem&) const noexcept = default;
 
 	private:
 		size_t mValue;
@@ -218,8 +215,9 @@ class SimpleArrayTester
 		Array ar;
 		static const size_t count = 20000;
 
-		for (size_t i = 0; i < count; ++i)
-			ar.AddBack(Item(i));
+		std::fill_n(std::back_inserter(ar), 1, Item(0));
+		std::generate_n(std::back_inserter(ar), count - 1,
+			[&ar] () { return Item(ar.GetCount()); });
 
 		ar.Reserve(count * 3);
 		ar.Shrink();