[sprout.iterator] support for C++14 constexpr iterator operation

sprout/iterator/distance.hpp

@@ -22,6 +22,27 @@ namespace sprout_adl {
 
 namespace sprout {
 	namespace iterator_detail {
+		template<typename RandomAccessIterator>
+		inline SPROUT_CXX14_CONSTEXPR typename std::iterator_traits<RandomAccessIterator>::difference_type
+		cxx14_distance(RandomAccessIterator first, RandomAccessIterator last, std::random_access_iterator_tag*) {
+			return last - first;
+		}
+		template<typename InputIterator>
+		inline SPROUT_CXX14_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
+		cxx14_distance(InputIterator first, InputIterator last, std::input_iterator_tag*) {
+			typename std::iterator_traits<InputIterator>::difference_type n = 0;
+			for (; first != last; ++first) {
+				++n;
+			}
+			return n;
+		}
+		template<typename InputIterator>
+		inline SPROUT_CXX14_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
+		cxx14_distance(InputIterator first, InputIterator last) {
+			typedef typename std::iterator_traits<InputIterator>::iterator_category* category;
+			return sprout::iterator_detail::cxx14_distance(first, last, category());
+		}
+
 		template<typename RandomAccessIterator>
 		inline SPROUT_CONSTEXPR typename std::enable_if<
 			sprout::is_constant_distance_iterator<RandomAccessIterator>::value,
@@ -67,29 +88,29 @@ namespace sprout {
 					)
 				;
 		}
-		template<typename InputIterator>
-		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
-		iterator_distance(InputIterator first, InputIterator last, std::input_iterator_tag*) {
-			typedef sprout::pair<InputIterator, typename std::iterator_traits<InputIterator>::difference_type> type;
-			return sprout::iterator_detail::iterator_distance_impl(type(first, 0), last, 1).second;
-		}
-
 		template<typename InputIterator>
 		inline SPROUT_CONSTEXPR typename std::enable_if<
 			std::is_literal_type<InputIterator>::value,
 			typename std::iterator_traits<InputIterator>::difference_type
 		>::type
-		iterator_distance(InputIterator first, InputIterator last) {
+		iterator_distance(InputIterator first, InputIterator last, std::input_iterator_tag*) {
-			typedef typename std::iterator_traits<InputIterator>::iterator_category* category;
+			typedef sprout::pair<InputIterator, typename std::iterator_traits<InputIterator>::difference_type> type;
-			return sprout::iterator_detail::iterator_distance(first, last, category());
+			return sprout::iterator_detail::iterator_distance_impl(type(first, 0), last, 1).second;
 		}
 		template<typename InputIterator>
 		inline SPROUT_CONSTEXPR typename std::enable_if<
 			!std::is_literal_type<InputIterator>::value,
 			typename std::iterator_traits<InputIterator>::difference_type
 		>::type
+		iterator_distance(InputIterator first, InputIterator last, std::input_iterator_tag*) {
+			return sprout::iterator_detail::cxx14_distance(first, last);
+		}
+
+		template<typename InputIterator>
+		inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
 		iterator_distance(InputIterator first, InputIterator last) {
-			return std::distance(first, last);
+			typedef typename std::iterator_traits<InputIterator>::iterator_category* category;
+			return sprout::iterator_detail::iterator_distance(first, last, category());
 		}
 	}	// namespace iterator_detail
 }	// namespace sprout
@@ -110,9 +131,9 @@ namespace sprout {
 	//
 	//	effect:
 	//		ADL callable iterator_distance(first, last) -> iterator_distance(first, last)
-	//		otherwise, [first, last) is not LiteralType -> std::distance(first, last)
+	//		otherwise, [first, last) is RandomAccessIterator && ConstantDistanceIterator -> last - first
-	//		otherwise, [first, last) is RandomAccessIterator && not Pointer -> last - first
+	//		otherwise, [first, last) is LiteralType -> linearly count: first to last
-	//		otherwise -> linearly count: first to last
+	//		otherwise -> cxx14_distance(first, last)
 	//
 	template<typename InputIterator>
 	inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type

sprout/iterator/next.hpp

@@ -11,6 +11,7 @@
 #include <iterator>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/iterator/advance.hpp>
 #include <sprout/iterator/next_fwd.hpp>
 #include <sprout/iterator/prev_fwd.hpp>
 #include <sprout/adl/not_found.hpp>
@@ -24,36 +25,25 @@ namespace sprout_adl {
 namespace sprout {
 	namespace iterator_detail {
 		template<typename InputIterator>
-		InputIterator
+		inline SPROUT_CXX14_CONSTEXPR InputIterator
-		single_pass_next(InputIterator it, typename std::iterator_traits<InputIterator>::difference_type n = 1) {
+		cxx14_next(InputIterator it, typename std::iterator_traits<InputIterator>::difference_type n = 1) {
-			std::advance(it, n);
+			sprout::advance(it, n);
 			return it;
 		}
 
 		template<typename RandomAccessIterator>
-		inline SPROUT_CONSTEXPR typename std::enable_if<
+		inline SPROUT_CONSTEXPR RandomAccessIterator
-			std::is_literal_type<RandomAccessIterator>::value,
-			RandomAccessIterator
-		>::type
 		next_impl(RandomAccessIterator const& it, std::random_access_iterator_tag*) {
 			return it + 1;
 		}
-		template<typename ForwardIterator>
-		inline SPROUT_CONSTEXPR ForwardIterator
-		next_impl(ForwardIterator const& it, std::forward_iterator_tag*) {
-			return std::next(it);
-		}
 		template<typename InputIterator>
 		inline SPROUT_CONSTEXPR InputIterator
 		next_impl(InputIterator const& it, std::input_iterator_tag*) {
-			return sprout::iterator_detail::single_pass_next(it);
+			return sprout::iterator_detail::cxx14_next(it);
 		}
 
 		template<typename RandomAccessIterator>
-		inline SPROUT_CONSTEXPR typename std::enable_if<
+		inline SPROUT_CONSTEXPR RandomAccessIterator
-			std::is_literal_type<RandomAccessIterator>::value,
-			RandomAccessIterator
-		>::type
 		next_impl(
 			RandomAccessIterator const& it, typename std::iterator_traits<RandomAccessIterator>::difference_type n,
 			std::random_access_iterator_tag*
@@ -121,18 +111,6 @@ namespace sprout {
 			typedef typename std::iterator_traits<InputIterator>::iterator_category* category;
 			return sprout::iterator_detail::next_impl_1(it, n, category());
 		}
-		template<typename ForwardIterator>
-		inline SPROUT_CONSTEXPR typename std::enable_if<
-			!std::is_literal_type<ForwardIterator>::value,
-			ForwardIterator
-		>::type
-		next_impl(
-			ForwardIterator const& it, typename std::iterator_traits<ForwardIterator>::difference_type n,
-			std::forward_iterator_tag*
-			)
-		{
-			return std::next(it, n);
-		}
 		template<typename InputIterator>
 		inline SPROUT_CONSTEXPR typename std::enable_if<
 			!std::is_literal_type<InputIterator>::value,
@@ -143,7 +121,7 @@ namespace sprout {
 			std::input_iterator_tag*
 			)
 		{
-			return sprout::iterator_detail::single_pass_next(it, n);
+			return sprout::iterator_detail::cxx14_next(it, n);
 		}
 
 		template<typename InputIterator>
@@ -184,9 +162,8 @@ namespace sprout {
 	//
 	//	effect:
 	//		ADL callable iterator_next(it) -> iterator_next(it)
-	//		it is RandomAccessIterator && LiteralType -> it + 1
+	//		it is RandomAccessIterator -> it + 1
-	//		it is ForwardIterator -> std::next(it)
+	//		otherwise -> cxx14_next(it)
-	//		otherwise -> single_pass_next(it)
 	//
 	template<typename InputIterator>
 	inline SPROUT_CONSTEXPR InputIterator
@@ -196,11 +173,10 @@ namespace sprout {
 	//
 	//	effect:
 	//		ADL callable iterator_next(it, n) -> iterator_next(it, n)
-	//		it is RandomAccessIterator && LiteralType -> it + n
+	//		it is RandomAccessIterator -> it + n
 	//		it is LiteralType && n >= 0 -> sprout::next(it)...
 	//		it is LiteralType && n < 0 -> sprout::prev(it)...
-	//		it is ForwardIterator -> std::next(it, n)
+	//		otherwise -> cxx14_next(it, n)
-	//		otherwise -> single_pass_next(it, n)
 	//
 	template<typename InputIterator>
 	inline SPROUT_CONSTEXPR InputIterator

sprout/iterator/prev.hpp

@@ -11,6 +11,7 @@
 #include <iterator>
 #include <type_traits>
 #include <sprout/config.hpp>
+#include <sprout/iterator/advance.hpp>
 #include <sprout/iterator/next_fwd.hpp>
 #include <sprout/iterator/prev_fwd.hpp>
 #include <sprout/adl/not_found.hpp>
@@ -21,25 +22,26 @@ namespace sprout_adl {
 
 namespace sprout {
 	namespace iterator_detail {
+		template<typename InputIterator>
+		inline SPROUT_CXX14_CONSTEXPR InputIterator
+		cxx14_prev(InputIterator it, typename std::iterator_traits<InputIterator>::difference_type n = 1) {
+			sprout::advance(it, -n);
+			return it;
+		}
+
 		template<typename RandomAccessIterator>
-		inline SPROUT_CONSTEXPR typename std::enable_if<
+		inline SPROUT_CONSTEXPR RandomAccessIterator
-			std::is_literal_type<RandomAccessIterator>::value,
-			RandomAccessIterator
-		>::type
 		prev_impl(RandomAccessIterator const& it, std::random_access_iterator_tag*) {
 			return it - 1;
 		}
 		template<typename BidirectionalIterator>
 		inline SPROUT_CONSTEXPR BidirectionalIterator
 		prev_impl(BidirectionalIterator const& it, std::bidirectional_iterator_tag*) {
-			return std::prev(it);
+			return sprout::iterator_detail::cxx14_prev(it);
 		}
 
 		template<typename RandomAccessIterator>
-		inline SPROUT_CONSTEXPR typename std::enable_if<
+		inline SPROUT_CONSTEXPR RandomAccessIterator
-			std::is_literal_type<RandomAccessIterator>::value,
-			RandomAccessIterator
-		>::type
 		prev_impl(
 			RandomAccessIterator const& it, typename std::iterator_traits<RandomAccessIterator>::difference_type n,
 			std::random_access_iterator_tag*
@@ -94,7 +96,7 @@ namespace sprout {
 			std::bidirectional_iterator_tag*
 			)
 		{
-			return std::prev(it, n);
+			return sprout::iterator_detail::cxx14_prev(it, n);
 		}
 
 		template<typename BidirectionalIterator>
@@ -135,8 +137,8 @@ namespace sprout {
 	//
 	//	effect:
 	//		ADL callable iterator_prev(it) -> iterator_prev(it)
-	//		it is RandomAccessIterator && LiteralType -> it - 1
+	//		it is RandomAccessIterator -> it - 1
-	//		otherwise -> std::prev(it)
+	//		otherwise -> cxx14_prev(it)
 	//
 	template<typename BidirectionalIterator>
 	inline SPROUT_CONSTEXPR BidirectionalIterator
@@ -146,9 +148,10 @@ namespace sprout {
 	//
 	//	effect:
 	//		ADL callable iterator_prev(it, n) -> iterator_prev(it, n)
-	//		it is RandomAccessIterator && LiteralType -> it - n
+	//		it is RandomAccessIterator -> it - n
-	//		it is LiteralType -> sprout::prev(it)... || sprout::next(it)...
+	//		it is LiteralType && n >= 0 -> sprout::prev(it)...
-	//		otherwise -> std::prev(it, n)
+	//		it is LiteralType && n < 0 -> sprout::next(it)...
+	//		otherwise -> cxx14_prev(it, n)
 	//
 	template<typename BidirectionalIterator>
 	inline SPROUT_CONSTEXPR BidirectionalIterator

sprout/iterator/type_traits/is_constant_distance_iterator.hpp

@@ -13,7 +13,6 @@
 #include <sprout/iterator/type_traits/is_iterator_of.hpp>
 
 namespace sprout {
-
 	//
 	// is_constant_distance_iterator
 	//
@@ -21,7 +20,11 @@ namespace sprout {
 	struct is_constant_distance_iterator
 		: public std::integral_constant<
 			bool,
+#ifdef SPROUT_NO_CXX14_CONSTEXPR
 			sprout::is_random_access_iterator<MaybeIterator>::value && !std::is_pointer<MaybeIterator>::value
+#else	// #ifdef SPROUT_NO_CXX14_CONSTEXPR
+			sprout::is_random_access_iterator<MaybeIterator>::value
+#endif	// #ifdef SPROUT_NO_CXX14_CONSTEXPR
 		>
 	{};
 }	// namespace sprout