refactor(*): refactor the tool library's parent folder to plural form

Redcraft.Utility/Source/Public/Iterators/Sentinel.h

@@ -0,0 +1,115 @@
+#pragma once
+
+#include "CoreTypes.h"
+#include "Iterators/Utility.h"
+#include "TypeTraits/TypeTraits.h"
+
+NAMESPACE_REDCRAFT_BEGIN
+NAMESPACE_MODULE_BEGIN(Redcraft)
+NAMESPACE_MODULE_BEGIN(Utility)
+
+#if PLATFORM_COMPILER_GCC
+#	pragma GCC diagnostic push
+#	pragma GCC diagnostic ignored "-Wnon-template-friend"
+#endif
+
+/**
+ * A concept specifies a type is a sentinel for an iterator and expression 'Iter == Sentinel' is valid.
+ * In addition, the type must be default constructible and copyable.
+ */
+template <typename S, typename I>
+concept CSentinelFor = CSemiregular<S> && CInputOrOutputIterator<I> && CWeaklyEqualityComparable<S, I>;
+
+/** This is an example of a sentinel for an iterator, indicate the traits that define a sentinel for an iterator. */
+template <CInputOrOutputIterator I>
+struct ISentinelFor
+{
+	ISentinelFor();
+	ISentinelFor(const ISentinelFor&);
+	ISentinelFor* operator=(const ISentinelFor&);
+
+	bool operator==(const I&) const&;
+};
+
+// Use ISentinelFor represents a sentinel for an iterator.
+static_assert(CSentinelFor<ISentinelFor<IInputOrOutputIterator<int>>, IInputOrOutputIterator<int>>);
+
+// The CSentinelFor requires this code is valid.
+static_assert(
+	requires(ISentinelFor<IInputOrOutputIterator<int>> Sentinel, IInputOrOutputIterator<int> Iter)
+	{
+		{ Iter == Sentinel } -> CBooleanTestable;
+		{ Sentinel == Iter } -> CBooleanTestable;
+	}
+);
+
+/** Disable the CSizedSentinelFor concept for specific types. */
+template <typename S, typename I>
+inline constexpr bool bDisableSizedSentinelFor = false;
+
+/**
+ * A concept specifies a type is a sized sentinel for an iterator and expressions 'Sentinel - Iter' and 'Iter - Sentinel' are valid,
+ * and the 'Sentinel - Iter' is equal to negative 'Iter - Sentinel'.
+ * In addition, the type must be default constructible and copyable.
+ */
+template <typename S, typename I>
+concept CSizedSentinelFor = CSentinelFor<S, I>
+	&& !bDisableSizedSentinelFor<TRemoveCVRef<S>, TRemoveCVRef<I>>
+	&& requires(const I& Iter, const S& Sentinel)
+	{
+		{ Sentinel - Iter } -> CSameAs<ptrdiff>;
+		{ Iter - Sentinel } -> CSameAs<ptrdiff>;
+	};
+
+/** This is an example of a sized sentinel for an iterator, indicate the traits that define a sized sentinel for an iterator. */
+template <CInputOrOutputIterator I>
+struct ISizedSentinelFor /* : ISentinelFor<I> */
+{
+	ISizedSentinelFor();                                    // Also satisfies ISentinelFor<I>.
+	ISizedSentinelFor(const ISizedSentinelFor&);
+	ISizedSentinelFor(ISizedSentinelFor&&);                 // Also satisfies ISentinelFor<I>.
+	ISizedSentinelFor& operator=(const ISizedSentinelFor&);
+	ISizedSentinelFor& operator=(ISizedSentinelFor&&);      // Also satisfies ISentinelFor<I>.
+
+	bool operator==(const I&) const&; // Also satisfies ISentinelFor<I>.
+
+	/** Subtraction operator. The 'Sentinel - Iter' is equal to negative 'Iter - Sentinel'. */
+	friend ptrdiff operator-(const I&, const ISizedSentinelFor&);
+	friend ptrdiff operator-(const ISizedSentinelFor&, const I&);
+};
+
+// Use ISizedSentinelFor represents a sized sentinel for an iterator.
+static_assert(CSizedSentinelFor<ISizedSentinelFor<IInputOrOutputIterator<int>>, IInputOrOutputIterator<int>>);
+
+// The CSentinelFor requires this code is valid.
+static_assert(
+	requires(ISizedSentinelFor<IInputOrOutputIterator<int>> Sentinel, IInputOrOutputIterator<int> Iter)
+	{
+		{ Iter == Sentinel } -> CBooleanTestable;
+		{ Sentinel == Iter } -> CBooleanTestable;
+		{ Iter - Sentinel }  -> CSameAs<ptrdiff>;
+		{ Sentinel - Iter }  -> CSameAs<ptrdiff>;
+	}
+);
+
+struct FDefaultSentinel { explicit FDefaultSentinel() = default; };
+
+inline constexpr FDefaultSentinel DefaultSentinel{ };
+
+struct FUnreachableSentinel
+{
+	explicit FUnreachableSentinel() = default;
+
+	template <CWeaklyIncrementable I>
+	NODISCARD FORCEINLINE constexpr bool operator==(const I&) const& { return false; }
+};
+
+inline constexpr FUnreachableSentinel UnreachableSentinel{ };
+
+#if PLATFORM_COMPILER_GCC
+#	pragma GCC diagnostic pop
+#endif
+
+NAMESPACE_MODULE_END(Utility)
+NAMESPACE_MODULE_END(Redcraft)
+NAMESPACE_REDCRAFT_END