feat(algorithms): add basic iterator algorithm and the corresponding testing

Redcraft.Utility/Source/Public/Algorithms/Algorithms.h

@@ -0,0 +1,4 @@
+#pragma once
+
+#include "CoreTypes.h"
+#include "Algorithms/Basic.h"

Redcraft.Utility/Source/Public/Algorithms/Basic.h

@@ -0,0 +1,85 @@
+#pragma once
+
+#include "CoreTypes.h"
+#include "TypeTraits/TypeTraits.h"
+#include "Iterators/Utility.h"
+#include "Iterators/BasicIterator.h"
+#include "Ranges/Utility.h"
+#include "Miscellaneous/AssertionMacros.h"
+
+NAMESPACE_REDCRAFT_BEGIN
+NAMESPACE_MODULE_BEGIN(Redcraft)
+NAMESPACE_MODULE_BEGIN(Utility)
+
+NAMESPACE_BEGIN(Algorithm)
+
+/** Increments given iterator 'Iter' by 'N' elements. */
+template <CInputIterator I>
+FORCEINLINE constexpr void Advance(I& Iter, ptrdiff N)
+{
+	if constexpr (CRandomAccessIterator<I>)
+	{
+		Iter += N;
+	}
+
+	else if constexpr (CBidirectionalIterator<I>)
+	{
+		for (; N > 0; --N) ++Iter;
+		for (; N < 0; ++N) --Iter;
+	}
+
+	else
+	{
+		checkf(N >= 0, TEXT("The iterator must satisfy the CBidirectionalIterator in order to be decremented."));
+		for (; N > 0; --N) ++Iter;
+	}
+}
+
+/** @return The number of hops from 'First' to 'Last'. */
+template <CInputIterator I, CSentinelFor<I> S>
+NODISCARD FORCEINLINE constexpr ptrdiff Distance(I First, S Last)
+{
+	if constexpr (CSizedSentinelFor<S, I>)
+	{
+		return Last - First;
+	}
+	else
+	{
+		ptrdiff Result = 0;
+		for (; First != Last; ++First) ++Result;
+		return Result;
+	}
+}
+
+/** @return The size of the range. */
+template <CRange R>
+NODISCARD FORCEINLINE constexpr ptrdiff Distance(R&& Range)
+{
+	if constexpr (CSizedRange<R>)
+	{
+		return static_cast<ptrdiff>(Range::Num(Range));
+	}
+	else return Algorithm::Distance(Range::Begin(Range), Range::End(Range));
+}
+
+/** @return The 'N'-th successor of iterator 'Iter'. */
+template <CInputIterator I>
+NODISCARD FORCEINLINE constexpr I Next(I Iter, ptrdiff N = 1)
+{
+	Algorithm::Advance(Iter, N);
+	return Iter;
+}
+
+/** @return The 'N'-th predecessor of iterator 'Iter'. */
+template <CBidirectionalIterator I>
+NODISCARD FORCEINLINE constexpr I Prev(I Iter, ptrdiff N = 1)
+{
+	Algorithm::Advance(Iter, -N);
+	return Iter;
+}
+
+NAMESPACE_END(Algorithm)
+
+NAMESPACE_MODULE_END(Utility)
+NAMESPACE_MODULE_END(Redcraft)
+NAMESPACE_REDCRAFT_END