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physx/source/foundation/include/PsSort.h

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+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//  * Redistributions of source code must retain the above copyright
+//    notice, this list of conditions and the following disclaimer.
+//  * Redistributions in binary form must reproduce the above copyright
+//    notice, this list of conditions and the following disclaimer in the
+//    documentation and/or other materials provided with the distribution.
+//  * Neither the name of NVIDIA CORPORATION nor the names of its
+//    contributors may be used to endorse or promote products derived
+//    from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+// PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Copyright (c) 2008-2021 NVIDIA Corporation. All rights reserved.
+// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
+// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
+
+#ifndef PSFOUNDATION_PSSORT_H
+#define PSFOUNDATION_PSSORT_H
+
+/** \addtogroup foundation
+@{
+*/
+
+#include "PsSortInternals.h"
+#include "PsAlloca.h"
+
+#define PX_SORT_PARANOIA PX_DEBUG
+
+/**
+\brief Sorts an array of objects in ascending order, assuming
+that the predicate implements the < operator:
+
+\see Less, Greater
+*/
+
+#if PX_VC
+#pragma warning(push)
+#pragma warning(disable : 4706) // disable the warning that we did an assignment within a conditional expression, as
+// this was intentional.
+#endif
+
+namespace physx
+{
+namespace shdfnd
+{
+template <class T, class Predicate, class Allocator>
+void sort(T* elements, uint32_t count, const Predicate& compare, const Allocator& inAllocator,
+          const uint32_t initialStackSize = 32)
+{
+	static const uint32_t SMALL_SORT_CUTOFF = 5; // must be >= 3 since we need 3 for median
+
+	PX_ALLOCA(stackMem, int32_t, initialStackSize);
+	internal::Stack<Allocator> stack(stackMem, initialStackSize, inAllocator);
+
+	int32_t first = 0, last = int32_t(count - 1);
+	if(last > first)
+	{
+		for(;;)
+		{
+			while(last > first)
+			{
+				PX_ASSERT(first >= 0 && last < int32_t(count));
+				if(uint32_t(last - first) < SMALL_SORT_CUTOFF)
+				{
+					internal::smallSort(elements, first, last, compare);
+					break;
+				}
+				else
+				{
+					const int32_t partIndex = internal::partition(elements, first, last, compare);
+
+					// push smaller sublist to minimize stack usage
+					if((partIndex - first) < (last - partIndex))
+					{
+						stack.push(first, partIndex - 1);
+						first = partIndex + 1;
+					}
+					else
+					{
+						stack.push(partIndex + 1, last);
+						last = partIndex - 1;
+					}
+				}
+			}
+
+			if(stack.empty())
+				break;
+
+			stack.pop(first, last);
+		}
+	}
+#if PX_SORT_PARANOIA
+	for(uint32_t i = 1; i < count; i++)
+		PX_ASSERT(!compare(elements[i], elements[i - 1]));
+#endif
+}
+
+template <class T, class Predicate>
+void sort(T* elements, uint32_t count, const Predicate& compare)
+{
+	sort(elements, count, compare, typename shdfnd::AllocatorTraits<T>::Type());
+}
+
+template <class T>
+void sort(T* elements, uint32_t count)
+{
+	sort(elements, count, shdfnd::Less<T>(), typename shdfnd::AllocatorTraits<T>::Type());
+}
+
+} // namespace shdfnd
+} // namespace physx
+
+#if PX_VC
+#pragma warning(pop)
+#endif
+
+#endif // #ifndef PSFOUNDATION_PSSORT_H