include/foundation/PxSort.h

File members: include/foundation/PxSort.h

// 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) 2008-2023 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 PX_SORT_H
#define PX_SORT_H

#include "foundation/PxSortInternals.h"
#include "foundation/PxAlloca.h"

#define PX_SORT_PARANOIA PX_DEBUG

#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

#if !PX_DOXYGEN
namespace physx
{
#endif
template <class T, class Predicate, class PxAllocator>
void PxSort(T* elements, uint32_t count, const Predicate& compare, const PxAllocator& 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);
    PxStack<PxAllocator> 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)
                {
                    PxSmallSort(elements, first, last, compare);
                    break;
                }
                else
                {
                    const int32_t partIndex = PxPartition(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 PxSort(T* elements, uint32_t count, const Predicate& compare)
{
    PxSort(elements, count, compare, typename PxAllocatorTraits<T>::Type());
}

template <class T>
void PxSort(T* elements, uint32_t count)
{
    PxSort(elements, count, PxLess<T>(), typename PxAllocatorTraits<T>::Type());
}

#if !PX_DOXYGEN
} // namespace physx
#endif

#if PX_VC
#pragma warning(pop)
#endif
#endif