text: //
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  // 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 CM_BLOCK_ARRAY_H
  #define CM_BLOCK_ARRAY_H
  
  #include "foundation/PxAssert.h"
  #include "foundation/PxMath.h"
  #include "foundation/PxMemory.h"
  #include "PsAllocator.h"
  #include "PsUserAllocated.h"
  #include "PsIntrinsics.h"
  #include "PsMathUtils.h"
  #include "CmPhysXCommon.h"
  #include "PsArray.h"
  
  namespace physx
  {
  namespace Cm
  {
  
  template <typename T>
  class BlockArray
  {
  	Ps::Array<T*> mBlocks;
  	PxU32 mSize;
  	PxU32 mCapacity;
  	PxU32 mSlabSize;
  
  public:
  
  	BlockArray(PxU32 slabSize = 2048) : mSize(0), mCapacity(0), mSlabSize(slabSize)
  	{
  		PX_ASSERT(slabSize > 0);
  	}
  
  	~BlockArray()
  	{
  		for (PxU32 a = 0; a < mBlocks.size(); ++a)
  		{
  			PX_FREE(mBlocks[a]);
  		}
  		mBlocks.resize(0);
  	}
  
  	void reserve(PxU32 capacity)
  	{
  		if (capacity > mCapacity)
  		{
  			PxU32 nbSlabsRequired = (capacity + mSlabSize - 1) / mSlabSize;
  
  			PxU32 nbSlabsToAllocate = nbSlabsRequired - mBlocks.size();
  
  			mCapacity += nbSlabsToAllocate * mSlabSize;
  
  			for (PxU32 a = 0; a < nbSlabsToAllocate; ++a)
  			{
  				mBlocks.pushBack(reinterpret_cast<T*>(PX_ALLOC(sizeof(T) * mSlabSize, PX_DEBUG_EXP("BlockArray"))));
  			}
  		}
  	}
  
  	void resize(PxU32 size)
  	{
  		reserve(size);
  		for (PxU32 a = mSize; a < size; ++a)
  		{
  			mBlocks[a / mSlabSize][a%mSlabSize] = T();
  		}
  		mSize = size;
  	}
  
  	void forceSize_Unsafe(PxU32 size)
  	{
  		PX_ASSERT(size <= mCapacity);
  		mSize = size;
  	}
  
  	void remove(PxU32 idx)
  	{
  		PX_ASSERT(idx < mSize);
  		for (PxU32 a = idx; a < mSize; ++a)
  		{
  			mBlocks[a / mSlabSize][a%mSlabSize] = mBlocks[(a + 1) / mSlabSize][(a + 1) % mSlabSize];
  		}
  
  		mSize--;
  	}
  
  	void replaceWithLast(PxU32 idx)
  	{
  		PX_ASSERT(idx < mSize);
  		--mSize;
  		mBlocks[idx / mSlabSize][idx%mSlabSize] = mBlocks[mSize / mSlabSize][mSize%mSlabSize];
  	}
  
  	T& operator [] (const PxU32 idx)
  	{
  		PX_ASSERT(idx < mSize);
  
  		return mBlocks[idx / mSlabSize][idx%mSlabSize];
  	}
  
  	const T& operator [] (const PxU32 idx) const
  	{
  		PX_ASSERT(idx < mSize);
  
  		return mBlocks[idx / mSlabSize][idx%mSlabSize];
  	}
  
  	void pushBack(const T& item)
  	{
  		reserve(mSize + 1);
  		mBlocks[mSize / mSlabSize][mSize%mSlabSize] = item;
  		mSize++;
  	}
  
  	PxU32 capacity() const { return mCapacity; }
  
  	PxU32 size() const { return mSize;  }
  };
  
  }
  }
  
  #endif
  
  