CmBlockArray.h

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// 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 "foundation/PxAllocator.h"
#include "foundation/PxUserAllocated.h"
#include "foundation/PxIntrinsics.h"
#include "foundation/PxArray.h"
 
namespace physx
{
namespace Cm
{
 
template <typename T, PxU32 SlabSize = 4096>
class BlockArray
{
    PxArray<T*> mBlocks;
    PxU32 mSize;
    PxU32 mCapacity;
 
public:
 
    BlockArray() : mSize(0), mCapacity(0)
    {
    }
 
    ~BlockArray()
    {
        for (PxU32 a = 0; a < mBlocks.size(); ++a)
        {
            for (PxU32 i = 0; i < SlabSize; ++i)
            {
                mBlocks[a][i].~T();
            }
            PX_FREE(mBlocks[a]);
        }
        mBlocks.resize(0);
    }
 
    void reserve(PxU32 capacity)
    {
        if (capacity > mCapacity)
        {
            PxU32 nbSlabsRequired = (capacity + SlabSize - 1) / SlabSize;
 
            PxU32 nbSlabsToAllocate = nbSlabsRequired - mBlocks.size();
 
            mCapacity += nbSlabsToAllocate * SlabSize;
 
            for (PxU32 a = 0; a < nbSlabsToAllocate; ++a)
            {
                T* ts = reinterpret_cast<T*>(PX_ALLOC(sizeof(T) * SlabSize, "BlockArray"));
                for(PxU32 i = 0; i < SlabSize; ++i)
                    PX_PLACEMENT_NEW(ts+i, T)();
                mBlocks.pushBack(ts);
            }
        }
    }
 
    void resize(PxU32 size)
    {
        reserve(size);
        for (PxU32 a = mSize; a < size; ++a)
        {
            mBlocks[a / SlabSize][a&(SlabSize - 1)].~T();
            mBlocks[a / SlabSize][a&(SlabSize-1)] = 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 / SlabSize][a&(SlabSize-1)] = mBlocks[(a + 1) / SlabSize][(a + 1) &(SlabSize-1)];
        }
 
        mSize--;
        mBlocks[mSize / SlabSize][mSize&(SlabSize - 1)].~T();
    }
 
    void replaceWithLast(PxU32 idx)
    {
        PX_ASSERT(idx < mSize);
        --mSize;
        mBlocks[idx / SlabSize][idx%SlabSize] = mBlocks[mSize / SlabSize][mSize%SlabSize];
    }
 
    T& operator [] (const PxU32 idx)
    {
        PX_ASSERT(idx < mSize);
 
        return mBlocks[idx / SlabSize][idx%SlabSize];
    }
 
    const T& operator [] (const PxU32 idx) const
    {
        PX_ASSERT(idx < mSize);
 
        return mBlocks[idx / SlabSize][idx%SlabSize];
    }
 
    void pushBack(const T& item)
    {
        reserve(mSize + 1);
        mBlocks[mSize / SlabSize][mSize%SlabSize] = item;
        mSize++;
    }
 
    PxU32 capacity() const { return mCapacity; }
 
    PxU32 size() const { return mSize;  }
};
 
}
}
 
#endif