CmPtrTable.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_PTR_TABLE_H
#define CM_PTR_TABLE_H
 
#include "common/PxPhysXCommonConfig.h"
 
namespace physx
{
class PxSerializationContext;
class PxDeserializationContext;
 
namespace Cm
{
class PtrTableStorageManager
{
    // This will typically be backed by a MultiPool implementation with fallback to the user
    // allocator. For MultiPool, when deallocating we want to know what the previously requested size was
    // so we can release into the right pool
 
public:
 
    virtual void**  allocate(PxU32 capacity)                            = 0;
    virtual void    deallocate(void** addr, PxU32 originalCapacity)     = 0;
 
    // whether memory allocated at one capacity can (and should) be safely reused at a different capacity
    // allows realloc-style reuse by clients.
 
    virtual bool    canReuse(PxU32 originalCapacity, PxU32 newCapacity)     = 0;
protected:
    virtual ~PtrTableStorageManager() {}
};
 
// specialized class to hold an array of pointers with extrinsic storage management, 
// serialization-compatible with 3.3.1 PtrTable
//
// note that extrinsic storage implies you *must* clear the table before the destructor runs
//
// capacity is implicit: 
// if the memory is not owned (i.e. came from deserialization) then the capacity is exactly mCount
// else if mCount==0,  capacity is 0
// else the capacity is the power of 2 >= mCount
// 
// one implication of this is that if we want to add or remove a pointer from unowned memory, we always realloc
struct PX_PHYSX_COMMON_API PtrTable
{
//= ATTENTION! =====================================================================================
// Changing the data layout of this class breaks the binary serialization format.  See comments for 
// PX_BINARY_SERIAL_VERSION.  If a modification is required, please adjust the getBinaryMetaData 
// function.  If the modification is made on a custom branch, please change PX_BINARY_SERIAL_VERSION
// accordingly.
//==================================================================================================
 
    PtrTable();
    ~PtrTable();
 
    void    add(void* ptr, PtrTableStorageManager& sm);
    void    replaceWithLast(PxU32 index, PtrTableStorageManager& sm);
    void    clear(PtrTableStorageManager& sm);
 
    PxU32   find(const void* ptr) const;
 
    PX_FORCE_INLINE PxU32       getCount()  const   { return mCount; }
    PX_FORCE_INLINE void*const* getPtrs()   const   { return mCount == 1 ? &mSingle : mList;    }
    PX_FORCE_INLINE void**      getPtrs()           { return mCount == 1 ? &mSingle : mList;    }
 
    // SERIALIZATION
 
    // 3.3.1 compatibility fixup: this implementation ALWAYS sets 'ownsMemory' if the size is 0 or 1
    PtrTable(const PxEMPTY)
    {
        mOwnsMemory = mCount<2;
        if(mCount == 0)
            mList = NULL;
    }
 
    void    exportExtraData(PxSerializationContext& stream);
    void    importExtraData(PxDeserializationContext& context);
 
    static void getBinaryMetaData(physx::PxOutputStream& stream);
 
private:
    void realloc(PxU32 oldCapacity, PxU32 newCapacity, PtrTableStorageManager& sm);
 
    union
    {
        void*   mSingle;
        void**  mList;
    };
 
    PxU16   mCount;
    bool    mOwnsMemory;
    bool    mBufferUsed;    // dark magic in serialization requires this, otherwise redundant because it's logically equivalent to mCount == 1.
public:
    PxU32   mFreeSlot;      // PT: padding bytes on x64
};
 
} // namespace Cm
 
}
 
#endif