_ak_object_pool_8h

Other Documentation

Wwise SDK 2022.1.8

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 #ifndef _AKPOOLALLOCATOR_H

 #define _AKPOOLALLOCATOR_H

 #include <AK/Tools/Common/AkObject.h>

 #include <AK/Tools/Common/AkAssert.h>

 #include <AK/Tools/Common/AkArray.h>

 /// Extra debug option when calling ObjectPool::Deallocate.

 /// Going through the free list can be slow when the object count is high.

 #define AK_OBJECT_POOL_EXTRA_SAFETY

 namespace UnitTest { struct ObjectPoolHelper; }

 namespace AK

 {

     template<AkMemID T_MEMID = AkMemID_Object>

     using ObjectPoolDefaultAllocator = AkArrayAllocatorNoAlign<T_MEMID>;

     struct ObjectPoolNoLock

     {

         inline static constexpr void Lock() {}

         inline static constexpr void Unlock() {}

     };

     using ObjectPoolDefaultLockType = ObjectPoolNoLock;

     /// An object pool of N reusable objects with one allocation.

     template<

         typename T,

         typename AllocatorType = ObjectPoolDefaultAllocator<>,

         typename LockType = ObjectPoolDefaultLockType>

         class ObjectPool : AllocatorType, LockType

     {

     public:

         using ValueType = T;

         using SizeType = AkUInt32;

         static constexpr SizeType kInvalidIndex = (SizeType)-1;

         union DataType

         {

             inline ValueType& Data() { return *(ValueType*)data; }

             inline const ValueType& Data() const { return *(const ValueType*)data; }

             alignas(ValueType) uint8_t data[sizeof(ValueType)];

             SizeType next;

         };

         using AllocatorType::AllocatorType;

         ObjectPool() = default;

         ObjectPool(const ObjectPool&) = delete;

         ObjectPool(ObjectPool&&) = delete;

         inline ~ObjectPool() { AKASSERT(!m_data); }

         ObjectPool& operator=(const ObjectPool&) = delete;

         ObjectPool& operator=(ObjectPool&&) = delete;

         inline AKRESULT Init(SizeType count)

         {

             AKASSERT(!m_data && "ObjectPool is already initialized, call 'Term' before calling 'Init' again");

             AKASSERT(count && "ObjectPool count must be greater than zero");

             AKASSERT(count < kInvalidIndex && "ObjectPool count is above SizeType's maximum capacity");

             if (m_data || !count)

                 return AK_InvalidParameter;

             m_data = reinterpret_cast<DataType*>(AllocatorType::Alloc(count * sizeof(DataType)));

             m_capacity = 0;

             m_size = 0;

             m_freeList = 0;

             if (!m_data)

                 return AK_InsufficientMemory;

             m_capacity = count;

             for (SizeType i = 0; i < m_capacity - 1; i++)

                 m_data[i].next = i + 1;

             m_data[m_capacity - 1].next = kInvalidIndex;

             return AK_Success;

         }

         inline void Term()

         {

             // Only assert when some object are still allocated and ValueType is not trivially destructible.

             AKASSERT(m_size == 0 && "Can't call Term() when some objects are still allocated");

             if (!m_data)

                 return;

             AllocatorType::Free(m_data);

             m_data = nullptr;

             m_capacity = 0;

             m_size = 0;

             m_freeList = 0;

         }

         AK_NODISCARD inline SizeType Size() const { return m_size; }

         AK_NODISCARD inline SizeType Capacity() const { return m_capacity; }

         AK_NODISCARD inline bool IsFull() const { return m_size >= m_capacity; }

         AK_NODISCARD inline bool IsEmpty() const { return m_size == 0; }

         /// Allocates a new object.

         /// @returns the object on success or nullptr if it fails (already full).

         /// @{

         AK_NODISCARD inline ValueType* Allocate()

         {

             if (IsFull())

                 return nullptr;

             LockType::Lock();

             DataType& data = m_data[m_freeList];

             m_freeList = data.next;

             m_size++;

             LockType::Unlock();

             return &data.Data();

         }

         /// Initialize memory before returning.

         AK_NODISCARD inline ValueType* AllocateZeroFilled()

         {

             ValueType* value = Allocate();

             if (value)

                 AKPLATFORM::AkMemSet((void*)value, 0, (AkUInt32)sizeof(ValueType));

             return value;

         }

         /// @}

         /// Deallocates given pointer.

         /// Calling Deallocate when IsEmpty() returns true is undefined behaviour.

         /// Calling Deallocate with a pointer that wasn't allocated by this pool is undefined behaviour.

         ///

         /// You can define AK_OBJECT_POOL_EXTRA_SAFETY for extra debugging check.

         inline AKRESULT Deallocate(ValueType* data)

         {

             AKASSERT(data && "Deallocating null data");

             DataType* tdata = reinterpret_cast<DataType*>(data);

             // Check if data is in memory range.

             AKASSERT((tdata >= m_data && tdata < m_data + m_capacity) && "Pointer address out of range");

             if (tdata < m_data || tdata >= m_data + m_capacity)

                 return AK_InvalidParameter;

             LockType::Lock();

             AKASSERT(m_size && "Trying to deallocate when empty");

 #ifdef AK_OBJECT_POOL_EXTRA_SAFETY

             AKASSERT(IsAllocated((SizeType)(tdata - m_data)));

 #endif

             m_size--;

             tdata->next = m_freeList;

             m_freeList = (SizeType)(tdata - m_data);

             LockType::Unlock();

             return AK_Success;

         }

         /// Deallocates all objects.

         /// This function should only be called if ValueType is trivially destructible.

         inline void Clear()

         {

             for (SizeType i = 0; i < m_capacity - 1; i++)

                 m_data[i].next = i + 1;

             m_data[m_capacity - 1].next = kInvalidIndex;

             m_size = 0;

             m_freeList = 0;

         }

     private:

         DataType* m_data = nullptr;

         SizeType m_capacity = 0;

         SizeType m_size = 0;

         SizeType m_freeList = 0;

         friend struct UnitTest::ObjectPoolHelper;

         inline bool IsAllocated(SizeType index) const

         {

             for (SizeType k = m_freeList; k != kInvalidIndex; k = m_data[k].next)

                 if (index == k)

                     return false;

             return true;

         }

     };

 } // namespace AK

 #endif