_ak_ring_buffer_8h

Other Documentation

Wwise SDK 2022.1.4

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 released in source code form as part of the SDK installer package.

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 may use this file in accordance with the end user license agreement provided 

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 Alternatively, this file may be used under the Apache License, Version 2.0 (the 

 "Apache License"); you may not use this file except in compliance with the 

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 http://www.apache.org/licenses/LICENSE-2.0.

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 the specific language governing permissions and limitations under the License.

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 #pragma once

 #include <AK/SoundEngine/Common/AkTypes.h>

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

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

 template <AkMemID T_MEMID>

 struct AkRingBufferAllocatorNoAlign

 {

     static AkForceInline void* Alloc(size_t in_uSize)

     {

         return AkAlloc(T_MEMID, in_uSize);

     }

     static AkForceInline void Free(void * in_pAddress)

     {

         AkFree(T_MEMID, in_pAddress);

     }

 };

 template <AkMemID T_MEMID>

 struct AkRingBufferAllocatorAligned

 {

     static AkForceInline void* Alloc(size_t in_uSize)

     {

         return AkMalign(T_MEMID, in_uSize, AK_SIMD_ALIGNMENT);

     }

     static AkForceInline void Free(void * in_pAddress)

     {

         AkFree(T_MEMID, in_pAddress);

     }

 };

 typedef AkRingBufferAllocatorNoAlign<AkMemID_Object> AkRingBufferAllocatorDefault;

 typedef AkRingBufferAllocatorNoAlign<AkMemID_Processing> AkRingBufferAllocatorLEngine;

 typedef AkRingBufferAllocatorAligned<AkMemID_Processing> AkRingBufferAllocatorLEngineAligned;

 template <class T, class TAlloc = AkRingBufferAllocatorDefault>

 //Single producer, single consumer pattern implementation.

 class AkRingBuffer

 {

 public:

     AkRingBuffer()

         : m_nbItems(0)

         , m_readIndex(0)

         , m_writeIndex(0)

         , m_nbReadableItems(0)

     {

     }

     AKRESULT Init(AkUInt32 nbItems)

     {

         m_nbItems = nbItems;

         m_readIndex = 0;

         m_writeIndex = 0;

         m_nbReadableItems = 0;

         m_data = reinterpret_cast<T*>(TAlloc::Alloc(m_nbItems * sizeof(T)));

         if (m_data == NULL)

         {

             return AK_InsufficientMemory;

         }

         return AK_Success;

     }

     void Term()

     {

         m_nbItems = 0;

         m_readIndex = 0;

         m_writeIndex = 0;

         m_nbReadableItems = 0;

         if (m_data != NULL)

         {

             TAlloc::Free(reinterpret_cast<void*>(m_data));

             m_data = NULL;

         }

     }

     // Reset ringbuffer to initial state without freeing memory. Not thread-safe.

     void Reset()

     {

         m_readIndex = 0;

         m_writeIndex = 0;

         m_nbReadableItems = 0;

     }

     // ---- Producer ---- //

     AkUInt32 GetWriteIndex() const

     {

         return m_writeIndex;

     }

     T* GetWritePtr()

     {

         return &m_data[m_writeIndex];

     }

     void IncrementWriteIndex(AkUInt32 nbItems)

     {

         AKASSERT(GetNbWritableItems() >= nbItems);

         m_writeIndex = (m_writeIndex + nbItems) % m_nbItems;

         AkAtomicAdd32(&m_nbReadableItems, nbItems);

     }

     // ---- Consumer ----

     AkUInt32 GetReadIndex() const

     {

         return m_readIndex;

     }

     const T* GetReadPtr() const

     {

         return &m_data[m_readIndex];

     }

     // Peek at any item between the read and write pointer without advancing the read pointer.

     const T* Peek(AkUInt32 uOffset) const

     {

         AKASSERT((AkUInt32)m_nbReadableItems > uOffset);

         AkUInt32 uReadIndex = (m_readIndex + uOffset) % m_nbItems;

         return &m_data[uReadIndex];

     }

     void IncrementReadIndex(AkUInt32 nbItems)

     {

         AKASSERT((AkUInt32)m_nbReadableItems >= nbItems);

         m_readIndex = (m_readIndex + nbItems) % m_nbItems;

         AkAtomicSub32(&m_nbReadableItems, nbItems);

     }

     AkUInt32 GetNbReadableItems() const

     {

         return m_nbReadableItems;

     }

     AkUInt32 GetNbWritableItems() const

     {

         return m_nbItems - (AkUInt32)m_nbReadableItems;

     }

     AkUInt32 Size() const

     {

         return m_nbItems;

     }

     // Warning: requires external locking to prevent concurrent Grow+Read in a multi-threaded scenario. 

     // Like the rest of the class, assumes a single writing thread.

     bool Grow(AkUInt32 in_uGrowBy)

     {

         AkUInt32 uTargetItems = m_nbItems + in_uGrowBy;

         if (T* pNewData = reinterpret_cast<T*>(TAlloc::Alloc(uTargetItems * sizeof(T))))

         {

             if (m_nbReadableItems)

             {

                 if (m_readIndex >= m_writeIndex)

                 {

                     // insert new free space in the middle of the buffer.

                     if (m_writeIndex)

                         memcpy(pNewData, m_data, sizeof(T) * m_writeIndex);

                     memcpy(pNewData + m_readIndex + in_uGrowBy, m_data + m_readIndex, sizeof(T) * (m_nbItems - m_readIndex));

                     m_readIndex += in_uGrowBy;

                 }

                 else

                 {

                     // insert new free space at the end of the buffer.

                     memcpy(pNewData + m_readIndex, m_data + m_readIndex, sizeof(T) * (AkUInt32)m_nbReadableItems);

                 }

             }

             TAlloc::Free(reinterpret_cast<void*>(m_data));

             m_data = pNewData;

             m_nbItems = uTargetItems;

             return true;

         }

         else

         {

             return false;

         }

     }

 private:

     T* m_data{nullptr};

     AkUInt32 m_nbItems;

     AkUInt32 m_readIndex;

     AkUInt32 m_writeIndex;

     AkAtomic32 m_nbReadableItems;

 };