/****************************************************************************
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* Copyright (C) 2016 Intel Corporation. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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* @file arena.h
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*
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* @brief RingBuffer
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* The RingBuffer class manages all aspects of the ring buffer including
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* the head/tail indices, etc.
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*
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******************************************************************************/
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#pragma once
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template<typename T>
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class RingBuffer
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{
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public:
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RingBuffer()
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: mpRingBuffer(nullptr), mNumEntries(0), mRingHead(0), mRingTail(0)
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{
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}
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~RingBuffer()
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{
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Destroy();
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}
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void Init(uint32_t numEntries)
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{
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SWR_ASSERT(numEntries > 0);
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SWR_ASSERT(((1ULL << 32) % numEntries) == 0, "%d is not evenly divisible into 2 ^ 32. Wrap errors will occur!", numEntries);
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mNumEntries = numEntries;
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mpRingBuffer = (T*)AlignedMalloc(sizeof(T)*numEntries, 64);
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SWR_ASSERT(mpRingBuffer != nullptr);
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memset(mpRingBuffer, 0, sizeof(T)*numEntries);
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}
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void Destroy()
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{
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AlignedFree(mpRingBuffer);
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mpRingBuffer = nullptr;
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}
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T& operator[](const uint32_t index)
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{
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SWR_ASSERT(index < mNumEntries);
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return mpRingBuffer[index];
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}
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INLINE void Enqueue()
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{
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mRingHead++; // There's only one producer.
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// Assert to find wrap-around cases, NEVER ENABLE DURING CHECKIN!!
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// SWR_REL_ASSERT(mRingHead);
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}
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INLINE void Dequeue()
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{
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InterlockedIncrement(&mRingTail); // There are multiple consumers.
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}
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INLINE bool IsEmpty()
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{
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return (GetHead() == GetTail());
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}
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INLINE bool IsFull()
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{
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uint32_t numEnqueued = GetHead() - GetTail();
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SWR_ASSERT(numEnqueued <= mNumEntries);
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return (numEnqueued == mNumEntries);
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}
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INLINE uint32_t GetTail() volatile { return mRingTail; }
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INLINE uint32_t GetHead() volatile { return mRingHead; }
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protected:
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T* mpRingBuffer;
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uint32_t mNumEntries;
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OSALIGNLINE(volatile uint32_t) mRingHead; // Consumer Counter
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OSALIGNLINE(volatile uint32_t) mRingTail; // Producer Counter
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};
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