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