1 /**************************************************************************** 2 * Copyright (C) 2016 Intel Corporation. All Rights Reserved. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 * @file arena.h 24 * 25 * @brief RingBuffer 26 * The RingBuffer class manages all aspects of the ring buffer including 27 * the head/tail indices, etc. 28 * 29 ******************************************************************************/ 30 #pragma once 31 32 template<typename T> 33 class RingBuffer 34 { 35 public: RingBuffer()36 RingBuffer() 37 : mpRingBuffer(nullptr), mNumEntries(0), mRingHead(0), mRingTail(0) 38 { 39 } 40 ~RingBuffer()41 ~RingBuffer() 42 { 43 Destroy(); 44 } 45 Init(uint32_t numEntries)46 void Init(uint32_t numEntries) 47 { 48 SWR_ASSERT(numEntries > 0); 49 SWR_ASSERT(((1ULL << 32) % numEntries) == 0, "%d is not evenly divisible into 2 ^ 32. Wrap errors will occur!", numEntries); 50 mNumEntries = numEntries; 51 mpRingBuffer = (T*)AlignedMalloc(sizeof(T)*numEntries, 64); 52 SWR_ASSERT(mpRingBuffer != nullptr); 53 memset(mpRingBuffer, 0, sizeof(T)*numEntries); 54 } 55 Destroy()56 void Destroy() 57 { 58 AlignedFree(mpRingBuffer); 59 mpRingBuffer = nullptr; 60 } 61 62 T& operator[](const uint32_t index) 63 { 64 SWR_ASSERT(index < mNumEntries); 65 return mpRingBuffer[index]; 66 } 67 Enqueue()68 INLINE void Enqueue() 69 { 70 mRingHead++; // There's only one producer. 71 // Assert to find wrap-around cases, NEVER ENABLE DURING CHECKIN!! 72 // SWR_REL_ASSERT(mRingHead); 73 } 74 Dequeue()75 INLINE void Dequeue() 76 { 77 InterlockedIncrement(&mRingTail); // There are multiple consumers. 78 } 79 IsEmpty()80 INLINE bool IsEmpty() 81 { 82 return (GetHead() == GetTail()); 83 } 84 IsFull()85 INLINE bool IsFull() 86 { 87 uint32_t numEnqueued = GetHead() - GetTail(); 88 SWR_ASSERT(numEnqueued <= mNumEntries); 89 90 return (numEnqueued == mNumEntries); 91 } 92 GetTail()93 INLINE uint32_t GetTail() volatile { return mRingTail; } GetHead()94 INLINE uint32_t GetHead() volatile { return mRingHead; } 95 96 protected: 97 T* mpRingBuffer; 98 uint32_t mNumEntries; 99 100 OSALIGNLINE(volatile uint32_t) mRingHead; // Consumer Counter 101 OSALIGNLINE(volatile uint32_t) mRingTail; // Producer Counter 102 }; 103