alexpete
122 lines
3.7 KiB
C++
122 lines
3.7 KiB
C++
/*
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* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
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* its licensors.
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*
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* For complete copyright and license terms please see the LICENSE at the root of this
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* distribution (the "License"). All use of this software is governed by the License,
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* or, if provided, by the license below or the license accompanying this file. Do not
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* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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*
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*/
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// Original file Copyright Crytek GMBH or its affiliates, used under license.
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// This is free and unencumbered software released into the public domain.
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// Anyone is free to copy, modify, publish, use, compile, sell, or
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// distribute this software, either in source code form or as a compiled
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// binary, for any purpose, commercial or non-commercial, and by any
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// means.
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// In jurisdictions that recognize copyright laws, the author or authors
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// of this software dedicate any and all copyright interest in the
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// software to the public domain. We make this dedication for the benefit
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// of the public at large and to the detriment of our heirs and
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// successors. We intend this dedication to be an overt act of
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// relinquishment in perpetuity of all present and future rights to this
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// software under copyright law.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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// OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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// OTHER DEALINGS IN THE SOFTWARE.
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// For more information, please refer to <http://unlicense.org/>
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// non-intrusive lock free unbounded SPSC queue
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// the algorithm was taken from the blog post below, and converted to C++11
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// http://cbloomrants.blogspot.com/2009/02/02-26-09-low-level-threading-part-51.html
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#ifndef __SPSC_QUEUE_INCLUDED__
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#define __SPSC_QUEUE_INCLUDED__
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#include <atomic>
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namespace concqueue
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{
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template<typename T>
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class spsc_queue_t
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{
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public:
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spsc_queue_t()
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: _head(reinterpret_cast<node_t*>(new node_aligned_t))
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, _tail(_head)
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{
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_head->next = NULL;
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}
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~spsc_queue_t()
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{
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T output;
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while (this->dequeue(output))
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{
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}
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delete _head;
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}
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bool enqueue(const T& input)
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{
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node_t* node = reinterpret_cast<node_t*>(new node_aligned_t);
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node->data = input;
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node->next = NULL;
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std::atomic_thread_fence(std::memory_order_acq_rel);
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_head->next = node;
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_head = node;
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return true;
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}
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bool dequeue(T& output)
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{
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std::atomic_thread_fence(std::memory_order_consume);
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if (!_tail->next)
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{
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return false;
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}
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output = _tail->next->data;
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std::atomic_thread_fence(std::memory_order_acq_rel);
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_back = _tail;
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_tail = _back->next;
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delete _back;
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return true;
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}
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private:
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struct node_t
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{
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node_t* next;
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T data;
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};
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typedef typename std::aligned_storage<sizeof(node_t), std::alignment_of<node_t>::value>::type node_aligned_t;
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node_t* _head;
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char _cache_line[64];
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node_t* _tail;
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node_t* _back;
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spsc_queue_t(const spsc_queue_t&) {}
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void operator=(const spsc_queue_t&) {}
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};
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}
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#endif
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