lock_free_queue.h

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/** @file
 *  @author Bram de Greve (bram@cocamware.com)
 *  @author Tom De Muer (tom@cocamware.com)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2004-2022 the Initial Developer.
 *  All Rights Reserved.
 *  
 *  Contributor(s):
 *
 *  Alternatively, the contents of this file may be used under the terms of the 
 *  GNU General Public License Version 2 or later (the GPL), in which case the 
 *  provisions of GPL are applicable instead of those above.  If you wish to allow use
 *  of your version of this file only under the terms of the GPL and not to allow 
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 *  deleting the provisions above and replace them with the notice and other 
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 *  a recipient may use your version of this file under either the CPAL or the GPL.
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 *  *** END LICENSE INFORMATION ***
 */
 
/** @class lass::stde::lock_free_queue
 *  @brief Non-blocking, lock-free FIFO data structure
 *
 *  M. M. Michael, M. L. Scott, "Simple, Fast, and Practical Non-Blocking and Blocking Concurrent
 *  Queue Algorithms", Proc. of the 15th Annual ACM Symposium on Principles of Distributed
 *  Computing (PODC' 96), New York, USA, pp. 267-275 (1996).
 */
 
#ifndef LASS_GUARDIAN_OF_INCLUSION_STDE_LOCK_FREE_QUEUE_H
#define LASS_GUARDIAN_OF_INCLUSION_STDE_LOCK_FREE_QUEUE_H
 
#include "stde_common.h"
#include "../util/allocator.h"
 
namespace lass
{
namespace stde
{
 
 
template 
<
    typename T, 
    typename FixedAllocator = util::AllocatorFixed<util::AllocatorMalloc>
>
class lock_free_queue
{
public:
 
    typedef T value_type;
 
    lock_free_queue();
    ~lock_free_queue();
 
    void push(const value_type& x);
    void push(value_type&& x);
    template <class... Args> void emplace(Args&&... args);
 
    bool pop(value_type& x);
 
private:
    
    struct node_t;
    typedef util::TaggedPtr<node_t> pointer_t;
    
    struct node_t
    {
        node_t() = default;
        explicit node_t(value_type* value): next(pointer_t(nullptr, 0)), value(value) {}
        std::atomic<pointer_t> next;
        std::atomic<value_type*> value = nullptr;
    };
 
    typedef util::AllocatorThrow< util::AllocatorConcurrentFreeList<FixedAllocator> > allocator_t;
 
    lock_free_queue(const lock_free_queue&);
    lock_free_queue& operator=(const lock_free_queue&);
 
    template <class... Args> value_type* make_value(Args&&... args);
    void free_value(value_type* value);
    void push_value(value_type* value);
    node_t* make_node(value_type* x);
    void free_node(node_t* node);
 
    alignas(LASS_LOCK_FREE_ALIGNMENT) std::atomic<pointer_t> head_;
    alignas(LASS_LOCK_FREE_ALIGNMENT) std::atomic<pointer_t> tail_;
    allocator_t node_allocator_;
    allocator_t value_allocator_;
};
 
}
 
}
 
#include "lock_free_queue.inl"
 
#endif
 
// EOF