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 //  Copyright (C) 2008-2013 Tim Blechmann
 //
 //  Distributed under the Boost Software License, Version 1.0. (See
 //  accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt)
 
 #ifndef BOOST_LOCKFREE_STACK_HPP_INCLUDED
 #define BOOST_LOCKFREE_STACK_HPP_INCLUDED
 
 #include <boost/assert.hpp>
 #include <boost/checked_delete.hpp>
 #include <boost/core/allocator_access.hpp>
 #include <boost/core/no_exceptions_support.hpp>
 #include <boost/integer_traits.hpp>
 #include <boost/static_assert.hpp>
 #include <boost/tuple/tuple.hpp>
 #include <boost/type_traits/is_copy_constructible.hpp>
 
 #include <boost/lockfree/detail/atomic.hpp>
 #include <boost/lockfree/detail/copy_payload.hpp>
 #include <boost/lockfree/detail/freelist.hpp>
 #include <boost/lockfree/detail/parameter.hpp>
 #include <boost/lockfree/detail/tagged_ptr.hpp>
 
 #include <boost/lockfree/lockfree_forward.hpp>
 
 #ifdef BOOST_HAS_PRAGMA_ONCE
 #pragma once
 #endif
 
 namespace boost    {
 namespace lockfree {
 namespace detail   {
 
 typedef parameter::parameters<boost::parameter::optional<tag::allocator>,
                               boost::parameter::optional<tag::capacity>
                              > stack_signature;
 
 }
 
 /** The stack class provides a multi-writer/multi-reader stack, pushing and popping is lock-free,
  *  construction/destruction has to be synchronized. It uses a freelist for memory management,
  *  freed nodes are pushed to the freelist and not returned to the OS before the stack is destroyed.
  *
  *  \b Policies:
  *
  *  - \c boost::lockfree::fixed_sized<>, defaults to \c boost::lockfree::fixed_sized<false> <br>
  *    Can be used to completely disable dynamic memory allocations during push in order to ensure lockfree behavior.<br>
  *    If the data structure is configured as fixed-sized, the internal nodes are stored inside an array and they are addressed
  *    by array indexing. This limits the possible size of the stack to the number of elements that can be addressed by the index
  *    type (usually 2**16-2), but on platforms that lack double-width compare-and-exchange instructions, this is the best way
  *    to achieve lock-freedom.
  *
  *  - \c boost::lockfree::capacity<>, optional <br>
  *    If this template argument is passed to the options, the size of the stack is set at compile-time. <br>
  *    It this option implies \c fixed_sized<true>
  *
  *  - \c boost::lockfree::allocator<>, defaults to \c boost::lockfree::allocator<std::allocator<void>> <br>
  *    Specifies the allocator that is used for the internal freelist
  *
  *  \b Requirements:
  *  - T must have a copy constructor
  * */
 #ifdef BOOST_NO_CXX11_VARIADIC_TEMPLATES
 template <typename T, class A0, class A1, class A2>
 #else
 template <typename T, typename ...Options>
 #endif
 class stack
 {
 private:
 #ifndef BOOST_DOXYGEN_INVOKED
     BOOST_STATIC_ASSERT(boost::is_copy_constructible<T>::value);
 
 #ifdef BOOST_NO_CXX11_VARIADIC_TEMPLATES
     typedef typename detail::stack_signature::bind<A0, A1, A2>::type bound_args;
 #else
     typedef typename detail::stack_signature::bind<Options...>::type bound_args;
 #endif
 
     static const bool has_capacity = detail::extract_capacity<bound_args>::has_capacity;
     static const size_t capacity = detail::extract_capacity<bound_args>::capacity;
     static const bool fixed_sized = detail::extract_fixed_sized<bound_args>::value;
     static const bool node_based = !(has_capacity || fixed_sized);
     static const bool compile_time_sized = has_capacity;
 
     struct node
     {
         node(T const & val):
             v(val)
         {}
 
         typedef typename detail::select_tagged_handle<node, node_based>::handle_type handle_t;
         handle_t next;
         const T v;
     };
 
     typedef typename detail::extract_allocator<bound_args, node>::type node_allocator;
     typedef typename detail::select_freelist<node, node_allocator, compile_time_sized, fixed_sized, capacity>::type pool_t;
     typedef typename pool_t::tagged_node_handle tagged_node_handle;
 
     // check compile-time capacity
     BOOST_STATIC_ASSERT((mpl::if_c<has_capacity,
                                    mpl::bool_<capacity - 1 < boost::integer_traits<boost::uint16_t>::const_max>,
                                    mpl::true_
                                   >::type::value));
 
     struct implementation_defined
     {
         typedef node_allocator allocator;
         typedef std::size_t size_type;
     };
 
 #endif
 
     BOOST_DELETED_FUNCTION(stack(stack const&))
     BOOST_DELETED_FUNCTION(stack& operator= (stack const&))
 
 public:
     typedef T value_type;
     typedef typename implementation_defined::allocator allocator;
     typedef typename implementation_defined::size_type size_type;
 
     /**
      * \return true, if implementation is lock-free.
      *
      * \warning It only checks, if the top stack node and the freelist can be modified in a lock-free manner.
      *          On most platforms, the whole implementation is lock-free, if this is true. Using c++0x-style atomics,
      *          there is no possibility to provide a completely accurate implementation, because one would need to test
      *          every internal node, which is impossible if further nodes will be allocated from the operating system.
      *
      * */
     bool is_lock_free (void) const
     {
         return tos.is_lock_free() && pool.is_lock_free();
     }
 
     /** Construct a fixed-sized stack
      *
      *  \pre Must specify a capacity<> argument
      * */
     stack(void):
         pool(node_allocator(), capacity)
     {
         // Don't use BOOST_STATIC_ASSERT() here since it will be evaluated when compiling
         // this function and this function may be compiled even when it isn't being used.
         BOOST_ASSERT(has_capacity);
         initialize();
     }
 
     /** Construct a fixed-sized stack with a custom allocator
      *
      *  \pre Must specify a capacity<> argument
      * */
     template <typename U>
     explicit stack(typename boost::allocator_rebind<node_allocator, U>::type const & alloc):
         pool(alloc, capacity)
     {
         BOOST_STATIC_ASSERT(has_capacity);
         initialize();
     }
 
     /** Construct a fixed-sized stack with a custom allocator
      *
      *  \pre Must specify a capacity<> argument
      * */
     explicit stack(allocator const & alloc):
         pool(alloc, capacity)
     {
         // Don't use BOOST_STATIC_ASSERT() here since it will be evaluated when compiling
         // this function and this function may be compiled even when it isn't being used.
         BOOST_ASSERT(has_capacity);
         initialize();
     }
 
     /** Construct a variable-sized stack
      *
      *  Allocate n nodes initially for the freelist
      *
      *  \pre Must \b not specify a capacity<> argument
      * */
     explicit stack(size_type n):
         pool(node_allocator(), n)
     {
         // Don't use BOOST_STATIC_ASSERT() here since it will be evaluated when compiling
         // this function and this function may be compiled even when it isn't being used.
         BOOST_ASSERT(!has_capacity);
         initialize();
     }
 
     /** Construct a variable-sized stack with a custom allocator
      *
      *  Allocate n nodes initially for the freelist
      *
      *  \pre Must \b not specify a capacity<> argument
      * */
     template <typename U>
     stack(size_type n, typename boost::allocator_rebind<node_allocator, U>::type const & alloc):
         pool(alloc, n)
     {
         BOOST_STATIC_ASSERT(!has_capacity);
         initialize();
     }
 
     /** Allocate n nodes for freelist
      *
      *  \pre  only valid if no capacity<> argument given
      *  \note thread-safe, may block if memory allocator blocks
      *
      * */
     void reserve(size_type n)
     {
         // Don't use BOOST_STATIC_ASSERT() here since it will be evaluated when compiling
         // this function and this function may be compiled even when it isn't being used.
         BOOST_ASSERT(!has_capacity);
         pool.template reserve<true>(n);
     }
 
     /** Allocate n nodes for freelist
      *
      *  \pre  only valid if no capacity<> argument given
      *  \note not thread-safe, may block if memory allocator blocks
      *
      * */
     void reserve_unsafe(size_type n)
     {
         // Don't use BOOST_STATIC_ASSERT() here since it will be evaluated when compiling
         // this function and this function may be compiled even when it isn't being used.
         BOOST_ASSERT(!has_capacity);
         pool.template reserve<false>(n);
     }
 
     /** Destroys stack, free all nodes from freelist.
      *
      *  \note not thread-safe
      *
      * */
     ~stack(void)
     {
         detail::consume_noop consume_functor;
         (void)consume_all(consume_functor);
     }
 
 private:
 #ifndef BOOST_DOXYGEN_INVOKED
     void initialize(void)
     {
         tos.store(tagged_node_handle(pool.null_handle(), 0));
     }
 
     void link_nodes_atomic(node * new_top_node, node * end_node)
     {
         tagged_node_handle old_tos = tos.load(detail::memory_order_relaxed);
         for (;;) {
             tagged_node_handle new_tos (pool.get_handle(new_top_node), old_tos.get_tag());
             end_node->next = pool.get_handle(old_tos);
 
             if (tos.compare_exchange_weak(old_tos, new_tos))
                 break;
         }
     }
 
     void link_nodes_unsafe(node * new_top_node, node * end_node)
     {
         tagged_node_handle old_tos = tos.load(detail::memory_order_relaxed);
 
         tagged_node_handle new_tos (pool.get_handle(new_top_node), old_tos.get_tag());
         end_node->next = pool.get_handle(old_tos);
 
         tos.store(new_tos, memory_order_relaxed);
     }
 
     template <bool Threadsafe, bool Bounded, typename ConstIterator>
     tuple<node*, node*> prepare_node_list(ConstIterator begin, ConstIterator end, ConstIterator & ret)
     {
         ConstIterator it = begin;
         node * end_node = pool.template construct<Threadsafe, Bounded>(*it++);
         if (end_node == NULL) {
             ret = begin;
             return make_tuple<node*, node*>(NULL, NULL);
         }
 
         node * new_top_node = end_node;
         end_node->next = NULL;
 
         BOOST_TRY {
             /* link nodes */
             for (; it != end; ++it) {
                 node * newnode = pool.template construct<Threadsafe, Bounded>(*it);
                 if (newnode == NULL)
                     break;
                 newnode->next = new_top_node;
                 new_top_node = newnode;
             }
         } BOOST_CATCH (...) {
             for (node * current_node = new_top_node; current_node != NULL;) {
                 node * next = current_node->next;
                 pool.template destruct<Threadsafe>(current_node);
                 current_node = next;
             }
             BOOST_RETHROW;
         }
         BOOST_CATCH_END
 
         ret = it;
         return make_tuple(new_top_node, end_node);
     }
 #endif
 
 public:
     /** Pushes object t to the stack.
      *
      * \post object will be pushed to the stack, if internal node can be allocated
      * \returns true, if the push operation is successful.
      *
      * \note Thread-safe. If internal memory pool is exhausted and the memory pool is not fixed-sized, a new node will be allocated
      *                    from the OS. This may not be lock-free.
      * \throws if memory allocator throws
      * */
     bool push(T const & v)
     {
         return do_push<false>(v);
     }
 
     /** Pushes object t to the stack.
      *
      * \post object will be pushed to the stack, if internal node can be allocated
      * \returns true, if the push operation is successful.
      *
      * \note Thread-safe and non-blocking. If internal memory pool is exhausted, the push operation will fail
      * */
     bool bounded_push(T const & v)
     {
         return do_push<true>(v);
     }
 
 #ifndef BOOST_DOXYGEN_INVOKED
 private:
     template <bool Bounded>
     bool do_push(T const & v)
     {
         node * newnode = pool.template construct<true, Bounded>(v);
         if (newnode == 0)
             return false;
 
         link_nodes_atomic(newnode, newnode);
         return true;
     }
 
     template <bool Bounded, typename ConstIterator>
     ConstIterator do_push(ConstIterator begin, ConstIterator end)
     {
         node * new_top_node;
         node * end_node;
         ConstIterator ret;
 
         tie(new_top_node, end_node) = prepare_node_list<true, Bounded>(begin, end, ret);
         if (new_top_node)
             link_nodes_atomic(new_top_node, end_node);
 
         return ret;
     }
 
 public:
 #endif
 
     /** Pushes as many objects from the range [begin, end) as freelist node can be allocated.
      *
      * \return iterator to the first element, which has not been pushed
      *
      * \note Operation is applied atomically
      * \note Thread-safe. If internal memory pool is exhausted and the memory pool is not fixed-sized, a new node will be allocated
      *                    from the OS. This may not be lock-free.
      * \throws if memory allocator throws
      */
     template <typename ConstIterator>
     ConstIterator push(ConstIterator begin, ConstIterator end)
     {
         return do_push<false, ConstIterator>(begin, end);
     }
 
     /** Pushes as many objects from the range [begin, end) as freelist node can be allocated.
      *
      * \return iterator to the first element, which has not been pushed
      *
      * \note Operation is applied atomically
      * \note Thread-safe and non-blocking. If internal memory pool is exhausted, the push operation will fail
      * \throws if memory allocator throws
      */
     template <typename ConstIterator>
     ConstIterator bounded_push(ConstIterator begin, ConstIterator end)
     {
         return do_push<true, ConstIterator>(begin, end);
     }
 
 
     /** Pushes object t to the stack.
      *
      * \post object will be pushed to the stack, if internal node can be allocated
      * \returns true, if the push operation is successful.
      *
      * \note Not thread-safe. If internal memory pool is exhausted and the memory pool is not fixed-sized, a new node will be allocated
      *       from the OS. This may not be lock-free.
      * \throws if memory allocator throws
      * */
     bool unsynchronized_push(T const & v)
     {
         node * newnode = pool.template construct<false, false>(v);
         if (newnode == 0)
             return false;
 
         link_nodes_unsafe(newnode, newnode);
         return true;
     }
 
     /** Pushes as many objects from the range [begin, end) as freelist node can be allocated.
      *
      * \return iterator to the first element, which has not been pushed
      *
      * \note Not thread-safe. If internal memory pool is exhausted and the memory pool is not fixed-sized, a new node will be allocated
      *       from the OS. This may not be lock-free.
      * \throws if memory allocator throws
      */
     template <typename ConstIterator>
     ConstIterator unsynchronized_push(ConstIterator begin, ConstIterator end)
     {
         node * new_top_node;
         node * end_node;
         ConstIterator ret;
 
         tie(new_top_node, end_node) = prepare_node_list<false, false>(begin, end, ret);
         if (new_top_node)
             link_nodes_unsafe(new_top_node, end_node);
 
         return ret;
     }
 
 
     /** Pops object from stack.
      *
      * \post if pop operation is successful, object will be copied to ret.
      * \returns true, if the pop operation is successful, false if stack was empty.
      *
      * \note Thread-safe and non-blocking
      *
      * */
     bool pop(T & ret)
     {
         return pop<T>(ret);
     }
 
     /** Pops object from stack.
      *
      * \pre type T must be convertible to U
      * \post if pop operation is successful, object will be copied to ret.
      * \returns true, if the pop operation is successful, false if stack was empty.
      *
      * \note Thread-safe and non-blocking
      *
      * */
     template <typename U>
     bool pop(U & ret)
     {
         BOOST_STATIC_ASSERT((boost::is_convertible<T, U>::value));
         detail::consume_via_copy<U> consumer(ret);
 
         return consume_one(consumer);
     }
 
 
     /** Pops object from stack.
      *
      * \post if pop operation is successful, object will be copied to ret.
      * \returns true, if the pop operation is successful, false if stack was empty.
      *
      * \note Not thread-safe, but non-blocking
      *
      * */
     bool unsynchronized_pop(T & ret)
     {
         return unsynchronized_pop<T>(ret);
     }
 
     /** Pops object from stack.
      *
      * \pre type T must be convertible to U
      * \post if pop operation is successful, object will be copied to ret.
      * \returns true, if the pop operation is successful, false if stack was empty.
      *
      * \note Not thread-safe, but non-blocking
      *
      * */
     template <typename U>
     bool unsynchronized_pop(U & ret)
     {
         BOOST_STATIC_ASSERT((boost::is_convertible<T, U>::value));
         tagged_node_handle old_tos = tos.load(detail::memory_order_relaxed);
         node * old_tos_pointer = pool.get_pointer(old_tos);
 
         if (!pool.get_pointer(old_tos))
             return false;
 
         node * new_tos_ptr = pool.get_pointer(old_tos_pointer->next);
         tagged_node_handle new_tos(pool.get_handle(new_tos_ptr), old_tos.get_next_tag());
 
         tos.store(new_tos, memory_order_relaxed);
         detail::copy_payload(old_tos_pointer->v, ret);
         pool.template destruct<false>(old_tos);
         return true;
     }
 
     /** consumes one element via a functor
      *
      *  pops one element from the stack and applies the functor on this object
      *
      * \returns true, if one element was consumed
      *
      * \note Thread-safe and non-blocking, if functor is thread-safe and non-blocking
      * */
     template <typename Functor>
     bool consume_one(Functor & f)
     {
         tagged_node_handle old_tos = tos.load(detail::memory_order_consume);
 
         for (;;) {
             node * old_tos_pointer = pool.get_pointer(old_tos);
             if (!old_tos_pointer)
                 return false;
 
             tagged_node_handle new_tos(old_tos_pointer->next, old_tos.get_next_tag());
 
             if (tos.compare_exchange_weak(old_tos, new_tos)) {
                 f(old_tos_pointer->v);
                 pool.template destruct<true>(old_tos);
                 return true;
             }
         }
     }
 
     /// \copydoc boost::lockfree::stack::consume_one(Functor & rhs)
     template <typename Functor>
     bool consume_one(Functor const & f)
     {
         tagged_node_handle old_tos = tos.load(detail::memory_order_consume);
 
         for (;;) {
             node * old_tos_pointer = pool.get_pointer(old_tos);
             if (!old_tos_pointer)
                 return false;
 
             tagged_node_handle new_tos(old_tos_pointer->next, old_tos.get_next_tag());
 
             if (tos.compare_exchange_weak(old_tos, new_tos)) {
                 f(old_tos_pointer->v);
                 pool.template destruct<true>(old_tos);
                 return true;
             }
         }
     }
 
     /** consumes all elements via a functor
      *
      * sequentially pops all elements from the stack and applies the functor on each object
      *
      * \returns number of elements that are consumed
      *
      * \note Thread-safe and non-blocking, if functor is thread-safe and non-blocking
      * */
     template <typename Functor>
     size_t consume_all(Functor & f)
     {
         size_t element_count = 0;
         while (consume_one(f))
             element_count += 1;
 
         return element_count;
     }
 
     /// \copydoc boost::lockfree::stack::consume_all(Functor & rhs)
     template <typename Functor>
     size_t consume_all(Functor const & f)
     {
         size_t element_count = 0;
         while (consume_one(f))
             element_count += 1;
 
         return element_count;
     }
 
     /** consumes all elements via a functor
      *
      * atomically pops all elements from the stack and applies the functor on each object
      *
      * \returns number of elements that are consumed
      *
      * \note Thread-safe and non-blocking, if functor is thread-safe and non-blocking
      * */
     template <typename Functor>
     size_t consume_all_atomic(Functor & f)
     {
         size_t element_count = 0;
         tagged_node_handle old_tos = tos.load(detail::memory_order_consume);
 
         for (;;) {
             node * old_tos_pointer = pool.get_pointer(old_tos);
             if (!old_tos_pointer)
                 return 0;
 
             tagged_node_handle new_tos(pool.null_handle(), old_tos.get_next_tag());
 
             if (tos.compare_exchange_weak(old_tos, new_tos))
                 break;
         }
 
         tagged_node_handle nodes_to_consume = old_tos;
 
         for(;;) {
             node * node_pointer = pool.get_pointer(nodes_to_consume);
             f(node_pointer->v);
             element_count += 1;
 
             node * next_node = pool.get_pointer(node_pointer->next);
 
             if (!next_node) {
                 pool.template destruct<true>(nodes_to_consume);
                 break;
             }
 
             tagged_node_handle next(pool.get_handle(next_node), nodes_to_consume.get_next_tag());
             pool.template destruct<true>(nodes_to_consume);
             nodes_to_consume = next;
         }
 
         return element_count;
     }
 
     /// \copydoc boost::lockfree::stack::consume_all_atomic(Functor & rhs)
     template <typename Functor>
     size_t consume_all_atomic(Functor const & f)
     {
         size_t element_count = 0;
         tagged_node_handle old_tos = tos.load(detail::memory_order_consume);
 
         for (;;) {
             node * old_tos_pointer = pool.get_pointer(old_tos);
             if (!old_tos_pointer)
                 return 0;
 
             tagged_node_handle new_tos(pool.null_handle(), old_tos.get_next_tag());
 
             if (tos.compare_exchange_weak(old_tos, new_tos))
                 break;
         }
 
         tagged_node_handle nodes_to_consume = old_tos;
 
         for(;;) {
             node * node_pointer = pool.get_pointer(nodes_to_consume);
             f(node_pointer->v);
             element_count += 1;
 
             node * next_node = pool.get_pointer(node_pointer->next);
 
             if (!next_node) {
                 pool.template destruct<true>(nodes_to_consume);
                 break;
             }
 
             tagged_node_handle next(pool.get_handle(next_node), nodes_to_consume.get_next_tag());
             pool.template destruct<true>(nodes_to_consume);
             nodes_to_consume = next;
         }
 
         return element_count;
     }
 
     /** consumes all elements via a functor
      *
      * atomically pops all elements from the stack and applies the functor on each object in reversed order
      *
      * \returns number of elements that are consumed
      *
      * \note Thread-safe and non-blocking, if functor is thread-safe and non-blocking
      * */
     template <typename Functor>
     size_t consume_all_atomic_reversed(Functor & f)
     {
         size_t element_count = 0;
         tagged_node_handle old_tos = tos.load(detail::memory_order_consume);
 
         for (;;) {
             node * old_tos_pointer = pool.get_pointer(old_tos);
             if (!old_tos_pointer)
                 return 0;
 
             tagged_node_handle new_tos(pool.null_handle(), old_tos.get_next_tag());
 
             if (tos.compare_exchange_weak(old_tos, new_tos))
                 break;
         }
 
         tagged_node_handle nodes_to_consume = old_tos;
 
         node * last_node_pointer = NULL;
         tagged_node_handle nodes_in_reversed_order;
         for(;;) {
             node * node_pointer = pool.get_pointer(nodes_to_consume);
             node * next_node    = pool.get_pointer(node_pointer->next);
 
             node_pointer->next  = pool.get_handle(last_node_pointer);
             last_node_pointer   = node_pointer;
 
             if (!next_node) {
                 nodes_in_reversed_order = nodes_to_consume;
                 break;
             }
 
             tagged_node_handle next(pool.get_handle(next_node), nodes_to_consume.get_next_tag());
             nodes_to_consume = next;
         }
 
         for(;;) {
             node * node_pointer = pool.get_pointer(nodes_in_reversed_order);
             f(node_pointer->v);
             element_count += 1;
 
             node * next_node = pool.get_pointer(node_pointer->next);
 
             if (!next_node) {
                 pool.template destruct<true>(nodes_in_reversed_order);
                 break;
             }
 
             tagged_node_handle next(pool.get_handle(next_node), nodes_in_reversed_order.get_next_tag());
             pool.template destruct<true>(nodes_in_reversed_order);
             nodes_in_reversed_order = next;
         }
 
         return element_count;
     }
 
     /// \copydoc boost::lockfree::stack::consume_all_atomic_reversed(Functor & rhs)
     template <typename Functor>
     size_t consume_all_atomic_reversed(Functor const & f)
     {
         size_t element_count = 0;
         tagged_node_handle old_tos = tos.load(detail::memory_order_consume);
 
         for (;;) {
             node * old_tos_pointer = pool.get_pointer(old_tos);
             if (!old_tos_pointer)
                 return 0;
 
             tagged_node_handle new_tos(pool.null_handle(), old_tos.get_next_tag());
 
             if (tos.compare_exchange_weak(old_tos, new_tos))
                 break;
         }
 
         tagged_node_handle nodes_to_consume = old_tos;
 
         node * last_node_pointer = NULL;
         tagged_node_handle nodes_in_reversed_order;
         for(;;) {
             node * node_pointer = pool.get_pointer(nodes_to_consume);
             node * next_node    = pool.get_pointer(node_pointer->next);
 
             node_pointer->next  = pool.get_handle(last_node_pointer);
             last_node_pointer   = node_pointer;
 
             if (!next_node) {
                 nodes_in_reversed_order = nodes_to_consume;
                 break;
             }
 
             tagged_node_handle next(pool.get_handle(next_node), nodes_to_consume.get_next_tag());
             nodes_to_consume = next;
         }
 
         for(;;) {
             node * node_pointer = pool.get_pointer(nodes_in_reversed_order);
             f(node_pointer->v);
             element_count += 1;
 
             node * next_node = pool.get_pointer(node_pointer->next);
 
             if (!next_node) {
                 pool.template destruct<true>(nodes_in_reversed_order);
                 break;
             }
 
             tagged_node_handle next(pool.get_handle(next_node), nodes_in_reversed_order.get_next_tag());
             pool.template destruct<true>(nodes_in_reversed_order);
             nodes_in_reversed_order = next;
         }
 
         return element_count;
     }
     /**
      * \return true, if stack is empty.
      *
      * \note It only guarantees that at some point during the execution of the function the stack has been empty.
      *       It is rarely practical to use this value in program logic, because the stack can be modified by other threads.
      * */
     bool empty(void) const
     {
         return pool.get_pointer(tos.load()) == NULL;
     }
 
 private:
 #ifndef BOOST_DOXYGEN_INVOKED
     detail::atomic<tagged_node_handle> tos;
 
     static const int padding_size = BOOST_LOCKFREE_CACHELINE_BYTES - sizeof(tagged_node_handle);
     char padding[padding_size];
 
     pool_t pool;
 #endif
 };
 
 } /* namespace lockfree */
 } /* namespace boost */
 
 #endif /* BOOST_LOCKFREE_STACK_HPP_INCLUDED */

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