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_pointer(old_tos);
tos.store(new_tos, memory_order_relaxed);
}
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;
}
}
/** Pops object from stack.
*
* If pop operation is successful,
* object is written to memory location denoted by ret.
*
* \returns true, if the pop operation is successful, false if stack was empty.
*
* \note Not thread-safe
*
* */
bool pop_unsafe(T & ret)
{
tagged_node_ptr old_tos = tos.load(detail::memory_order_relaxed);
if (!old_tos.get_ptr())
return false;
node * new_tos_ptr = old_tos->next.get_ptr();
tagged_node_ptr new_tos(new_tos_ptr, old_tos.get_tag() + 1);
tos.store(new_tos, memory_order_relaxed);
ret = old_tos->v;
pool.destruct_unsafe(old_tos.get_ptr());
return true;
}
/** Pushes object t to the queue.
* May fail, if the freelist is not able to allocate a new queue node.
*
* \returns true, if the push operation is successful.
*
* \note Not thread-safe
* \warning \b Warning:
* May block if node needs to be allocated from the operating system
* */
bool push_unsafe(T const & v)
{
node * newnode = pool.construct_unsafe(v);
if (newnode == 0)
return false;
tagged_node_ptr old_tos = tos.load(detail::memory_order_relaxed);
tagged_node_ptr new_tos (newnode, old_tos.get_tag());
newnode->next.set_ptr(old_tos.get_ptr());
tos.store(new_tos, memory_order_relaxed);
return true;
}
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_tag() + 1);
tos.store(new_tos, memory_order_relaxed);
detail::copy_payload(old_tos_pointer->v, ret);
pool.template destruct<false>(old_tos);
return true;
}
/** Pushes object t to the queue.
* May fail, if the freelist is not able to allocate a new queue node.
*
* \returns true, if the push operation is successful.
*
* \note Thread-safe and non-blocking
* \warning \b Warning:
* May block if node needs to be allocated from the operating system
* */
bool push(T const & v)
{
node * newnode = pool.construct(v);
if (newnode == 0)
return false;
tagged_node_ptr old_tos = tos.load(detail::memory_order_relaxed);
for (;;) {
tagged_node_ptr new_tos (newnode, old_tos.get_tag());
newnode->next.set_ptr(old_tos.get_ptr());
if (tos.compare_exchange_weak(old_tos, new_tos))
return true;
}
}
/** Pops object from stack.
*
* If pop operation is successful,
* object is written to memory location denoted by ret.
*
* \returns true, if the pop operation is successful, false if stack was empty.
*
* \note Thread-safe and non-blocking
*
* */
bool pop(T & ret)
{
tagged_node_ptr old_tos = tos.load(detail::memory_order_consume);
for (;;) {
if (!old_tos.get_ptr())
return false;
node * new_tos_ptr = old_tos->next.get_ptr();
tagged_node_ptr new_tos(new_tos_ptr, old_tos.get_tag() + 1);
if (tos.compare_exchange_weak(old_tos, new_tos)) {
ret = old_tos->v;
pool.destruct(old_tos.get_ptr());
return true;
}
}
}
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;
}
}
}
bool pop(U & ret)
{
BOOST_STATIC_ASSERT((boost::is_convertible<T, U>::value));
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_tag() + 1);
if (tos.compare_exchange_weak(old_tos, new_tos)) {
detail::copy_payload(old_tos_pointer->v, ret);
pool.template destruct<true>(old_tos);
return true;
}
}
}
