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This commit is contained in:
Bassem Girgis
2018-10-18 00:40:34 -05:00
parent fffe4528da
commit 31c32e368a
149 changed files with 5974 additions and 6287 deletions
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94
source/listing_7.21.cpp
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@@ -1,55 +1,49 @@
template<typename T>
class lock_free_queue
{
template <typename T>
class lock_free_queue {
private:
void set_new_tail(counted_node_ptr &old_tail,
counted_node_ptr const &new_tail)
{
node* const current_tail_ptr=old_tail.ptr;
while(!tail.compare_exchange_weak(old_tail,new_tail) &&
old_tail.ptr==current_tail_ptr);
if(old_tail.ptr==current_tail_ptr)
free_external_counter(old_tail);
else
current_tail_ptr->release_ref();
}
void set_new_tail(counted_node_ptr& old_tail,
counted_node_ptr const& new_tail)
{
node* const current_tail_ptr = old_tail.ptr;
while (!tail.compare_exchange_weak(old_tail, new_tail) &&
old_tail.ptr == current_tail_ptr)
;
if (old_tail.ptr == current_tail_ptr)
free_external_counter(old_tail);
else
current_tail_ptr->release_ref();
}
public:
void push(T new_value)
{
std::unique_ptr<T> new_data(new T(new_value));
counted_node_ptr new_next;
new_next.ptr=new node;
new_next.external_count=1;
counted_node_ptr old_tail=tail.load();
for(;;)
{
increase_external_count(tail,old_tail);
T* old_data=nullptr;
if(old_tail.ptr->data.compare_exchange_strong(
old_data,new_data.get()))
{
counted_node_ptr old_next={0};
if(!old_tail.ptr->next.compare_exchange_strong(
old_next,new_next))
{
delete new_next.ptr;
new_next=old_next;
}
set_new_tail(old_tail, new_next);
new_data.release();
break;
}
else
{
counted_node_ptr old_next={0};
if(old_tail.ptr->next.compare_exchange_strong(
old_next,new_next))
{
old_next=new_next;
new_next.ptr=new node;
}
set_new_tail(old_tail, old_next);
}
void push(T new_value)
{
std::unique_ptr<T> new_data(new T(new_value));
counted_node_ptr new_next;
new_next.ptr = new node;
new_next.external_count = 1;
counted_node_ptr old_tail = tail.load();
for (;;) {
increase_external_count(tail, old_tail);
T* old_data = nullptr;
if (old_tail.ptr->data.compare_exchange_strong(old_data,
new_data.get())) {
counted_node_ptr old_next = {0};
if (!old_tail.ptr->next.compare_exchange_strong(old_next, new_next)) {
delete new_next.ptr;
new_next = old_next;
}
set_new_tail(old_tail, new_next);
new_data.release();
break;
}
else {
counted_node_ptr old_next = {0};
if (old_tail.ptr->next.compare_exchange_strong(old_next, new_next)) {
old_next = new_next;
new_next.ptr = new node;
}
set_new_tail(old_tail, old_next);
}
}
}
};