spsc-example/queue.h

   1 #include <unrelacy.h>
   2 #include <atomic>
   3 #include "wildcard.h"
   4
   5 using namespace std;
   6
   7 #define acquire memory_order_acquire
   8 #define release memory_order_release
   9 #define relaxed memory_order_relaxed
  10
  11 struct node {
  12         node(int idx) {
  13                 index.store(idx, relaxed);
  14                 next.store(0, relaxed);
  15         }
  16         atomic<node*> next;
  17         atomic<int> index;
  18 };
  19
  20 class spsc_queue
  21 {
  22         node *head, *tail;
  23         public:
  24         spsc_queue() {
  25                 head = tail = new node(-1);
  26         }
  27         void enqueue(int idx) {
  28                 node* n = new node(idx);
  29                 tail->next.store(n, release);
  30                 tail = n;
  31         }
  32         bool dequeue(int *idx) {
  33                 node *tmp = head;
  34                 node *n = tmp->next.load(acquire);
  35                 if (NULL == n) return false;
  36                 head = n;
  37                 *idx = n->index.load(relaxed);
  38                 delete (tmp);
  39                 return true;
  40         }
  41 };