From aef0ed035d8fcdb582b1a5e870c2803b6884b8b7 Mon Sep 17 00:00:00 2001
From: mutouyun <mark.lonr@tom.com>
Date: Thu, 22 Nov 2018 15:51:17 +0800
Subject: [PATCH] use cas instead of load & store; modify "commit" to "put"

---
 src/circ_queue.h         | 9 +++++----
 test/test_circ_queue.cpp | 2 +-
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/circ_queue.h b/src/circ_queue.h
index e510760..d191177 100644
--- a/src/circ_queue.h
+++ b/src/circ_queue.h
@@ -83,10 +83,11 @@ public:
 
     void* acquire(void) {
         auto st = elem_start() + id(cr_.load(std::memory_order_relaxed));
+        // check remain count of consumers
         do {
-            // check remain count of consumers
-            if (!st->head_.load(std::memory_order_acquire)) {
-                st->head_.store(conn_count());
+            std::size_t expected = 0;
+            if (st->head_.compare_exchange_weak(expected, conn_count(),
+                std::memory_order_acquire, std::memory_order_relaxed)) {
                 break;
             }
         } while(1);
@@ -105,7 +106,7 @@ public:
         return (elem_start() + id(index))->data_;
     }
 
-    void commit(std::uint16_t index) {
+    void put(std::uint16_t index) {
         auto st = elem_start() + id(index);
         st->head_.fetch_sub(1, std::memory_order_release);
     }
diff --git a/test/test_circ_queue.cpp b/test/test_circ_queue.cpp
index 0f5ef08..22d2209 100644
--- a/test/test_circ_queue.cpp
+++ b/test/test_circ_queue.cpp
@@ -53,7 +53,7 @@ void Unit::test_producer(void) {
             do {
                 while (cur != cq__->cursor()) {
                     int d = *static_cast<const int*>(cq__->get(cur));
-                    cq__->commit(cur);
+                    cq__->put(cur);
                     if (d < 0) return;
                     cur = cq__->next(cur);
                     list.push_back(d);