first commit

utils/vp_gate.h

@@ -0,0 +1,41 @@
+#pragma once
+
+#include <condition_variable>
+#include <mutex>
+
+namespace vp_utils {
+    // semaphore used to resume/pause loop structure, it blocks thread while received unactive signal and unblock thread while received active signal.
+    // refer to vp_semaphore also
+    class vp_gate
+    {
+    public:
+        vp_gate() {
+            opened_ = false;
+        }
+
+        void open() {
+            std::unique_lock<std::mutex> lock(mutex_);
+            opened_ = true;
+            cv_.notify_one();
+        }
+
+        // wait until opened
+        void knock() {
+            std::unique_lock<std::mutex> lock(mutex_);
+            cv_.wait(lock, [=] { return opened_; });
+        }
+
+        void close() {
+            std::unique_lock<std::mutex> lock(mutex_);
+            opened_ = false;
+        }
+
+        bool is_open() {
+            return opened_;
+        }
+    private:
+        std::mutex mutex_;
+        std::condition_variable cv_;
+        bool opened_;
+    };
+}