Implement frequency limiting class to be used for controlled messages-per-second ratio during send to syslog

src/FrequencyLimit.cpp

@@ -0,0 +1,35 @@
+/*
+ The MIT License (MIT)
+
+Copyright (c) 2015 Marko Živanović
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+ */
+
+#include "FrequencyLimit.h"
+
+FrequencyLimit::FrequencyLimit() {
+}
+
+FrequencyLimit::FrequencyLimit(const FrequencyLimit& orig) {
+}
+
+FrequencyLimit::~FrequencyLimit() {
+}
+

src/FrequencyLimit.h

@@ -0,0 +1,63 @@
+/*
+ The MIT License (MIT)
+
+Copyright (c) 2015 Marko Živanović
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+ */
+
+#ifndef FREQUENCYLIMIT_H
+#define	FREQUENCYLIMIT_H
+
+#include <boost/noncopyable.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
+#include <boost/thread/thread.hpp>
+
+class FrequencyLimit {
+public:
+
+    FrequencyLimit(const size_t& limit) : _target(boost::posix_time::microseconds(1000000 / limit)), _delay(boost::posix_time::milliseconds(0)) {
+    };
+
+    void tick() {
+        auto now(boost::posix_time::microsec_clock::local_time());
+        if (_prev == boost::posix_time::not_a_date_time) {
+            _prev = now;
+        } else {
+            auto dur = now - _prev;
+            auto diff = _target - dur;
+//            _delay = (_delay + diff) / 2;
+            _delay = _delay + diff;
+//            std::cout << "dur: " << dur << " diff: " << diff << " _delay: " << _delay << std::endl;
+            if (diff > boost::posix_time::microseconds(0)) {
+                boost::this_thread::sleep(_delay);
+            }
+//            _prev = boost::posix_time::microsec_clock::local_time();
+            _prev = now;
+        }
+    };
+
+private:
+    const boost::posix_time::time_duration _target;
+    boost::posix_time::time_duration _delay;
+    boost::posix_time::ptime _prev;
+};
+
+#endif	/* FREQUENCYLIMIT_H */
+