forked from cawka/ndn.cxx
diff --git a/scheduler/random-interval-generator.h b/scheduler/random-interval-generator.h
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+++ b/scheduler/random-interval-generator.h
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+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2013, Regents of the University of California
+ * Alexander Afanasyev
+ * Zhenkai Zhu
+ *
+ * BSD license, See the LICENSE file for more information
+ *
+ * Author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
+ * Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#ifndef RANDOM_INTERVAL_GENERATOR_H
+#define RANDOM_INTERVAL_GENERATOR_H
+
+#include "interval-generator.h"
+
+#include <boost/random/mersenne_twister.hpp>
+#include <boost/random/uniform_real.hpp>
+#include <boost/random/variate_generator.hpp>
+#include <boost/date_time/posix_time/posix_time_types.hpp>
+
+// generates intervals with uniform distribution
+class RandomIntervalGenerator : public IntervalGenerator
+{
+public:
+ typedef enum
+ {
+ UP = 1,
+ DOWN = 2,
+ EVEN = 3
+ } Direction;
+
+public:
+ // percent is random-range/interval; e.g. if interval is 10 and you wish the random-range to be 2
+ // e.g. 9 ~ 11, percent = 0.2
+ // direction shifts the random range; e.g. in the above example, UP would produce a range of
+ // 10 ~ 12, DOWN of 8 ~ 10, and EVEN of 9 ~ 11
+ RandomIntervalGenerator(double interval, double percent, Direction direction = EVEN)
+ // : m_rng(time(NULL))
+ : m_rng (static_cast<int> (boost::posix_time::microsec_clock::local_time().time_of_day ().total_nanoseconds ()))
+ , m_dist(0.0, fractional(percent))
+ , m_random(m_rng, m_dist)
+ , m_direction(direction)
+ , m_percent(percent)
+ , m_interval(interval)
+ { }
+
+ virtual ~RandomIntervalGenerator(){}
+
+ virtual double
+ nextInterval() _OVERRIDE
+ {
+ double percent = m_random();
+ double interval = m_interval;
+ switch (m_direction)
+ {
+ case UP: interval = m_interval * (1.0 + percent); break;
+ case DOWN: interval = m_interval * (1.0 - percent); break;
+ case EVEN: interval = m_interval * (1.0 - m_percent/2.0 + percent); break;
+ default: break;
+ }
+
+ return interval;
+ }
+
+private:
+ inline double fractional(double x) { double dummy; return abs(modf(x, &dummy)); }
+
+private:
+ typedef boost::mt19937 RNG_TYPE;
+ RNG_TYPE m_rng;
+ boost::uniform_real<> m_dist;
+ boost::variate_generator<RNG_TYPE &, boost::uniform_real<> > m_random;
+ Direction m_direction;
+ double m_percent;
+ double m_interval;
+
+};
+#endif // RANDOM_INTERVAL_GENERATOR_H