servlib/routing/LinkScheduleEstimator.h
changeset 0 2b3e5ec03512
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/servlib/routing/LinkScheduleEstimator.h	Thu Apr 21 14:57:45 2011 +0100
@@ -0,0 +1,96 @@
+/*
+ *    Copyright 2005-2006 Intel Corporation
+ * 
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ * 
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#include <vector>
+#include <oasys/util/IntUtils.h>
+#include <oasys/debug/Log.h>
+
+#define CONTACT(s, d) { s, d }
+#define absdiff(x,y) ((x<y)?((y)-(x)):((x)-(y)))
+
+#define WARPING_WINDOW .02
+#define PERIOD_TOLERANCE .02
+#define MAX_DIST 1<<30
+
+namespace dtn {
+    
+/**
+ *    Given a log on the form (start1, duration1), ... ,(startN,
+ *    durationN), the LinkScheduleEstimator algorithm figures out a
+ *    periodic schedule that this log conforms to.
+ *
+ *    The schedule computed can then be used to predict future link-up
+ *    events, and to inform far-away nodes about the future predicted
+ *    availability of the link in question.
+ *
+ *    Usage:
+ *      Log* find_schedule(Log* log);
+ *
+ *    Returns the best schedule for the given log. If there's no
+ *    discernible periodicity in the log, the return value will be
+ *    NULL.
+ */
+class LinkScheduleEstimator : public oasys::Logger {
+public:
+    typedef struct {
+      unsigned int start;
+      unsigned int duration;
+    } LogEntry;
+    
+    typedef std::vector<LogEntry> Log;
+    
+    static Log* find_schedule(Log* log);
+
+    LinkScheduleEstimator();
+private:
+    unsigned int entry_dist(Log &a, unsigned int a_index, unsigned int a_offset,
+                            Log &b, unsigned int b_index, unsigned int b_offset,
+                            unsigned int warping_window);
+
+    unsigned int log_dist_r(Log &a, unsigned int a_index, unsigned int a_offset,
+                            Log &b, unsigned int b_index, unsigned int b_offset,
+                            unsigned int warping_window);
+    
+       
+    unsigned int log_dist(Log &a, unsigned int a_offset,
+                 Log &b, unsigned int b_offset,
+                 unsigned int warping_window, int print_table);
+    
+    unsigned int autocorrelation(Log &log, unsigned int phase, int print_table);    
+    void print_log(Log &log, int relative_dates);
+    
+    Log* generate_samples(Log &schedule,
+                          unsigned int log_size,
+                          unsigned int start_jitter,
+                          double duration_jitter);
+    
+    unsigned int estimate_period(Log &log);       
+    unsigned int seek_to_before_date(Log &log, unsigned int date);                
+    unsigned int closest_entry_to_date(Log &log, unsigned int date);
+    Log* clone_subsequence(Log &log, unsigned int start, unsigned int len);
+        
+    unsigned int badness_of_match(Log &pattern,
+                                  Log &log,
+                                  unsigned int warping_window, 
+                                  unsigned int period);
+    
+    Log* extract_schedule(Log &log, unsigned int period_estimate);    
+    unsigned int refine_period(Log &log, unsigned int period_estimate);
+    Log* find_schedule(Log &log);    
+};
+
+
+}