r1

src/timedata.h

@@ -0,0 +1,76 @@
+// Copyright (c) 2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_TIMEDATA_H
+#define BITCOIN_TIMEDATA_H
+
+#include <algorithm>
+#include <assert.h>
+#include <stdint.h>
+#include <vector>
+
+class CNetAddr;
+
+/** 
+ * Median filter over a stream of values.
+ * Returns the median of the last N numbers
+ */
+template <typename T>
+class CMedianFilter
+{
+private:
+    std::vector<T> vValues;
+    std::vector<T> vSorted;
+    unsigned int nSize;
+
+public:
+    CMedianFilter(unsigned int size, T initial_value) : nSize(size)
+    {
+        vValues.reserve(size);
+        vValues.push_back(initial_value);
+        vSorted = vValues;
+    }
+
+    void input(T value)
+    {
+        if (vValues.size() == nSize) {
+            vValues.erase(vValues.begin());
+        }
+        vValues.push_back(value);
+
+        vSorted.resize(vValues.size());
+        std::copy(vValues.begin(), vValues.end(), vSorted.begin());
+        std::sort(vSorted.begin(), vSorted.end());
+    }
+
+    T median() const
+    {
+        int size = vSorted.size();
+        assert(size > 0);
+        if (size & 1) // Odd number of elements
+        {
+            return vSorted[size / 2];
+        } else // Even number of elements
+        {
+            return (vSorted[size / 2 - 1] + vSorted[size / 2]) / 2;
+        }
+    }
+
+    int size() const
+    {
+        return vValues.size();
+    }
+
+    std::vector<T> sorted() const
+    {
+        return vSorted;
+    }
+};
+
+/** Functions to keep track of adjusted P2P time */
+int64_t GetTimeOffset();
+int64_t GetAdjustedTime();
+void AddTimeData(const CNetAddr& ip, int64_t nTime);
+
+#endif // BITCOIN_TIMEDATA_H