1 files changed, 202 insertions, 0 deletions
diff --git a/src/Sockets/RandomNumber.h b/src/Sockets/RandomNumber.h
new file mode 100644
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--- /dev/null
+++ b/src/Sockets/RandomNumber.h
@@ -0,0 +1,202 @@
+/**
+ * @author Adam McLaurin
+ * @date   September 2006
+ */
+/*
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+*/
+
+#ifndef _SOCKET_RandomNumber_H
+#define _SOCKET_RandomNumber_H
+
+#include "sockets-config.h"
+#include <limits>
+
+#ifdef SOCKETS_NAMESPACE
+namespace SOCKETS_NAMESPACE {
+#endif
+
+/**
+ * The following class uses an xorshift algorithm proposed in the following
+ * paper:
+ *  - http://www.jstatsoft.org/v08/i14/xorshift.pdf
+ *
+ * The algorithm provides a PRNG with a period of (2^128)-1
+ *
+ * This PRNG is *not* intended for cryptographic purposes
+ */
+class RandomNumber
+{
+
+public:
+  /**
+   * Default constructor
+   *
+   * NOTE: Internal seeds are set to defaults proposed by the paper
+   */
+  RandomNumber(bool time_shuffle = false);
+
+  /**
+   * Custom constructor
+   *
+   * @param x_seed X seed
+   *
+   * @param y_seed Y seed
+   *
+   * @param z_seed Z seed
+   *
+   * @param w_seed W seed
+   */
+  RandomNumber(
+    unsigned long int x_seed,
+    unsigned long int y_seed,
+    unsigned long int z_seed,
+    unsigned long int w_seed);
+
+  /**
+   * Destructor
+   */
+  ~RandomNumber();
+
+  // public methods
+
+  /**
+   * Reset internal state to initial seed values
+   */
+  void reset();
+
+  /**
+   * Cast operator to obtain current random value in the PRNG
+   *
+   * @return Current random value in the PRNG
+   */
+  operator unsigned long int() const;
+
+  /**
+   * Go to the next number in the PRNG sequence
+   *
+   * NOTE: This method is a slightly modified implementation of the xor128()
+   * function proposed in the paper
+   *
+   * @return Next value produced by the PRNG (after updating)
+   */
+  unsigned long int next();
+
+  /**
+   * Skip ahead in the PRNG sequence by a given number of iterations
+   *
+   * @param s Number of iterations to skip ahead
+   *
+   * @return Value produced by the PRNG after skipping ahead in the sequence
+   */
+  unsigned long int skip(unsigned long int s);
+
+  /**
+   * Obtain all the initial seeds for this PRNG
+   *
+   * @param x_seed X seed (output)
+   *
+   * @param y_seed Y seed (output)
+   *
+   * @param z_seed Z seed (output)
+   *
+   * @param w_seed W seed (output)
+   */
+  void getSeed(
+    unsigned long int& x_seed,
+    unsigned long int& y_seed,
+    unsigned long int& z_seed,
+    unsigned long int& w_seed);
+
+  /**
+   * Get the maximum possible random number from this PRNG
+   *
+   * @return Maximum possible random number from this PRNG
+   */
+  static unsigned long int max_random();
+
+  // public constants
+
+  /**
+   * Default x-seed as proposed by the paper
+   */
+  static const unsigned long int X_SEED_DEFAULT;
+
+  /**
+   * Default y-seed as proposed by the paper
+   */
+  static const unsigned long int Y_SEED_DEFAULT;
+
+  /**
+   * Default z-seed as proposed by the paper
+   */
+  static const unsigned long int Z_SEED_DEFAULT;
+
+  /**
+   * Default w-seed as proposed by the paper
+   */
+  static const unsigned long int W_SEED_DEFAULT;
+
+private:
+  /**
+   * X seed
+   */
+  unsigned long int mXSeed;
+
+  /**
+   * Y seed
+   */
+  unsigned long int mYSeed;
+
+  /**
+   * Z seed
+   */
+  unsigned long int mZSeed;
+
+  /**
+   * W seed
+   */
+  unsigned long int mWSeed;
+
+  /**
+   * X value
+   */
+  unsigned long int mX;
+
+  /**
+   * Y value
+   */
+  unsigned long int mY;
+
+  /**
+   * Z value
+   */
+  unsigned long int mZ;
+
+  /**
+   * W value
+   *
+   * NOTE: This is the externally-visible next value produced by the PRNG
+   */
+  unsigned long int mW;
+
+};
+
+#ifdef SOCKETS_NAMESPACE
+} // namespace SOCKETS_NAMESPACE {
+#endif
+
+#endif // _SOCKETS_RandomNumber_H
+