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+// -*- C++ -*-
+
+// ============================================================================
+/**
+ * @file randomize.h
+ *
+ * $Id$
+ *
+ * Randomize the contents of an array.
+ *
+ * @author Ossama Othman
+ *
+ * @note Based on code originally found in test_config.h and Test_Output.cpp
+ */
+// ============================================================================
+
+#ifndef ACE_TESTS_RANDOMIZE_H
+#define ACE_TESTS_RANDOMIZE_H
+
+#include "ace/OS_NS_stdlib.h"
+
+#include <algorithm>
+#include <functional>
+
+namespace
+{
+  /**
+   * @class randomize_index
+   *
+   * @brief Functor that randomoly swaps the order of two array
+   *        elements.
+   *
+   * @internal Do not directly use this class.  Use the @c randomize()
+   *           function template found below instead.
+   *
+   * This functor generates random array index using high-order bits (e.g.,
+   * MAX_VAL * rand() / (RAND_MAX + 1.0)) rather than low-order ones
+   * (e.g. rand() % MAX_VAL) to improve randomness.  The array element
+   * reference by that index is then swapped with the array element
+   * provided to the functor.
+   *
+   * @note The improved randomness may be overkill for this functor's
+   *       intended use cases, but it is a good thing to practice/have
+   *       nonetheless.
+   *
+   * @see Numerical Recipes in C: The Art of Scientific Computing
+   *      (William H. Press, Brian P. Flannery, Saul A. Teukolsky,
+   *      William T. Vetterling; New York: Cambridge University Press,
+   *      1992 (2nd ed., p. 277).
+   */
+  template<typename T>
+  class randomize_element
+    : public std::unary_function<T &, void>
+  {
+  public:
+
+    randomize_element (T * array, size_t size, ACE_RANDR_TYPE seed)
+      : array_ (array)
+      , coefficient_ (static_cast<double> (size) / (RAND_MAX + 1.0f))
+      , seed_ (seed)
+    {
+    }
+
+    void
+    operator() (T & value)    // We need this to be a reference!
+    {
+      size_t const index =
+        static_cast<size_t> (
+          this->coefficient_ * ACE_OS::rand_r (this->seed_));
+
+      // Swap rather than assign so that we don't lose the original
+      // value.
+      std::swap (value, this->array_[index]);
+    }
+
+  private:
+
+    // The array.
+    T * const array_;
+
+    // Factor out the constant coefficient.
+    double const coefficient_;
+
+    // Random number generator seed value.
+    ACE_RANDR_TYPE seed_;
+
+  };
+
+  /**
+   * @fn randomize
+   *
+   * @brief Randomize the order of elements in an array.
+   *
+   * @param array The array whose elements will be reordered
+   *              randomly.
+   * @param size  The number of elements in the array.
+   * @param seed  The random number generator seed value.  A default
+   *              value is provided so that the generated random
+                  number order may be "repeatable" if so desired.
+   *
+   * This function template randomizes the order of elements in an
+   * array of any type.  It is also reentrant (unless the array itself
+   * is accessed by multiple threads).
+   * @par
+   * Sample usage:
+   * @par
+   * \verbatim
+     static size_t const NUM_TIMES = 100;
+     ACE_Time_Value times[NUM_TIMES] = { ... };
+     randomize (times,
+                NUM_TIMES,
+                static_cast<ACE_RANDR_TYPE> (ACE_OS::time (0L)));
+    \endverbatim
+   */
+  template<typename T>
+  void
+  randomize (T * array, size_t size, ACE_RANDR_TYPE seed = 0)
+  {
+    // Randomize all elements of the array.
+    std::for_each (array,
+                   array + size,
+                   randomize_element<T> (array, size, seed));
+  }
+}
+
+#endif  /* !ACE_TESTS_RANDOMIZE_H */