Added Windows support to the BenchTimer.

bench/BenchTimer.h

@@ -26,8 +26,14 @@
 #ifndef EIGEN_BENCH_TIMER_H
 #define EIGEN_BENCH_TIMER_H
 
+#ifndef WIN32
 #include <sys/time.h>
 #include <unistd.h>
+#else
+#define NOMINMAX
+#include <windows.h>
+#endif
+
 #include <cstdlib>
 #include <numeric>
 
@@ -40,7 +46,15 @@ class BenchTimer
 {
 public:
 
-  BenchTimer() { reset(); }
+  BenchTimer() 
+  { 
+#ifdef WIN32
+    LARGE_INTEGER freq;
+    QueryPerformanceFrequency(&freq);
+    m_frequency = (double)freq.QuadPart;
+#endif
+    reset(); 
+  }
 
   ~BenchTimer() {}
 
@@ -51,23 +65,35 @@ public:
     m_best = std::min(m_best, getTime() - m_start);
   }
 
-  /** Return the best elapsed time.
+  /** Return the best elapsed time in seconds.
     */
   inline double value(void)
   {
-      return m_best;
+    return m_best;
   }
 
+#ifdef WIN32
+  inline double getTime(void)
+#else
   static inline double getTime(void)
+#endif
   {
+#ifdef WIN32
+    LARGE_INTEGER query_ticks;
+    QueryPerformanceCounter(&query_ticks);
+    return query_ticks.QuadPart/m_frequency;
+#else
       struct timeval tv;
       struct timezone tz;
       gettimeofday(&tv, &tz);
       return (double)tv.tv_sec + 1.e-6 * (double)tv.tv_usec;
+#endif
   }
 
 protected:
-
+#ifdef WIN32
+  double m_frequency;
+#endif
   double m_best, m_start;
 
 };