Add performance example

1 files changed, 46 insertions, 0 deletions

diff --git a/examples/performance/time.cxx b/examples/performance/time.cxx
new file mode 100644
index 0000000..cfb6d09
--- /dev/null
+++ b/examples/performance/time.cxx
@@ -0,0 +1,46 @@
+// file      : examples/performance/time.cxx
+// copyright : not copyrighted - public domain
+
+#include "time.hxx"
+
+#if defined (WIN32) || defined (__WIN32__)
+#  define WIN32_LEAN_AND_MEAN
+#  include <windows.h>  // GetSystemTimeAsFileTime
+#else
+#  include <time.h>     // gettimeofday
+#  include <sys/time.h> // timeval
+#endif
+
+#include <ostream> // std::ostream
+#include <iomanip> // std::setfill, std::setw
+
+namespace os
+{
+  time::
+  time ()
+  {
+#if defined (WIN32) || defined (__WIN32__)
+    FILETIME ft;
+    GetSystemTimeAsFileTime (&ft);
+    unsigned long long v (
+      ((unsigned long long) (ft.dwHighDateTime) << 32) + ft.dwLowDateTime);
+
+    sec_  = static_cast<unsigned long> (v / 10000000ULL);
+    nsec_ = static_cast<unsigned long> ((v % 10000000ULL) * 100);
+#else
+    timeval tv;
+    if (gettimeofday(&tv, 0) != 0)
+      throw failed ();
+
+    sec_  = static_cast<unsigned long> (tv.tv_sec);
+    nsec_ = static_cast<unsigned long> (tv.tv_usec * 1000);
+#endif
+  }
+
+  std::ostream&
+  operator<< (std::ostream& o, time const& t)
+  {
+    return o << t.sec () << '.'
+             << std::setfill ('0') << std::setw (9) << t.nsec ();
+  }
+}