Add benchmark.cpp and timer related support files

git-svn-id: http://svn.boost.org/svn/boost/sandbox/endian@74296 b8fc166d-592f-0410-95f2-cb63ce0dd405

libs/endian/support/timer.cpp

@@ -0,0 +1,167 @@
+//  boost timer.cpp  ---------------------------------------------------------//
+
+//  Copyright Beman Dawes 1994-2006
+
+//  Distributed under the Boost Software License, Version 1.0. (See accompanying
+//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+//  See http://www.boost.org/libs/system for documentation.
+
+//----------------------------------------------------------------------------//
+
+// define BOOST_ENDIAN_SOURCE so that <boost/system/config.hpp> knows
+// the library is being built (possibly exporting rather than importing code)
+#define BOOST_ENDIAN_SOURCE 
+
+#include <boost/endian/support/timer.hpp>
+#include <boost/system/system_error.hpp>
+#include <boost/io/ios_state.hpp>
+#include <boost/throw_exception.hpp>
+#include <boost/cerrno.hpp>
+#include <cstring>
+#include <cassert>
+
+# if defined(BOOST_WINDOWS_API)
+#   include <windows.h>
+# elif defined(BOOST_POSIX_API)
+#   include <unistd.h>
+#   include <sys/times.h>
+# else
+# error unknown API
+# endif
+
+using boost::system::error_code;
+
+# if defined(BOOST_POSIX_API)
+namespace
+{
+  long tick_factor()        // multiplier to convert ticks
+                            //  to microseconds; -1 if unknown
+  {
+    static long tick_factor = 0;
+    if (!tick_factor)
+    {
+      if ((tick_factor = ::sysconf(_SC_CLK_TCK)) <= 0)
+        tick_factor = -1;
+      else
+      {
+        assert(tick_factor <= 1000000L); // doesn't handle large ticks
+        tick_factor = 1000000L / tick_factor;  // compute factor
+        if (!tick_factor) tick_factor = -1;
+      }
+    }
+    return tick_factor;
+  }
+} // unnamed namespace
+# endif
+
+namespace boost
+{
+  namespace endian
+  {
+
+    BOOST_ENDIAN_DECL
+    void times(times_t& current)
+    {
+      error_code ec;
+      if (times(current, ec))
+        boost::throw_exception(system::system_error(ec, "boost::endian::times"));
+    }
+
+    BOOST_ENDIAN_DECL
+    error_code& times(times_t& current, error_code& ec)
+    {
+      ec = error_code();
+#   if defined(BOOST_WINDOWS_API)
+      ::GetSystemTimeAsFileTime((LPFILETIME)&current.wall);
+      FILETIME creation, exit;
+      if (::GetProcessTimes(::GetCurrentProcess(), &creation, &exit,
+             (LPFILETIME)&current.system, (LPFILETIME)&current.user))
+      {
+        current.wall   /= 10;  // Windows uses 100 nanosecond ticks
+        current.user   /= 10;
+        current.system /= 10;
+      }
+      else
+      {
+        ec = error_code(::GetLastError(), system::system_category());
+        current.wall = current.system = current.user = microsecond_t(-1);
+      }
+#   else
+      tms tm;
+      clock_t c = ::times(&tm);
+      if (c == -1) // error
+      {
+        ec = error_code(errno, system::system_category());
+        current.wall = current.system = current.user = microsecond_t(-1);
+      }
+      else
+      {
+        current.wall = microsecond_t(c);
+        current.system = microsecond_t(tm.tms_stime + tm.tms_cstime);
+        current.user = microsecond_t(tm.tms_utime + tm.tms_cutime);
+        if (tick_factor() != -1)
+        {
+          current.wall *= tick_factor();
+          current.user *= tick_factor();
+          current.system *= tick_factor();
+        }
+        else
+        {
+          ec = error_code(errno, system::system_category());
+          current.wall = current.user = current.system = microsecond_t(-1);
+        }
+      }
+#   endif
+      return ec;
+    }
+
+#define  BOOST_TIMES(C)            \
+      if (m_flags& m_nothrow)   \
+      {                            \
+        error_code ec;             \
+        times(C, ec);            \
+      }                            \
+      else                         \
+        times(C);
+
+    //  timer  ---------------------------------------------------------------//
+
+    void timer::start()
+    {
+      m_flags = static_cast<m_flags_t>(m_flags& ~m_stopped);
+      BOOST_TIMES(m_times);
+    }
+
+    const times_t& timer::stop()
+    {
+      if (stopped()) return m_times;
+      m_flags = static_cast<m_flags_t>(m_flags | m_stopped);
+      
+      times_t current;
+      BOOST_TIMES(current);
+      m_times.wall = (current.wall - m_times.wall);
+      m_times.user = (current.user - m_times.user);
+      m_times.system = (current.system - m_times.system);
+      return m_times;
+    }
+
+    void timer::elapsed(times_t& current)
+    {
+      if (stopped())
+      {
+        current.wall = m_times.wall;
+        current.user = m_times.user;
+        current.system = m_times.system;
+      }
+      else
+      {
+        BOOST_TIMES(current);
+        current.wall -= m_times.wall;
+        current.user -= m_times.user;
+        current.system -= m_times.system;
+      }
+    }
+
+  } // namespace endian
+} // namespace boost