1 files changed, 114 insertions, 0 deletions
diff --git a/zen/tick_count.h b/zen/tick_count.h
new file mode 100644
index 00000000..37c7cc59
--- /dev/null
+++ b/zen/tick_count.h
@@ -0,0 +1,114 @@
+// **************************************************************************
+// * This file is part of the zenXML project. It is 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.       *
+// * Copyright (C) ZenJu (zhnmju123 AT gmx DOT de) - All Rights Reserved    *
+// **************************************************************************
+
+#ifndef ZEN_TICK_COUNT_HEADER_3807326
+#define ZEN_TICK_COUNT_HEADER_3807326
+
+#include <cstdint>
+#include "type_traits.h"
+#include "assert_static.h"
+
+#ifdef FFS_WIN
+#include "win.h" //includes "windows.h"
+#elif defined FFS_LINUX
+#include <time.h> //Posix ::clock_gettime()
+#endif
+
+namespace zen
+{
+//a portable "GetTickCount()" using "wall time equivalent" - e.g. no jumps due to ntp time corrections
+class TickVal;
+std::int64_t operator-(const TickVal& lhs, const TickVal& rhs);
+
+std::int64_t ticksPerSec(); //return 0 on error
+TickVal getTicks();         //return invalid value on error
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+//############################ implementation ##############################
+class TickVal
+{
+public:
+#ifdef FFS_WIN
+    typedef LARGE_INTEGER NativeVal;
+#elif defined FFS_LINUX
+    typedef timespec NativeVal;
+#endif
+
+    TickVal() : val_() {}
+    TickVal(const NativeVal& val) : val_(val) {}
+
+    inline friend
+    std::int64_t operator-(const TickVal& lhs, const TickVal& rhs)
+    {
+#ifdef FFS_WIN
+		assert_static(IsSignedInt<decltype(lhs.val_.QuadPart)>::value);
+        return lhs.val_.QuadPart - rhs.val_.QuadPart;
+#elif defined FFS_LINUX
+		assert_static(IsSignedInt<decltype(lhs.val_.tv_sec)>::value);
+		assert_static(IsSignedInt<decltype(lhs.val_.tv_nsec)>::value);
+        return static_cast<std::int64_t>(lhs.val_.tv_sec - rhs.val_.tv_sec) * 1000000000.0 + lhs.val_.tv_nsec - rhs.val_.tv_nsec;
+#endif
+    }
+
+    bool isValid() const { return *this - TickVal() != 0; }
+
+private:
+    NativeVal val_;
+};
+
+
+inline
+std::int64_t ticksPerSec() //return 0 on error
+{
+#ifdef FFS_WIN
+    LARGE_INTEGER frequency = {};
+    if (!::QueryPerformanceFrequency(&frequency))
+        return 0;
+    return frequency.QuadPart;
+
+#elif defined FFS_LINUX
+    return 1000000000; //precision: nanoseconds
+#endif
+}
+
+
+inline
+TickVal getTicks() //return 0 on error
+{
+#ifdef FFS_WIN
+    LARGE_INTEGER now = {};
+    if (!::QueryPerformanceCounter(&now)) //msdn: SetThreadAffinityMask() may be required if there are bugs in BIOS or HAL"
+        return TickVal();
+
+#elif defined FFS_LINUX
+    //gettimeofday() seems fine but is deprecated
+    timespec now = {};
+    if (::clock_gettime(CLOCK_MONOTONIC_RAW, &now) != 0) //CLOCK_MONOTONIC measures time reliably across processors!
+        return TickVal();
+#endif
+    return now;
+}
+}
+
+#endif //ZEN_TICK_COUNT_HEADER_3807326