From 5a085560f319df720472d7ff5f045e2c0f77f28e Mon Sep 17 00:00:00 2001
From: Calcitem <calcitem@outlook.com>
Date: Sun, 10 Nov 2019 10:57:47 +0800
Subject: [PATCH] timestat: Add stopwatch

---
 millgame.pro             |  1 +
 millgame.vcxproj         |  5 ++-
 millgame.vcxproj.filters |  3 ++
 src/base/stopwatch.h     | 81 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 88 insertions(+), 2 deletions(-)
 create mode 100644 src/base/stopwatch.h

diff --git a/millgame.pro b/millgame.pro
index eb97cbc0..7e48f350 100644
--- a/millgame.pro
+++ b/millgame.pro
@@ -64,6 +64,7 @@ HEADERS  += \
     src/base/misc.h \
     src/base/sort.h \
     src/base/stack.h \
+    src/base/stopwatch.h \
     src/base/thread.h \
     src/ai/search.h \
     src/base/zobrist.h \
diff --git a/millgame.vcxproj b/millgame.vcxproj
index e2944d2c..287231a2 100644
--- a/millgame.vcxproj
+++ b/millgame.vcxproj
@@ -122,7 +122,7 @@
       <ExceptionHandling>Sync</ExceptionHandling>
       <ObjectFileName>$(IntDir)</ObjectFileName>
       <Optimization>MaxSpeed</Optimization>
-      <PreprocessorDefinitions>_WINDOWS;UNICODE;_UNICODE;WIN32;WIN64;QT_NO_DEBUG;NDEBUG;QT_CORE_LIB;QT_GUI_LIB;QT_MULTIMEDIA_LIB;QT_MULTIMEDIAWIDGETS_LIB;QT_NETWORK_LIB;QT_NETWORKAUTH_LIB;QT_WIDGETS_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>_WINDOWS;UNICODE;_UNICODE;WIN32;WIN64;QT_NO_DEBUG;QT_CORE_LIB;QT_GUI_LIB;QT_MULTIMEDIA_LIB;QT_MULTIMEDIAWIDGETS_LIB;QT_NETWORK_LIB;QT_NETWORKAUTH_LIB;QT_WIDGETS_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <PreprocessToFile>false</PreprocessToFile>
       <ProgramDataBaseFileName>$(IntDir)vc$(PlatformToolsetVersion).pdb</ProgramDataBaseFileName>
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
@@ -158,7 +158,7 @@
     <QtMoc>
       <QTDIR>$(QTDIR)</QTDIR>
       <OutputFile>.\GeneratedFiles\$(ConfigurationName)\moc_%(Filename).cpp</OutputFile>
-      <Define>_WINDOWS;UNICODE;_UNICODE;WIN32;WIN64;QT_NO_DEBUG;NDEBUG;QT_CORE_LIB;QT_GUI_LIB;QT_MULTIMEDIA_LIB;QT_MULTIMEDIAWIDGETS_LIB;QT_NETWORK_LIB;QT_NETWORKAUTH_LIB;QT_WIDGETS_LIB;%(PreprocessorDefinitions)</Define>
+      <Define>_WINDOWS;UNICODE;_UNICODE;WIN32;WIN64;QT_NO_DEBUG;QT_CORE_LIB;QT_GUI_LIB;QT_MULTIMEDIA_LIB;QT_MULTIMEDIAWIDGETS_LIB;QT_NETWORK_LIB;QT_NETWORKAUTH_LIB;QT_WIDGETS_LIB;%(PreprocessorDefinitions)</Define>
       <CompilerFlavor>msvc</CompilerFlavor>
       <Include>$(Configuration)/moc_predefs.h</Include>
       <ExecutionDescription>Moc'ing %(Identity)...</ExecutionDescription>
@@ -455,6 +455,7 @@
     <ClInclude Include="src\base\sort.h" />
     <ClInclude Include="src\base\stack.h" />
     <QtMoc Include="src\base\thread.h" />
+    <ClInclude Include="src\base\stopwatch.h" />
     <ClInclude Include="src\base\zobrist.h" />
     <ClInclude Include="src\game\board.h" />
     <ClInclude Include="src\game\location.h" />
diff --git a/millgame.vcxproj.filters b/millgame.vcxproj.filters
index 660fb981..ae34016c 100644
--- a/millgame.vcxproj.filters
+++ b/millgame.vcxproj.filters
@@ -132,6 +132,9 @@
     <ClInclude Include="src\ai\trainer.h">
       <Filter>ai</Filter>
     </ClInclude>
+    <ClInclude Include="src\base\stopwatch.h">
+      <Filter>base</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <CustomBuild Include="debug\moc_predefs.h.cbt">
diff --git a/src/base/stopwatch.h b/src/base/stopwatch.h
new file mode 100644
index 00000000..b1f40d15
--- /dev/null
+++ b/src/base/stopwatch.h
@@ -0,0 +1,81 @@
+#ifndef STOPWATCH_H_
+#define STOPWATCH_H_
+
+#include <algorithm>
+#include <array>
+#include <chrono>
+#include <cstdint>
+#include <ratio>
+#ifdef _WIN32
+#include <intrin.h> 
+#endif
+
+namespace stopwatch {
+// An implementation of the 'TrivialClock' concept using the rdtscp instruction.
+struct rdtscp_clock {
+  using rep = std::uint64_t;
+  using period = std::ratio<1>;
+  using duration = std::chrono::duration<rep, period>;
+  using time_point = std::chrono::time_point<rdtscp_clock, duration>;
+
+  static auto now() noexcept -> time_point
+  {
+#ifdef _WIN32
+    unsigned int ui;
+    return time_point(duration((static_cast<std::uint64_t>(__rdtscp(&ui)))));
+#else
+      std::uint32_t hi, lo;
+    __asm__ __volatile__("rdtscp" : "=d"(hi), "=a"(lo));
+    return time_point(duration((static_cast<std::uint64_t>(hi) << 32) | lo));
+#endif // WIN32
+  }
+};
+
+// A timer using the specified clock.
+template <class Clock = std::chrono::system_clock>
+struct timer {
+  using time_point = typename Clock::time_point;
+  using duration = typename Clock::duration;
+
+  timer(const duration duration) noexcept : expiry(Clock::now() + duration) {}
+  timer(const time_point expiry) noexcept : expiry(expiry) {}
+
+  bool done(time_point now = Clock::now()) const noexcept {
+    return now >= expiry;
+  }
+
+  auto remaining(time_point now = Clock::now()) const noexcept -> duration {
+    return expiry - now;
+  }
+
+  const time_point expiry;
+};
+
+template <class Clock = std::chrono::system_clock>
+constexpr auto make_timer(typename Clock::duration duration) -> timer<Clock> {
+  return timer<Clock>(duration);
+}
+
+// Times how long it takes a function to execute using the specified clock.
+template <class Clock = rdtscp_clock, class Func>
+auto time(Func&& function) -> typename Clock::duration {
+  const auto start = Clock::now();
+  function();
+  return Clock::now() - start;
+}
+
+// Samples the given function N times using the specified clock.
+template <std::size_t N, class Clock = rdtscp_clock, class Func>
+auto sample(Func&& function) -> std::array<typename Clock::duration, N> {
+  std::array<typename Clock::duration, N> samples;
+
+  for (std::size_t i = 0u; i < N; ++i) {
+    samples[i] = time<Clock>(function);
+  }
+
+  std::sort(samples.begin(), samples.end());
+  return samples;
+}
+} /* namespace stopwatch */
+
+#endif  // STOPWATCH_H_