From 11fdc64447b2d4ae55d10180421ca21402bae765 Mon Sep 17 00:00:00 2001
From: Riyyi <riyyi3@gmail.com>
Date: Mon, 18 Jul 2022 17:30:13 +0200
Subject: [PATCH] Util: Add pause() and resume() to Timer

---
 src/util/timer.cpp | 51 ++++++++++++++++++++++++++++++++++++++++++----
 src/util/timer.h   | 11 ++++++----
 2 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/src/util/timer.cpp b/src/util/timer.cpp
index 59d99ab..2292d66 100644
--- a/src/util/timer.cpp
+++ b/src/util/timer.cpp
@@ -1,21 +1,57 @@
 #include <chrono>  // high_resolution_clock, seconds, milliseconds, microseconds, nanoseconds
 #include <cstdint> // uint64_t
-#include <cstdio> // printf
+#include <cstdio>  // printf
 
 #include "util/timer.h"
 
 namespace Util {
 
 Timer::Timer()
-	: m_start(std::chrono::high_resolution_clock::now())
+	: m_running(true)
+	, m_accumulated(TimePoint::min())
+	, m_start(now())
 {
 }
 
+Timer::Timer(const TimePoint& timePoint)
+	: m_running(true)
+	, m_accumulated(TimePoint::min())
+	, m_start(timePoint)
+{
+}
+
+// -----------------------------------------
+
 Timer Timer::operator-(const Timer& timer)
 {
 	return Timer(TimePoint { m_start - timer.start() });
 }
 
+TimePoint Timer::now()
+{
+	return std::chrono::high_resolution_clock::now();
+}
+
+void Timer::pause()
+{
+	if (!m_running) {
+		return;
+	}
+
+	m_accumulated += now() - m_start;
+	m_running = false;
+}
+
+void Timer::resume()
+{
+	if (m_running) {
+		return;
+	}
+
+	m_running = true;
+	m_start = now();
+}
+
 template<typename To, typename From>
 To Timer::to(From from)
 {
@@ -45,8 +81,15 @@ uint64_t Timer::toNanoseconds()
 template<typename T>
 uint64_t Timer::elapsed()
 {
-	auto now = std::chrono::high_resolution_clock::now();
-	return std::chrono::duration_cast<T>(now - m_start).count();
+	uint64_t elapsed = 0;
+
+	if (m_running) {
+		elapsed += std::chrono::duration_cast<T>(now() - m_start).count();
+	}
+
+	elapsed += std::chrono::duration_cast<T>(m_accumulated - TimePoint::min()).count();
+
+	return elapsed;
 }
 
 uint64_t Timer::elapsedSeconds()
diff --git a/src/util/timer.h b/src/util/timer.h
index 8de2d5c..8b63a46 100644
--- a/src/util/timer.h
+++ b/src/util/timer.h
@@ -11,13 +11,14 @@ using TimePoint = std::chrono::high_resolution_clock::time_point;
 class Timer {
 public:
 	Timer();
-	Timer(const TimePoint& timePoint)
-		: m_start(timePoint)
-	{
-	}
+	Timer(const TimePoint& timePoint);
 
 	Timer operator-(const Timer& timer);
 
+	static TimePoint now();
+	void pause();
+	void resume();
+
 	template<typename To, typename From>
 	To to(From from);
 	uint64_t toSeconds();
@@ -37,6 +38,8 @@ public:
 	const TimePoint& start() const { return m_start; }
 
 private:
+	bool m_running { true };
+	TimePoint m_accumulated;
 	TimePoint m_start;
 };