From f5fb87f33603f99b1bc8cb991629b6c8dea623af Mon Sep 17 00:00:00 2001
From: Birunthan Mohanathas <birunthan@mohanathas.com>
Date: Sun, 8 Dec 2013 15:06:01 +0200
Subject: [PATCH] Calc: Use std::mt19937 with a deterministic seed as the
 random engine

---
 Library/MeasureCalc.cpp | 12 ++++++++----
 Library/MeasureCalc.h   |  4 ----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Library/MeasureCalc.cpp b/Library/MeasureCalc.cpp
index ec0b79a4..b408c035 100644
--- a/Library/MeasureCalc.cpp
+++ b/Library/MeasureCalc.cpp
@@ -20,12 +20,16 @@
 #include "../Common/MathParser.h"
 #include "MeasureCalc.h"
 #include "Rainmeter.h"
+#include <random>
 
 const int DEFAULT_LOWER_BOUND = 0;
 const int DEFAULT_UPPER_BOUND = 100;
 
-std::default_random_engine MeasureCalc::c_RandomEngine =
-	std::default_random_engine(std::random_device()());
+std::mt19937& GetRandomEngine()
+{
+	static std::unique_ptr<std::mt19937> s_Engine(new std::mt19937((uint32_t)time(0)));
+	return *s_Engine;
+}
 
 /*
 ** The constructor
@@ -216,7 +220,7 @@ int MeasureCalc::GetRandom()
 	else
 	{
 		const std::uniform_int_distribution<int> distribution(m_LowBound, m_HighBound);
-		return distribution(c_RandomEngine);
+		return distribution(GetRandomEngine());
 	}
 }
 
@@ -230,5 +234,5 @@ void MeasureCalc::UpdateUniqueNumberList()
 		m_UniqueNumbers[i] = m_LowBound + i;
 	}
 
-	std::shuffle(m_UniqueNumbers.begin(), m_UniqueNumbers.end(), c_RandomEngine);
+	std::shuffle(m_UniqueNumbers.begin(), m_UniqueNumbers.end(), GetRandomEngine());
 }
diff --git a/Library/MeasureCalc.h b/Library/MeasureCalc.h
index 5d659f33..179cd40a 100644
--- a/Library/MeasureCalc.h
+++ b/Library/MeasureCalc.h
@@ -20,7 +20,6 @@
 #define __MEASURECALC_H__
 
 #include "Measure.h"
-#include <random>
 
 class MeasureCalc : public Measure
 {
@@ -51,9 +50,6 @@ private:
 
 	std::vector<int> m_UniqueNumbers;
 	void UpdateUniqueNumberList();
-
-	// Uniform Random Number Generator
-	static std::default_random_engine c_RandomEngine;
 };
 
 #endif