From 8ecc9a2518df62a9366c8c295b5ec46189c246a8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me?= <jerome.tabeaud@gmail.com>
Date: Mon, 29 Apr 2019 16:54:41 +0200
Subject: [PATCH] Added clamp function. Added random generation macros. Added
 MIN and MAX macros. Added very simple uniform random numbers generator (Park
 Miller). Updated Chronometer so that any string can be displayed.

---
 utils.hpp | 38 +++++++++++++++++++++++++++++++++++---
 1 file changed, 35 insertions(+), 3 deletions(-)

diff --git a/utils.hpp b/utils.hpp
index 6db340d..c7366b9 100644
--- a/utils.hpp
+++ b/utils.hpp
@@ -11,12 +11,41 @@
 						std::cout << "\n";}
 #define PRINT_STR(x) std::cout << (x) << "\n"
 
+#define RAND_A_B(a, b) ((double(rand())/RAND_MAX)*(b-a) + a)
+#define RAND_0_1()      (double(rand())/RAND_MAX)
+
+#define MIN(a, b) ((a) < (b)) ? (a) : (b)
+#define MAX(a, b) ((a) > (b)) ? (a) : (b)
+
 template<typename T, typename T2> auto min(const T & a, const T2 & b) -> decltype(a | b) { return (a < b) ? T(a) : T(b); }
 template<typename T, typename T2> auto max(const T & a, const T2 & b) -> decltype(a | b) { return (a < b) ? T(b) : T(a); }
 
 /// To be sure that floating point numbers won't be casted to integers in ::abs()...
 template<typename T> T sureAbs(const T & x) { return (x < T(0)) ? -x : x; }
 
+/// Clamps the input so that it remains within the interval [a, b]
+template<typename T>
+T clamp(const T & x, const T & a, const T & b)
+{
+    if(x < a)
+        return a;
+    if(x > b)
+        return b;
+    return x;
+}
+
+/// VERY simple uniform random numbers generator (Park Miller)
+///
+/// http://www.cems.uwe.ac.uk/~irjohnso/coursenotes/ufeen8-15-m/p1192-parkmiller.pdf
+/// http://www0.cs.ucl.ac.uk/staff/ucacbbl/ftp/papers/langdon_2009_CIGPU.pdf
+template<int x=1>
+int intrnd(int & seed) 			// 1 <= seed < m
+{
+	const int a = 16807;      	//ie 7**5
+	const int m = 2147483647; 	//ie 2**31-1
+	seed = (long(seed) * a) % m;
+	return seed;
+}
 
 /*
 /// Generic operator<< for ostream, (to print std::vector, etd::list, std::map, etc). Can generate conflicts with specialized operator<< overloads.
@@ -118,12 +147,15 @@ struct Chronometer
 		return double(resolution_ratio.num)/resolution_ratio.den;
 	}
 
-	/// Measures the time elapsed between the creation of the object and its destruction, and prints the result in std::cout.
-	void MeasureTimeElapsed() const
+	/// Measures the time elapsed between the creation of the object and its destruction, and prints the result in std::cout. If displayname = "", the name stored in the object is used.
+	void MeasureTimeElapsed(const std::string & displayname = "") const
 	{
 		// measure time since object creation and print it in the console
+		const std::string *newname = &name;
+		if(displayname.size())
+			newname = &displayname;
 		std::cout.precision(16);
-		std::cout << name.c_str() << "\t: " << GetTime() << " s (+/- " << GetResolution() << " s)" << std::endl;// use of c_str() so that there is no ambiguity with the generic operator<<
+		std::cout << newname->c_str() << "\t: " << GetTime() << " s (+/- " << GetResolution() << " s)" << std::endl;// use of c_str() so that there is no ambiguity with the generic operator<<
 	}
 };