From 2bde611d3317e751c411062089d12d7b901ea4e9 Mon Sep 17 00:00:00 2001
From: Lynix <lynix680@gmail.com>
Date: Mon, 16 Mar 2015 15:16:05 +0100
Subject: [PATCH] (Math) Added CountBits function

Former-commit-id: 11e825a95a7bda300e46eb321f0fdb51bea93343
---
 include/Nazara/Math/Algorithm.hpp |  1 +
 include/Nazara/Math/Algorithm.inl | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/Nazara/Math/Algorithm.hpp b/include/Nazara/Math/Algorithm.hpp
index 92ea232bd..44b2a3f1b 100644
--- a/include/Nazara/Math/Algorithm.hpp
+++ b/include/Nazara/Math/Algorithm.hpp
@@ -22,6 +22,7 @@
 
 template<typename T> T NzApproach(T value, T objective, T increment);
 template<typename T> constexpr T NzClamp(T value, T min, T max);
+template<typename T> T NzCountBits(T value);
 template<typename T> constexpr T NzFromDegrees(T degrees);
 template<typename T> constexpr T NzFromRadians(T radians);
 template<typename T> constexpr T NzDegreeToRadian(T degrees);
diff --git a/include/Nazara/Math/Algorithm.inl b/include/Nazara/Math/Algorithm.inl
index 394d6a407..d935bbe07 100644
--- a/include/Nazara/Math/Algorithm.inl
+++ b/include/Nazara/Math/Algorithm.inl
@@ -114,6 +114,20 @@ constexpr T NzClamp(T value, T min, T max)
 	return std::max(std::min(value, max), min);
 }
 
+template<typename T>
+T NzCountBits(T value)
+{
+	// https://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetKernighan
+	unsigned int count = 0;
+	while (value)
+	{
+		value &= value - 1;
+		count++;
+	}
+
+	return count;
+}
+
 template<typename T>
 constexpr T NzDegreeToRadian(T degrees)
 {