From 92071a342c96ed105e8375aa260bdcfac43d1787 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Fri, 30 Mar 2018 16:20:07 +0200
Subject: [PATCH] Math: added isInf() and isNan()

---
 doc/changelog.dox                      |  4 ++++
 src/Magnum/Math/Constants.h            | 15 +++++++++++++--
 src/Magnum/Math/Functions.h            | 15 +++++++++++++++
 src/Magnum/Math/Test/FunctionsTest.cpp | 18 ++++++++++++++++++
 4 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/doc/changelog.dox b/doc/changelog.dox
index 1e0a114db3..bf68af5e67 100644
--- a/doc/changelog.dox
+++ b/doc/changelog.dox
@@ -60,6 +60,10 @@ See also:
         @webgl_extension{EXT,color_buffer_float}
 -   Ported @ref OpenGLTester to WebGL
 
+@subsubsection changelog-latest-new-math Math library
+
+-   Added @ref Math::isInf(), @ref Math::isNan()
+
 @subsubsection changelog-latest-new-platform Platform libraries
 
 -   Added @ref Platform::AndroidApplication::windowSize()
diff --git a/src/Magnum/Math/Constants.h b/src/Magnum/Math/Constants.h
index e8b72ae0d6..df27393630 100644
--- a/src/Magnum/Math/Constants.h
+++ b/src/Magnum/Math/Constants.h
@@ -71,8 +71,19 @@ template<class T> struct Constants {
     static constexpr T sqrt2(); /**< @brief Square root of 2 */
     static constexpr T sqrt3(); /**< @brief Square root of 3 */
 
-    static constexpr T nan();   /**< @brief Quiet NaN */
-    static constexpr T inf();   /**< @brief Positive infinity */
+    /**
+     * @brief Quiet NaN
+     *
+     * @see @ref isNan()
+     */
+    static constexpr T nan();
+
+    /**
+     * @brief Positive infinity
+     *
+     * @see @ref isInf()
+     */
+    static constexpr T inf();
     #endif
 };
 
diff --git a/src/Magnum/Math/Functions.h b/src/Magnum/Math/Functions.h
index 6dbae49032..163c9318b3 100644
--- a/src/Magnum/Math/Functions.h
+++ b/src/Magnum/Math/Functions.h
@@ -112,6 +112,21 @@ template<class Integral> std::pair<Integral, Integral> div(Integral x, Integral
     return {result.quot, result.rem};
 }
 
+/**
+@brief If given number is a positive or negative infinity
+
+@see @ref isNan(), @ref Constants::inf()
+*/
+template<class T> bool isInf(T value) { return std::isinf(value); }
+
+/**
+@brief If given number is NaN
+
+Equivalent to @cpp value != value @ce.
+@see @ref isInf(), @ref Constants::nan()
+*/
+template<class T> bool isNan(T value) { return std::isnan(value); }
+
 /** @todo Can't trigonometric functions be done with only one overload? */
 
 /* The functions accept Unit instead of Rad to make them working with operator
diff --git a/src/Magnum/Math/Test/FunctionsTest.cpp b/src/Magnum/Math/Test/FunctionsTest.cpp
index 7244a1c3d4..d1e4a758be 100644
--- a/src/Magnum/Math/Test/FunctionsTest.cpp
+++ b/src/Magnum/Math/Test/FunctionsTest.cpp
@@ -65,6 +65,8 @@ struct FunctionsTest: Corrade::TestSuite::Tester {
     void log();
     void exp();
     void div();
+    void isInf();
+    void isNan();
     void trigonometric();
     void trigonometricWithBase();
 };
@@ -110,6 +112,8 @@ FunctionsTest::FunctionsTest() {
               &FunctionsTest::log,
               &FunctionsTest::exp,
               &FunctionsTest::div,
+              &FunctionsTest::isInf,
+              &FunctionsTest::isNan,
               &FunctionsTest::trigonometric,
               &FunctionsTest::trigonometricWithBase});
 }
@@ -332,6 +336,20 @@ void FunctionsTest::div() {
     CORRADE_COMPARE(remainder, 3);
 }
 
+void FunctionsTest::isInf() {
+    CORRADE_VERIFY(Math::isInf(Constants::inf()));
+    CORRADE_VERIFY(Math::isInf(-Constants::inf()));
+    CORRADE_VERIFY(!Math::isInf(Constants::nan()));
+    CORRADE_VERIFY(!Math::isInf(5.3f));
+}
+
+void FunctionsTest::isNan() {
+    CORRADE_VERIFY(!Math::isNan(Constants::inf()));
+    CORRADE_VERIFY(!Math::isNan(-Constants::inf()));
+    CORRADE_VERIFY(Math::isNan(Constants::nan()));
+    CORRADE_VERIFY(!Math::isNan(5.3f));
+}
+
 void FunctionsTest::trigonometric() {
     CORRADE_COMPARE(Math::sin(Deg(30.0f)), 0.5f);
     CORRADE_COMPARE(Math::sin(Rad(Constants::pi()/6)), 0.5f);