From e536c892c4db4f3e621d4a02585a2aa8ad722455 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Wed, 7 Dec 2011 21:07:45 +0100
Subject: [PATCH] Added Math::pow() and Math::log() functions.

Math::pow() is templated on exponent, so it should be as fast as
possible (without recursion).
---
 src/CMakeLists.txt           |  2 +-
 src/Math/CMakeLists.txt      |  4 ++++
 src/Math/Math.cpp            | 27 +++++++++++++++++++++++++++
 src/Math/Math.h              | 22 ++++++++++++++++++++++
 src/Math/Test/CMakeLists.txt |  1 +
 src/Math/Test/MathTest.cpp   | 10 ++++++++++
 src/Math/Test/MathTest.h     |  2 ++
 7 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 src/Math/Math.cpp

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 4cb717232..2fcf351e2 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -20,7 +20,7 @@ set(Magnum_SRCS
 )
 
 add_library(Magnum SHARED ${Magnum_SRCS})
-target_link_libraries(Magnum CorradePluginManager CorradeUtility ${OPENGL_gl_LIBRARY} ${GLEW_LIBRARY})
+target_link_libraries(Magnum CorradePluginManager CorradeUtility MagnumMath ${OPENGL_gl_LIBRARY} ${GLEW_LIBRARY})
 
 install(TARGETS Magnum DESTINATION ${MAGNUM_LIBRARY_INSTALL_DIR})
 
diff --git a/src/Math/CMakeLists.txt b/src/Math/CMakeLists.txt
index 6879e1b55..1ce5fe56a 100644
--- a/src/Math/CMakeLists.txt
+++ b/src/Math/CMakeLists.txt
@@ -1,5 +1,9 @@
 include_directories(${CMAKE_CURRENT_SOURCE_DIR})
 
+add_library(MagnumMath STATIC
+    Math.cpp
+)
+
 if(BUILD_TESTS)
     enable_testing()
     add_subdirectory(Test)
diff --git a/src/Math/Math.cpp b/src/Math/Math.cpp
new file mode 100644
index 000000000..0c74ebbbc
--- /dev/null
+++ b/src/Math/Math.cpp
@@ -0,0 +1,27 @@
+/*
+    Copyright © 2010, 2011 Vladimír Vondruš <mosra@centrum.cz>
+
+    This file is part of Magnum.
+
+    Magnum is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License version 3
+    only, as published by the Free Software Foundation.
+
+    Magnum is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+    GNU Lesser General Public License version 3 for more details.
+*/
+
+#include "Math.h"
+
+namespace Magnum { namespace Math {
+
+size_t log(size_t base, size_t number) {
+    size_t log = 0;
+    while(number /= base)
+        ++log;
+    return log;
+}
+
+}}
diff --git a/src/Math/Math.h b/src/Math/Math.h
index 107c6b2aa..0c82b0279 100644
--- a/src/Math/Math.h
+++ b/src/Math/Math.h
@@ -15,6 +15,8 @@
     GNU Lesser General Public License version 3 for more details.
 */
 
+#include <cstddef>
+
 /** @file
  * @brief Math constants and utilities
  */
@@ -27,6 +29,26 @@ namespace Magnum { namespace Math {
 /** @brief Maximal tolerance when comparing floats */
 #define EPSILON 1.0e-6
 
+/**
+ * @brief Integral power
+ *
+ * Returns integral power of base to the exponent.
+ */
+template<size_t exponent> inline constexpr size_t pow(size_t base) {
+    return base*pow<exponent-1>(base);
+}
+
+#ifndef DOXYGEN_GENERATING_OUTPUT
+template<> inline constexpr size_t pow<0>(size_t base) { return 1; }
+#endif
+
+/**
+ * @brief Integral logarithm
+ *
+ * Returns integral logarithm of given number with given base.
+ */
+size_t log(size_t base, size_t number);
+
 /**
  * @brief Angle in degrees
  *
diff --git a/src/Math/Test/CMakeLists.txt b/src/Math/Test/CMakeLists.txt
index e1812efa1..4badfbaf6 100644
--- a/src/Math/Test/CMakeLists.txt
+++ b/src/Math/Test/CMakeLists.txt
@@ -15,4 +15,5 @@ corrade_add_test(Matrix4Test Matrix4Test.h Matrix4Test.cpp)
 target_link_libraries(Matrix4Test ${CORRADE_UTILITY_LIBRARY})
 
 corrade_add_test(MathTest MathTest.h MathTest.cpp)
+target_link_libraries(MathTest MagnumMath)
 corrade_add_test(GeometryUtilsTest GeometryUtilsTest.h GeometryUtilsTest.cpp)
diff --git a/src/Math/Test/MathTest.cpp b/src/Math/Test/MathTest.cpp
index dfce8d3df..460afb5a8 100644
--- a/src/Math/Test/MathTest.cpp
+++ b/src/Math/Test/MathTest.cpp
@@ -32,4 +32,14 @@ void MathTest::degrad() {
     QVERIFY(deg(90) == PI/2);
 }
 
+void MathTest::pow() {
+    QCOMPARE(Math::pow<10>(2), 1024ul);
+    QCOMPARE(Math::pow<0>(3), 1ul);
+}
+
+void MathTest::log() {
+    QCOMPARE(Math::log(2, 256), 8ul);
+    QCOMPARE(Math::log(256, 2), 0ul);
+}
+
 }}}
diff --git a/src/Math/Test/MathTest.h b/src/Math/Test/MathTest.h
index 41388f489..88b32e977 100644
--- a/src/Math/Test/MathTest.h
+++ b/src/Math/Test/MathTest.h
@@ -24,6 +24,8 @@ class MathTest: public QObject {
 
     private slots:
         void degrad();
+        void pow();
+        void log();
 };
 
 }}}