From 0c3f9a38f45125e265afe9155e47af8889b3204e Mon Sep 17 00:00:00 2001
From: Marshall Clow <marshall@idio.com>
Date: Tue, 2 Dec 2014 14:38:25 -0800
Subject: [PATCH] Add new algorithm boost::power, which raises a number to an
 integer power

---
 include/boost/algorithm/algorithm.hpp | 50 +++++++++++++++++++++++++++
 test/Jamfile.v2                       |  6 ++--
 test/power_test.cpp                   | 36 +++++++++++++++++++
 3 files changed, 88 insertions(+), 4 deletions(-)
 create mode 100644 include/boost/algorithm/algorithm.hpp
 create mode 100644 test/power_test.cpp

diff --git a/include/boost/algorithm/algorithm.hpp b/include/boost/algorithm/algorithm.hpp
new file mode 100644
index 0000000..3304831
--- /dev/null
+++ b/include/boost/algorithm/algorithm.hpp
@@ -0,0 +1,50 @@
+/* 
+   Copyright (c) Marshall Clow 2014.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+ Revision history:
+    2 Dec 2014 mtc First version; power
+   
+*/
+
+/// \file algorithm.hpp
+/// \brief Misc Algorithms
+/// \author Marshall Clow
+///
+
+#ifndef BOOST_ALGORITHM_HPP
+#define BOOST_ALGORITHM_HPP
+
+#include <boost/utility/enable_if.hpp> // for boost::disable_if
+
+namespace boost { namespace algorithm {
+
+/// \fn power ( T x, Integer n )
+/// \return the value "x" raised to the power "n"
+/// 
+/// \param x     The value to be exponentiated
+/// \param n     The exponent
+///
+//	\remark Taken from Knuth, The Art of Computer Programming, Volume 2:
+//		Seminumerical Algorithms, Section 4.6.3
+template <typename T, typename Integer>
+T power (T x, Integer n) {
+	T y = 1; // Should be "T y{1};" 
+	if (n == 0) return y;
+	while (true) {
+		if (n % 2 == 1) {
+			y = x * y;
+			if (n == 1)
+				return y;
+			}
+		n = n / 2;
+		x = x * x;
+		}
+	return y;
+	}
+
+}}
+
+#endif // BOOST_ALGORITHM_HPP
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index bb4dff6..727cada 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -27,8 +27,9 @@ alias unit_test_framework
      [ compile-fail search_fail2.cpp  : : : : ]
      [ compile-fail search_fail3.cpp  : : : : ]
 
-# Clamp tests
+# Misc tests
      [ run clamp_test.cpp unit_test_framework         : : : : clamp_test ]
+     [ run power_test.cpp unit_test_framework         : : : : power_test ]
    
 # Cxx11 tests
      [ run all_of_test.cpp unit_test_framework         : : : : all_of_test ]
@@ -58,9 +59,6 @@ alias unit_test_framework
      [ run hex_test4.cpp unit_test_framework         : : : : hex_test4 ]
      [ compile-fail hex_fail1.cpp ]
 
-# Wrapper tests
-     [ run wrapper_test1.cpp unit_test_framework         : : : : wrapper_test1 ]
-
 # Gather tests
      [ run gather_test1.cpp unit_test_framework        : : : : gather_test1 ]
      [ compile-fail gather_fail1.cpp ]
diff --git a/test/power_test.cpp b/test/power_test.cpp
new file mode 100644
index 0000000..b4d8cf9
--- /dev/null
+++ b/test/power_test.cpp
@@ -0,0 +1,36 @@
+/* 
+   Copyright (c) Marshall Clow 2014.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+    For more information, see http://www.boost.org
+*/
+
+#include <iostream>
+
+#include <boost/config.hpp>
+#include <boost/algorithm/algorithm.hpp>
+
+#define BOOST_TEST_MAIN
+#include <boost/test/unit_test.hpp>
+
+#include <string>
+#include <vector>
+#include <list>
+
+namespace ba = boost::algorithm;
+
+BOOST_AUTO_TEST_CASE( test_main )
+{
+	BOOST_CHECK ( ba::power(0, 0) == 1);
+	BOOST_CHECK ( ba::power(5, 0) == 1);
+	BOOST_CHECK ( ba::power(1, 1) == 1);
+	BOOST_CHECK ( ba::power(1, 4) == 1);
+	BOOST_CHECK ( ba::power(3, 2) == 9);
+	BOOST_CHECK ( ba::power(2, 3) == 8);
+	BOOST_CHECK ( ba::power(3, 3) == 27);
+	BOOST_CHECK ( ba::power(2, 30) == 0x40000000);
+	BOOST_CHECK ( ba::power(5L, 10) == 3125*3125);
+	BOOST_CHECK ( ba::power(18, 3) == 18*18*18);
+}