Diff: power.h

Revision:

0:b47c2a7920c2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/power.h	Fri Mar 16 16:34:18 2018 +0000
@@ -0,0 +1,184 @@
+///\file
+
+/******************************************************************************
+The MIT License(MIT)
+
+Embedded Template Library.
+https://github.com/ETLCPP/etl
+http://www.etlcpp.com
+
+Copyright(c) 2014 jwellbelove
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files(the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions :
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+******************************************************************************/
+
+#ifndef __ETL_POW__
+#define __ETL_POW__
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "platform.h"
+#include "log.h"
+
+///\defgroup power power
+/// power<N, POWER> : Calculates N to the power POWER.
+///\ingroup maths
+
+namespace etl 
+{
+  //***************************************************************************
+  ///\ingroup power
+  /// Calculates powers.
+  ///\note Only supports positive N.
+  //***************************************************************************
+  template <const size_t NV, const size_t POWER>
+  struct power
+  {
+    static const uint64_t value = NV * power<NV, POWER - 1>::value;
+  };
+
+  //***************************************************************************
+  /// Calculates powers.
+  ///\note Only supports positive N.
+  /// Specialisation for POWER == 0.
+  //***************************************************************************
+  template <const size_t NV>
+  struct power<NV, 0>
+  {
+    static const uint64_t value = 1;
+  };
+
+  //***************************************************************************
+  ///\ingroup power
+  /// Calculates the rounded up power of 2.
+  //***************************************************************************
+  template <const size_t NV>
+  struct power_of_2_round_up
+  {
+    enum value_type
+    {
+      value = 1 << (etl::log2<NV - 1>::value + 1)
+    };
+  };
+
+  //***************************************************************************
+  ///\ingroup power
+  /// Calculates the rounded up power of 2.
+  /// Specialisation for 0.
+  //***************************************************************************
+  template <>
+  struct power_of_2_round_up<0>
+  {
+    enum value_type
+    {
+      value = 2
+    };
+  };
+
+  //***************************************************************************
+  ///\ingroup power
+  /// Calculates the rounded down power of 2.
+  //***************************************************************************
+  template <const size_t NV>
+  struct power_of_2_round_down
+  {
+    enum value_type
+    {
+      value = 1 << (etl::log2<NV - 1>::value)
+    };
+  };
+
+  //***************************************************************************
+  ///\ingroup power
+  /// Calculates the rounded down power of 2.
+  /// Specialisation for 0.
+  //***************************************************************************
+  template <>
+  struct power_of_2_round_down<0>
+  {
+    enum value_type
+    {
+      value = 2
+    };
+  };
+
+  //***************************************************************************
+  ///\ingroup power
+  /// Calculates the rounded down power of 2.
+  /// Specialisation for 1.
+  //***************************************************************************
+  template <>
+  struct power_of_2_round_down<1>
+  {
+    enum value_type
+    {
+      value = 2
+    };
+  };
+
+  //***************************************************************************
+  ///\ingroup power
+  /// Calculates the rounded down power of 2.
+  /// Specialisation for 2.
+  //***************************************************************************
+  template <>
+  struct power_of_2_round_down<2>
+  {
+    enum value_type
+    {
+      value = 2
+    };
+  };
+
+  //***************************************************************************
+  ///\ingroup power
+  /// Checks if N is a power of 2.
+  //***************************************************************************
+  template <const size_t NV>
+  struct is_power_of_2
+  {
+    static const bool value = (NV & (NV - 1)) == 0;
+  };
+
+  //***************************************************************************
+  ///\ingroup power
+  /// Checks if N is a power of 2.
+  /// Specialisation for 0.
+  //***************************************************************************
+  template <>
+  struct is_power_of_2<0>
+  {
+    static const bool value = false;
+  };
+
+  //***************************************************************************
+  ///\ingroup power
+  /// Checks if N is a power of 2.
+  /// Specialisation for 1.
+  //***************************************************************************
+  template <>
+  struct is_power_of_2<1>
+  {
+    static const bool value = false;
+  };
+}
+
+#endif
+