Diff: log.h

Revision:

0:b47c2a7920c2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/log.h	Fri Mar 16 16:34:18 2018 +0000
@@ -0,0 +1,116 @@
+///\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_LOG__
+#define __ETL_LOG__
+
+#include <stddef.h>
+
+#include "platform.h"
+
+///\defgroup log log
+/// log<N, BASE> : Calculates logs to any base, rounded down to the nearest integer.<br>
+/// log2<N>      : Calculates logs to base 2, rounded down to the nearest integer.<br>
+/// log10<N>     : Calculates logs to base 10, rounded down to the nearest integer.<br>
+///\ingroup maths
+
+namespace etl 
+{
+  //***************************************************************************
+  ///\ingroup log
+  /// The base generic log template.
+  /// Defines <b>value</b> as the log of the number at the specified base.
+  /// The result is rounded down to the next integer.
+  ///\tparam NV   The number to find the log of.
+  ///\tparam BASE The base of the log.
+  //***************************************************************************
+  template <const size_t NV, const size_t BASE>
+  struct log
+  {
+    enum value_type
+    {
+      // Recursive definition.
+      value = (NV >= BASE) ? 1 + log<NV / BASE, BASE>::value : 0
+    };
+  };
+
+  //***************************************************************************
+  // Specialisation for N = 1
+  //***************************************************************************
+  template <const size_t BASE>
+  struct log<1, BASE>
+  {
+    enum value_type
+    {
+      value = 0
+    };
+  };
+
+  //***************************************************************************
+  // Specialisation for N = 0
+  //***************************************************************************
+  template <const size_t BASE>
+  struct log<0, BASE>
+  {
+    enum value_type
+    {
+      value = 0
+    };
+  };
+
+  //***************************************************************************
+  ///\ingroup log
+  /// Calculates base 2 logs.
+  //***************************************************************************
+  template <const size_t NV>
+  struct log2
+  {
+    enum value_type
+    {
+      value = log<NV, 2>::value
+    };
+  };
+
+  //***************************************************************************
+  ///\ingroup log
+  /// Calculates base 10 logs.
+  //***************************************************************************
+  template <const size_t NV>
+  struct log10
+  {
+    enum value_type
+    {
+      value = log<NV, 10>::value
+    };
+  };
+}
+
+#endif
+