Diff: smallest_generator.h

Revision:

0:b47c2a7920c2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/smallest_generator.h	Fri Mar 16 16:34:18 2018 +0000
@@ -0,0 +1,338 @@
+///\file
+
+/******************************************************************************
+The MIT License(MIT)
+
+Embedded Template Library.
+https://github.com/ETLCPP/etl
+https://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.
+******************************************************************************/
+
+/*[[[cog
+import cog
+cog.outl("#if 0")
+]]]*/
+/*[[[end]]]*/
+#error THIS HEADER IS A GENERATOR. DO NOT INCLUDE.
+/*[[[cog
+import cog
+cog.outl("#endif")
+]]]*/
+/*[[[end]]]*/
+
+/*[[[cog
+import cog
+cog.outl("//***************************************************************************")
+cog.outl("// This file has been auto generated. Do not edit this file.")
+cog.outl("//***************************************************************************")
+]]]*/
+/*[[[end]]]*/
+
+//***************************************************************************
+// To generate to header file, run this at the command line.
+// Note: You will need Python and COG installed.
+//
+// python -m cogapp -d -e -osmallest.h -DNTypes=<n> smallest_generator.h
+// Where <n> is the number of types to support.
+//
+// e.g.
+// To generate handlers for up to 16 types...
+// python -m cogapp -d -e -osmallest.h -DNTypes=16 smallest_generator.h
+//
+// See generate.bat
+//***************************************************************************
+
+#ifndef __ETL_SMALLEST__
+#define __ETL_SMALLEST__
+
+#include <stdint.h>
+
+#include "platform.h"
+#include "integral_limits.h"
+
+///\defgroup smallest smallest
+///\ingroup utilities
+
+namespace etl
+{
+  /*[[[cog
+  import cog
+  cog.outl("//***************************************************************************")
+  cog.outl("/// Template to determine the smallest type and size.")
+  cog.outl("/// Supports up to %s types." % NTypes)
+  cog.outl("/// Defines 'value_type' which is the type of the smallest parameter.")
+  cog.outl("/// Defines 'size' which is the size of the smallest parameter.")
+  cog.outl("///\ingroup smallest")
+  cog.outl("//***************************************************************************")
+  cog.out("template <typename T1, ")
+  for n in range(2, int(NTypes)):
+      cog.out("typename T%s = void, " % n)
+      if n % 4 == 0:
+          cog.outl("")
+          cog.out("          ")
+  cog.outl("typename T%s = void>" % int(NTypes))
+  cog.outl("struct smallest_type")
+  cog.outl("{")
+  cog.outl("private:")
+  cog.outl("")
+  cog.outl("  // Declaration.")
+  cog.outl("  template <const bool Boolean, typename TrueType, typename FalseType>")
+  cog.outl("  struct choose_type;")
+  cog.outl("")
+  cog.outl("  // Specialisation for 'true'.")
+  cog.outl("  // Defines 'type' as 'TrueType'.")
+  cog.outl("  template <typename TrueType, typename FalseType>")
+  cog.outl("  struct choose_type<true, TrueType, FalseType>")
+  cog.outl("  {")
+  cog.outl("    typedef TrueType type;")
+  cog.outl("  };")
+  cog.outl("")
+  cog.outl("  // Specialisation for 'false'. ")
+  cog.outl("  // Defines 'type' as 'FalseType'.")
+  cog.outl("  template <typename TrueType, typename FalseType>")
+  cog.outl("  struct choose_type<false, TrueType, FalseType>")
+  cog.outl("  {")
+  cog.outl("    typedef FalseType type;")
+  cog.outl("  };")
+  cog.outl("")
+  cog.outl("public:")
+  cog.outl("")
+  cog.outl("  // Define 'smallest_other' as 'smallest_type' with all but the first parameter. ")
+  cog.out("  typedef typename smallest_type<")
+  for n in range(2, int(NTypes)):
+      cog.out("T%s, " % n)
+      if n % 16 == 0:
+          cog.outl("")
+          cog.out("                                ")
+  cog.outl("T%s>::type smallest_other;" % int(NTypes))
+  cog.outl("")
+  cog.outl("  // Set 'type' to be the smallest of the first parameter and any of the others.")
+  cog.outl("  // This is recursive.")
+  cog.outl("  typedef typename choose_type<(sizeof(T1) < sizeof(smallest_other)), // Boolean")
+  cog.outl("                                T1,                                   // TrueType")
+  cog.outl("                                smallest_other>                       // FalseType")
+  cog.outl("                                ::type type;                          // The smallest type of the two.")
+  cog.outl("")
+  cog.outl("  // The size of the smallest type.")
+  cog.outl("  enum")
+  cog.outl("  {")
+  cog.outl("    size = sizeof(type)")
+  cog.outl("  };")
+  cog.outl("};")
+  cog.outl("")
+  cog.outl("//***************************************************************************")
+  cog.outl("// Specialisation for one template parameter.")
+  cog.outl("//***************************************************************************")
+  cog.outl("template <typename T1>")
+  cog.out("struct smallest_type<T1,   ")
+  for n in range(2, int(NTypes)):
+      cog.out("void, ")
+      if n % 8 == 0:
+          cog.outl("")
+          cog.out("                     ")
+  cog.outl("void>")
+  cog.outl("{")
+  cog.outl("  typedef T1 type;")
+  cog.outl("")
+  cog.outl("  enum")
+  cog.outl("  {")
+  cog.outl("    size = sizeof(type)")
+  cog.outl("  };")
+  cog.outl("};")
+  ]]]*/
+  /*[[[end]]]*/
+  
+  namespace __private_smallest__
+  {
+    //*************************************************************************
+    // Determine the type to hold the number of bits based on the index.
+    //*************************************************************************
+    template <const int index>
+    struct best_fit_uint_type;
+    
+    //*************************************************************************
+    // Less than or equal to 8 bits.
+    //*************************************************************************
+    template <>
+    struct best_fit_uint_type<0>
+    {
+      typedef uint_least8_t type;
+    };
+
+    //*************************************************************************
+    // 9 to 16 bits.
+    //*************************************************************************
+    template <>
+    struct best_fit_uint_type<1>
+    {
+      typedef uint_least16_t type;
+    };
+
+    //*************************************************************************
+    // 17 to 31 bits.
+    //*************************************************************************
+    template <>
+    struct best_fit_uint_type<2>
+    {
+      typedef uint_least32_t type;
+    };
+
+    //*************************************************************************
+    // Greater than 32 bits.
+    //*************************************************************************
+    template <>
+    struct best_fit_uint_type<3>
+    {
+      typedef uint_least64_t type;
+    };
+
+    //*************************************************************************
+    // Determine the type to hold the number of bits based on the index.
+    //*************************************************************************
+    template <const int index>
+    struct best_fit_int_type;
+
+    //*************************************************************************
+    // Less than or equal to 8 bits.
+    //*************************************************************************
+    template <>
+    struct best_fit_int_type<0>
+    {
+      typedef int_least8_t type;
+    };
+
+    //*************************************************************************
+    // 9 to 16 bits.
+    //*************************************************************************
+    template <>
+    struct best_fit_int_type<1>
+    {
+      typedef int_least16_t type;
+    };
+
+    //*************************************************************************
+    // 17 to 31 bits.
+    //*************************************************************************
+    template <>
+    struct best_fit_int_type<2>
+    {
+      typedef int_least32_t type;
+    };
+
+    //*************************************************************************
+    // Greater than 32 bits.
+    //*************************************************************************
+    template <>
+    struct best_fit_int_type<3>
+    {
+      typedef int_least64_t type;
+    };
+  }
+
+  //***************************************************************************
+  /// Template to determine the smallest unsigned int type that can contain a 
+  /// value with the specified number of bits.
+  /// Defines 'type' which is the type of the smallest unsigned integer.
+  ///\ingroup smallest
+  //***************************************************************************
+  template <const size_t NBITS>
+  struct smallest_uint_for_bits
+  {
+  private:
+    
+    // Determines the index of the best unsigned type for the required number of bits.
+    static const int TYPE_INDEX = ((NBITS >  8) ? 1 : 0) + 
+                                  ((NBITS > 16) ? 1 : 0) +
+                                  ((NBITS > 32) ? 1 : 0);
+
+  public:
+
+    typedef typename __private_smallest__::best_fit_uint_type<TYPE_INDEX>::type type;
+  };
+
+  //***************************************************************************
+  /// Template to determine the smallest signed int type that can contain a 
+  /// value with the specified number of bits.
+  /// Defines 'type' which is the type of the smallest signed integer.
+  ///\ingroup smallest
+  //***************************************************************************
+  template <const size_t NBITS>
+  struct smallest_int_for_bits
+  {
+  private:
+
+    // Determines the index of the best unsigned type for the required number of bits.
+    static const int TYPE_INDEX = ((NBITS >  8) ? 1 : 0) +
+                                  ((NBITS > 16) ? 1 : 0) +
+                                  ((NBITS > 32) ? 1 : 0);
+
+  public:
+
+    typedef typename __private_smallest__::best_fit_int_type<TYPE_INDEX>::type type;
+  };
+
+  //***************************************************************************
+  /// Template to determine the smallest unsigned int type that can contain the
+  /// specified unsigned value.
+  /// Defines 'type' which is the type of the smallest unsigned integer.
+  ///\ingroup smallest
+  //***************************************************************************
+  template <const uintmax_t VALUE>
+  struct smallest_uint_for_value
+  {
+  private:
+
+    // Determines the index of the best unsigned type for the required value.
+    static const int TYPE_INDEX = ((VALUE > UINT_LEAST8_MAX)  ? 1 : 0) +
+                                  ((VALUE > UINT16_MAX) ? 1 : 0) + 
+                                  ((VALUE > UINT32_MAX) ? 1 : 0);
+
+  public:
+
+    typedef typename __private_smallest__::best_fit_uint_type<TYPE_INDEX>::type type;
+  };
+
+  //***************************************************************************
+  /// Template to determine the smallest int type that can contain the
+  /// specified signed value.
+  /// Defines 'type' which is the type of the smallest signed integer.
+  ///\ingroup smallest
+  //***************************************************************************
+  template <const intmax_t VALUE>
+  struct smallest_int_for_value
+  {
+  private:
+
+    // Determines the index of the best signed type for the required value.
+    static const int TYPE_INDEX = (((VALUE > INT_LEAST8_MAX)  || (VALUE < INT_LEAST8_MIN))  ? 1 : 0) + 
+                                  (((VALUE > INT16_MAX) || (VALUE < INT16_MIN)) ? 1 : 0) +
+                                  (((VALUE > INT32_MAX) || (VALUE < INT32_MIN)) ? 1 : 0);
+
+  public:
+
+    typedef typename __private_smallest__::best_fit_int_type<TYPE_INDEX>::type type;
+  };
+}
+
+#endif
+