largest.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2014 John Wellbelove
 
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#ifndef ETL_LARGEST_INCLUDED
#define ETL_LARGEST_INCLUDED

 
#include "platform.h"
#include "smallest.h"
#include "static_assert.h"
#include "type_traits.h"
 
namespace etl
{
#if ETL_USING_CPP11 && !defined(ETL_LARGEST_TYPE_FORCE_CPP03_IMPLEMENTATION)
  //***************************************************************************
  //***************************************************************************
  template <typename T1, typename... TRest>
  class largest_type
  {
  private:
 
    // Define 'largest_other' as 'largest_type' with all but the first
    // parameter.
    using largest_other = typename largest_type<TRest...>::type;
 
  public:
 
    // Set 'type' to be the largest of the first parameter and any of the
    // others. This is recursive.
    using type = typename etl::conditional< (etl::size_of<T1>::value > etl::size_of<largest_other>::value), // Boolean
                                            T1,                                                             // TrueType
                                            largest_other>                                                  // FalseType
      ::type;                                                                                               // The largest type of the two.
 
    // The size of the largest type.
    enum
    {
      size = etl::size_of<type>::value
    };
  };
 
  //***************************************************************************
  // Specialisation for one template parameter.
  //***************************************************************************
  template <typename T1>
  class largest_type<T1>
  {
  public:
 
    using type = T1;
 
    enum
    {
      size = etl::size_of<type>::value
    };
  };
 
  #if ETL_USING_CPP11
  template <typename... T>
  using largest_type_t = typename largest_type<T...>::type;
  #endif
 
  #if ETL_USING_CPP17
  template <typename... T>
  constexpr size_t largest_type_v = largest_type<T...>::size;
  #endif
 
#else
  #include "private/largest_type_cpp03.h"
#endif
 
#if ETL_USING_CPP11 && !defined(ETL_LARGEST_ALIGNMENT_FORCE_CPP03_IMPLEMENTATION)
  //***************************************************************************
  //***************************************************************************
  template <typename T1, typename... TRest>
  struct largest_alignment
  {
    // Define 'largest_other' as 'largest_type' with all but the first
    // parameter.
    using largest_other = typename largest_alignment<TRest...>::type;
 
    // Set 'type' to be the largest of the first parameter and any of the
    // others. This is recursive.
    using type = typename etl::conditional< (etl::alignment_of<T1>::value > etl::alignment_of<largest_other>::value), // Boolean
                                            T1,                                                                       // TrueType
                                            largest_other>                                                            // FalseType
      ::type;                                                                                                         // The largest type of the two.
 
    // The largest alignment.
    enum
    {
      value = etl::alignment_of<type>::value
    };
  };
 
  //***************************************************************************
  // Specialisation for one template parameter.
  //***************************************************************************
  template <typename T1>
  struct largest_alignment<T1>
  {
    typedef T1 type;
 
    enum
    {
      value = etl::alignment_of<type>::value
    };
  };
 
  #if ETL_USING_CPP17
  template <typename... T>
  inline constexpr size_t largest_alignment_v = largest_alignment<T...>::value;
  #endif
 
#else
  #include "private/largest_alignment_cpp03.h"
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  struct larger_int_type
  {
    ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Must be an integral type");
 
    typedef typename etl::smallest_int_for_bits< etl::integral_limits<typename etl::make_signed<T>::type>::bits + 1>::type type;
  };
 
#if ETL_USING_CPP11
  template <typename T>
  using larger_int_type_t = typename larger_int_type<T>::type;
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  struct larger_uint_type
  {
    ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Must be an integral type");
 
    typedef typename etl::smallest_uint_for_bits< etl::integral_limits<typename etl::make_unsigned<T>::type>::bits + 1>::type type;
  };
 
#if ETL_USING_CPP11
  template <typename T>
  using larger_uint_type_t = typename larger_uint_type<T>::type;
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T, bool IS_SIGNED = etl::is_signed<T>::value>
  struct larger_type;
 
  template <typename T>
  struct larger_type<T, false>
  {
    ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Must be an integral type");
 
    typedef typename etl::smallest_uint_for_bits<etl::integral_limits<T>::bits + 1>::type type;
  };
 
  template <typename T>
  struct larger_type<T, true>
  {
    ETL_STATIC_ASSERT(etl::is_integral<T>::value, "Must be an integral type");
 
    typedef typename etl::smallest_int_for_bits<etl::integral_limits<T>::bits + 1>::type type;
  };
 
#if ETL_USING_CPP11
  template <typename T>
  using larger_type_t = typename larger_type<T>::type;
#endif
 
#if ETL_USING_CPP11 && !defined(ETL_LARGEST_FORCE_CPP03_IMPLEMENTATION)
  //***************************************************************************
  //***************************************************************************
  template <typename... T>
  struct largest
  {
    using type = typename etl::largest_type<T...>::type;
 
    enum
    {
      size      = etl::largest_type<T...>::size,
      alignment = etl::largest_alignment<T...>::value
    };
  };
 
  #if ETL_USING_CPP11
  template <typename... T>
  using largest_t = typename largest<T...>::type;
  #endif
 
  #if ETL_USING_CPP17
  template <typename... T>
  inline constexpr size_t largest_size = largest<T...>::size;
  #endif
 
#else
  #include "private/largest_cpp03.h"
#endif
} // namespace etl
 
#endif