compare.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2017 John Wellbelove
 
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#ifndef ETL_COMPARE_INCLUDED
#define ETL_COMPARE_INCLUDED
 
#include "platform.h"
#include "parameter_type.h"
#include "functional.h"
 
//*****************************************************************************
//*****************************************************************************
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  template <typename T, typename TLess = etl::less<T> >
  struct compare
  {
    enum cmp_result
    {
      Less    = -1,
      Equal   = 0,
      Greater = 1
    };
 
    typedef typename etl::parameter_type<T>::type first_argument_type;
    typedef typename etl::parameter_type<T>::type second_argument_type;
 
    static ETL_CONSTEXPR bool lt(first_argument_type lhs, second_argument_type rhs)
    {
      return TLess()(lhs, rhs);
    }
 
    static ETL_CONSTEXPR bool gt(first_argument_type lhs, second_argument_type rhs)
    {
      return TLess()(rhs, lhs);
    }
 
    static ETL_CONSTEXPR bool lte(first_argument_type lhs, second_argument_type rhs)
    {
      return !gt(lhs, rhs);
    }
 
    static ETL_CONSTEXPR bool gte(first_argument_type lhs, second_argument_type rhs)
    {
      return !lt(lhs, rhs);
    }
 
    static ETL_CONSTEXPR bool eq(first_argument_type lhs, second_argument_type rhs)
    {
      return gte(lhs, rhs) && lte(lhs, rhs);
    }
 
    static ETL_CONSTEXPR bool ne(first_argument_type lhs, second_argument_type rhs)
    {
      return !eq(lhs, rhs);
    }
 
    static ETL_CONSTEXPR cmp_result cmp(first_argument_type lhs, second_argument_type rhs)
    {
      return lt(lhs, rhs) ? Less : gt(lhs, rhs) ? Greater : Equal;
    }
  };
 
  //***************************************************************************
  //***************************************************************************
#if ETL_USING_CPP11
  template <typename T, typename TLess = etl::less<T> >
#else
  template <typename T, typename TLess>
#endif
  ETL_CONSTEXPR14 int three_way_compare(const T& lhs, const T& rhs)
  {
    return etl::compare<T>::cmp(lhs, rhs);
  }
}
 
#endif