float_cmp.hh

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// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
// SPDX-FileCopyrightInfo: Copyright © DUNE Project contributors, see file LICENSE.md in module root
// SPDX-License-Identifier: LicenseRef-GPL-2.0-only-with-DUNE-exception
#ifndef DUNE_COMMON_FLOAT_CMP_HH
#define DUNE_COMMON_FLOAT_CMP_HH

namespace Dune {
  namespace FloatCmp {
    // basic constants
    enum CmpStyle {
      relativeWeak,
      relativeStrong,
      absolute,
      defaultCmpStyle = relativeWeak
    };
    enum RoundingStyle {
      towardZero,
      towardInf,
      downward,
      upward,
      defaultRoundingStyle = towardZero
    };

    template<class T> struct EpsilonType;


    template<class T, CmpStyle style = defaultCmpStyle>
    struct DefaultEpsilon {
      static typename EpsilonType<T>::Type value();
    };

    // operations in functional style



    template <class T, CmpStyle style /*= defaultCmpStyle*/>
    bool eq(const T &first,
            const T &second,
            typename EpsilonType<T>::Type epsilon = DefaultEpsilon<T, style>::value());

    template <class T, CmpStyle style /*= defaultCmpStyle*/>
    bool ne(const T &first,
            const T &second,
            typename EpsilonType<T>::Type epsilon = DefaultEpsilon<T, style>::value());

    template <class T, CmpStyle style /*= defaultCmpStyle*/>
    bool gt(const T &first,
            const T &second,
            typename EpsilonType<T>::Type epsilon = DefaultEpsilon<T, style>::value());

    template <class T, CmpStyle style /*= defaultCmpStyle*/>
    bool lt(const T &first,
            const T &second,
            typename EpsilonType<T>::Type epsilon = DefaultEpsilon<T, style>::value());

    template <class T, CmpStyle style /*= defaultCmpStyle*/>
    bool ge(const T &first,
            const T &second,
            typename EpsilonType<T>::Type epsilon = DefaultEpsilon<T, style>::value());

    template <class T, CmpStyle style /*= defaultCmpStyle*/>
    bool le(const T &first,
            const T &second,
            typename EpsilonType<T>::Type epsilon = DefaultEpsilon<T, style>::value());

    // rounding operations

    template<class I, class T, CmpStyle cstyle /*= defaultCmpStyle*/, RoundingStyle rstyle /*= defaultRoundingStyle*/>
    I round(const T &val, typename EpsilonType<T>::Type epsilon = DefaultEpsilon<T, cstyle>::value());
    // truncation

    template<class I, class T, CmpStyle cstyle /*= defaultCmpStyle*/, RoundingStyle rstyle /*= defaultRoundingStyle*/>
    I trunc(const T &val, typename EpsilonType<T>::Type epsilon = DefaultEpsilon<T, cstyle>::value());

    // group FloatCmp
  } //namespace FloatCmp


  // oo interface

  template<class T, FloatCmp::CmpStyle cstyle_ = FloatCmp::defaultCmpStyle,
      FloatCmp::RoundingStyle rstyle_ = FloatCmp::defaultRoundingStyle>
  class FloatCmpOps {
    typedef FloatCmp::CmpStyle CmpStyle;
    typedef FloatCmp::RoundingStyle RoundingStyle;

  public:
    // record template parameters
    static const CmpStyle cstyle = cstyle_;
    static const RoundingStyle rstyle = rstyle_;
    typedef T ValueType;

    typedef typename FloatCmp::EpsilonType<T>::Type EpsilonType;

  private:
    EpsilonType epsilon_;

    typedef FloatCmp::DefaultEpsilon<EpsilonType, cstyle> DefaultEpsilon;

  public:

    FloatCmpOps(EpsilonType epsilon = DefaultEpsilon::value());

    EpsilonType epsilon() const;
    void epsilon(EpsilonType epsilon__);

    bool eq(const ValueType &first, const ValueType &second) const;

    bool ne(const ValueType &first, const ValueType &second) const;

    bool gt(const ValueType &first, const ValueType &second) const;

    bool lt(const ValueType &first, const ValueType &second) const;

    bool ge(const ValueType &first, const ValueType &second) const;

    bool le(const ValueType &first, const ValueType &second) const;


    template<class I>
    I round(const ValueType &val) const;


    template<class I>
    I trunc(const ValueType &val) const;

  };

} //namespace Dune

#include "float_cmp.cc"

#endif //DUNE_COMMON_FLOAT_CMP_HH