////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1996-2020 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Octave is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
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////////////////////////////////////////////////////////////////////////

#if ! defined (octave_lo_mappers_h)
#define octave_lo_mappers_h 1

#include "octave-config.h"

#include <cmath>

#include <limits>

#include "lo-ieee.h"
#include "oct-cmplx.h"
#include "oct-inttypes-fwd.h"

namespace octave
{
  namespace math
  {
    extern OCTAVE_API bool isna (double x);
    extern OCTAVE_API bool isna (float x);
    extern OCTAVE_API bool isna (const Complex& x);
    extern OCTAVE_API bool isna (const FloatComplex& x);

    extern OCTAVE_API bool is_NaN_or_NA (const Complex& x);
    extern OCTAVE_API bool is_NaN_or_NA (const FloatComplex& x);

    inline double copysign (double x, double y) { return std::copysign (x, y); }
    inline float copysign (float x, float y) { return std::copysignf (x, y); }

    inline double signbit (double x) { return std::signbit (x); }
    inline float signbit (float x) { return std::signbit (x); }

    // Test for negative sign.
    extern OCTAVE_API bool negative_sign (double x);
    extern OCTAVE_API bool negative_sign (float x);

    // Test for positive sign.
    inline bool positive_sign (double x) { return ! negative_sign (x); }
    inline bool positive_sign (float x) { return ! negative_sign (x); }

    extern OCTAVE_API Complex acos (const Complex& x);
    extern OCTAVE_API FloatComplex acos (const FloatComplex& x);

    extern OCTAVE_API Complex asin (const Complex& x);
    extern OCTAVE_API FloatComplex asin (const FloatComplex& x);

    inline Complex atan (const Complex& x) { return std::atan (x); }
    inline FloatComplex atan (const FloatComplex& x) { return std::atan (x); }

    // The C++ standard would normally return a std::complex value for conj
    // even when the input is fully real.  Octave overrides this.
    inline double conj (double x) { return x; }
    inline float conj (float x) { return x; }

    template <typename T>
    std::complex<T>
    conj (const std::complex<T>& x)
    {
      return std::conj (x);
    }

    inline double log2 (double x) { return std::log2 (x); }
    inline float log2 (float x) { return std::log2f (x); }

    extern OCTAVE_API Complex log2 (const Complex& x);
    extern OCTAVE_API FloatComplex log2 (const FloatComplex& x);

    extern OCTAVE_API double log2 (double x, int& exp);
    extern OCTAVE_API float log2 (float x, int& exp);

    extern OCTAVE_API Complex log2 (const Complex& x, int& exp);
    extern OCTAVE_API FloatComplex log2 (const FloatComplex& x, int& exp);

    inline double exp2 (double x) { return std::exp2 (x); }
    inline float exp2 (float x) { return std::exp2f (x); }

    template <typename T>
    std::complex<T>
    ceil (const std::complex<T>& x)
    {
      return std::complex<T> (std::ceil (std::real (x)),
                              std::ceil (std::imag (x)));
    }

    template <typename T>
    std::complex<T>
    trunc (const std::complex<T>& x)
    {
      return std::complex<T> (std::trunc (std::real (x)),
                              std::trunc (std::imag (x)));
    }

    // Provide alias for trunc under the more familiar name of fix.
    inline double fix (double x) { return std::trunc (x); }
    inline float fix (float x) { return std::trunc (x); }

    template <typename T>
    std::complex<T>
    fix (const std::complex<T>& x)
    {
      return trunc (x);
    }

    template <typename T>
    std::complex<T>
    floor (const std::complex<T>& x)
    {
      return std::complex<T> (std::floor (std::real (x)),
                              std::floor (std::imag (x)));
    }

    inline double round (double x) { return std::round (x); }
    inline float round (float x) { return std::roundf (x); }

    template <typename T>
    std::complex<T>
    round (const std::complex<T>& x)
    {
      return std::complex<T> (round (std::real (x)), round (std::imag (x)));
    }

    inline double
    roundb (double x)
    {
      double t = round (x);

      if (fabs (x - t) == 0.5)
        t = 2 * std::trunc (0.5 * t);

      return t;
    }

    inline float
    roundb (float x)
    {
      float t = round (x);

      if (fabsf (x - t) == 0.5f)
        t = 2 * std::trunc (0.5f * t);

      return t;
    }

    template <typename T>
    std::complex<T>
    roundb (const std::complex<T>& x)
    {
      return std::complex<T> (roundb (std::real (x)), roundb (std::imag (x)));
    }

    extern OCTAVE_API double frexp (double x, int *expptr);
    extern OCTAVE_API float frexp (float x, int *expptr);

    inline bool isnan (bool) { return false; }
    inline bool isnan (char) { return false; }

    inline bool isnan (double x) { return std::isnan (x); }
    inline bool isnan (float x) { return std::isnan (x); }

    // FIXME: Do we need the isnan overload for complex?
    template <typename T>
    bool
    isnan (const std::complex<T>& x)
    {
      return (isnan (std::real (x)) || isnan (std::imag (x)));
    }

    inline bool isfinite (double x) { return std::isfinite (x); }
    inline bool isfinite (float x) { return std::isfinite (x); }

    // FIXME: Do we need isfinite overload for complex?
    template <typename T>
    bool
    isfinite (const std::complex<T>& x)
    {
      return (isfinite (std::real (x)) && isfinite (std::imag (x)));
    }

    inline bool isinf (double x) { return std::isinf (x); }
    inline bool isinf (float x) { return std::isinf (x); }

    // FIXME: Do we need isinf overload for complex?
    template <typename T>
    bool
    isinf (const std::complex<T>& x)
    {
      return (isinf (std::real (x)) || isinf (std::imag (x)));
    }

    // Some useful tests, that are commonly repeated.
    // Test for a finite integer.

    // FIXME: Benchmark whether trunc might be faster than round here.
    inline bool isinteger (double x) { return isfinite (x) && x == round (x); }
    inline bool isinteger (float x) { return isfinite (x) && x == round (x); }

    inline double
    signum (double x)
    {
      double tmp = 0.0;

      if (x < 0.0)
        tmp = -1.0;
      else if (x > 0.0)
        tmp = 1.0;

      return isnan (x) ? numeric_limits<double>::NaN () : tmp;
    }

    inline float
    signum (float x)
    {
      float tmp = 0.0f;

      if (x < 0.0f)
        tmp = -1.0f;
      else if (x > 0.0f)
        tmp = 1.0f;

      return isnan (x) ? numeric_limits<float>::NaN () : tmp;
    }

    template <typename T>
    std::complex<T>
    signum (const std::complex<T>& x)
    {
      T tmp = abs (x);

      return tmp == 0 ? 0.0 : x / tmp;
    }

    // Convert X to the nearest integer value.  Should not pass NaN to
    // this function.

    // For integer types?  Hmm.  Need to be sure T is an integer type...
    template <typename T>
    T
    x_nint (T x)
    {
      return x;
    }

    template <>
    inline double x_nint (double x)
    {
      return (isfinite (x) ? std::floor (x + 0.5) : x);
    }

    template <>
    inline float x_nint (float x)
    {
      return (isfinite (x) ? std::floor (x + 0.5f) : x);
    }

    extern OCTAVE_API octave_idx_type nint_big (double x);
    extern OCTAVE_API octave_idx_type nint_big (float x);

    extern OCTAVE_API int nint (double x);
    extern OCTAVE_API int nint (float x);

    template <typename T>
    T
    mod (T x, T y)
    {
      T retval;

      if (y == 0)
        retval = x;
      else
        {
          T q = x / y;

          if (x_nint (y) != y
              && (std::abs ((q - x_nint (q)) / x_nint (q))
                  < std::numeric_limits<T>::epsilon ()))
            retval = 0;
          else
            {
              T n = std::floor (q);

              // Prevent use of extra precision.
              volatile T tmp = y * n;

              retval = x - tmp;
            }
        }

      if (x != y && y != 0)
        retval = copysign (retval, y);

      return retval;
    }

    template <typename T>
    T
    rem (T x, T y)
    {
      T retval;

      if (y == 0)
        retval = numeric_limits<T>::NaN ();
      else
        {
          T q = x / y;

          if (x_nint (y) != y
              && (std::abs ((q - x_nint (q)) / x_nint (q))
                  < std::numeric_limits<T>::epsilon ()))
            retval = 0;
          else
            {
              T n = std::trunc (q);

              // Prevent use of extra precision.
              volatile T tmp = y * n;

              retval = x - tmp;
            }
        }

      if (x != y && y != 0)
        retval = copysign (retval, x);

      return retval;
    }

    // Generic min, max definitions
    template <typename T>
    T
    min (T x, T y)
    {
      return x <= y ? x : y;
    }

    template <typename T>
    T
    max (T x, T y)
    {
      return x >= y ? x : y;
    }

    // This form is favorable.  GCC will translate (x <= y ? x : y) without a
    // jump, hence the only conditional jump involved will be the first
    // (isnan), infrequent and hence friendly to branch prediction.

    inline double
    min (double x, double y)
    {
      return isnan (y) ? x : (x <= y ? x : y);
    }

    inline double
    max (double x, double y)
    {
      return isnan (y) ? x : (x >= y ? x : y);
    }

    inline float
    min (float x, float y)
    {
      return isnan (y) ? x : (x <= y ? x : y);
    }

    inline float
    max (float x, float y)
    {
      return isnan (y) ? x : (x >= y ? x : y);
    }

    inline std::complex<double>
    min (const std::complex<double>& x, const std::complex<double>& y)
    {
      return abs (x) <= abs (y) ? x : (isnan (x) ? x : y);
    }

    inline std::complex<float>
    min (const std::complex<float>& x, const std::complex<float>& y)
    {
      return abs (x) <= abs (y) ? x : (isnan (x) ? x : y);
    }

    inline std::complex<double>
    max (const std::complex<double>& x, const std::complex<double>& y)
    {
      return abs (x) >= abs (y) ? x : (isnan (x) ? x : y);
    }

    inline std::complex<float>
    max (const std::complex<float>& x, const std::complex<float>& y)
    {
      return abs (x) >= abs (y) ? x : (isnan (x) ? x : y);
    }

    template <typename T>
    inline octave_int<T>
    min (const octave_int<T>& x, const octave_int<T>& y)
    {
      return xmin (x, y);
    }

    template <typename T>
    inline octave_int<T>
    max (const octave_int<T>& x, const octave_int<T>& y)
    {
      return xmax (x, y);
    }

    // These map reals to Complex.

    extern OCTAVE_API Complex rc_acos (double);
    extern OCTAVE_API FloatComplex rc_acos (float);

    extern OCTAVE_API Complex rc_acosh (double);
    extern OCTAVE_API FloatComplex rc_acosh (float);

    extern OCTAVE_API Complex rc_asin (double);
    extern OCTAVE_API FloatComplex rc_asin (float);

    extern OCTAVE_API Complex rc_atanh (double);
    extern OCTAVE_API FloatComplex rc_atanh (float);

    extern OCTAVE_API Complex rc_log (double);
    extern OCTAVE_API FloatComplex rc_log (float);

    extern OCTAVE_API Complex rc_log2 (double);
    extern OCTAVE_API FloatComplex rc_log2 (float);

    extern OCTAVE_API Complex rc_log10 (double);
    extern OCTAVE_API FloatComplex rc_log10 (float);

    extern OCTAVE_API Complex rc_sqrt (double);
    extern OCTAVE_API FloatComplex rc_sqrt (float);
  }
}

#endif
