/*

Copyright (C) 1994, 1995, 1996, 1997, 1998, 2000, 2001, 2003, 2004,
              2005, 2006, 2007, 2008, 2009 John W. Eaton
Copyright (C) 2009 VZLU Prague

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
<http://www.gnu.org/licenses/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

// Instantiate Arrays of double values.

#include "lo-mappers.h"
#include "Array.h"
#include "Array.cc"
#include "oct-locbuf.h"

#define INLINE_ASCENDING_SORT
#define INLINE_DESCENDING_SORT
#include "oct-sort.cc"

template <>
inline bool
sort_isnan<double> (double x)
{
  return xisnan (x);
}

static bool
nan_ascending_compare (double x, double y)
{
  return xisnan (y) ? ! xisnan (x) : x < y;
}

static bool
nan_descending_compare (double x, double y)
{
  return xisnan (x) ? ! xisnan (y) : x > y;
}

Array<double>::compare_fcn_type
safe_comparator (sortmode mode, const Array<double>& a , bool allow_chk)
{
  Array<double>::compare_fcn_type result = 0;

  if (allow_chk)
    {
      octave_idx_type k = 0;
      for (; k < a.numel () && ! xisnan (a(k)); k++) ;
      if (k == a.numel ())
        {
          if (mode == ASCENDING)
            result = octave_sort<double>::ascending_compare;
          else if (mode == DESCENDING)
            result = octave_sort<double>::descending_compare;
        }
    }

  if (! result)
    {
      if (mode == ASCENDING)
        result = nan_ascending_compare;
      else if (mode == DESCENDING)
        result = nan_descending_compare;
    }

  return result;
}

// The default solution using NaN-safe comparator is OK, but almost twice as
// slow than this code.
template <>
OCTAVE_API
sortmode
Array<double>::is_sorted (sortmode mode) const
{
  octave_idx_type n = numel ();

  const double *el = data ();

  if (n <= 1)
    return mode ? mode : ASCENDING;

  if (! mode)
    {
      // Auto-detect mode.
      if (el[n-1] < el[0] || xisnan (el[0]))
        mode = DESCENDING;
      else
        mode = ASCENDING;
    }

  if (mode == DESCENDING)
    {
      octave_idx_type j = 0;
      double r;
      // Sort out NaNs.
      do
        r = el[j++];
      while (xisnan (r) && j < n);

      // Orient the test so that NaN will not pass through. 
      for (; j < n; j++)
        {
          if (r >= el[j])
            r = el[j];
          else
            {
              mode = UNSORTED;
              break;
            }
        }

    }
  else if (mode == ASCENDING)
    {
      // Sort out NaNs.
      while (n > 0 && xisnan (el[n-1]))
        n--;

      if (n > 0)
        {
          // Orient the test so that NaN will not pass through. 
          double r = el[0];
          for (octave_idx_type j = 1; j < n; j++)
            {
              if (r <= el[j])
                r = el[j];
              else
                {
                  mode = UNSORTED;
                  break;
                }
            }
        }
    }

  return mode;
}

INSTANTIATE_ARRAY_SORT (double);

INSTANTIATE_ARRAY (double, OCTAVE_API);

template OCTAVE_API std::ostream& operator << (std::ostream&, const Array<double>&);

#include "DiagArray2.h"
#include "DiagArray2.cc"

template class OCTAVE_API DiagArray2<double>;