/* Implementation of the MAXLOC intrinsic
   Copyright 2002 Free Software Foundation, Inc.
   Contributed by Paul Brook <paul@nowt.org>

This file is part of the GNU Fortran 95 runtime library (libgfortran).

Libgfortran 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 2 of the License, or (at your option) any later version.

In addition to the permissions in the GNU General Public License, the
Free Software Foundation gives you unlimited permission to link the
compiled version of this file into combinations with other programs,
and to distribute those combinations without any restriction coming
from the use of this file.  (The General Public License restrictions
do apply in other respects; for example, they cover modification of
the file, and distribution when not linked into a combine
executable.)

Libgfortran 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 libgfortran; see the file COPYING.  If not,
write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */

#include "config.h"
#include <stdlib.h>
#include <assert.h>
#include <float.h>
#include <limits.h>
#include "libgfortran.h"


#if defined (HAVE_GFC_REAL_10) && defined (HAVE_GFC_INTEGER_4)


extern void maxloc0_4_r10 (gfc_array_i4 * retarray, gfc_array_r10 *array);
export_proto(maxloc0_4_r10);

void
maxloc0_4_r10 (gfc_array_i4 * retarray, gfc_array_r10 *array)
{
  index_type count[GFC_MAX_DIMENSIONS];
  index_type extent[GFC_MAX_DIMENSIONS];
  index_type sstride[GFC_MAX_DIMENSIONS];
  index_type dstride;
  GFC_REAL_10 *base;
  GFC_INTEGER_4 *dest;
  index_type rank;
  index_type n;

  rank = GFC_DESCRIPTOR_RANK (array);
  if (rank <= 0)
    runtime_error ("Rank of array needs to be > 0");

  if (retarray->data == NULL)
    {
      retarray->dim[0].lbound = 0;
      retarray->dim[0].ubound = rank-1;
      retarray->dim[0].stride = 1;
      retarray->dtype = (retarray->dtype & ~GFC_DTYPE_RANK_MASK) | 1;
      retarray->offset = 0;
      retarray->data = internal_malloc_size (sizeof (GFC_INTEGER_4) * rank);
    }
  else
    {
      if (GFC_DESCRIPTOR_RANK (retarray) != 1)
	runtime_error ("rank of return array does not equal 1");

      if (retarray->dim[0].ubound + 1 - retarray->dim[0].lbound != rank)
        runtime_error ("dimension of return array incorrect");

      if (retarray->dim[0].stride == 0)
	retarray->dim[0].stride = 1;
    }

  /* TODO:  It should be a front end job to correctly set the strides.  */

  if (array->dim[0].stride == 0)
    array->dim[0].stride = 1;

  dstride = retarray->dim[0].stride;
  dest = retarray->data;
  for (n = 0; n < rank; n++)
    {
      sstride[n] = array->dim[n].stride;
      extent[n] = array->dim[n].ubound + 1 - array->dim[n].lbound;
      count[n] = 0;
      if (extent[n] <= 0)
	{
	  /* Set the return value.  */
	  for (n = 0; n < rank; n++)
	    dest[n * dstride] = 0;
	  return;
	}
    }

  base = array->data;

  /* Initialize the return value.  */
  for (n = 0; n < rank; n++)
    dest[n * dstride] = 1;
  {

  GFC_REAL_10 maxval;

  maxval = -GFC_REAL_10_HUGE;

  while (base)
    {
      {
        /* Implementation start.  */

  if (*base > maxval)
    {
      maxval = *base;
      for (n = 0; n < rank; n++)
        dest[n * dstride] = count[n] + 1;
    }
        /* Implementation end.  */
      }
      /* Advance to the next element.  */
      count[0]++;
      base += sstride[0];
      n = 0;
      while (count[n] == extent[n])
        {
          /* When we get to the end of a dimension, reset it and increment
             the next dimension.  */
          count[n] = 0;
          /* We could precalculate these products, but this is a less
             frequently used path so proabably not worth it.  */
          base -= sstride[n] * extent[n];
          n++;
          if (n == rank)
            {
              /* Break out of the loop.  */
              base = NULL;
              break;
            }
          else
            {
              count[n]++;
              base += sstride[n];
            }
        }
    }
  }
}


extern void mmaxloc0_4_r10 (gfc_array_i4 *, gfc_array_r10 *, gfc_array_l4 *);
export_proto(mmaxloc0_4_r10);

void
mmaxloc0_4_r10 (gfc_array_i4 * retarray, gfc_array_r10 *array,
				  gfc_array_l4 * mask)
{
  index_type count[GFC_MAX_DIMENSIONS];
  index_type extent[GFC_MAX_DIMENSIONS];
  index_type sstride[GFC_MAX_DIMENSIONS];
  index_type mstride[GFC_MAX_DIMENSIONS];
  index_type dstride;
  GFC_INTEGER_4 *dest;
  GFC_REAL_10 *base;
  GFC_LOGICAL_4 *mbase;
  int rank;
  index_type n;

  rank = GFC_DESCRIPTOR_RANK (array);
  if (rank <= 0)
    runtime_error ("Rank of array needs to be > 0");

  if (retarray->data == NULL)
    {
      retarray->dim[0].lbound = 0;
      retarray->dim[0].ubound = rank-1;
      retarray->dim[0].stride = 1;
      retarray->dtype = (retarray->dtype & ~GFC_DTYPE_RANK_MASK) | 1;
      retarray->offset = 0;
      retarray->data = internal_malloc_size (sizeof (GFC_INTEGER_4) * rank);
    }
  else
    {
      if (GFC_DESCRIPTOR_RANK (retarray) != 1)
	runtime_error ("rank of return array does not equal 1");

      if (retarray->dim[0].ubound + 1 - retarray->dim[0].lbound != rank)
        runtime_error ("dimension of return array incorrect");

      if (retarray->dim[0].stride == 0)
	retarray->dim[0].stride = 1;
    }

  /* TODO:  It should be a front end job to correctly set the strides.  */

  if (array->dim[0].stride == 0)
    array->dim[0].stride = 1;

  if (mask->dim[0].stride == 0)
    mask->dim[0].stride = 1;

  dstride = retarray->dim[0].stride;
  dest = retarray->data;
  for (n = 0; n < rank; n++)
    {
      sstride[n] = array->dim[n].stride;
      mstride[n] = mask->dim[n].stride;
      extent[n] = array->dim[n].ubound + 1 - array->dim[n].lbound;
      count[n] = 0;
      if (extent[n] <= 0)
	{
	  /* Set the return value.  */
	  for (n = 0; n < rank; n++)
	    dest[n * dstride] = 0;
	  return;
	}
    }

  base = array->data;
  mbase = mask->data;

  if (GFC_DESCRIPTOR_SIZE (mask) != 4)
    {
      /* This allows the same loop to be used for all logical types.  */
      assert (GFC_DESCRIPTOR_SIZE (mask) == 8);
      for (n = 0; n < rank; n++)
        mstride[n] <<= 1;
      mbase = (GFOR_POINTER_L8_TO_L4 (mbase));
    }


  /* Initialize the return value.  */
  for (n = 0; n < rank; n++)
    dest[n * dstride] = 1;
  {

  GFC_REAL_10 maxval;

  maxval = -GFC_REAL_10_HUGE;

  while (base)
    {
      {
        /* Implementation start.  */

  if (*mbase && *base > maxval)
    {
      maxval = *base;
      for (n = 0; n < rank; n++)
        dest[n * dstride] = count[n] + 1;
    }
        /* Implementation end.  */
      }
      /* Advance to the next element.  */
      count[0]++;
      base += sstride[0];
      mbase += mstride[0];
      n = 0;
      while (count[n] == extent[n])
        {
          /* When we get to the end of a dimension, reset it and increment
             the next dimension.  */
          count[n] = 0;
          /* We could precalculate these products, but this is a less
             frequently used path so proabably not worth it.  */
          base -= sstride[n] * extent[n];
          mbase -= mstride[n] * extent[n];
          n++;
          if (n == rank)
            {
              /* Break out of the loop.  */
              base = NULL;
              break;
            }
          else
            {
              count[n]++;
              base += sstride[n];
              mbase += mstride[n];
            }
        }
    }
  }
}

#endif