/* Implementation of the MINVAL 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 "libgfortran.h"


extern void minval_r8 (gfc_array_r8 *, gfc_array_r8 *, index_type *);
export_proto(minval_r8);

void
minval_r8 (gfc_array_r8 *retarray, gfc_array_r8 *array, index_type *pdim)
{
  index_type count[GFC_MAX_DIMENSIONS];
  index_type extent[GFC_MAX_DIMENSIONS];
  index_type sstride[GFC_MAX_DIMENSIONS];
  index_type dstride[GFC_MAX_DIMENSIONS];
  GFC_REAL_8 *base;
  GFC_REAL_8 *dest;
  index_type rank;
  index_type n;
  index_type len;
  index_type delta;
  index_type dim;

  /* Make dim zero based to avoid confusion.  */
  dim = (*pdim) - 1;
  rank = GFC_DESCRIPTOR_RANK (array) - 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;

  len = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
  delta = array->dim[dim].stride;

  for (n = 0; n < dim; n++)
    {
      sstride[n] = array->dim[n].stride;
      extent[n] = array->dim[n].ubound + 1 - array->dim[n].lbound;
    }
  for (n = dim; n < rank; n++)
    {
      sstride[n] = array->dim[n + 1].stride;
      extent[n] =
        array->dim[n + 1].ubound + 1 - array->dim[n + 1].lbound;
    }

  if (retarray->data == NULL)
    {
      for (n = 0; n < rank; n++)
        {
          retarray->dim[n].lbound = 0;
          retarray->dim[n].ubound = extent[n]-1;
          if (n == 0)
            retarray->dim[n].stride = 1;
          else
            retarray->dim[n].stride = retarray->dim[n-1].stride * extent[n-1];
        }

      retarray->data
	 = internal_malloc_size (sizeof (GFC_REAL_8)
		 		 * retarray->dim[rank-1].stride
				 * extent[rank-1]);
      retarray->offset = 0;
      retarray->dtype = (array->dtype & ~GFC_DTYPE_RANK_MASK) | rank;
    }
  else
    {
      if (retarray->dim[0].stride == 0)
	retarray->dim[0].stride = 1;

      if (rank != GFC_DESCRIPTOR_RANK (retarray))
	runtime_error ("rank of return array incorrect");
    }

  for (n = 0; n < rank; n++)
    {
      count[n] = 0;
      dstride[n] = retarray->dim[n].stride;
      if (extent[n] <= 0)
        len = 0;
    }

  base = array->data;
  dest = retarray->data;

  while (base)
    {
      GFC_REAL_8 *src;
      GFC_REAL_8 result;
      src = base;
      {

  result = GFC_REAL_8_HUGE;
        if (len <= 0)
	  *dest = GFC_REAL_8_HUGE;
	else
	  {
	    for (n = 0; n < len; n++, src += delta)
	      {

  if (*src < result)
    result = *src;
          }
	    *dest = result;
	  }
      }
      /* Advance to the next element.  */
      count[0]++;
      base += sstride[0];
      dest += dstride[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];
          dest -= dstride[n] * extent[n];
          n++;
          if (n == rank)
            {
              /* Break out of the look.  */
              base = NULL;
              break;
            }
          else
            {
              count[n]++;
              base += sstride[n];
              dest += dstride[n];
            }
        }
    }
}


extern void mminval_r8 (gfc_array_r8 *, gfc_array_r8 *, index_type *,
					       gfc_array_l4 *);
export_proto(mminval_r8);

void
mminval_r8 (gfc_array_r8 * retarray, gfc_array_r8 * array,
				  index_type *pdim, gfc_array_l4 * mask)
{
  index_type count[GFC_MAX_DIMENSIONS];
  index_type extent[GFC_MAX_DIMENSIONS];
  index_type sstride[GFC_MAX_DIMENSIONS];
  index_type dstride[GFC_MAX_DIMENSIONS];
  index_type mstride[GFC_MAX_DIMENSIONS];
  GFC_REAL_8 *dest;
  GFC_REAL_8 *base;
  GFC_LOGICAL_4 *mbase;
  int rank;
  int dim;
  index_type n;
  index_type len;
  index_type delta;
  index_type mdelta;

  dim = (*pdim) - 1;
  rank = GFC_DESCRIPTOR_RANK (array) - 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;

  len = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
  if (len <= 0)
    return;
  delta = array->dim[dim].stride;
  mdelta = mask->dim[dim].stride;

  for (n = 0; n < dim; n++)
    {
      sstride[n] = array->dim[n].stride;
      mstride[n] = mask->dim[n].stride;
      extent[n] = array->dim[n].ubound + 1 - array->dim[n].lbound;
    }
  for (n = dim; n < rank; n++)
    {
      sstride[n] = array->dim[n + 1].stride;
      mstride[n] = mask->dim[n + 1].stride;
      extent[n] =
        array->dim[n + 1].ubound + 1 - array->dim[n + 1].lbound;
    }

  if (retarray->data == NULL)
    {
      for (n = 0; n < rank; n++)
        {
          retarray->dim[n].lbound = 0;
          retarray->dim[n].ubound = extent[n]-1;
          if (n == 0)
            retarray->dim[n].stride = 1;
          else
            retarray->dim[n].stride = retarray->dim[n-1].stride * extent[n-1];
        }

      retarray->data
	 = internal_malloc_size (sizeof (GFC_REAL_8)
		 		 * retarray->dim[rank-1].stride
				 * extent[rank-1]);
      retarray->offset = 0;
      retarray->dtype = (array->dtype & ~GFC_DTYPE_RANK_MASK) | rank;
    }
  else
    {
      if (retarray->dim[0].stride == 0)
	retarray->dim[0].stride = 1;

      if (rank != GFC_DESCRIPTOR_RANK (retarray))
	runtime_error ("rank of return array incorrect");
    }

  for (n = 0; n < rank; n++)
    {
      count[n] = 0;
      dstride[n] = retarray->dim[n].stride;
      if (extent[n] <= 0)
        return;
    }

  dest = retarray->data;
  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;
      mdelta <<= 1;
      mbase = (GFOR_POINTER_L8_TO_L4 (mbase));
    }

  while (base)
    {
      GFC_REAL_8 *src;
      GFC_LOGICAL_4 *msrc;
      GFC_REAL_8 result;
      src = base;
      msrc = mbase;
      {

  result = GFC_REAL_8_HUGE;
        if (len <= 0)
	  *dest = GFC_REAL_8_HUGE;
	else
	  {
	    for (n = 0; n < len; n++, src += delta, msrc += mdelta)
	      {

  if (*msrc && *src < result)
    result = *src;
              }
	    *dest = result;
	  }
      }
      /* Advance to the next element.  */
      count[0]++;
      base += sstride[0];
      mbase += mstride[0];
      dest += dstride[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];
          dest -= dstride[n] * extent[n];
          n++;
          if (n == rank)
            {
              /* Break out of the look.  */
              base = NULL;
              break;
            }
          else
            {
              count[n]++;
              base += sstride[n];
              mbase += mstride[n];
              dest += dstride[n];
            }
        }
    }
}