Subversion Repositories scarts

/* Generic implementation of the PACK intrinsic

   Copyright (C) 2002, 2004, 2005 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.)

Ligbfortran 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 <string.h>

#include "libgfortran.h"

/* PACK is specified as follows:

   13.14.80 PACK (ARRAY, MASK, [VECTOR])

   Description: Pack an array into an array of rank one under the

   control of a mask.

   Class: Transformational fucntion.

   Arguments:

      ARRAY   may be of any type. It shall not be scalar.

      MASK    shall be of type LOGICAL. It shall be conformable with ARRAY.

      VECTOR  (optional) shall be of the same type and type parameters

              as ARRAY. VECTOR shall have at least as many elements as

              there are true elements in MASK. If MASK is a scalar

              with the value true, VECTOR shall have at least as many

              elements as there are in ARRAY.

   Result Characteristics: The result is an array of rank one with the

   same type and type parameters as ARRAY. If VECTOR is present, the

   result size is that of VECTOR; otherwise, the result size is the

   number /t/ of true elements in MASK unless MASK is scalar with the

   value true, in which case the result size is the size of ARRAY.

   Result Value: Element /i/ of the result is the element of ARRAY

   that corresponds to the /i/th true element of MASK, taking elements

   in array element order, for /i/ = 1, 2, ..., /t/. If VECTOR is

   present and has size /n/ > /t/, element /i/ of the result has the

   value VECTOR(/i/), for /i/ = /t/ + 1, ..., /n/.

   Examples: The nonzero elements of an array M with the value

   | 0 0 0 |

   | 9 0 0 | may be "gathered" by the function PACK. The result of

   | 0 0 7 |

   PACK (M, MASK = M.NE.0) is [9,7] and the result of PACK (M, M.NE.0,

   VECTOR = (/ 2,4,6,8,10,12 /)) is [9,7,6,8,10,12].

There are two variants of the PACK intrinsic: one, where MASK is

array valued, and the other one where MASK is scalar.  */

static void

pack_internal (gfc_array_char *ret, const gfc_array_char *array,

               const gfc_array_l4 *mask, const gfc_array_char *vector,

               index_type size)

{

  /* r.* indicates the return array.  */

  index_type rstride0;

  char *rptr;

  /* s.* indicates the source array.  */

  index_type sstride[GFC_MAX_DIMENSIONS];

  index_type sstride0;

  const char *sptr;

  /* m.* indicates the mask array.  */

  index_type mstride[GFC_MAX_DIMENSIONS];

  index_type mstride0;

  const GFC_LOGICAL_4 *mptr;

  index_type count[GFC_MAX_DIMENSIONS];

  index_type extent[GFC_MAX_DIMENSIONS];

  index_type n;

  index_type dim;

  index_type nelem;

  dim = GFC_DESCRIPTOR_RANK (array);

  for (n = 0; n < dim; n++)

    {

      count[n] = 0;

      extent[n] = array->dim[n].ubound + 1 - array->dim[n].lbound;

      sstride[n] = array->dim[n].stride * size;

      mstride[n] = mask->dim[n].stride;

    }

  if (sstride[0] == 0)

    sstride[0] = size;

  if (mstride[0] == 0)

    mstride[0] = 1;

  sptr = array->data;

  mptr = mask->data;

  /* Use the same loop for both logical types. */

  if (GFC_DESCRIPTOR_SIZE (mask) != 4)

    {

      if (GFC_DESCRIPTOR_SIZE (mask) != 8)

        runtime_error ("Funny sized logical array");

      for (n = 0; n < dim; n++)

        mstride[n] <<= 1;

      mptr = GFOR_POINTER_L8_TO_L4 (mptr);

    }

  if (ret->data == NULL)

    {

      /* Allocate the memory for the result.  */

      int total;

      if (vector != NULL)

        {

          /* The return array will have as many

             elements as there are in VECTOR.  */

          total = vector->dim[0].ubound + 1 - vector->dim[0].lbound;

        }

      else

        {

          /* We have to count the true elements in MASK.  */

          /* TODO: We could speed up pack easily in the case of only

             few .TRUE. entries in MASK, by keeping track of where we

             would be in the source array during the initial traversal

             of MASK, and caching the pointers to those elements. Then,

             supposed the number of elements is small enough, we would

             only have to traverse the list, and copy those elements

             into the result array. In the case of datatypes which fit

             in one of the integer types we could also cache the

             value instead of a pointer to it.

             This approach might be bad from the point of view of

             cache behavior in the case where our cache is not big

             enough to hold all elements that have to be copied.  */

          const GFC_LOGICAL_4 *m = mptr;

          total = 0;

          while (m)

            {

              /* Test this element.  */

              if (*m)

                total++;

              /* Advance to the next element.  */

              m += mstride[0];

              count[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 this product, but this is a

                     less frequently used path so proabably not worth

                     it.  */

                  m -= mstride[n] * extent[n];

                  n++;

                  if (n >= dim)

                    {

                      /* Break out of the loop.  */

                      m = NULL;

                      break;

                    }

                  else

                    {

                      count[n]++;

                      m += mstride[n];

                    }

                }

            }

        }

      /* Setup the array descriptor.  */

      ret->dim[0].lbound = 0;

      ret->dim[0].ubound = total - 1;

      ret->dim[0].stride = 1;

      ret->data = internal_malloc_size (size * total);

      ret->offset = 0;

      if (total == 0)

        /* In this case, nothing remains to be done.  */

        return;

    }

  rstride0 = ret->dim[0].stride * size;

  if (rstride0 == 0)

    rstride0 = size;

  sstride0 = sstride[0];

  mstride0 = mstride[0];

  rptr = ret->data;

  while (sptr)

    {

      /* Test this element.  */

      if (*mptr)

        {

          /* Add it.  */

          memcpy (rptr, sptr, size);

          rptr += rstride0;

        }

      /* Advance to the next element.  */

      sptr += sstride0;

      mptr += mstride0;

      count[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.  */

          sptr -= sstride[n] * extent[n];

          mptr -= mstride[n] * extent[n];

          n++;

          if (n >= dim)

            {

              /* Break out of the loop.  */

              sptr = NULL;

              break;

            }

          else

            {

              count[n]++;

              sptr += sstride[n];

              mptr += mstride[n];

            }

        }

    }

  /* Add any remaining elements from VECTOR.  */

  if (vector)

    {

      n = vector->dim[0].ubound + 1 - vector->dim[0].lbound;

      nelem = ((rptr - ret->data) / rstride0);

      if (n > nelem)

        {

          sstride0 = vector->dim[0].stride * size;

          if (sstride0 == 0)

            sstride0 = size;

          sptr = vector->data + sstride0 * nelem;

          n -= nelem;

          while (n--)

            {

              memcpy (rptr, sptr, size);

              rptr += rstride0;

              sptr += sstride0;

            }

        }

    }

}

extern void pack (gfc_array_char *, const gfc_array_char *,

                  const gfc_array_l4 *, const gfc_array_char *);

export_proto(pack);

void

pack (gfc_array_char *ret, const gfc_array_char *array,

      const gfc_array_l4 *mask, const gfc_array_char *vector)

{

  pack_internal (ret, array, mask, vector, GFC_DESCRIPTOR_SIZE (array));

}

extern void pack_char (gfc_array_char *, GFC_INTEGER_4, const gfc_array_char *,

                       const gfc_array_l4 *, const gfc_array_char *,

                       GFC_INTEGER_4, GFC_INTEGER_4);

export_proto(pack_char);

void

pack_char (gfc_array_char *ret,

           GFC_INTEGER_4 ret_length __attribute__((unused)),

           const gfc_array_char *array, const gfc_array_l4 *mask,

           const gfc_array_char *vector, GFC_INTEGER_4 array_length,

           GFC_INTEGER_4 vector_length __attribute__((unused)))

{

  pack_internal (ret, array, mask, vector, array_length);

}

static void

pack_s_internal (gfc_array_char *ret, const gfc_array_char *array,

                 const GFC_LOGICAL_4 *mask, const gfc_array_char *vector,

                 index_type size)

{

  /* r.* indicates the return array.  */

  index_type rstride0;

  char *rptr;

  /* s.* indicates the source array.  */

  index_type sstride[GFC_MAX_DIMENSIONS];

  index_type sstride0;

  const char *sptr;

  index_type count[GFC_MAX_DIMENSIONS];

  index_type extent[GFC_MAX_DIMENSIONS];

  index_type n;

  index_type dim;

  index_type nelem;

  dim = GFC_DESCRIPTOR_RANK (array);

  for (n = 0; n < dim; n++)

    {

      count[n] = 0;

      extent[n] = array->dim[n].ubound + 1 - array->dim[n].lbound;

      sstride[n] = array->dim[n].stride * size;

    }

  if (sstride[0] == 0)

    sstride[0] = size;

  sstride0 = sstride[0];

  sptr = array->data;

  if (ret->data == NULL)

    {

      /* Allocate the memory for the result.  */

      int total;

      if (vector != NULL)

        {

          /* The return array will have as many elements as there are

             in vector.  */

          total = vector->dim[0].ubound + 1 - vector->dim[0].lbound;

        }

      else

        {

          if (*mask)

            {

              /* The result array will have as many elements as the input

                 array.  */

              total = extent[0];

              for (n = 1; n < dim; n++)

                total *= extent[n];

            }

          else

            {

              /* The result array will be empty.  */

              ret->dim[0].lbound = 0;

              ret->dim[0].ubound = -1;

              ret->dim[0].stride = 1;

              ret->data = internal_malloc_size (0);

              ret->offset = 0;

              return;

            }

        }

      /* Setup the array descriptor.  */

      ret->dim[0].lbound = 0;

      ret->dim[0].ubound = total - 1;

      ret->dim[0].stride = 1;

      ret->data = internal_malloc_size (size * total);

      ret->offset = 0;

    }

  rstride0 = ret->dim[0].stride * size;

  if (rstride0 == 0)

    rstride0 = size;

  rptr = ret->data;

  /* The remaining possibilities are now:

       If MASK is .TRUE., we have to copy the source array into the

     result array. We then have to fill it up with elements from VECTOR.

       If MASK is .FALSE., we have to copy VECTOR into the result

     array. If VECTOR were not present we would have already returned.  */

  if (*mask)

    {

      while (sptr)

        {

          /* Add this element.  */

          memcpy (rptr, sptr, size);

          rptr += rstride0;

          /* Advance to the next element.  */

          sptr += sstride0;

          count[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.  */

              sptr -= sstride[n] * extent[n];

              n++;

              if (n >= dim)

                {

                  /* Break out of the loop.  */

                  sptr = NULL;

                  break;

                }

              else

                {

                  count[n]++;

                  sptr += sstride[n];

                }

            }

        }

    }

  /* Add any remaining elements from VECTOR.  */

  if (vector)

    {

      n = vector->dim[0].ubound + 1 - vector->dim[0].lbound;

      nelem = ((rptr - ret->data) / rstride0);

      if (n > nelem)

        {

          sstride0 = vector->dim[0].stride * size;

          if (sstride0 == 0)

            sstride0 = size;

          sptr = vector->data + sstride0 * nelem;

          n -= nelem;

          while (n--)

            {

              memcpy (rptr, sptr, size);

              rptr += rstride0;

              sptr += sstride0;

            }

        }

    }

}

extern void pack_s (gfc_array_char *ret, const gfc_array_char *array,

                    const GFC_LOGICAL_4 *, const gfc_array_char *);

export_proto(pack_s);

void

pack_s (gfc_array_char *ret, const gfc_array_char *array,

        const GFC_LOGICAL_4 *mask, const gfc_array_char *vector)

{

  pack_s_internal (ret, array, mask, vector, GFC_DESCRIPTOR_SIZE (array));

}

extern void pack_s_char (gfc_array_char *ret, GFC_INTEGER_4,

                         const gfc_array_char *array, const GFC_LOGICAL_4 *,

                         const gfc_array_char *, GFC_INTEGER_4,

                         GFC_INTEGER_4);

export_proto(pack_s_char);

void

pack_s_char (gfc_array_char *ret,

             GFC_INTEGER_4 ret_length __attribute__((unused)),

             const gfc_array_char *array, const GFC_LOGICAL_4 *mask,

             const gfc_array_char *vector, GFC_INTEGER_4 array_length,

             GFC_INTEGER_4 vector_length __attribute__((unused)))

{

  pack_s_internal (ret, array, mask, vector, array_length);

}