libgfortran/intrinsics/spread_generic.c

   1 /* Generic implementation of the SPREAD intrinsic
   2    Copyright 2002 Free Software Foundation, Inc.
   3    Contributed by Paul Brook <paul@nowt.org>
   4
   5 This file is part of the GNU Fortran 95 runtime library (libgfortran).
   6
   7 Libgfortran is free software; you can redistribute it and/or
   8 modify it under the terms of the GNU General Public
   9 License as published by the Free Software Foundation; either
  10 version 2 of the License, or (at your option) any later version.
  11
  12 In addition to the permissions in the GNU General Public License, the
  13 Free Software Foundation gives you unlimited permission to link the
  14 compiled version of this file into combinations with other programs,
  15 and to distribute those combinations without any restriction coming
  16 from the use of this file.  (The General Public License restrictions
  17 do apply in other respects; for example, they cover modification of
  18 the file, and distribution when not linked into a combine
  19 executable.)
  20
  21 Ligbfortran is distributed in the hope that it will be useful,
  22 but WITHOUT ANY WARRANTY; without even the implied warranty of
  23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24 GNU General Public License for more details.
  25
  26 You should have received a copy of the GNU General Public
  27 License along with libgfortran; see the file COPYING.  If not,
  28 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  29 Boston, MA 02111-1307, USA.  */
  30
  31 #include "config.h"
  32 #include <stdlib.h>
  33 #include <assert.h>
  34 #include <string.h>
  35 #include "libgfortran.h"
  36
  37 extern void spread (const gfc_array_char *, const gfc_array_char *,
  38                     const index_type *, const index_type *);
  39 export_proto(spread);
  40
  41 void
  42 spread (const gfc_array_char *ret, const gfc_array_char *source,
  43         const index_type *along, const index_type *pncopies)
  44 {
  45   /* r.* indicates the return array.  */
  46   index_type rstride[GFC_MAX_DIMENSIONS - 1];
  47   index_type rstride0;
  48   index_type rdelta;
  49   char *rptr;
  50   char *dest;
  51   /* s.* indicates the source array.  */
  52   index_type sstride[GFC_MAX_DIMENSIONS - 1];
  53   index_type sstride0;
  54   const char *sptr;
  55
  56   index_type count[GFC_MAX_DIMENSIONS - 1];
  57   index_type extent[GFC_MAX_DIMENSIONS - 1];
  58   index_type n;
  59   index_type dim;
  60   index_type size;
  61   index_type ncopies;
  62
  63   size = GFC_DESCRIPTOR_SIZE (source);
  64   dim = 0;
  65   for (n = 0; n < GFC_DESCRIPTOR_RANK (ret); n++)
  66     {
  67       if (n == *along - 1)
  68         {
  69           rdelta = ret->dim[n].stride * size;
  70         }
  71       else
  72         {
  73           count[dim] = 0;
  74           extent[dim] = source->dim[dim].ubound + 1 - source->dim[dim].lbound;
  75           sstride[dim] = source->dim[dim].stride * size;
  76           rstride[dim] = ret->dim[n].stride * size;
  77           dim++;
  78         }
  79     }
  80   dim = GFC_DESCRIPTOR_RANK (source);
  81   if (sstride[0] == 0)
  82     sstride[0] = size;
  83   if (rstride[0] == 0)
  84     rstride[0] = size;
  85
  86   sstride0 = sstride[0];
  87   rstride0 = rstride[0];
  88   rptr = ret->data;
  89   sptr = source->data;
  90   ncopies = *pncopies;
  91
  92   while (sptr)
  93     {
  94       /* Spread this element.  */
  95       dest = rptr;
  96       for (n = 0; n < ncopies; n++)
  97         {
  98           memcpy (dest, sptr, size);
  99           dest += rdelta;
 100         }
 101       /* Advance to the next element.  */
 102       sptr += sstride0;
 103       rptr += rstride0;
 104       count[0]++;
 105       n = 0;
 106       while (count[n] == extent[n])
 107         {
 108           /* When we get to the end of a dimension, reset it and increment
 109              the next dimension.  */
 110           count[n] = 0;
 111           /* We could precalculate these products, but this is a less
 112              frequently used path so probably not worth it.  */
 113           sptr -= sstride[n] * extent[n];
 114           rptr -= rstride[n] * extent[n];
 115           n++;
 116           if (n >= dim)
 117             {
 118               /* Break out of the loop.  */
 119               sptr = NULL;
 120               break;
 121             }
 122           else
 123             {
 124               count[n]++;
 125               sptr += sstride[n];
 126               rptr += rstride[n];
 127             }
 128         }
 129     }
 130 }