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 (gfc_array_char *, const gfc_array_char *,
  38                     const index_type *, const index_type *);
  39 export_proto(spread);
  40
  41 void
  42 spread (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   index_type rrank;
  50   index_type rs;
  51   char *rptr;
  52   char *dest;
  53   /* s.* indicates the source array.  */
  54   index_type sstride[GFC_MAX_DIMENSIONS - 1];
  55   index_type sstride0;
  56   index_type srank;
  57   const char *sptr;
  58
  59   index_type count[GFC_MAX_DIMENSIONS - 1];
  60   index_type extent[GFC_MAX_DIMENSIONS - 1];
  61   index_type n;
  62   index_type dim;
  63   index_type size;
  64   index_type ncopies;
  65
  66   srank = GFC_DESCRIPTOR_RANK(source);
  67
  68   rrank = srank + 1;
  69   if (rrank > GFC_MAX_DIMENSIONS)
  70     runtime_error ("return rank too large in spread()");
  71
  72   if (*along > rrank)
  73       runtime_error ("dim outside of rank in spread()");
  74
  75   ncopies = *pncopies;
  76
  77   size = GFC_DESCRIPTOR_SIZE (source);
  78   if (ret->data == NULL)
  79     {
  80       /* The front end has signalled that we need to populate the
  81          return array descriptor.  */
  82       ret->dtype = (source->dtype & ~GFC_DTYPE_RANK_MASK) | rrank;
  83       dim = 0;
  84       rs = 1;
  85       for (n = 0; n < rrank; n++)
  86         {
  87           ret->dim[n].stride = rs;
  88           ret->dim[n].lbound = 0;
  89           if (n == *along - 1)
  90             {
  91               ret->dim[n].ubound = ncopies - 1;
  92               rdelta = rs * size;
  93               rs *= ncopies;
  94             }
  95           else
  96             {
  97               count[dim] = 0;
  98               extent[dim] = source->dim[dim].ubound + 1
  99                 - source->dim[dim].lbound;
 100               sstride[dim] = source->dim[dim].stride * size;
 101               rstride[dim] = rs * size;
 102
 103               ret->dim[n].ubound = extent[dim]-1;
 104               rs *= extent[dim];
 105               dim++;
 106             }
 107         }
 108       ret->base = 0;
 109       ret->data = internal_malloc_size (rs * size);
 110     }
 111   else
 112     {
 113       dim = 0;
 114       if (GFC_DESCRIPTOR_RANK(ret) != rrank)
 115         runtime_error ("rank mismatch in spread()");
 116
 117       if (ret->dim[0].stride == 0)
 118         ret->dim[0].stride = 1;
 119
 120       for (n = 0; n < rrank; n++)
 121         {
 122           if (n == *along - 1)
 123             {
 124               rdelta = ret->dim[n].stride * size;
 125             }
 126           else
 127             {
 128               count[dim] = 0;
 129               extent[dim] = source->dim[dim].ubound + 1
 130                 - source->dim[dim].lbound;
 131               sstride[dim] = source->dim[dim].stride * size;
 132               rstride[dim] = ret->dim[n].stride * size;
 133               dim++;
 134             }
 135         }
 136       if (sstride[0] == 0)
 137         sstride[0] = size;
 138     }
 139   sstride0 = sstride[0];
 140   rstride0 = rstride[0];
 141   rptr = ret->data;
 142   sptr = source->data;
 143
 144   while (sptr)
 145     {
 146       /* Spread this element.  */
 147       dest = rptr;
 148       for (n = 0; n < ncopies; n++)
 149         {
 150           memcpy (dest, sptr, size);
 151           dest += rdelta;
 152         }
 153       /* Advance to the next element.  */
 154       sptr += sstride0;
 155       rptr += rstride0;
 156       count[0]++;
 157       n = 0;
 158       while (count[n] == extent[n])
 159         {
 160           /* When we get to the end of a dimension, reset it and increment
 161              the next dimension.  */
 162           count[n] = 0;
 163           /* We could precalculate these products, but this is a less
 164              frequently used path so probably not worth it.  */
 165           sptr -= sstride[n] * extent[n];
 166           rptr -= rstride[n] * extent[n];
 167           n++;
 168           if (n >= srank)
 169             {
 170               /* Break out of the loop.  */
 171               sptr = NULL;
 172               break;
 173             }
 174           else
 175             {
 176               count[n]++;
 177               sptr += sstride[n];
 178               rptr += rstride[n];
 179             }
 180         }
 181     }
 182 }