libgfortran/intrinsics/eoshift2.c

   1 /* Generic implementation of the EOSHIFT 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 (libgfor).
   6
   7 Libgfor is free software; you can redistribute it and/or
   8 modify it under the terms of the GNU Lesser General Public
   9 License as published by the Free Software Foundation; either
  10 version 2.1 of the License, or (at your option) any later version.
  11
  12 Ligbfor is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU Lesser General Public License for more details.
  16
  17 You should have received a copy of the GNU Lesser General Public
  18 License along with libgfor; see the file COPYING.LIB.  If not,
  19 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include <stdlib.h>
  24 #include <assert.h>
  25 #include <string.h>
  26 #include "libgfortran.h"
  27
  28 static const char zeros[16] =
  29   {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
  30
  31 /* TODO: make this work for large shifts when
  32    sizeof(int) < sizeof (index_type).  */
  33
  34 static void
  35 __eoshift2 (gfc_array_char * ret, const gfc_array_char * array,
  36     int shift, const gfc_array_char * bound, int which)
  37 {
  38   /* r.* indicates the return array.  */
  39   index_type rstride[GFC_MAX_DIMENSIONS - 1];
  40   index_type rstride0;
  41   index_type roffset;
  42   char *rptr;
  43   char *dest;
  44   /* s.* indicates the source array.  */
  45   index_type sstride[GFC_MAX_DIMENSIONS - 1];
  46   index_type sstride0;
  47   index_type soffset;
  48   const char *sptr;
  49   const char *src;
  50   /* b.* indicates the bound array.  */
  51   index_type bstride[GFC_MAX_DIMENSIONS - 1];
  52   index_type bstride0;
  53   const char *bptr;
  54
  55   index_type count[GFC_MAX_DIMENSIONS - 1];
  56   index_type extent[GFC_MAX_DIMENSIONS - 1];
  57   index_type dim;
  58   index_type size;
  59   index_type len;
  60   index_type n;
  61
  62   size = GFC_DESCRIPTOR_SIZE (ret);
  63
  64   if (ret->data == NULL)
  65     {
  66       int i;
  67
  68       ret->data = internal_malloc (size * size0 ((array_t *)array));
  69       ret->base = 0;
  70       ret->dtype = array->dtype;
  71       for (i = 0; i < GFC_DESCRIPTOR_RANK (array); i++)
  72         {
  73           ret->dim[i].lbound = 0;
  74           ret->dim[i].ubound = array->dim[i].ubound - array->dim[i].lbound;
  75
  76           if (i == 0)
  77             ret->dim[i].stride = 1;
  78           else
  79             ret->dim[i].stride = (ret->dim[i-1].ubound + 1) * ret->dim[i-1].stride;
  80         }
  81     }
  82
  83   which = which - 1;
  84
  85   extent[0] = 1;
  86   count[0] = 0;
  87   size = GFC_DESCRIPTOR_SIZE (array);
  88   n = 0;
  89   for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
  90     {
  91       if (dim == which)
  92         {
  93           roffset = ret->dim[dim].stride * size;
  94           if (roffset == 0)
  95             roffset = size;
  96           soffset = array->dim[dim].stride * size;
  97           if (soffset == 0)
  98             soffset = size;
  99           len = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
 100         }
 101       else
 102         {
 103           count[n] = 0;
 104           extent[n] = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
 105           rstride[n] = ret->dim[dim].stride * size;
 106           sstride[n] = array->dim[dim].stride * size;
 107           if (bound)
 108             bstride[n] = bound->dim[n].stride * size;
 109           else
 110             bstride[n] = 0;
 111           n++;
 112         }
 113     }
 114   if (sstride[0] == 0)
 115     sstride[0] = size;
 116   if (rstride[0] == 0)
 117     rstride[0] = size;
 118   if (bound && bstride[0] == 0)
 119     bstride[0] = size;
 120
 121   dim = GFC_DESCRIPTOR_RANK (array);
 122   rstride0 = rstride[0];
 123   sstride0 = sstride[0];
 124   bstride0 = bstride[0];
 125   rptr = ret->data;
 126   sptr = array->data;
 127   if (bound)
 128     bptr = bound->data;
 129   else
 130     bptr = zeros;
 131
 132   if (shift > 0)
 133     len = len - shift;
 134   else
 135     len = len + shift;
 136
 137   while (rptr)
 138     {
 139       /* Do the shift for this dimension.  */
 140       if (shift > 0)
 141         {
 142           src = &sptr[shift * soffset];
 143           dest = rptr;
 144         }
 145       else
 146         {
 147           src = sptr;
 148           dest = &rptr[-shift * roffset];
 149         }
 150       for (n = 0; n < len; n++)
 151         {
 152           memcpy (dest, src, size);
 153           dest += roffset;
 154           src += soffset;
 155         }
 156       if (shift >= 0)
 157         {
 158           n = shift;
 159         }
 160       else
 161         {
 162           dest = rptr;
 163           n = -shift;
 164         }
 165
 166       while (n--)
 167         {
 168           memcpy (dest, bptr, size);
 169           dest += roffset;
 170         }
 171
 172       /* Advance to the next section.  */
 173       rptr += rstride0;
 174       sptr += sstride0;
 175       bptr += bstride0;
 176       count[0]++;
 177       n = 0;
 178       while (count[n] == extent[n])
 179         {
 180           /* When we get to the end of a dimension, reset it and increment
 181              the next dimension.  */
 182           count[n] = 0;
 183           /* We could precalculate these products, but this is a less
 184              frequently used path so proabably not worth it.  */
 185           rptr -= rstride[n] * extent[n];
 186           sptr -= sstride[n] * extent[n];
 187           bptr -= bstride[n] * extent[n];
 188           n++;
 189           if (n >= dim - 1)
 190             {
 191               /* Break out of the loop.  */
 192               rptr = NULL;
 193               break;
 194             }
 195           else
 196             {
 197               count[n]++;
 198               rptr += rstride[n];
 199               sptr += sstride[n];
 200               bptr += bstride[n];
 201             }
 202         }
 203     }
 204 }
 205
 206
 207 void
 208 __eoshift2_4 (gfc_array_char * ret, const gfc_array_char * array,
 209     const GFC_INTEGER_4 * pshift, const gfc_array_char * bound,
 210     const GFC_INTEGER_4 * pdim)
 211 {
 212   __eoshift2 (ret, array, *pshift, bound, pdim ? *pdim : 1);
 213 }
 214
 215
 216 void
 217 __eoshift2_8 (gfc_array_char * ret, const gfc_array_char * array,
 218     const GFC_INTEGER_8 * pshift, const gfc_array_char * bound,
 219     const GFC_INTEGER_8 * pdim)
 220 {
 221   __eoshift2 (ret, array, *pshift, bound, pdim ? *pdim : 1);
 222 }
 223