libgfortran/intrinsics/cshift0.c

   1 /* Generic implementation of the CSHIFT intrinsic
   2    Copyright 2003 Free Software Foundation, Inc.
   3    Contributed by Feng Wang <wf_cs@yahoo.com>
   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 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 /* TODO: make this work for large shifts when
  29    sizeof(int) < sizeof (index_type).  */
  30
  31 static void
  32 __cshift0 (gfc_array_char * ret, const gfc_array_char * array,
  33     int shift, int which)
  34 {
  35   /* r.* indicates the return array.  */
  36   index_type rstride[GFC_MAX_DIMENSIONS - 1];
  37   index_type rstride0;
  38   index_type roffset;
  39   char *rptr;
  40   char *dest;
  41   /* s.* indicates the source array.  */
  42   index_type sstride[GFC_MAX_DIMENSIONS - 1];
  43   index_type sstride0;
  44   index_type soffset;
  45   const char *sptr;
  46   const char *src;
  47
  48   index_type count[GFC_MAX_DIMENSIONS - 1];
  49   index_type extent[GFC_MAX_DIMENSIONS - 1];
  50   index_type dim;
  51   index_type size;
  52   index_type len;
  53   index_type n;
  54
  55   if (which < 1 || which > GFC_DESCRIPTOR_RANK (array))
  56     runtime_error ("Argument 'DIM' is out of range in call to 'CSHIFT'");
  57
  58   size = GFC_DESCRIPTOR_SIZE (ret);
  59
  60   which = which - 1;
  61
  62   extent[0] = 1;
  63   count[0] = 0;
  64   size = GFC_DESCRIPTOR_SIZE (array);
  65   n = 0;
  66
  67 /* Initialized for avoiding compiler warnings.  */
  68   roffset = size;
  69   soffset = size;
  70   len = 0;
  71
  72   if (ret->data == NULL)
  73     {
  74       int i;
  75
  76       ret->data = internal_malloc (size * size0 ((array_t *)array));
  77       ret->base = 0;
  78       ret->dtype = array->dtype;
  79       for (i = 0; i < GFC_DESCRIPTOR_RANK (array); i++)
  80         {
  81           ret->dim[i].lbound = 0;
  82           ret->dim[i].ubound = array->dim[i].ubound - array->dim[i].lbound;
  83
  84           if (i == 0)
  85             ret->dim[i].stride = 1;
  86           else
  87             ret->dim[i].stride = (ret->dim[i-1].ubound + 1) * ret->dim[i-1].stride;
  88         }
  89     }
  90
  91   for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
  92     {
  93       if (dim == which)
  94         {
  95           roffset = ret->dim[dim].stride * size;
  96           if (roffset == 0)
  97             roffset = size;
  98           soffset = array->dim[dim].stride * size;
  99           if (soffset == 0)
 100             soffset = size;
 101           len = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
 102         }
 103       else
 104         {
 105           count[n] = 0;
 106           extent[n] = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
 107           rstride[n] = ret->dim[dim].stride * size;
 108           sstride[n] = array->dim[dim].stride * size;
 109           n++;
 110         }
 111     }
 112   if (sstride[0] == 0)
 113     sstride[0] = size;
 114   if (rstride[0] == 0)
 115     rstride[0] = size;
 116
 117   dim = GFC_DESCRIPTOR_RANK (array);
 118   rstride0 = rstride[0];
 119   sstride0 = sstride[0];
 120   rptr = ret->data;
 121   sptr = array->data;
 122
 123   shift = (div (shift, len)).rem;
 124   if (shift < 0)
 125     shift += len;
 126
 127   while (rptr)
 128     {
 129       /* Do the shift for this dimension.  */
 130       src = &sptr[shift * soffset];
 131       dest = rptr;
 132       for (n = 0; n < len; n++)
 133         {
 134           memcpy (dest, src, size);
 135           dest += roffset;
 136           if (n == len - shift - 1)
 137             src = sptr;
 138           else
 139             src += soffset;
 140         }
 141
 142       /* Advance to the next section.  */
 143       rptr += rstride0;
 144       sptr += sstride0;
 145       count[0]++;
 146       n = 0;
 147       while (count[n] == extent[n])
 148         {
 149           /* When we get to the end of a dimension, reset it and increment
 150              the next dimension.  */
 151           count[n] = 0;
 152           /* We could precalculate these products, but this is a less
 153              frequently used path so proabably not worth it.  */
 154           rptr -= rstride[n] * extent[n];
 155           sptr -= sstride[n] * extent[n];
 156           n++;
 157           if (n >= dim - 1)
 158             {
 159               /* Break out of the loop.  */
 160               rptr = NULL;
 161               break;
 162             }
 163           else
 164             {
 165               count[n]++;
 166               rptr += rstride[n];
 167               sptr += sstride[n];
 168             }
 169         }
 170     }
 171 }
 172
 173
 174 void
 175 __cshift0_4 (gfc_array_char * ret, const gfc_array_char * array,
 176     const GFC_INTEGER_4 * pshift, const GFC_INTEGER_4 * pdim)
 177 {
 178   __cshift0 (ret, array, *pshift, pdim ? *pdim : 1);
 179 }
 180
 181
 182 void
 183 __cshift0_8 (gfc_array_char * ret, const gfc_array_char * array,
 184     const GFC_INTEGER_8 * pshift, const GFC_INTEGER_8 * pdim)
 185 {
 186   __cshift0 (ret, array, *pshift, pdim ? *pdim : 1);
 187 }
 188