libgfortran/m4/cshift1.m4

   1 `/* 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 include(iparm.m4)dnl
  28
  29 void cshift1_`'atype_kind (const gfc_array_char * ret,
  30                            const gfc_array_char * array,
  31                            const atype * h, const atype_name * pwhich);
  32 export_proto(cshift1_`'atype_kind);
  33
  34 void
  35 cshift1_`'atype_kind (const gfc_array_char * ret,
  36                       const gfc_array_char * array,
  37                       const atype * h, const atype_name * pwhich)
  38 {
  39   /* r.* indicates the return array.  */
  40   index_type rstride[GFC_MAX_DIMENSIONS - 1];
  41   index_type rstride0;
  42   index_type roffset;
  43   char *rptr;
  44   char *dest;
  45   /* s.* indicates the source array.  */
  46   index_type sstride[GFC_MAX_DIMENSIONS - 1];
  47   index_type sstride0;
  48   index_type soffset;
  49   const char *sptr;
  50   const char *src;
  51   /* h.* indicates the shift array.  */
  52   index_type hstride[GFC_MAX_DIMENSIONS - 1];
  53   index_type hstride0;
  54   const atype_name *hptr;
  55
  56   index_type count[GFC_MAX_DIMENSIONS - 1];
  57   index_type extent[GFC_MAX_DIMENSIONS - 1];
  58   index_type dim;
  59   index_type size;
  60   index_type len;
  61   index_type n;
  62   int which;
  63   atype_name sh;
  64
  65   if (pwhich)
  66     which = *pwhich - 1;
  67   else
  68     which = 0;
  69
  70   if (which < 0 || (which + 1) > GFC_DESCRIPTOR_RANK (array))
  71     runtime_error ("Argument 'DIM' is out of range in call to 'CSHIFT'");
  72
  73   size = GFC_DESCRIPTOR_SIZE (ret);
  74
  75   extent[0] = 1;
  76   count[0] = 0;
  77   size = GFC_DESCRIPTOR_SIZE (array);
  78   n = 0;
  79
  80   /* Initialized for avoiding compiler warnings.  */
  81   roffset = size;
  82   soffset = size;
  83   len = 0;
  84
  85   for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
  86     {
  87       if (dim == which)
  88         {
  89           roffset = ret->dim[dim].stride * size;
  90           if (roffset == 0)
  91             roffset = size;
  92           soffset = array->dim[dim].stride * size;
  93           if (soffset == 0)
  94             soffset = size;
  95           len = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
  96         }
  97       else
  98         {
  99           count[n] = 0;
 100           extent[n] = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
 101           rstride[n] = ret->dim[dim].stride * size;
 102           sstride[n] = array->dim[dim].stride * size;
 103
 104           hstride[n] = h->dim[n].stride;
 105           n++;
 106         }
 107     }
 108   if (sstride[0] == 0)
 109     sstride[0] = size;
 110   if (rstride[0] == 0)
 111     rstride[0] = size;
 112   if (hstride[0] == 0)
 113     hstride[0] = 1;
 114
 115   dim = GFC_DESCRIPTOR_RANK (array);
 116   rstride0 = rstride[0];
 117   sstride0 = sstride[0];
 118   hstride0 = hstride[0];
 119   rptr = ret->data;
 120   sptr = array->data;
 121   hptr = h->data;
 122
 123   while (rptr)
 124     {
 125       /* Do the shift for this dimension.  */
 126       sh = *hptr;
 127       sh = (div (sh, len)).rem;
 128       if (sh < 0)
 129         sh += len;
 130
 131       src = &sptr[sh * soffset];
 132       dest = rptr;
 133
 134       for (n = 0; n < len; n++)
 135         {
 136           memcpy (dest, src, size);
 137           dest += roffset;
 138           if (n == len - sh - 1)
 139             src = sptr;
 140           else
 141             src += soffset;
 142         }
 143
 144       /* Advance to the next section.  */
 145       rptr += rstride0;
 146       sptr += sstride0;
 147       hptr += hstride0;
 148       count[0]++;
 149       n = 0;
 150       while (count[n] == extent[n])
 151         {
 152           /* When we get to the end of a dimension, reset it and increment
 153              the next dimension.  */
 154           count[n] = 0;
 155           /* We could precalculate these products, but this is a less
 156              frequently used path so proabably not worth it.  */
 157           rptr -= rstride[n] * extent[n];
 158           sptr -= sstride[n] * extent[n];
 159           hptr -= hstride[n] * extent[n];
 160           n++;
 161           if (n >= dim - 1)
 162             {
 163               /* Break out of the loop.  */
 164               rptr = NULL;
 165               break;
 166             }
 167           else
 168             {
 169               count[n]++;
 170               rptr += rstride[n];
 171               sptr += sstride[n];
 172               hptr += hstride[n];
 173             }
 174         }
 175     }
 176 }