libgfortran/generated/cshift0_r8.c

   1 /* Helper function for cshift functions.
   2    Copyright 2008, 2009 Free Software Foundation, Inc.
   3    Contributed by Thomas Koenig <tkoenig@gcc.gnu.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 3 of the License, or (at your option) any later version.
  11
  12 Libgfortran 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 General Public License for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26 #include "libgfortran.h"
  27 #include <stdlib.h>
  28 #include <assert.h>
  29 #include <string.h>
  30
  31
  32 #if defined (HAVE_GFC_REAL_8)
  33
  34 void
  35 cshift0_r8 (gfc_array_r8 *ret, const gfc_array_r8 *array, ssize_t shift,
  36                      int which)
  37 {
  38   /* r.* indicates the return array.  */
  39   index_type rstride[GFC_MAX_DIMENSIONS];
  40   index_type rstride0;
  41   index_type roffset;
  42   GFC_REAL_8 *rptr;
  43
  44   /* s.* indicates the source array.  */
  45   index_type sstride[GFC_MAX_DIMENSIONS];
  46   index_type sstride0;
  47   index_type soffset;
  48   const GFC_REAL_8 *sptr;
  49
  50   index_type count[GFC_MAX_DIMENSIONS];
  51   index_type extent[GFC_MAX_DIMENSIONS];
  52   index_type dim;
  53   index_type len;
  54   index_type n;
  55
  56   which = which - 1;
  57   sstride[0] = 0;
  58   rstride[0] = 0;
  59
  60   extent[0] = 1;
  61   count[0] = 0;
  62   n = 0;
  63   /* Initialized for avoiding compiler warnings.  */
  64   roffset = 1;
  65   soffset = 1;
  66   len = 0;
  67
  68   for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
  69     {
  70       if (dim == which)
  71         {
  72           roffset = GFC_DESCRIPTOR_STRIDE(ret,dim);
  73           if (roffset == 0)
  74             roffset = 1;
  75           soffset = GFC_DESCRIPTOR_STRIDE(array,dim);
  76           if (soffset == 0)
  77             soffset = 1;
  78           len = GFC_DESCRIPTOR_EXTENT(array,dim);
  79         }
  80       else
  81         {
  82           count[n] = 0;
  83           extent[n] = GFC_DESCRIPTOR_EXTENT(array,dim);
  84           rstride[n] = GFC_DESCRIPTOR_STRIDE(ret,dim);
  85           sstride[n] = GFC_DESCRIPTOR_STRIDE(array,dim);
  86           n++;
  87         }
  88     }
  89   if (sstride[0] == 0)
  90     sstride[0] = 1;
  91   if (rstride[0] == 0)
  92     rstride[0] = 1;
  93
  94   dim = GFC_DESCRIPTOR_RANK (array);
  95   rstride0 = rstride[0];
  96   sstride0 = sstride[0];
  97   rptr = ret->data;
  98   sptr = array->data;
  99
 100   shift = len == 0 ? 0 : shift % (ssize_t)len;
 101   if (shift < 0)
 102     shift += len;
 103
 104   while (rptr)
 105     {
 106       /* Do the shift for this dimension.  */
 107
 108       /* If elements are contiguous, perform the operation
 109          in two block moves.  */
 110       if (soffset == 1 && roffset == 1)
 111         {
 112           size_t len1 = shift * sizeof (GFC_REAL_8);
 113           size_t len2 = (len - shift) * sizeof (GFC_REAL_8);
 114           memcpy (rptr, sptr + shift, len2);
 115           memcpy (rptr + (len - shift), sptr, len1);
 116         }
 117       else
 118         {
 119           /* Otherwise, we will have to perform the copy one element at
 120              a time.  */
 121           GFC_REAL_8 *dest = rptr;
 122           const GFC_REAL_8 *src = &sptr[shift * soffset];
 123
 124           for (n = 0; n < len - shift; n++)
 125             {
 126               *dest = *src;
 127               dest += roffset;
 128               src += soffset;
 129             }
 130           for (src = sptr, n = 0; n < shift; n++)
 131             {
 132               *dest = *src;
 133               dest += roffset;
 134               src += soffset;
 135             }
 136         }
 137
 138       /* Advance to the next section.  */
 139       rptr += rstride0;
 140       sptr += sstride0;
 141       count[0]++;
 142       n = 0;
 143       while (count[n] == extent[n])
 144         {
 145           /* When we get to the end of a dimension, reset it and increment
 146              the next dimension.  */
 147           count[n] = 0;
 148           /* We could precalculate these products, but this is a less
 149              frequently used path so probably not worth it.  */
 150           rptr -= rstride[n] * extent[n];
 151           sptr -= sstride[n] * extent[n];
 152           n++;
 153           if (n >= dim - 1)
 154             {
 155               /* Break out of the loop.  */
 156               rptr = NULL;
 157               break;
 158             }
 159           else
 160             {
 161               count[n]++;
 162               rptr += rstride[n];
 163               sptr += sstride[n];
 164             }
 165         }
 166     }
 167
 168   return;
 169 }
 170
 171 #endif