libgfortran/m4/cshift0.m4

   1 `/* Helper function for cshift functions.
   2    Copyright (C) 2008-2016 Free Software Foundation, Inc.
   3    Contributed by Thomas Koenig <tkoenig@gcc.gnu.org>
   4
   5 This file is part of the GNU Fortran 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 include(iparm.m4)dnl
  32
  33 `#if defined (HAVE_'rtype_name`)
  34
  35 void
  36 cshift0_'rtype_code` ('rtype` *ret, const 'rtype` *array, ptrdiff_t shift,
  37                      int which)
  38 {
  39   /* r.* indicates the return array.  */
  40   index_type rstride[GFC_MAX_DIMENSIONS];
  41   index_type rstride0;
  42   index_type roffset;
  43   'rtype_name` *rptr;
  44
  45   /* s.* indicates the source array.  */
  46   index_type sstride[GFC_MAX_DIMENSIONS];
  47   index_type sstride0;
  48   index_type soffset;
  49   const 'rtype_name` *sptr;
  50
  51   index_type count[GFC_MAX_DIMENSIONS];
  52   index_type extent[GFC_MAX_DIMENSIONS];
  53   index_type dim;
  54   index_type len;
  55   index_type n;
  56
  57   which = which - 1;
  58   sstride[0] = 0;
  59   rstride[0] = 0;
  60
  61   extent[0] = 1;
  62   count[0] = 0;
  63   n = 0;
  64   /* Initialized for avoiding compiler warnings.  */
  65   roffset = 1;
  66   soffset = 1;
  67   len = 0;
  68
  69   for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
  70     {
  71       if (dim == which)
  72         {
  73           roffset = GFC_DESCRIPTOR_STRIDE(ret,dim);
  74           if (roffset == 0)
  75             roffset = 1;
  76           soffset = GFC_DESCRIPTOR_STRIDE(array,dim);
  77           if (soffset == 0)
  78             soffset = 1;
  79           len = GFC_DESCRIPTOR_EXTENT(array,dim);
  80         }
  81       else
  82         {
  83           count[n] = 0;
  84           extent[n] = GFC_DESCRIPTOR_EXTENT(array,dim);
  85           rstride[n] = GFC_DESCRIPTOR_STRIDE(ret,dim);
  86           sstride[n] = GFC_DESCRIPTOR_STRIDE(array,dim);
  87           n++;
  88         }
  89     }
  90   if (sstride[0] == 0)
  91     sstride[0] = 1;
  92   if (rstride[0] == 0)
  93     rstride[0] = 1;
  94
  95   dim = GFC_DESCRIPTOR_RANK (array);
  96   rstride0 = rstride[0];
  97   sstride0 = sstride[0];
  98   rptr = ret->base_addr;
  99   sptr = array->base_addr;
 100
 101   /* Avoid the costly modulo for trivially in-bound shifts.  */
 102   if (shift < 0 || shift >= len)
 103     {
 104       shift = len == 0 ? 0 : shift % (ptrdiff_t)len;
 105       if (shift < 0)
 106         shift += len;
 107     }
 108
 109   while (rptr)
 110     {
 111       /* Do the shift for this dimension.  */
 112
 113       /* If elements are contiguous, perform the operation
 114          in two block moves.  */
 115       if (soffset == 1 && roffset == 1)
 116         {
 117           size_t len1 = shift * sizeof ('rtype_name`);
 118           size_t len2 = (len - shift) * sizeof ('rtype_name`);
 119           memcpy (rptr, sptr + shift, len2);
 120           memcpy (rptr + (len - shift), sptr, len1);
 121         }
 122       else
 123         {
 124           /* Otherwise, we will have to perform the copy one element at
 125              a time.  */
 126           'rtype_name` *dest = rptr;
 127           const 'rtype_name` *src = &sptr[shift * soffset];
 128
 129           for (n = 0; n < len - shift; n++)
 130             {
 131               *dest = *src;
 132               dest += roffset;
 133               src += soffset;
 134             }
 135           for (src = sptr, n = 0; n < shift; n++)
 136             {
 137               *dest = *src;
 138               dest += roffset;
 139               src += soffset;
 140             }
 141         }
 142
 143       /* Advance to the next section.  */
 144       rptr += rstride0;
 145       sptr += sstride0;
 146       count[0]++;
 147       n = 0;
 148       while (count[n] == extent[n])
 149         {
 150           /* When we get to the end of a dimension, reset it and increment
 151              the next dimension.  */
 152           count[n] = 0;
 153           /* We could precalculate these products, but this is a less
 154              frequently used path so probably not worth it.  */
 155           rptr -= rstride[n] * extent[n];
 156           sptr -= sstride[n] * extent[n];
 157           n++;
 158           if (n >= dim - 1)
 159             {
 160               /* Break out of the loop.  */
 161               rptr = NULL;
 162               break;
 163             }
 164           else
 165             {
 166               count[n]++;
 167               rptr += rstride[n];
 168               sptr += sstride[n];
 169             }
 170         }
 171     }
 172
 173   return;
 174 }
 175
 176 #endif'