libgfortran/generated/cshift0_i16.c

   1 /* Helper function for cshift functions.
   2    Copyright 2008 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 2 of the License, or (at your option) any later version.
  11
  12 In addition to the permissions in the GNU General Public License, the
  13 Free Software Foundation gives you unlimited permission to link the
  14 compiled version of this file into combinations with other programs,
  15 and to distribute those combinations without any restriction coming
  16 from the use of this file.  (The General Public License restrictions
  17 do apply in other respects; for example, they cover modification of
  18 the file, and distribution when not linked into a combine
  19 executable.)
  20
  21 Libgfortran is distributed in the hope that it will be useful,
  22 but WITHOUT ANY WARRANTY; without even the implied warranty of
  23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24 GNU General Public License for more details.
  25
  26 You should have received a copy of the GNU General Public
  27 License along with libgfortran; see the file COPYING.  If not,
  28 write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  29 Boston, MA 02110-1301, USA.  */
  30
  31 #include "libgfortran.h"
  32 #include <stdlib.h>
  33 #include <assert.h>
  34 #include <string.h>
  35
  36
  37 #if defined (HAVE_GFC_INTEGER_16)
  38
  39 void
  40 cshift0_i16 (gfc_array_i16 *ret, const gfc_array_i16 *array, ssize_t shift,
  41                      int which)
  42 {
  43   /* r.* indicates the return array.  */
  44   index_type rstride[GFC_MAX_DIMENSIONS];
  45   index_type rstride0;
  46   index_type roffset;
  47   GFC_INTEGER_16 *rptr;
  48
  49   /* s.* indicates the source array.  */
  50   index_type sstride[GFC_MAX_DIMENSIONS];
  51   index_type sstride0;
  52   index_type soffset;
  53   const GFC_INTEGER_16 *sptr;
  54
  55   index_type count[GFC_MAX_DIMENSIONS];
  56   index_type extent[GFC_MAX_DIMENSIONS];
  57   index_type dim;
  58   index_type len;
  59   index_type n;
  60
  61   which = which - 1;
  62   sstride[0] = 0;
  63   rstride[0] = 0;
  64
  65   extent[0] = 1;
  66   count[0] = 0;
  67   n = 0;
  68   /* Initialized for avoiding compiler warnings.  */
  69   roffset = 1;
  70   soffset = 1;
  71   len = 0;
  72
  73   for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
  74     {
  75       if (dim == which)
  76         {
  77           roffset = ret->dim[dim].stride;
  78           if (roffset == 0)
  79             roffset = 1;
  80           soffset = array->dim[dim].stride;
  81           if (soffset == 0)
  82             soffset = 1;
  83           len = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
  84         }
  85       else
  86         {
  87           count[n] = 0;
  88           extent[n] = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
  89           rstride[n] = ret->dim[dim].stride;
  90           sstride[n] = array->dim[dim].stride;
  91           n++;
  92         }
  93     }
  94   if (sstride[0] == 0)
  95     sstride[0] = 1;
  96   if (rstride[0] == 0)
  97     rstride[0] = 1;
  98
  99   dim = GFC_DESCRIPTOR_RANK (array);
 100   rstride0 = rstride[0];
 101   sstride0 = sstride[0];
 102   rptr = ret->data;
 103   sptr = array->data;
 104
 105   shift = len == 0 ? 0 : shift % (ssize_t)len;
 106   if (shift < 0)
 107     shift += len;
 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 (GFC_INTEGER_16);
 118           size_t len2 = (len - shift) * sizeof (GFC_INTEGER_16);
 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           GFC_INTEGER_16 *dest = rptr;
 127           const GFC_INTEGER_16 *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