libgfortran/intrinsics/eoshift0.c

   1 /* Generic implementation of the EOSHIFT intrinsic
   2    Copyright 2002, 2005, 2007 Free Software Foundation, Inc.
   3    Contributed by Paul Brook <paul@nowt.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 /* TODO: make this work for large shifts when
  37    sizeof(int) < sizeof (index_type).  */
  38
  39 static void
  40 eoshift0 (gfc_array_char * ret, const gfc_array_char * array,
  41           int shift, const char * pbound, int which, index_type size,
  42           char filler)
  43 {
  44   /* r.* indicates the return array.  */
  45   index_type rstride[GFC_MAX_DIMENSIONS];
  46   index_type rstride0;
  47   index_type roffset;
  48   char *rptr;
  49   char *dest;
  50   /* s.* indicates the source array.  */
  51   index_type sstride[GFC_MAX_DIMENSIONS];
  52   index_type sstride0;
  53   index_type soffset;
  54   const char *sptr;
  55   const char *src;
  56
  57   index_type count[GFC_MAX_DIMENSIONS];
  58   index_type extent[GFC_MAX_DIMENSIONS];
  59   index_type dim;
  60   index_type len;
  61   index_type n;
  62
  63   /* The compiler cannot figure out that these are set, initialize
  64      them to avoid warnings.  */
  65   len = 0;
  66   soffset = 0;
  67   roffset = 0;
  68
  69   if (ret->data == NULL)
  70     {
  71       int i;
  72
  73       ret->data = internal_malloc_size (size * size0 ((array_t *)array));
  74       ret->offset = 0;
  75       ret->dtype = array->dtype;
  76       for (i = 0; i < GFC_DESCRIPTOR_RANK (array); i++)
  77         {
  78           ret->dim[i].lbound = 0;
  79           ret->dim[i].ubound = array->dim[i].ubound - array->dim[i].lbound;
  80
  81           if (i == 0)
  82             ret->dim[i].stride = 1;
  83           else
  84             ret->dim[i].stride = (ret->dim[i-1].ubound + 1) * ret->dim[i-1].stride;
  85         }
  86     }
  87
  88   which = which - 1;
  89
  90   extent[0] = 1;
  91   count[0] = 0;
  92   sstride[0] = -1;
  93   rstride[0] = -1;
  94   n = 0;
  95   for (dim = 0; dim < GFC_DESCRIPTOR_RANK (array); dim++)
  96     {
  97       if (dim == which)
  98         {
  99           roffset = ret->dim[dim].stride * size;
 100           if (roffset == 0)
 101             roffset = size;
 102           soffset = array->dim[dim].stride * size;
 103           if (soffset == 0)
 104             soffset = size;
 105           len = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
 106         }
 107       else
 108         {
 109           count[n] = 0;
 110           extent[n] = array->dim[dim].ubound + 1 - array->dim[dim].lbound;
 111           rstride[n] = ret->dim[dim].stride * size;
 112           sstride[n] = array->dim[dim].stride * size;
 113           n++;
 114         }
 115     }
 116   if (sstride[0] == 0)
 117     sstride[0] = size;
 118   if (rstride[0] == 0)
 119     rstride[0] = size;
 120
 121   dim = GFC_DESCRIPTOR_RANK (array);
 122   rstride0 = rstride[0];
 123   sstride0 = sstride[0];
 124   rptr = ret->data;
 125   sptr = array->data;
 126
 127   if ((shift >= 0 ? shift : -shift) > len)
 128     {
 129       shift = len;
 130       len = 0;
 131     }
 132   else
 133     {
 134       if (shift > 0)
 135         len = len - shift;
 136       else
 137         len = len + shift;
 138     }
 139
 140   while (rptr)
 141     {
 142       /* Do the shift for this dimension.  */
 143       if (shift > 0)
 144         {
 145           src = &sptr[shift * soffset];
 146           dest = rptr;
 147         }
 148       else
 149         {
 150           src = sptr;
 151           dest = &rptr[-shift * roffset];
 152         }
 153       for (n = 0; n < len; n++)
 154         {
 155           memcpy (dest, src, size);
 156           dest += roffset;
 157           src += soffset;
 158         }
 159       if (shift >= 0)
 160         {
 161           n = shift;
 162         }
 163       else
 164         {
 165           dest = rptr;
 166           n = -shift;
 167         }
 168
 169       if (pbound)
 170         while (n--)
 171           {
 172             memcpy (dest, pbound, size);
 173             dest += roffset;
 174           }
 175       else
 176         while (n--)
 177           {
 178             memset (dest, filler, size);
 179             dest += roffset;
 180           }
 181
 182       /* Advance to the next section.  */
 183       rptr += rstride0;
 184       sptr += sstride0;
 185       count[0]++;
 186       n = 0;
 187       while (count[n] == extent[n])
 188         {
 189           /* When we get to the end of a dimension, reset it and increment
 190              the next dimension.  */
 191           count[n] = 0;
 192           /* We could precalculate these products, but this is a less
 193              frequently used path so probably not worth it.  */
 194           rptr -= rstride[n] * extent[n];
 195           sptr -= sstride[n] * extent[n];
 196           n++;
 197           if (n >= dim - 1)
 198             {
 199               /* Break out of the loop.  */
 200               rptr = NULL;
 201               break;
 202             }
 203           else
 204             {
 205               count[n]++;
 206               rptr += rstride[n];
 207               sptr += sstride[n];
 208             }
 209         }
 210     }
 211 }
 212
 213
 214 #define DEFINE_EOSHIFT(N)                                                     \
 215   extern void eoshift0_##N (gfc_array_char *, const gfc_array_char *,         \
 216                             const GFC_INTEGER_##N *, const char *,            \
 217                             const GFC_INTEGER_##N *);                         \
 218   export_proto(eoshift0_##N);                                                 \
 219                                                                               \
 220   void                                                                        \
 221   eoshift0_##N (gfc_array_char *ret, const gfc_array_char *array,             \
 222                 const GFC_INTEGER_##N *pshift, const char *pbound,            \
 223                 const GFC_INTEGER_##N *pdim)                                  \
 224   {                                                                           \
 225     eoshift0 (ret, array, *pshift, pbound, pdim ? *pdim : 1,                  \
 226               GFC_DESCRIPTOR_SIZE (array), 0);                                \
 227   }                                                                           \
 228                                                                               \
 229   extern void eoshift0_##N##_char (gfc_array_char *, GFC_INTEGER_4,           \
 230                                    const gfc_array_char *,                    \
 231                                    const GFC_INTEGER_##N *, const char *,     \
 232                                    const GFC_INTEGER_##N *, GFC_INTEGER_4,    \
 233                                    GFC_INTEGER_4);                            \
 234   export_proto(eoshift0_##N##_char);                                          \
 235                                                                               \
 236   void                                                                        \
 237   eoshift0_##N##_char (gfc_array_char *ret,                                   \
 238                        GFC_INTEGER_4 ret_length __attribute__((unused)),      \
 239                        const gfc_array_char *array,                           \
 240                        const GFC_INTEGER_##N *pshift,                         \
 241                        const char *pbound,                                    \
 242                        const GFC_INTEGER_##N *pdim,                           \
 243                        GFC_INTEGER_4 array_length,                            \
 244                        GFC_INTEGER_4 bound_length __attribute__((unused)))    \
 245   {                                                                           \
 246     eoshift0 (ret, array, *pshift, pbound, pdim ? *pdim : 1,                  \
 247               array_length, ' ');                                             \
 248   }
 249
 250 DEFINE_EOSHIFT (1);
 251 DEFINE_EOSHIFT (2);
 252 DEFINE_EOSHIFT (4);
 253 DEFINE_EOSHIFT (8);