mes/scaffold/tests/76-pointer-arithmetic.c

/* -*-comment-start: "//";comment-end:""-*-
 * Mes --- Maxwell Equations of Software
 * Copyright © 2017 Jan Nieuwenhuizen <janneke@gnu.org>
 *
 * This file is part of Mes.
 *
 * Mes is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or (at
 * your option) any later version.
 *
 * Mes is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Mes.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "30-test.i"
#include <stdio.h>

char *list[2] = {"foo\n", "bar\n"};

struct foo {
  int a;
  int b;
  int c;
  unsigned char *d;
};

int
test ()
{
  char *pc = 0;
  void *pv = 0;
  int *pi = 0;
  char **ppc = 0;
  void **ppv = 0;
  int **ppi = 0;

  if (++pc != 1) return 1;
  if (++pv != 1) return 2;
  if (++pi != 4) return 3;
  if (++ppc != 4) return 4;
  if (++ppv != 4) return 5;
  if (++ppi != 4) return 6;
  if (pc + 1 != 2) return 7;
  if (pv + 1 != 2) return 8;
  if (pi + 1 != 8) return 9;
  if (ppc + 1 != 8) return 10;
  if (ppv + 1 != 8) return 11;
  if (ppi + 1 != 8) return 12;

  char **p = list;
  ++*p;
  eputs (*p);
  if (strcmp (*p, "oo\n")) return 13;
  --*p;
  eputs (*p);
  if (strcmp (*p, "foo\n")) return 14;

  struct foo* pfoo = 0;
  eputs ("pfoo="); eputs (itoa (pfoo)); eputs ("\n");
  pfoo++;
  eputs ("pfoo="); eputs (itoa (pfoo)); eputs ("\n");
  if (pfoo != 16) return 15;

  pfoo--;
  eputs ("pfoo="); eputs (itoa (pfoo)); eputs ("\n");
  if (pfoo) return 16;

  pfoo++;
  eputs ("pfoo="); eputs (itoa (pfoo)); eputs ("\n");
  if (pfoo != 16) return 17;

  int one = 1;
  int two = 2;
  pfoo = pfoo - one;
  eputs ("pfoo="); eputs (itoa (pfoo)); eputs ("\n");
  if (pfoo) return 18;

  pfoo = pfoo + one;
  eputs ("pfoo="); eputs (itoa (pfoo)); eputs ("\n");
  if (pfoo != 16) return 19;

  pfoo -= one;
  eputs ("pfoo="); eputs (itoa (pfoo)); eputs ("\n");
  if (pfoo) return 20;

  pfoo += one;
  eputs ("pfoo="); eputs (itoa (pfoo)); eputs ("\n");
  if (pfoo != 16) return 21;

  if (&one - 1 != &two) return 22;

  struct foo* sym = 32;
  int d = 16;
  int i = sym + 16;
  eputs ("i="); eputs (itoa (i)); eputs ("\n");
  if (i != 288) return 23;

  i = sym + d;
  eputs ("i="); eputs (itoa (i)); eputs ("\n");
  if (i != 288) return 24;

  i = sym - 16;
  eputs ("i="); eputs (itoa (i)); eputs ("\n");
  if (i != -224) return 25;

  i = sym - d;
  eputs ("i="); eputs (itoa (i)); eputs ("\n");
  if (i != -224) return 26;

  i = sym - (struct foo*)d;
  eputs ("i="); eputs (itoa (i)); eputs ("\n");
  if (i != 1) return 27;

  pfoo = sym + 1;
  pfoo -= sym;
  eputs ("pfoo="); eputs (itoa (pfoo)); eputs ("\n");
  if (pfoo != 1) return 28;

  return 0;
}