string/testcopy.c

   1 /* Copyright (C) 1990-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <stdlib.h>
  19 #include <stdio.h>
  20 #include <string.h>
  21 #include <support/support.h>
  22
  23 static int
  24 do_test (void)
  25 {
  26   char *mem, *memp;
  27   char *rand_mem;
  28   char *lo_around, *hi_around;
  29   int size, max_size;
  30   int src_off, dst_off;
  31   int i;
  32   int space_around = 10;
  33
  34   max_size = 256;
  35
  36   mem = xmalloc (max_size + 2 * max_size + 2 * space_around);
  37   rand_mem = xmalloc (max_size);
  38   lo_around = xmalloc (space_around);
  39   hi_around = xmalloc (space_around);
  40   memp = mem + space_around;
  41
  42   /* Fill RAND_MEM with random bytes, each non-zero.  */
  43   for (i = 0; i < max_size; i++)
  44     {
  45       int x;
  46       do
  47         x = random ();
  48       while (x == 0);
  49       rand_mem[i] = x;
  50     }
  51
  52   for (size = 0; size < max_size; size++)
  53     {
  54       printf("phase %d\n", size);
  55       for (src_off = 0; src_off <= 16; src_off++)
  56         {
  57           for (dst_off = 0; dst_off <= 16; dst_off++)
  58             {
  59               /* Put zero around the intended destination, to check
  60                  that it's not clobbered.  */
  61               for (i = 1; i < space_around; i++)
  62                 {
  63                   memp[dst_off - i] = 0;
  64                   memp[dst_off + size - 1 + i] = 0;
  65                 }
  66
  67               /* Fill the source area with known contents.  */
  68               for (i = 0; i < size; i++)
  69                 memp[src_off + i] = rand_mem[i];
  70
  71               /* Remember the contents around the destination area.
  72                  (It might not be what we wrote some lines above, since
  73                  the src area and the dst area overlap.)  */
  74               for (i = 1; i < space_around; i++)
  75                 {
  76                   lo_around[i] = memp[dst_off - i];
  77                   hi_around[i] = memp[dst_off + size - 1 + i];
  78                 }
  79
  80               memmove (memp + dst_off, memp + src_off, size);
  81
  82               /* Check that the destination area has the same
  83                  contents we wrote to the source area.  */
  84               for (i = 0; i < size; i++)
  85                 {
  86                   if (memp[dst_off + i] != rand_mem[i])
  87                     abort ();
  88                 }
  89
  90               /* Check that the area around the destination is not
  91                  clobbered.  */
  92               for (i = 1; i < space_around; i++)
  93                 {
  94                   if (memp[dst_off - i] != lo_around[i])
  95                     abort ();
  96                   if (memp[dst_off + size - 1 + i] != hi_around[i])
  97                     abort ();
  98                 }
  99             }
 100         }
 101     }
 102
 103   puts ("Test succeeded.");
 104
 105   return 0;
 106 }
 107
 108 #include <support/test-driver.c>