stdio/test-fseek.c

   1 #include <ansidecl.h>
   2 #include <stdio.h>
   3
   4 #define TESTFILE "test.dat"
   5
   6 int
   7 main __P((void))
   8 {
   9   FILE *fp;
  10   int i, j;
  11
  12   puts ("\nFile seek test");
  13   fp = fopen (TESTFILE, "w");
  14   if (fp == NULL)
  15     {
  16       perror (TESTFILE);
  17       return 1;
  18     }
  19
  20   for (i = 0; i < 256; i++)
  21     putc (i, fp);
  22   if (freopen (TESTFILE, "r", fp) != fp)
  23     {
  24       perror ("Cannot open file for reading");
  25       return 1;
  26     }
  27
  28   for (i = 1; i <= 255; i++)
  29     {
  30       printf ("%3d\n", i);
  31       fseek (fp, (long) -i, SEEK_END);
  32       if ((j = getc (fp)) != 256 - i)
  33         {
  34           printf ("SEEK_END failed %d\n", j);
  35           break;
  36         }
  37       if (fseek (fp, (long) i, SEEK_SET))
  38         {
  39           puts ("Cannot SEEK_SET");
  40           break;
  41         }
  42       if ((j = getc (fp)) != i)
  43         {
  44           printf ("SEEK_SET failed %d\n", j);
  45           break;
  46         }
  47       if (fseek (fp, (long) i, SEEK_SET))
  48         {
  49           puts ("Cannot SEEK_SET");
  50           break;
  51         }
  52       if (fseek (fp, (long) (i >= 128 ? -128 : 128), SEEK_CUR))
  53         {
  54           puts ("Cannot SEEK_CUR");
  55           break;
  56         }
  57       if ((j = getc (fp)) != (i >= 128 ? i - 128 : i + 128))
  58         {
  59           printf ("SEEK_CUR failed %d\n", j);
  60           break;
  61         }
  62     }
  63   fclose (fp);
  64
  65   puts ((i > 255) ? "Test succeeded." : "Test FAILED!");
  66   return (i > 255) ? 0 : 1;
  67 }