/* Test of fseeko() function.

   Copyright (C) 2007-2018 Free Software Foundation, Inc.

   This program 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.

   This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible <bruno@clisp.org>, 2007.  */

#include <config.h>

/* None of the files accessed by this test are large, so disable the

   fseek link warning if we are not using the gnulib fseek module.  */

#define _GL_NO_LARGE_FILES

#include <stdio.h>

#include "signature.h"

SIGNATURE_CHECK (fseeko, int, (FILE *, off_t, int));

#include "macros.h"

#ifndef FUNC_UNGETC_BROKEN

# define FUNC_UNGETC_BROKEN 0

#endif

int

main (int argc, char **argv _GL_UNUSED)

{

  /* Assume stdin is non-empty, seekable, and starts with '#!/bin/sh'

     iff argc > 1.  */

  int expected = argc > 1 ? 0 : -1;

  /* Exit with success only if fseek/fseeko agree.  */

  int r1 = fseeko (stdin, 0, SEEK_CUR);

  int r2 = fseek (stdin, 0, SEEK_CUR);

  ASSERT (r1 == r2 && r1 == expected);

  if (argc > 1)

    {

      /* Test that fseek discards previously read ungetc data.  */

      int ch = fgetc (stdin);

      ASSERT (ch == '#');

      ASSERT (ungetc (ch, stdin) == ch);

      ASSERT (fseeko (stdin, 2, SEEK_SET) == 0);

      ch = fgetc (stdin);

      ASSERT (ch == '/');

      if (2 < argc)

        {

          if (FUNC_UNGETC_BROKEN)

            {

              fputs ("Skipping test: ungetc cannot handle arbitrary bytes\n",

                     stderr);

              return 77;

            }

          /* Test that fseek discards random ungetc data.  */

          ASSERT (ungetc (ch ^ 0xff, stdin) == (ch ^ 0xff));

        }

      ASSERT (fseeko (stdin, 0, SEEK_END) == 0);

      ASSERT (fgetc (stdin) == EOF);

      /* Test that fseek resets end-of-file marker.  */

      ASSERT (feof (stdin));

      ASSERT (fseeko (stdin, 0, SEEK_END) == 0);

      ASSERT (!feof (stdin));

    }

  return 0;

}