/* Verify that ftell returns the correct value after a read and a write on a

   file opened in a+ mode.

   Copyright (C) 2014-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <unistd.h>

#include <locale.h>

#include <wchar.h>

/* data points to either char_data or wide_data, depending on whether we're

   testing regular file mode or wide mode respectively.  Similarly,

   fputs_func points to either fputs or fputws.  data_len keeps track of the

   length of the current data and file_len maintains the current file

   length.  */

#define BUF_LEN 4

static void *buf;

static char char_buf[BUF_LEN];

static wchar_t wide_buf[BUF_LEN];

static const void *data;

static const char *char_data = "abcdefghijklmnopqrstuvwxyz";

static const wchar_t *wide_data = L"abcdefghijklmnopqrstuvwxyz";

static size_t data_len;

static size_t file_len;

typedef int (*fputs_func_t) (const void *data, FILE *fp);

fputs_func_t fputs_func;

typedef void *(*fgets_func_t) (void *s, int size, FILE *stream);

fgets_func_t fgets_func;

static int do_test (void);

#define TEST_FUNCTION do_test ()

#include "../test-skeleton.c"

static FILE *

init_file (const char *filename)

{

  FILE *fp = fopen (filename, "w");

  if (fp == NULL)

    {

      printf ("fopen: %m\n");

      return NULL;

    }

  int written = fputs_func (data, fp);

  if (written == EOF)

    {

      printf ("fputs failed to write data\n");

      fclose (fp);

      return NULL;

    }

  file_len = data_len;

  fclose (fp);

  fp = fopen (filename, "a+");

  if (fp == NULL)

    {

      printf ("fopen(a+): %m\n");

      return NULL;

    }

  return fp;

}

static int

do_one_test (const char *filename)

{

  FILE *fp = init_file (filename);

  if (fp == NULL)

    return 1;

  void *ret = fgets_func (buf, BUF_LEN, fp);

  if (ret == NULL)

    {

      printf ("read failed: %m\n");

      fclose (fp);

      return 1;

    }

  int written = fputs_func (data, fp);

  if (written == EOF)

    {

      printf ("fputs failed to write data\n");

      fclose (fp);

      return 1;

    }

  file_len += data_len;

  long off = ftell (fp);

  if (off != file_len)

    {

      printf ("Incorrect offset %ld, expected %zu\n", off, file_len);

      fclose (fp);

      return 1;

    }

  else

    printf ("Correct offset %ld after write.\n", off);

  return 0;

}

/* Run the tests for regular files and wide mode files.  */

static int

do_test (void)

{

  int ret = 0;

  char *filename;

  int fd = create_temp_file ("tst-ftell-append-tmp.", &filename);

  if (fd == -1)

    {

      printf ("create_temp_file: %m\n");

      return 1;

    }

  close (fd);

  /* Tests for regular files.  */

  puts ("Regular mode:");

  fputs_func = (fputs_func_t) fputs;

  fgets_func = (fgets_func_t) fgets;

  data = char_data;

  buf = char_buf;

  data_len = strlen (char_data);

  ret |= do_one_test (filename);

  /* Tests for wide files.  */

  puts ("Wide mode:");

  if (setlocale (LC_ALL, "en_US.UTF-8") == NULL)

    {

      printf ("Cannot set en_US.UTF-8 locale.\n");

      return 1;

    }

  fputs_func = (fputs_func_t) fputws;

  fgets_func = (fgets_func_t) fgetws;

  data = wide_data;

  buf = wide_buf;

  data_len = wcslen (wide_data);

  ret |= do_one_test (filename);

  return ret;

}