/* safe-fgets.c --- like fgets, but allocates its own static buffer.

Copyright (C) 2005-2020 Free Software Foundation, Inc.
Contributed by Red Hat, Inc.

This file is part of the GNU simulators.

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


#include <stdio.h>
#include <stdlib.h>

#include "safe-fgets.h"

static char *line_buf = 0;
static int line_buf_size = 0;

#define LBUFINCR 100

char *
safe_fgets (FILE * f)
{
  char *line_ptr;

  if (line_buf == 0)
    {
      line_buf = (char *) malloc (LBUFINCR);
      line_buf_size = LBUFINCR;
    }

  /* points to last byte */
  line_ptr = line_buf + line_buf_size - 1;

  /* so we can see if fgets put a 0 there */
  *line_ptr = 1;
  if (fgets (line_buf, line_buf_size, f) == 0)
    return 0;

  /* we filled the buffer? */
  while (line_ptr[0] == 0 && line_ptr[-1] != '\n')
    {
      /* Make the buffer bigger and read more of the line */
      line_buf_size += LBUFINCR;
      line_buf = (char *) realloc (line_buf, line_buf_size);

      /* points to last byte again */
      line_ptr = line_buf + line_buf_size - 1;
      /* so we can see if fgets put a 0 there */
      *line_ptr = 1;

      if (fgets (line_buf + line_buf_size - LBUFINCR - 1, LBUFINCR + 1, f) ==
	  0)
	return 0;
    }

  return line_buf;
}