1/* safe-fgets.c --- like fgets, but allocates its own static buffer.
2
3Copyright (C) 2005, 2007 Free Software Foundation, Inc.
4Contributed by Red Hat, Inc.
5
6This file is part of the GNU simulators.
7
8This program is free software; you can redistribute it and/or modify
9it under the terms of the GNU General Public License as published by
10the Free Software Foundation; either version 3 of the License, or
11(at your option) any later version.
12
13This program is distributed in the hope that it will be useful,
14but WITHOUT ANY WARRANTY; without even the implied warranty of
15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16GNU General Public License for more details.
17
18You should have received a copy of the GNU General Public License
19along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
20
21
22#include <stdio.h>
23#include <stdlib.h>
24
25#include "safe-fgets.h"
26
27static char *line_buf = 0;
28static int line_buf_size = 0;
29
30#define LBUFINCR 100
31
32char *
33safe_fgets (FILE *f)
34{
35  char *line_ptr;
36
37  if (line_buf == 0)
38    {
39      line_buf = (char *) malloc (LBUFINCR);
40      line_buf_size = LBUFINCR;
41    }
42
43  /* points to last byte */
44  line_ptr = line_buf + line_buf_size - 1;
45
46  /* so we can see if fgets put a 0 there */
47  *line_ptr = 1;
48  if (fgets (line_buf, line_buf_size, f) == 0)
49    return 0;
50
51  /* we filled the buffer? */
52  while (line_ptr[0] == 0 && line_ptr[-1] != '\n')
53    {
54      /* Make the buffer bigger and read more of the line */
55      line_buf_size += LBUFINCR;
56      line_buf = (char *) realloc (line_buf, line_buf_size);
57
58      /* points to last byte again */
59      line_ptr = line_buf + line_buf_size - 1;
60      /* so we can see if fgets put a 0 there */
61      *line_ptr = 1;
62
63      if (fgets (line_buf + line_buf_size - LBUFINCR - 1, LBUFINCR + 1, f) ==
64	  0)
65	return 0;
66    }
67
68  return line_buf;
69}
70