sim/m32c/safe-fgets.c

   1 /* safe-fgets.c --- like fgets, but allocates its own static buffer.
   2
   3 Copyright (C) 2005-2018 Free Software Foundation, Inc.
   4 Contributed by Red Hat, Inc.
   5
   6 This file is part of the GNU simulators.
   7
   8 This program is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3 of the License, or
  11 (at your option) any later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along 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
  27 static char *line_buf = 0;
  28 static int line_buf_size = 0;
  29
  30 #define LBUFINCR 100
  31
  32 char *
  33 safe_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 }