1 /* Test of freadahead() function.
2    Copyright (C) 2007-2018 Free Software Foundation, Inc.
3 
4    This program is free software: you can redistribute it and/or modify
5    it under the terms of the GNU General Public License as published by
6    the Free Software Foundation; either version 3 of the License, or
7    (at your option) any later version.
8 
9    This program is distributed in the hope that it will be useful,
10    but WITHOUT ANY WARRANTY; without even the implied warranty of
11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12    GNU General Public License for more details.
13 
14    You should have received a copy of the GNU General Public License
15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
16 
17 /* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
18 
19 #include <config.h>
20 
21 #include "freadahead.h"
22 
23 #include <stdlib.h>
24 #include <unistd.h>
25 
26 #include "macros.h"
27 
28 int
main(int argc,char ** argv)29 main (int argc, char **argv)
30 {
31   int nbytes = atoi (argv[1]);
32   if (nbytes > 0)
33     {
34       void *buf = malloc (nbytes);
35       ASSERT (fread (buf, 1, nbytes, stdin) == nbytes);
36     }
37 
38   if (nbytes == 0)
39     ASSERT (freadahead (stdin) == 0);
40   else
41     {
42       if (lseek (0, 0, SEEK_CUR) == nbytes)
43         /* An unbuffered stdio, such as BeOS or on uClibc compiled without
44            __STDIO_BUFFERS.  */
45         ASSERT (freadahead (stdin) == 0);
46       else
47         {
48           /* Normal buffered stdio.  */
49           size_t buffered;
50           int c, c2;
51 
52           ASSERT (freadahead (stdin) != 0);
53           buffered = freadahead (stdin);
54 
55           c = fgetc (stdin);
56           ASSERT (freadahead (stdin) == buffered - 1);
57           ungetc (c, stdin);
58           ASSERT (freadahead (stdin) == buffered);
59           c2 = fgetc (stdin);
60           ASSERT (c2 == c);
61           ASSERT (freadahead (stdin) == buffered - 1);
62 
63           c = '@';
64           ungetc (c, stdin);
65           ASSERT (freadahead (stdin) == buffered);
66           c2 = fgetc (stdin);
67           ASSERT (c2 == c);
68           ASSERT (freadahead (stdin) == buffered - 1);
69         }
70     }
71 
72   return 0;
73 }
74