2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2014, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure, Markus Armbruster
6 * Empire is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 * See files README, COPYING and CREDITS in the root of the source
22 * tree for related information and legal notices. It is expected
23 * that future projects/authors will amend these files as needed.
27 * secure.c: Check redir etc. to protect against tampering deity
29 * Known contributors to this file:
30 * Markus Armbruster, 2007
40 static struct ring recent_input;
41 static size_t saved_bytes;
44 * Remember line of input INP for a while.
45 * It must end with a newline.
46 * Return value is suitable for forget_input(): it makes it forget all
47 * input up to and including this line.
52 size_t len = strlen(inp);
55 assert(len && inp[len - 1] == '\n');
57 while (ring_putm(&recent_input, inp, len) < 0) {
58 eol = ring_search(&recent_input, "\n");
60 ring_discard(&recent_input, eol + 1);
67 * Can you still remember a line of input that ends with TAIL?
68 * It must end with a newline.
69 * Return non-zero iff TAIL can be remembered.
70 * Passing that value to forget_input() will forget all input up to
71 * and including this line.
74 seen_input(char *tail)
76 size_t len = strlen(tail);
77 size_t remembered = ring_len(&recent_input);
80 assert(len && tail[len - 1] == '\n');
82 dist = ring_search(&recent_input, tail);
86 assert(dist + len <= remembered && remembered <= saved_bytes);
87 return saved_bytes - remembered + dist + len;
91 * Forget remembered input up to SEEN.
92 * SEEN should be obtained from save_input() or seen_input().
95 forget_input(size_t seen)
97 size_t forgotten = saved_bytes - ring_len(&recent_input);
101 if (seen > forgotten) {
102 assert(ring_peek(&recent_input, seen - forgotten - 1) == '\n');
103 ring_discard(&recent_input, seen - forgotten);