1 /*
2 * Copyright (c) 2002-2018 Balabit
3 * Copyright (c) 2018 Laszlo Budai <laszlo.budai@balabit.com>
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * As an additional exemption you are allowed to compile & link against the
20 * OpenSSL libraries as published by the OpenSSL project. See the file
21 * COPYING for details.
22 *
23 */
24
25 #include "window-size-counter.h"
26
27 #define COUNTER_MASK (((gsize)1<<(8*sizeof(gsize)-1)) - 1)
28 static const gsize COUNTER_MAX = COUNTER_MASK;
29 static const gsize SUSPEND_MASK = G_MAXSIZE ^ COUNTER_MASK;
30 static const gsize RESUME_MASK = G_MAXSIZE >> 1;
31
32 static gboolean
_is_suspended(gsize v)33 _is_suspended(gsize v)
34 {
35 return (v == 0) || ((v & SUSPEND_MASK) == SUSPEND_MASK);
36 }
37
38 gsize
window_size_counter_get_max(void)39 window_size_counter_get_max(void)
40 {
41 return COUNTER_MAX;
42 }
43
44 void
window_size_counter_set(WindowSizeCounter * c,gsize value)45 window_size_counter_set(WindowSizeCounter *c, gsize value)
46 {
47 atomic_gssize_set(&c->counter, value & COUNTER_MASK);
48 }
49
50 gsize
window_size_counter_get(WindowSizeCounter * c,gboolean * suspended)51 window_size_counter_get(WindowSizeCounter *c, gboolean *suspended)
52 {
53 gsize v = atomic_gssize_get_unsigned(&c->counter);
54 if (suspended)
55 *suspended = _is_suspended(v);
56 return v & COUNTER_MASK;
57 }
58
59 gsize
window_size_counter_add(WindowSizeCounter * c,gsize value,gboolean * suspended)60 window_size_counter_add(WindowSizeCounter *c, gsize value, gboolean *suspended)
61 {
62 gsize v = (gsize)atomic_gssize_add(&c->counter, value);
63 gsize old_value = v & COUNTER_MASK;
64 g_assert (old_value + value <= COUNTER_MAX);
65 if (suspended)
66 *suspended = _is_suspended(v);
67
68 return old_value;
69 }
70
71 gsize
window_size_counter_sub(WindowSizeCounter * c,gsize value,gboolean * suspended)72 window_size_counter_sub(WindowSizeCounter *c, gsize value, gboolean *suspended)
73 {
74 gsize v = (gsize)atomic_gssize_add(&c->counter, -1 * value);
75 gsize old_value = v & COUNTER_MASK;
76 g_assert (old_value >= value);
77 if (suspended)
78 *suspended = _is_suspended(v);
79
80 return old_value;
81 }
82
83 void
window_size_counter_suspend(WindowSizeCounter * c)84 window_size_counter_suspend(WindowSizeCounter *c)
85 {
86 atomic_gssize_or(&c->counter, SUSPEND_MASK);
87 }
88
89 void
window_size_counter_resume(WindowSizeCounter * c)90 window_size_counter_resume(WindowSizeCounter *c)
91 {
92 atomic_gssize_and(&c->counter, RESUME_MASK);
93 }
94
95 gboolean
window_size_counter_suspended(WindowSizeCounter * c)96 window_size_counter_suspended(WindowSizeCounter *c)
97 {
98 gsize v = atomic_gssize_get_unsigned(&c->counter);
99 return _is_suspended(v);
100 }
101
102