summaryrefslogtreecommitdiff
path: root/core/safe_refcount.cpp
blob: 95a274cda7c64057e56c95bf1f218d1098d5e596 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
/*************************************************************************/
/*  safe_refcount.cpp                                                    */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md)    */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/
#include "safe_refcount.h"

// Atomic functions, these are used for multithread safe reference counters!

#ifdef NO_THREADS

uint32_t atomic_conditional_increment(register uint32_t *pw) {

	if (*pw == 0)
		return 0;

	(*pw)++;

	return *pw;
}

uint32_t atomic_increment(register uint32_t *pw) {

	(*pw)++;

	return *pw;
}

uint32_t atomic_decrement(register uint32_t *pw) {

	(*pw)--;

	return *pw;
}

uint64_t atomic_conditional_increment(register uint64_t *pw) {

	if (*pw == 0)
		return 0;

	(*pw)++;

	return *pw;
}

uint64_t atomic_increment(register uint64_t *pw) {

	(*pw)++;

	return *pw;
}

uint64_t atomic_decrement(register uint64_t *pw) {

	(*pw)--;

	return *pw;
}

#else

#ifdef _MSC_VER

// don't pollute my namespace!
#include <windows.h>
uint32_t atomic_conditional_increment(register uint32_t *pw) {

	/* try to increment until it actually works */
	// taken from boost

	while (true) {
		uint32_t tmp = static_cast<uint32_t const volatile &>(*pw);
		if (tmp == 0)
			return 0; // if zero, can't add to it anymore
		if (InterlockedCompareExchange((LONG volatile *)pw, tmp + 1, tmp) == tmp)
			return tmp + 1;
	}
}

uint32_t atomic_decrement(register uint32_t *pw) {
	return InterlockedDecrement((LONG volatile *)pw);
}

uint32_t atomic_increment(register uint32_t *pw) {
	return InterlockedIncrement((LONG volatile *)pw);
}

uint64_t atomic_conditional_increment(register uint64_t *pw) {

	/* try to increment until it actually works */
	// taken from boost

	while (true) {
		uint64_t tmp = static_cast<uint64_t const volatile &>(*pw);
		if (tmp == 0)
			return 0; // if zero, can't add to it anymore
		if (InterlockedCompareExchange64((LONGLONG volatile *)pw, tmp + 1, tmp) == tmp)
			return tmp + 1;
	}
}

uint64_t atomic_decrement(register uint64_t *pw) {
	return InterlockedDecrement64((LONGLONG volatile *)pw);
}

uint64_t atomic_increment(register uint64_t *pw) {
	return InterlockedIncrement64((LONGLONG volatile *)pw);
}
#elif defined(__GNUC__)

uint32_t atomic_conditional_increment(register uint32_t *pw) {

	while (true) {
		uint32_t tmp = static_cast<uint32_t const volatile &>(*pw);
		if (tmp == 0)
			return 0; // if zero, can't add to it anymore
		if (__sync_val_compare_and_swap(pw, tmp, tmp + 1) == tmp)
			return tmp + 1;
	}
}

uint32_t atomic_decrement(register uint32_t *pw) {

	return __sync_sub_and_fetch(pw, 1);
}

uint32_t atomic_increment(register uint32_t *pw) {

	return __sync_add_and_fetch(pw, 1);
}

uint64_t atomic_conditional_increment(register uint64_t *pw) {

	while (true) {
		uint64_t tmp = static_cast<uint64_t const volatile &>(*pw);
		if (tmp == 0)
			return 0; // if zero, can't add to it anymore
		if (__sync_val_compare_and_swap(pw, tmp, tmp + 1) == tmp)
			return tmp + 1;
	}
}

uint64_t atomic_decrement(register uint64_t *pw) {

	return __sync_sub_and_fetch(pw, 1);
}

uint64_t atomic_increment(register uint64_t *pw) {

	return __sync_add_and_fetch(pw, 1);
}

#else
//no threads supported?
#error Must provide atomic functions for this platform or compiler!

#endif

#endif