This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
/
SDL_syssem.c
172 lines (152 loc) · 4.11 KB
1
/*
2
3
Simple DirectMedia Layer
Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>
4
5
6
7
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
8
9
10
11
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
12
13
14
15
16
17
18
19
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
20
*/
21
#include "SDL_config.h"
22
23
24
/* Semaphore functions using the Win32 API */
25
#include "../../core/windows/SDL_windows.h"
26
27
28
#include "SDL_thread.h"
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
29
30
#include "win_ce_semaphore.h"
#endif
31
32
33
34
struct SDL_semaphore
{
35
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
36
SYNCHHANDLE id;
37
#else
38
HANDLE id;
39
#endif
40
LONG count;
41
42
43
44
};
/* Create a semaphore */
45
46
SDL_sem *
SDL_CreateSemaphore(Uint32 initial_value)
47
{
48
SDL_sem *sem;
49
50
51
52
53
/* Allocate sem memory */
sem = (SDL_sem *) SDL_malloc(sizeof(*sem));
if (sem) {
/* Create the semaphore, with max value 32K */
54
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
55
sem->id = CreateSemaphoreCE(NULL, initial_value, 32 * 1024, NULL);
56
#else
57
sem->id = CreateSemaphore(NULL, initial_value, 32 * 1024, NULL);
58
#endif
59
60
61
62
63
64
65
66
67
68
sem->count = initial_value;
if (!sem->id) {
SDL_SetError("Couldn't create semaphore");
SDL_free(sem);
sem = NULL;
}
} else {
SDL_OutOfMemory();
}
return (sem);
69
70
71
}
/* Free the semaphore */
72
73
void
SDL_DestroySemaphore(SDL_sem * sem)
74
{
75
76
if (sem) {
if (sem->id) {
77
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
78
CloseSynchHandle(sem->id);
79
#else
80
CloseHandle(sem->id);
81
#endif
82
83
84
85
sem->id = 0;
}
SDL_free(sem);
}
86
87
}
88
89
int
SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
90
{
91
92
93
94
95
96
97
98
99
100
101
102
103
int retval;
DWORD dwMilliseconds;
if (!sem) {
SDL_SetError("Passed a NULL sem");
return -1;
}
if (timeout == SDL_MUTEX_MAXWAIT) {
dwMilliseconds = INFINITE;
} else {
dwMilliseconds = (DWORD) timeout;
}
104
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
105
switch (WaitForSemaphoreCE(sem->id, dwMilliseconds)) {
106
#else
107
switch (WaitForSingleObject(sem->id, dwMilliseconds)) {
108
#endif
109
case WAIT_OBJECT_0:
110
InterlockedDecrement(&sem->count);
111
112
113
114
115
116
117
118
119
120
121
retval = 0;
break;
case WAIT_TIMEOUT:
retval = SDL_MUTEX_TIMEDOUT;
break;
default:
SDL_SetError("WaitForSingleObject() failed");
retval = -1;
break;
}
return retval;
122
123
}
124
125
int
SDL_SemTryWait(SDL_sem * sem)
126
{
127
return SDL_SemWaitTimeout(sem, 0);
128
129
}
130
131
int
SDL_SemWait(SDL_sem * sem)
132
{
133
return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
134
135
136
}
/* Returns the current count of the semaphore */
137
138
Uint32
SDL_SemValue(SDL_sem * sem)
139
{
140
141
142
143
if (!sem) {
SDL_SetError("Passed a NULL sem");
return 0;
}
144
return (Uint32)sem->count;
145
146
}
147
148
int
SDL_SemPost(SDL_sem * sem)
149
{
150
151
152
153
154
155
156
157
158
if (!sem) {
SDL_SetError("Passed a NULL sem");
return -1;
}
/* Increase the counter in the first place, because
* after a successful release the semaphore may
* immediately get destroyed by another thread which
* is waiting for this semaphore.
*/
159
InterlockedIncrement(&sem->count);
160
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
161
if (ReleaseSemaphoreCE(sem->id, 1, NULL) == FALSE) {
162
#else
163
if (ReleaseSemaphore(sem->id, 1, NULL) == FALSE) {
164
#endif
165
InterlockedDecrement(&sem->count); /* restore */
166
167
168
169
SDL_SetError("ReleaseSemaphore() failed");
return -1;
}
return 0;
170
}
171
172
/* vi: set ts=4 sw=4 expandtab: */