aboutsummaryrefslogtreecommitdiffstats
path: root/distrib/sdl-1.2.15/src/thread/win32/SDL_syssem.c
blob: 261d24cbfe95f739c8cfddf82ac53bbbc2765c3d (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
/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2012 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* Semaphore functions using the Win32 API */

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

#include "SDL_thread.h"
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
#include "win_ce_semaphore.h"
#endif


struct SDL_semaphore {
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
	SYNCHHANDLE id;
#else
	HANDLE id;
#endif
	volatile LONG count;
};


/* Create a semaphore */
SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
{
	SDL_sem *sem;

	/* Allocate sem memory */
	sem = (SDL_sem *)SDL_malloc(sizeof(*sem));
	if ( sem ) {
		/* Create the semaphore, with max value 32K */
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
		sem->id = CreateSemaphoreCE(NULL, initial_value, 32*1024, NULL);
#else
		sem->id = CreateSemaphore(NULL, initial_value, 32*1024, NULL);
#endif
		sem->count = (LONG) initial_value;
		if ( ! sem->id ) {
			SDL_SetError("Couldn't create semaphore");
			SDL_free(sem);
			sem = NULL;
		}
	} else {
		SDL_OutOfMemory();
	}
	return(sem);
}

/* Free the semaphore */
void SDL_DestroySemaphore(SDL_sem *sem)
{
	if ( sem ) {
		if ( sem->id ) {
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
			CloseSynchHandle(sem->id);
#else
			CloseHandle(sem->id);
#endif
			sem->id = 0;
		}
		SDL_free(sem);
	}
}

int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
{
	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;
	}
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
	switch (WaitForSemaphoreCE(sem->id, dwMilliseconds)) {
#else
	switch (WaitForSingleObject(sem->id, dwMilliseconds)) {
#endif
	    case WAIT_OBJECT_0:
		InterlockedDecrement(&sem->count);
		retval = 0;
		break;
	    case WAIT_TIMEOUT:
		retval = SDL_MUTEX_TIMEDOUT;
		break;
	    default:
		SDL_SetError("WaitForSingleObject() failed");
		retval = -1;
		break;
	}
	return retval;
}

int SDL_SemTryWait(SDL_sem *sem)
{
	return SDL_SemWaitTimeout(sem, 0);
}

int SDL_SemWait(SDL_sem *sem)
{
	return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
}

/* Returns the current count of the semaphore */
Uint32 SDL_SemValue(SDL_sem *sem)
{
	if ( ! sem ) {
		SDL_SetError("Passed a NULL sem");
		return 0;
	}
	return (Uint32) sem->count;
}

int SDL_SemPost(SDL_sem *sem)
{
	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.
	 */
	InterlockedIncrement(&sem->count);
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
	if ( ReleaseSemaphoreCE(sem->id, 1, NULL) == FALSE ) {
#else
	if ( ReleaseSemaphore(sem->id, 1, NULL) == FALSE ) {
#endif
		InterlockedDecrement(&sem->count);	/* restore */
		SDL_SetError("ReleaseSemaphore() failed");
		return -1;
	}
	return 0;
}