1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2006 Sam Lantinga
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 Sam Lantinga
20 slouken@libsdl.org
21 */
22 #include "SDL_config.h"
23
24 #ifdef SDL_TIMER_WIN32
25
26 #define WIN32_LEAN_AND_MEAN
27 #include <windows.h>
28 #include <mmsystem.h>
29
30 #include "SDL_timer.h"
31 #include "../SDL_timer_c.h"
32
33 #ifdef _WIN32_WCE
34 #error This is WinCE. Please use src/timer/wince/SDL_systimer.c instead.
35 #endif
36
37 #define TIME_WRAP_VALUE (~(DWORD)0)
38
39 /* The first (low-resolution) ticks value of the application */
40 static DWORD start;
41
42 #ifndef USE_GETTICKCOUNT
43 /* Store if a high-resolution performance counter exists on the system */
44 static BOOL hires_timer_available;
45 /* The first high-resolution ticks value of the application */
46 static LARGE_INTEGER hires_start_ticks;
47 /* The number of ticks per second of the high-resolution performance counter */
48 static LARGE_INTEGER hires_ticks_per_second;
49 #endif
50
SDL_StartTicks(void)51 void SDL_StartTicks(void)
52 {
53 /* Set first ticks value */
54 #ifdef USE_GETTICKCOUNT
55 start = GetTickCount();
56 #else
57 #if 0 /* Apparently there are problems with QPC on Win2K */
58 if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE)
59 {
60 hires_timer_available = TRUE;
61 QueryPerformanceCounter(&hires_start_ticks);
62 }
63 else
64 #endif
65 {
66 hires_timer_available = FALSE;
67 timeBeginPeriod(1); /* use 1 ms timer precision */
68 start = timeGetTime();
69 }
70 #endif
71 }
72
SDL_GetTicks(void)73 Uint32 SDL_GetTicks(void)
74 {
75 DWORD now, ticks;
76 #ifndef USE_GETTICKCOUNT
77 LARGE_INTEGER hires_now;
78 #endif
79
80 #ifdef USE_GETTICKCOUNT
81 now = GetTickCount();
82 #else
83 if (hires_timer_available)
84 {
85 QueryPerformanceCounter(&hires_now);
86
87 hires_now.QuadPart -= hires_start_ticks.QuadPart;
88 hires_now.QuadPart *= 1000;
89 hires_now.QuadPart /= hires_ticks_per_second.QuadPart;
90
91 return (DWORD)hires_now.QuadPart;
92 }
93 else
94 {
95 now = timeGetTime();
96 }
97 #endif
98
99 if ( now < start ) {
100 ticks = (TIME_WRAP_VALUE-start) + now;
101 } else {
102 ticks = (now - start);
103 }
104 return(ticks);
105 }
106
SDL_Delay(Uint32 ms)107 void SDL_Delay(Uint32 ms)
108 {
109 Sleep(ms);
110 }
111
112 /* Data to handle a single periodic alarm */
113 static UINT timerID = 0;
114
HandleAlarm(UINT uID,UINT uMsg,DWORD_PTR dwUser,DWORD_PTR dw1,DWORD_PTR dw2)115 static void CALLBACK HandleAlarm(UINT uID, UINT uMsg, DWORD_PTR dwUser,
116 DWORD_PTR dw1, DWORD_PTR dw2)
117 {
118 SDL_ThreadedTimerCheck();
119 }
120
121
SDL_SYS_TimerInit(void)122 int SDL_SYS_TimerInit(void)
123 {
124 MMRESULT result;
125
126 /* Set timer resolution */
127 result = timeBeginPeriod(TIMER_RESOLUTION);
128 if ( result != TIMERR_NOERROR ) {
129 SDL_SetError("Warning: Can't set %d ms timer resolution",
130 TIMER_RESOLUTION);
131 }
132 /* Allow 10 ms of drift so we don't chew on CPU */
133 timerID = timeSetEvent(TIMER_RESOLUTION,1,HandleAlarm,0,TIME_PERIODIC);
134 if ( ! timerID ) {
135 SDL_SetError("timeSetEvent() failed");
136 return(-1);
137 }
138 return(SDL_SetTimerThreaded(1));
139 }
140
SDL_SYS_TimerQuit(void)141 void SDL_SYS_TimerQuit(void)
142 {
143 if ( timerID ) {
144 timeKillEvent(timerID);
145 }
146 timeEndPeriod(TIMER_RESOLUTION);
147 }
148
SDL_SYS_StartTimer(void)149 int SDL_SYS_StartTimer(void)
150 {
151 SDL_SetError("Internal logic error: Win32 uses threaded timer");
152 return(-1);
153 }
154
SDL_SYS_StopTimer(void)155 void SDL_SYS_StopTimer(void)
156 {
157 return;
158 }
159
160 #endif /* SDL_TIMER_WIN32 */
161