1/*
2    SDL - Simple DirectMedia Layer
3    Copyright (C) 1997-2012 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 */
40static DWORD start;
41
42#ifndef USE_GETTICKCOUNT
43/* Store if a high-resolution performance counter exists on the system */
44static BOOL hires_timer_available;
45/* The first high-resolution ticks value of the application */
46static LARGE_INTEGER hires_start_ticks;
47/* The number of ticks per second of the high-resolution performance counter */
48static LARGE_INTEGER hires_ticks_per_second;
49#endif
50
51void 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
73Uint32 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
107void SDL_Delay(Uint32 ms)
108{
109	Sleep(ms);
110}
111
112/* Data to handle a single periodic alarm */
113static UINT timerID = 0;
114
115static void CALLBACK HandleAlarm(UINT uID,  UINT uMsg, DWORD_PTR dwUser,
116						DWORD_PTR dw1, DWORD_PTR dw2)
117{
118	SDL_ThreadedTimerCheck();
119}
120
121
122int 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
141void SDL_SYS_TimerQuit(void)
142{
143	if ( timerID ) {
144		timeKillEvent(timerID);
145	}
146	timeEndPeriod(TIMER_RESOLUTION);
147}
148
149int SDL_SYS_StartTimer(void)
150{
151	SDL_SetError("Internal logic error: Win32 uses threaded timer");
152	return(-1);
153}
154
155void SDL_SYS_StopTimer(void)
156{
157	return;
158}
159
160#endif /* SDL_TIMER_WIN32 */
161