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_MACOS
25
26#include <Types.h>
27#include <Timer.h>
28#include <OSUtils.h>
29#include <Gestalt.h>
30#include <Processes.h>
31
32#include <LowMem.h>
33
34#include "SDL_timer.h"
35#include "../SDL_timer_c.h"
36
37#define MS_PER_TICK	(1000/60)		/* MacOS tick = 1/60 second */
38
39/* Note: This is only a step above the original 1/60s implementation.
40 *       For a good implementation, see FastTimes.[ch], by Matt Slot.
41 */
42#define USE_MICROSECONDS
43#define WideTo64bit(w)	(*(UInt64 *) &(w))
44
45UInt64 start;
46
47void SDL_StartTicks(void)
48{
49#ifdef USE_MICROSECONDS
50	UnsignedWide now;
51
52	Microseconds(&now);
53	start = WideTo64bit(now);
54#else
55	/* FIXME: Should we implement a wrapping algorithm, like Win32? */
56#endif
57}
58
59Uint32 SDL_GetTicks(void)
60{
61#ifdef USE_MICROSECONDS
62	UnsignedWide now;
63
64	Microseconds(&now);
65	return (Uint32)((WideTo64bit(now)-start)/1000);
66#else
67	return(LMGetTicks()*MS_PER_TICK);
68#endif
69}
70
71void SDL_Delay(Uint32 ms)
72{
73#ifdef USE_MICROSECONDS
74	Uint32 end_ms;
75
76	end_ms = SDL_GetTicks() + ms;
77	do {
78		/* FIXME: Yield CPU? */ ;
79	} while ( SDL_GetTicks() < end_ms );
80#else
81	UInt32		unused; /* MJS */
82	Delay(ms/MS_PER_TICK, &unused);
83#endif
84}
85
86
87/* Data to handle a single periodic alarm */
88typedef struct _ExtendedTimerRec
89{
90	TMTask		     tmTask;
91	ProcessSerialNumber  taskPSN;
92} ExtendedTimerRec, *ExtendedTimerPtr;
93
94static ExtendedTimerRec gExtendedTimerRec;
95
96
97int SDL_SYS_TimerInit(void)
98{
99	/* We don't need a setup? */
100	return(0);
101}
102
103void SDL_SYS_TimerQuit(void)
104{
105	/* We don't need a cleanup? */
106	return;
107}
108
109/* Our Stub routine to set up and then call the real routine. */
110pascal void TimerCallbackProc(TMTaskPtr tmTaskPtr)
111{
112	Uint32 ms;
113
114	WakeUpProcess(&((ExtendedTimerPtr) tmTaskPtr)->taskPSN);
115
116	ms = SDL_alarm_callback(SDL_alarm_interval);
117	if ( ms ) {
118		SDL_alarm_interval = ROUND_RESOLUTION(ms);
119		PrimeTime((QElemPtr)&gExtendedTimerRec.tmTask,
120		          SDL_alarm_interval);
121	} else {
122		SDL_alarm_interval = 0;
123	}
124}
125
126int SDL_SYS_StartTimer(void)
127{
128	/*
129	 * Configure the global structure that stores the timing information.
130	 */
131	gExtendedTimerRec.tmTask.qLink = NULL;
132	gExtendedTimerRec.tmTask.qType = 0;
133	gExtendedTimerRec.tmTask.tmAddr = NewTimerUPP(TimerCallbackProc);
134	gExtendedTimerRec.tmTask.tmCount = 0;
135	gExtendedTimerRec.tmTask.tmWakeUp = 0;
136	gExtendedTimerRec.tmTask.tmReserved = 0;
137	GetCurrentProcess(&gExtendedTimerRec.taskPSN);
138
139	/* Install the task record */
140	InsXTime((QElemPtr)&gExtendedTimerRec.tmTask);
141
142	/* Go! */
143	PrimeTime((QElemPtr)&gExtendedTimerRec.tmTask, SDL_alarm_interval);
144	return(0);
145}
146
147void SDL_SYS_StopTimer(void)
148{
149	RmvTime((QElemPtr)&gExtendedTimerRec.tmTask);
150}
151
152#endif /* SDL_TIMER_MACOS */
153