/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 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"

#ifdef SDL_TIMER_MACOS

#include <Types.h>
#include <Timer.h>
#include <OSUtils.h>
#include <Gestalt.h>
#include <Processes.h>

#include <LowMem.h>

#include "SDL_timer.h"
#include "../SDL_timer_c.h"

#define MS_PER_TICK	(1000/60)       /* MacOS tick = 1/60 second */

/* Note: This is only a step above the original 1/60s implementation.
 *       For a good implementation, see FastTimes.[ch], by Matt Slot.
 */
#define USE_MICROSECONDS
#define WideTo64bit(w)	(*(UInt64 *) &(w))

UInt64 start;

void
SDL_StartTicks(void)
{
#ifdef USE_MICROSECONDS
    UnsignedWide now;

    Microseconds(&now);
    start = WideTo64bit(now);
#else
    /* FIXME: Should we implement a wrapping algorithm, like Win32? */
#endif
}

Uint32
SDL_GetTicks(void)
{
#ifdef USE_MICROSECONDS
    UnsignedWide now;

    Microseconds(&now);
    return (Uint32) ((WideTo64bit(now) - start) / 1000);
#else
    return (LMGetTicks() * MS_PER_TICK);
#endif
}

void
SDL_Delay(Uint32 ms)
{
#ifdef USE_MICROSECONDS
    Uint32 end_ms;

    end_ms = SDL_GetTicks() + ms;
    do {
        /* FIXME: Yield CPU? */ ;
    }
    while (SDL_GetTicks() < end_ms);
#else
    UInt32 unused;              /* MJS */
    Delay(ms / MS_PER_TICK, &unused);
#endif
}


/* Data to handle a single periodic alarm */
typedef struct _ExtendedTimerRec
{
    TMTask tmTask;
    ProcessSerialNumber taskPSN;
} ExtendedTimerRec, *ExtendedTimerPtr;

static ExtendedTimerRec gExtendedTimerRec;


int
SDL_SYS_TimerInit(void)
{
    /* We don't need a setup? */
    return (0);
}

void
SDL_SYS_TimerQuit(void)
{
    /* We don't need a cleanup? */
    return;
}

/* Our Stub routine to set up and then call the real routine. */
pascal void
TimerCallbackProc(TMTaskPtr tmTaskPtr)
{
    Uint32 ms;

    WakeUpProcess(&((ExtendedTimerPtr) tmTaskPtr)->taskPSN);

    ms = SDL_alarm_callback(SDL_alarm_interval);
    if (ms) {
        SDL_alarm_interval = ROUND_RESOLUTION(ms);
        PrimeTime((QElemPtr) & gExtendedTimerRec.tmTask, SDL_alarm_interval);
    } else {
        SDL_alarm_interval = 0;
    }
}

int
SDL_SYS_StartTimer(void)
{
    /*
     * Configure the global structure that stores the timing information.
     */
    gExtendedTimerRec.tmTask.qLink = NULL;
    gExtendedTimerRec.tmTask.qType = 0;
    gExtendedTimerRec.tmTask.tmAddr = NewTimerUPP(TimerCallbackProc);
    gExtendedTimerRec.tmTask.tmCount = 0;
    gExtendedTimerRec.tmTask.tmWakeUp = 0;
    gExtendedTimerRec.tmTask.tmReserved = 0;
    GetCurrentProcess(&gExtendedTimerRec.taskPSN);

    /* Install the task record */
    InsXTime((QElemPtr) & gExtendedTimerRec.tmTask);

    /* Go! */
    PrimeTime((QElemPtr) & gExtendedTimerRec.tmTask, SDL_alarm_interval);
    return (0);
}

void
SDL_SYS_StopTimer(void)
{
    RmvTime((QElemPtr) & gExtendedTimerRec.tmTask);
}

#endif /* SDL_TIMER_MACOS */
/* vi: set ts=4 sw=4 expandtab: */