/*  timer.cpp  by K.Tsuru  */
/**************************************************************
Timer class
reference:H.Hisano,C Magazine No.9(1993 Soft Bank,in Japanese)
***************************************************************/
#include "timer.h"

double  Timer::unitSecond = -1.0;
int     Timer::timerObjects = 0;
double  Timer::lossTime[maxTimer];

// constructor
Timer::Timer(bool start):usesClock(true){   //Stand by in default.
    objectID = timerObjects;    //It begins at 0.
    timerObjects++;
    if(unitSecond <= 0){
        int i;
        for(i=0; i<maxTimer;i++) lossTime[i] =0.0;
        GetUnitSecond();
    }
    active = start;
    if(active) Start();
}
//destructor
Timer::~Timer(){
    lossTime[objectID] = 0.0;
    timerObjects--;
}

void Timer::GetUnitSecond(){
    unsigned n = 0;
    clock_t s = clock();
    clock_t e;

    while(clock() == s);        /*wait next boundary*/
    e = clock();
    while(clock() == e) ++n;    //wait within one step
    s = clock();
    unitSecond = (double(s - e)/CLOCKS_PER_SEC)/(double)n;
}

double Timer::WaitTick(double *lt){
    unsigned n = 0;
    double sec;
    clock_t s = clock();            //present value

    while(clock() == s) ++n;        //wait next value
    s = clock();                    //value after one step
    sec = (double)s/(double)CLOCKS_PER_SEC;//passed time since start of program
    //loss time in this routine
    *lt = (double)n*unitSecond;
    return sec;
}

double Timer::StopWatch(timer sw){
    double lt;
    int j;
    if(!active || (objectID >= maxTimer)) return 0;
    if(sw == START) {
        /*wait next tick and let it the starting time*/
        startClock = WaitTick(&lt);
        for(j = 0; j < objectID; j++) lossTime[j] += lt;
        startTime = time(NULL);
        return 0.0;
    }

// sw == STOP || LAP && active = true
    double t, dt;
    time_t now = time(NULL);
    dt = difftime(now, startTime);
    if(dt > 1000.0){
        usesClock=false;
        return dt;
    }
    /*wait next tick and let it the ending time*/
    double stop = WaitTick(&lt);
    for(j = 0; j < timerObjects; j++) lossTime[j] += lt;
    t = stop - startClock - lossTime[objectID];
    //It is possible t<0 by error. Order of -1.0e-5.
    if(t < 0.0) t = 0.0;
    return t;
}