時間修正

因為系統時間與實際時間不一樣,程式目的為將系統時間校正至真實時間:

已知系統時間的起始點stime0 與對應的真實時間stime1,給定某個系統時間dtime0,程式,將之轉換為真實時間dtime1

應該有更好的方法,但目前就是直接算stime0與dtime0的差距,再加到stime1;即dtime1=stime1+(dtime0-stime0)
原本以為半天可以做完,最後花了整整兩天... 就為了考慮所有狀況..,測試過是沒問題,還是有小部份可以精簡的地方,但是懶的改了.

#include
#include

typedef struct OBSTIME{  
 int yr;
 int mon;
 int day;
 int hr;
 int min;
 int sec;        
}obstime;

void add_time();
void cmptime(obstime *t1,obstime *t2);
int julian_cnt(int yr,int mon,int day);


//Global variable 
obstime stime0={1,1,1,3,0,0};//system start time : dummy
obstime stime1={2012,12,15,14,53,40}; //system start time : true
obstime dtime0; //data time : dummy
obstime dtime1; //data time : ture
int day_lyr[12]={31,29,31,30,31,30,31,31,30,31,30,31}; //leap year day array
int day_cyr[12]={31,28,31,30,31,30,31,31,30,31,30,31}; //common year day array
int del_sec;//delta seconds 
int del_day;//delta days



void add_time(){

 int *day_yr; //ptr to day arry of the year

 cmptime(&stime0,&dtime0); //compute delta time in second & day

 dtime1.sec=stime1.sec+del_sec;  //add seconds
 dtime1.min=stime1.min+(dtime1.sec/60);
 dtime1.sec=dtime1.sec%60; //sec. ok  
 dtime1.hr=stime1.hr+(dtime1.min/60);
 dtime1.min=dtime1.min%60;//min. ok
 dtime1.day=stime1.day+(dtime1.hr/24);
 dtime1.hr=dtime1.hr%24;//hr. ok
 dtime1.day+=del_day; //add days
 dtime1.mon=stime1.mon;
 dtime1.yr=stime1.yr;

 if((stime1.yr%4==0 && stime1.yr%100!=0) || stime1.yr%400==0){ //leap year
   day_yr=day_lyr;
 } 
 else{ //common year
   day_yr=day_cyr;
 } 
 while((dtime1.day-day_yr[dtime1.mon-1])>0){
  dtime1.day=dtime1.day-day_yr[dtime1.mon-1];
  dtime1.mon=dtime1.mon+1;
  if(dtime1.mon==13){
   dtime1.mon=1;                 
   dtime1.yr++;
   if((dtime1.yr%4==0 && dtime1.yr%100!=0) || dtime1.yr%400==0){ //leap year
    day_yr=day_lyr;
   } 
   else{ //common year
    day_yr=day_cyr;
   }
  }
 }

}



void cmptime(obstime *t1,obstime *t2){
 int jday1,jday2;
 int sec1,sec2;
 int yr=t2->yr;
 int lday=366,cday=365;


 jday1=julian_cnt(t1->yr,t1->mon,t1->day);
 jday2=julian_cnt(t2->yr,t2->mon,t2->day);

 while(yr>t1->yr){//over the year or futher..
  yr--;
  if((yr%4==0 && yr%100!=0) || yr%400==0){ //leap year
    jday2=jday2+366;
  } 
  else{ //common year
    jday2=jday2+365;
  }
 }
 sec1=t1->hr*3600+t1->min*60+t1->sec;
 sec2=t2->hr*3600+t2->min*60+t2->sec;
 if(sec2>=sec1){
  del_sec=sec2-sec1;
  del_day=jday2-jday1;
 }
 else{
  del_sec=sec2-sec1+86400; 
  del_day=jday2-jday1-1; 
 }
 //printf("del_day=%d",del_day);
 //system("PAUSE");
 //printf("del_sec=%d",del_sec);
 //system("PAUSE");
} 



int julian_cnt(int yr,int mon,int day){
 int jday=0;
 int *day_yr;
 int i=0;
  
 if((yr%4==0 && yr%100!=0) || yr%400==0){ //leap year
   day_yr=day_lyr;
 } 
 else{ //common year
   day_yr=day_cyr;
 }

 while(i+1 != mon){
  jday=jday+day_yr[i];
  i++;
 }
 jday=jday+day;

 return jday;
}