arduino日付関数

0001  //----------------------------------------------------------------
0002  // 日時 <-> 1970/1/1 00:00:00からの秒数(UNIXの日付) 相互変換
0003  //----------------------------------------------------------------
0004  #define SECONDS_IN_DAY   86400   // 24 * 60 * 60
0005  #define SECONDS_IN_HOUR  3600    // 60 * 60
0006  
0007  typedef struct {
0008    int  year;
0009    byte month;
0010    byte day;
0011    byte hour;
0012    byte min;
0013    byte sec;
0014  } date_time;
0015  
0016  date_time tm;
0017  void unix_time_to_date( unsigned long unix_datetime, date_time *tm );
0018  
0019  //----------------------------------------------------------------
0020  // 西暦０年１月１日からの日数を返す
0021  //----------------------------------------------------------------
0022  unsigned long calc_0_days(int year, byte month, byte day) {
0023    unsigned long days;
0024    int daysinmonth_ruiseki[12] = {0,31,59,90,120,151,181,212,243,273,304,334};
0025    
0026    year--; // 当年は含まず 
0027    days = (unsigned long)year * 365;
0028    days += year / 4;  // 閏年の日数を足しこむ
0029    days -= year/100;  // 閏年で無い日数を差し引く
0030    days += year/400;  // 差し引きすぎた日数を足しこむ
0031    days += (unsigned long)daysinmonth_ruiseki[month-1];
0032    if( is_leapyear( year ) &&  3 <= month ) {
0033      day++;
0034    }
0035    days += (unsigned long)day;
0036    
0037    return days;
0038  }
0039  
0040  //----------------------------------------------------------------
0041  // 西暦１９７０年１月１日からの日数を返す
0042  //----------------------------------------------------------------
0043  unsigned long calc_unix_days(int year, byte month, byte day) {
0044    unsigned long days;
0045  
0046    return calc_0_days(year, month, day) - calc_0_days(1970, 1, 1);
0047  }
0048  
0049  //----------------------------------------------------------------
0050  // 西暦１９７０年１月１日　００：００：００　からの秒数を返す
0051  //----------------------------------------------------------------
0052  unsigned long calc_unix_seconds(int year, byte month, byte day, byte hour, byte minutes, byte second) {
0053    unsigned long days;
0054    unsigned long seconds;
0055  
0056    days = calc_unix_days(year, month, day);
0057    seconds = days * SECONDS_IN_DAY;
0058    seconds += (unsigned long)hour * SECONDS_IN_HOUR;
0059    seconds += (unsigned long)minutes * 60;
0060    seconds += (unsigned long)second;
0061    seconds += -9 * SECONDS_IN_HOUR; // JPN(GMT+9) 日本時間
0062  
0063    return seconds;
0064  }
0065  
0066  //----------------------------------------------------------------
0067  // 閏年か否かを返す
0068  //----------------------------------------------------------------
0069  boolean is_leapyear( int year )
0070  {
0071    if( (year % 400) == 0 || ((year % 4) == 0 && (year % 100) != 0)) {
0072      return true;
0073    } else {
0074      return false;
0075    }
0076  }
0077  
0078  //----------------------------------------------------------------
0079  // Unixの日付を日時に変換　ループ処理しているので2msec程度かかる
0080  //----------------------------------------------------------------
0081  void unix_time_to_date( unsigned long unix_datetime, date_time *tm )
0082  {
0083    tm->year  = 1970;
0084    tm->month = 1;
0085    tm->day   = 1;
0086    tm->hour  = 0;
0087    tm->min   = 0;
0088    tm->sec   = 0;
0089    
0090    unsigned long yearindate;
0091    unsigned long seconds_year;
0092    unsigned long seconds_month;
0093    byte daysinmonth[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
0094  
0095    unix_datetime += 9 * SECONDS_IN_HOUR;
0096    while( unix_datetime > 0 ) {
0097      if( is_leapyear(tm->year) ) {
0098        yearindate = 366;
0099        daysinmonth[1] = 29;
0100      } else {
0101        yearindate = 365;
0102        daysinmonth[1] = 28;
0103      }
0104      seconds_year  = yearindate * SECONDS_IN_DAY;
0105      seconds_month = daysinmonth[tm->month - 1] * SECONDS_IN_DAY;
0106      if( unix_datetime >= seconds_year ) {
0107        tm->year++;
0108        unix_datetime -= seconds_year;
0109      } else if( unix_datetime >= seconds_month ) {
0110        tm->month++;
0111        unix_datetime -= seconds_month;
0112      } else if( unix_datetime >= SECONDS_IN_DAY ) {
0113        tm->day++;
0114        unix_datetime -= SECONDS_IN_DAY;  
0115      } else if( unix_datetime >= SECONDS_IN_HOUR ) {
0116        tm->hour++;
0117        unix_datetime -= SECONDS_IN_HOUR; 
0118      } else if( unix_datetime >= 60 ) {
0119        tm->min++;
0120        unix_datetime -= 60;
0121      } else {
0122        tm->sec = (byte)unix_datetime;
0123        unix_datetime= 0;
0124      }
0125    }
0126  }
0127  
0128  //---------------------------------------------------------------------------
0129  // arduino setup
0130  //---------------------------------------------------------------------------
0131  void setup() {
0132    unsigned long days;
0133    unsigned long unix_seconds;
0134    long a,b;
0135  
0136    Serial.begin(9600);
0137  
0138    unix_seconds = calc_unix_seconds( 2014,7,18,1,2,3 );
0139    Serial.println(unix_seconds);
0140    unix_time_to_date( unix_seconds, &tm );
0141    
0142    Serial.println(tm.year);
0143    Serial.println(tm.month);  
0144    Serial.println(tm.day);  
0145    Serial.println(tm.hour);  
0146    Serial.println(tm.min);  
0147    Serial.println(tm.sec); 
0148  }
0149  
0150  //---------------------------------------------------------------------------
0151  // arduino loop
0152  //---------------------------------------------------------------------------
0153  void loop() {
0154     //  nothing to do       
0155  }
0156  
0157  //--------- E N D -----------------------------------------------------------