Add Time library

Signed-off-by: Mike Beattie <mike@ethernal.org>

1 files changed, 307 insertions, 0 deletions

diff --git a/Time/Time.cpp b/Time/Time.cpp
new file mode 100644
index 0000000..86bdcd5
--- /dev/null
+++ b/Time/Time.cpp
@@ -0,0 +1,307 @@
+/*
+  time.c - low level time and date functions
+  Copyright (c) Michael Margolis 2009
+
+  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
+  
+  6  Jan 2010 - initial release 
+  12 Feb 2010 - fixed leap year calculation error
+  1  Nov 2010 - fixed setTime bug (thanks to Korman for this)
+*/
+
+#if ARDUINO >= 100
+#include <Arduino.h> 
+#else
+#include <WProgram.h> 
+#endif
+
+#include "Time.h"
+
+static tmElements_t tm;          // a cache of time elements
+static time_t       cacheTime;   // the time the cache was updated
+static time_t       syncInterval = 300;  // time sync will be attempted after this many seconds
+
+void refreshCache( time_t t){
+  if( t != cacheTime)
+  {
+    breakTime(t, tm); 
+    cacheTime = t; 
+  }
+}
+
+int hour() { // the hour now 
+  return hour(now()); 
+}
+
+int hour(time_t t) { // the hour for the given time
+  refreshCache(t);
+  return tm.Hour;  
+}
+
+int hourFormat12() { // the hour now in 12 hour format
+  return hourFormat12(now()); 
+}
+
+int hourFormat12(time_t t) { // the hour for the given time in 12 hour format
+  refreshCache(t);
+  if( tm.Hour == 0 )
+    return 12; // 12 midnight
+  else if( tm.Hour  > 12)
+    return tm.Hour - 12 ;
+  else
+    return tm.Hour ;
+}
+
+uint8_t isAM() { // returns true if time now is AM
+  return !isPM(now()); 
+}
+
+uint8_t isAM(time_t t) { // returns true if given time is AM
+  return !isPM(t);  
+}
+
+uint8_t isPM() { // returns true if PM
+  return isPM(now()); 
+}
+
+uint8_t isPM(time_t t) { // returns true if PM
+  return (hour(t) >= 12); 
+}
+
+int minute() {
+  return minute(now()); 
+}
+
+int minute(time_t t) { // the minute for the given time
+  refreshCache(t);
+  return tm.Minute;  
+}
+
+int second() {
+  return second(now()); 
+}
+
+int second(time_t t) {  // the second for the given time
+  refreshCache(t);
+  return tm.Second;
+}
+
+int day(){
+  return(day(now())); 
+}
+
+int day(time_t t) { // the day for the given time (0-6)
+  refreshCache(t);
+  return tm.Day;
+}
+
+int weekday() {   // Sunday is day 1
+  return  weekday(now()); 
+}
+
+int weekday(time_t t) {
+  refreshCache(t);
+  return tm.Wday;
+}
+   
+int month(){
+  return month(now()); 
+}
+
+int month(time_t t) {  // the month for the given time
+  refreshCache(t);
+  return tm.Month;
+}
+
+int year() {  // as in Processing, the full four digit year: (2009, 2010 etc) 
+  return year(now()); 
+}
+
+int year(time_t t) { // the year for the given time
+  refreshCache(t);
+  return tmYearToCalendar(tm.Year);
+}
+
+/*============================================================================*/	
+/* functions to convert to and from system time */
+/* These are for interfacing with time serivces and are not normally needed in a sketch */
+
+// leap year calulator expects year argument as years offset from 1970
+#define LEAP_YEAR(Y)     ( ((1970+Y)>0) && !((1970+Y)%4) && ( ((1970+Y)%100) || !((1970+Y)%400) ) )
+
+static  const uint8_t monthDays[]={31,28,31,30,31,30,31,31,30,31,30,31}; // API starts months from 1, this array starts from 0
+ 
+void breakTime(time_t time, tmElements_t &tm){
+// break the given time_t into time components
+// this is a more compact version of the C library localtime function
+// note that year is offset from 1970 !!!
+
+  uint8_t year;
+  uint8_t month, monthLength;
+  unsigned long days;
+  
+  tm.Second = time % 60;
+  time /= 60; // now it is minutes
+  tm.Minute = time % 60;
+  time /= 60; // now it is hours
+  tm.Hour = time % 24;
+  time /= 24; // now it is days
+  tm.Wday = ((time + 4) % 7) + 1;  // Sunday is day 1 
+  
+  year = 0;  
+  days = 0;
+  while((unsigned)(days += (LEAP_YEAR(year) ? 366 : 365)) <= time) {
+    year++;
+  }
+  tm.Year = year; // year is offset from 1970 
+  
+  days -= LEAP_YEAR(year) ? 366 : 365;
+  time  -= days; // now it is days in this year, starting at 0
+  
+  days=0;
+  month=0;
+  monthLength=0;
+  for (month=0; month<12; month++) {
+    if (month==1) { // february
+      if (LEAP_YEAR(year)) {
+        monthLength=29;
+      } else {
+        monthLength=28;
+      }
+    } else {
+      monthLength = monthDays[month];
+    }
+    
+    if (time >= monthLength) {
+      time -= monthLength;
+    } else {
+        break;
+    }
+  }
+  tm.Month = month + 1;  // jan is month 1  
+  tm.Day = time + 1;     // day of month
+}
+
+time_t makeTime(tmElements_t &tm){   
+// assemble time elements into time_t 
+// note year argument is offset from 1970 (see macros in time.h to convert to other formats)
+// previous version used full four digit year (or digits since 2000),i.e. 2009 was 2009 or 9
+  
+  int i;
+  time_t seconds;
+
+  // seconds from 1970 till 1 jan 00:00:00 of the given year
+  seconds= tm.Year*(SECS_PER_DAY * 365);
+  for (i = 0; i < tm.Year; i++) {
+    if (LEAP_YEAR(i)) {
+      seconds +=  SECS_PER_DAY;   // add extra days for leap years
+    }
+  }
+  
+  // add days for this year, months start from 1
+  for (i = 1; i < tm.Month; i++) {
+    if ( (i == 2) && LEAP_YEAR(tm.Year)) { 
+      seconds += SECS_PER_DAY * 29;
+    } else {
+      seconds += SECS_PER_DAY * monthDays[i-1];  //monthDay array starts from 0
+    }
+  }
+  seconds+= (tm.Day-1) * SECS_PER_DAY;
+  seconds+= tm.Hour * SECS_PER_HOUR;
+  seconds+= tm.Minute * SECS_PER_MIN;
+  seconds+= tm.Second;
+  return seconds; 
+}
+/*=====================================================*/	
+/* Low level system time functions  */
+
+static time_t sysTime = 0;
+static time_t prevMillis = 0;
+static time_t nextSyncTime = 0;
+static timeStatus_t Status = timeNotSet;
+
+getExternalTime getTimePtr;  // pointer to external sync function
+//setExternalTime setTimePtr; // not used in this version
+
+#ifdef TIME_DRIFT_INFO   // define this to get drift data
+time_t sysUnsyncedTime = 0; // the time sysTime unadjusted by sync  
+#endif
+
+
+time_t now(){
+  while( millis() - prevMillis >= 1000){      
+    sysTime++;
+    prevMillis += 1000;	
+#ifdef TIME_DRIFT_INFO
+    sysUnsyncedTime++; // this can be compared to the synced time to measure long term drift     
+#endif	
+  }
+  if(nextSyncTime <= sysTime){
+	if(getTimePtr != 0){
+	  time_t t = getTimePtr();
+      if( t != 0)
+        setTime(t);
+      else
+        Status = (Status == timeNotSet) ?  timeNotSet : timeNeedsSync;        
+    }
+  }  
+  return sysTime;
+}
+
+void setTime(time_t t){ 
+#ifdef TIME_DRIFT_INFO
+ if(sysUnsyncedTime == 0) 
+   sysUnsyncedTime = t;   // store the time of the first call to set a valid Time   
+#endif
+
+  sysTime = t;  
+  nextSyncTime = t + syncInterval;
+  Status = timeSet; 
+  prevMillis = millis();  // restart counting from now (thanks to Korman for this fix)
+} 
+
+void  setTime(int hr,int min,int sec,int dy, int mnth, int yr){
+ // year can be given as full four digit year or two digts (2010 or 10 for 2010);  
+ //it is converted to years since 1970
+  if( yr > 99)
+      yr = yr - 1970;
+  else
+      yr += 30;  
+  tm.Year = yr;
+  tm.Month = mnth;
+  tm.Day = dy;
+  tm.Hour = hr;
+  tm.Minute = min;
+  tm.Second = sec;
+  setTime(makeTime(tm));
+}
+
+void adjustTime(long adjustment){
+  sysTime += adjustment;
+}
+
+timeStatus_t timeStatus(){ // indicates if time has been set and recently synchronized
+  return Status;
+}
+
+void setSyncProvider( getExternalTime getTimeFunction){
+  getTimePtr = getTimeFunction;  
+  nextSyncTime = sysTime;
+  now(); // this will sync the clock
+}
+
+void setSyncInterval(time_t interval){ // set the number of seconds between re-sync
+  syncInterval = interval;
+}
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