Diff: DateTime.cpp

Revision:

0:7f90c8e04249

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DateTime.cpp	Tue Jul 17 05:49:20 2012 +0000
@@ -0,0 +1,154 @@
+// Code by JeeLabs http://news.jeelabs.org/code/
+// Released to the public domain! Enjoy!
+
+/*
+ * Taken from https://github.com/adafruit/RTClib
+ * and modified for LPC1768 by Neal Horman July 2012
+ */
+
+#include "DateTime.h"
+
+#define SECONDS_PER_DAY 86400L
+#define SECONDS_FROM_1970_TO_2000 946684800
+
+////////////////////////////////////////////////////////////////////////////////
+// utility code, some of this could be exposed in the DateTime API if needed
+
+static const uint8_t daysInMonth [] = { 31,28,31,30,31,30,31,31,30,31,30,31 }; //has to be const or compiler compaints
+
+// number of days since 2000/01/01, valid for 2001..2099
+static uint16_t date2days(uint16_t y, uint8_t m, uint8_t d)
+{
+    if (y >= 2000)
+        y -= 2000;
+    
+    uint16_t days = d;
+    for (uint8_t i = 1; i < m; ++i)
+        days += daysInMonth[i - 1];
+    
+    if (m > 2 && y % 4 == 0)
+        ++days;
+    
+    return days + 365 * y + (y + 3) / 4 - 1;
+}
+
+static long time2long(uint16_t days, uint8_t h, uint8_t m, uint8_t s)
+{
+    return ((days * 24L + h) * 60 + m) * 60 + s;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// DateTime implementation - ignores time zones and DST changes
+// NOTE: also ignores leap seconds, see http://en.wikipedia.org/wiki/Leap_second
+
+DateTime::DateTime (uint32_t t)
+{
+    t -= SECONDS_FROM_1970_TO_2000;    // bring to 2000 timestamp from 1970
+
+    ss = t % 60;
+    t /= 60;
+    mm = t % 60;
+    t /= 60;
+    hh = t % 24;
+    
+    uint16_t days = t / 24;
+    uint8_t leap;
+    
+    for (yOff = 0; ; ++yOff)
+    {
+        leap = yOff % 4 == 0;
+        if (days < 365 + leap)
+            break;
+        days -= 365 + leap;
+    }
+    
+    for (m = 1; ; ++m)
+    {
+        uint8_t daysPerMonth = daysInMonth[m - 1];
+        
+        if (leap && m == 2)
+            ++daysPerMonth;
+        if (days < daysPerMonth)
+            break;
+        days -= daysPerMonth;
+    }
+    d = days + 1;
+}
+
+DateTime::DateTime (uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t min, uint8_t sec)
+{
+    if (year >= 2000)
+        year -= 2000;
+    yOff = year;
+    m = month;
+    d = day;
+    hh = hour;
+    mm = min;
+    ss = sec;
+}
+
+static uint8_t conv2d(const char* p)
+{   uint8_t v = 0;
+
+    if ('0' <= *p && *p <= '9')
+        v = *p - '0';
+        
+    return 10 * v + *++p - '0';
+}
+
+// A convenient constructor for using "the compiler's time":
+//   DateTime now (__DATE__, __TIME__);
+// NOTE: using PSTR would further reduce the RAM footprint
+DateTime::DateTime (const char* date, const char* time)
+{
+    // sample input: date = "Dec 26 2009", time = "12:34:56"
+    yOff = conv2d(date + 9);
+    // Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 
+    switch (date[0])
+    {
+        case 'J': m = date[1] == 'a' ? 1 : m = date[2] == 'n' ? 6 : 7; break;
+        case 'F': m = 2; break;
+        case 'A': m = date[2] == 'r' ? 4 : 8; break;
+        case 'M': m = date[2] == 'r' ? 3 : 5; break;
+        case 'S': m = 9; break;
+        case 'O': m = 10; break;
+        case 'N': m = 11; break;
+        case 'D': m = 12; break;
+    }
+    
+    d = conv2d(date + 4);
+    hh = conv2d(time);
+    mm = conv2d(time + 3);
+    ss = conv2d(time + 6);
+}
+
+uint8_t DateTime::dayOfWeek() const
+{   uint16_t day = date2days(yOff, m, d);
+
+    return (day + 6) % 7; // Jan 1, 2000 is a Saturday, i.e. returns 6
+}
+
+uint32_t DateTime::unixtime(void) const
+{   uint16_t days = date2days(yOff, m, d);
+    
+    return time2long(days, hh, mm, ss) + SECONDS_FROM_1970_TO_2000;  // seconds from 1970 to 2000
+}
+
+#ifdef WANT_RTC_MILLIS
+////////////////////////////////////////////////////////////////////////////////
+// RTC_Millis implementation
+
+long RTC_Millis::offset = 0;
+
+void RTC_Millis::adjust(const DateTime& dt)
+{
+    offset = dt.unixtime() - millis() / 1000;
+}
+
+DateTime RTC_Millis::now()
+{
+  return (uint32_t)(offset + millis() / 1000);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+#endif
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