add ProDOS date/time class

git-svn-id: https://profuse.googlecode.com/svn/trunk@47 aa027e90-d47c-11dd-86d7-074df07e0730

DateTime.cpp

@@ -0,0 +1,130 @@
+#include "DateTime.h"
+
+#include <strings.h>
+
+namespace ProDOS {
+
+/*
+ *  date is a 16 bit value:
+ *
+ *  7 6 5 4 3 2 1 0   7 6 5 4 3 2 1 0 
+ * +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ 
+ * |    Year     |  Month  |   Day   |  
+ * +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ 
+ *
+ * time is a 16 bit value:
+ *
+ *  7 6 5 4 3 2 1 0   7 6 5 4 3 2 1 0 
+ * +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ 
+ * |0 0 0|  Hour   | |0 0|  Minute   | 
+ * +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ 
+ *
+ */
+DateTime::DateTime() 
+{
+    DateTime(time(NULL));
+}
+
+DateTime::DateTime(uint32_t dtm) :
+    _yymmdd((dtm >> 16) & 0xff), _hhmm(dtm & 0xff)
+{
+}
+
+DateTime::DateTime(unsigned yymmdd, unsigned hhmm) :
+    _yymmdd(yymmdd), _hhmm(hhmm)
+{
+}
+
+DateTime::DateTime(time_t time)
+{
+    tm t;
+
+    localtime_r(&time, &t);
+
+    DateTime(t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, t.tm_hour, t.tm_min);
+
+}
+
+
+DateTime::DateTime(unsigned year, unsigned month, unsigned day,
+        unsigned hour, unsigned minute)
+{
+  
+    // 1940 is the earliest year, so clamp to 1940-01-01 00:00
+    if (year < 1940)
+    {
+        _yymmdd = (40 << 9) | (1 << 5) | 1;
+        _hhmm = 0;
+        return;
+    }
+    // 2039 is the latest year, so clamp to 2039-12-31 23:59
+    if (year > 2039)
+    {
+        _yymmdd = (39 << 9) | (12 << 5) | 31;
+        _hhmm = (23 << 8) | 59;
+        return;
+    }
+
+    if (year >= 2000) year -= 2000;
+    else year -= 1900;
+
+
+    _hhmm = minute | (hour << 8);
+
+    _yymmdd = day | (month << 5) | (year << 9);
+}
+
+/*
+ * ProDOS technote 28
+ *
+ * The following definition allows the same range of years that the Apple IIgs
+ * Control Panel CDA currently does:
+ *
+ * o  A seven-bit ProDOS year value is in the range 0 to 99
+ * (100 through 127 are invalid)
+ * o  Year values from 40 to 99 represent 1940 through 1999
+ * o  Year values from 0 to 39 represent 2000 through 2039
+ */
+
+
+unsigned DateTime::year() const
+{
+    unsigned tmp = _yymmdd >> 9;
+    if (tmp == 0 || tmp > 100) return 0;
+  
+    if (tmp <= 39) tmp += 2000;
+    else tmp += 1900;
+
+    return tmp;
+}
+
+/*
+ * A positive or 0 value for tm_isdst causes mktime() to presume initially
+ * that Daylight Savings Time, respectively, is or is not in effect for
+ * the specified time. A negative value for tm_isdst causes mktime() to
+ * attempt to determine whether Daylight Saving Time is in effect for the
+ * specified time.
+ */
+
+time_t DateTime::toUnix() const
+{
+    tm t;
+
+    if (_yymmdd == 0) return 0;
+
+    bzero(&t, sizeof(tm));
+
+    t.tm_min = minute();
+    // tm_hour is 0-23, but is_dst -1 compensates
+    t.tm_hour = hour() - 1;
+    t.tm_isdst = -1;
+
+    t.tm_mday = day();
+    t.tm_mon = month() - 1;
+    t.tm_year = year() - 1900;
+
+    return mktime(&t);
+    // convert back via locatime & fudge for dst?
+}
+
+} // namespace

DateTime.h

@@ -0,0 +1,75 @@
+#ifndef __PRODOS_DATE_TIME__
+#define __PRODOS_DATE_TIME__
+
+#include <ctime>
+#include <stdint.h>
+
+namespace ProDOS {
+
+class DateTime
+{
+public:
+    DateTime(); 
+    DateTime(time_t);
+    DateTime(uint32_t);
+    DateTime(unsigned, unsigned);
+
+    DateTime(unsigned year, unsigned month, unsigned day, 
+        unsigned hour, unsigned minute);
+
+    time_t toUnix() const;
+   
+
+    operator time_t() const;
+    unsigned minute() const;
+    unsigned hour() const;
+    unsigned day() const;
+    unsigned month() const;
+    unsigned year() const;
+
+private:
+    unsigned _hhmm;
+    unsigned _yymmdd;
+};
+
+
+DateTime::operator time_t() const
+{
+    return toUnix();
+}
+
+
+unsigned DateTime::minute() const 
+{
+    return _hhmm & 0x3f;
+}
+
+unsigned DateTime::hour() const
+{
+    return (_hhmm >> 8) & 0x1f;
+}
+
+
+unsigned DateTime::day() const
+{
+    return _yymmdd & 0x1f;
+}
+
+unsigned DateTime::month() const
+{
+    return (_yymmdd >> 5) & 0x1f;
+}
+
+/*
+unsigned DateTime::year() const
+{
+    unsigned tmp = _yymmdd >> 9;
+    if (tmp <= 39) tmp += 100;
+    return tmp + 1900;
+}
+*/
+
+} // namespace
+
+#endif
+