X-Git-Url: http://git.kpe.io/?p=kmrcl.git;a=blobdiff_plain;f=datetime.lisp;h=8357da030b95b5e028d80711e072e6fb83cfdc30;hp=771d75ad794f3e7cc06331bdc7beecb7449ab5c4;hb=22765cd49d01672b58873f98554c3b5f3069663f;hpb=d11d6cc43fd9227a8aeed28dc2cfecdbc587ec4a

diff --git a/datetime.lisp b/datetime.lisp
index 771d75a..8357da0 100644
--- a/datetime.lisp
+++ b/datetime.lisp
@@ -32,16 +32,20 @@
 		   "July" "August" "September" "October" "November"
 		   "December")
 		 (1- mn))
-	    (format nil "~A" dy) (format nil "~A" yr)
+	    (format nil "~A" dy)
+            (format nil "~A" yr)
 	    (format nil "~2,'0D:~2,'0D:~2,'0D" hr min sec))))
 
+(defun pretty-date-ut (&optional (tm (get-universal-time)))
+  (multiple-value-bind (sec min hr dy mn yr) (decode-universal-time tm)
+    (pretty-date yr mn dy hr min sec)))
 
 (defun date-string (ut)
   (if (typep ut 'integer)
       (multiple-value-bind (sec min hr day mon year dow daylight-p zone)
 	  (decode-universal-time ut)
 	(declare (ignore daylight-p zone))
-	(format nil "~[Mon~;Tue~;Wed~;Thu~;Fri~;Sat~;Sun~], ~d ~[Jan~;Feb~;Mar~;Apr~;May~;Jun~;Jul~;Aug~;Sep~;Oct~;Nov~;Dec~] ~d ~2,'0d:~2,'0d:~2,'0d" 
+	(format nil "~[Mon~;Tue~;Wed~;Thu~;Fri~;Sat~;Sun~], ~d ~[Jan~;Feb~;Mar~;Apr~;May~;Jun~;Jul~;Aug~;Sep~;Oct~;Nov~;Dec~] ~d ~2,'0d:~2,'0d:~2,'0d"
 		dow
 		day
 		(1- mon)
@@ -68,3 +72,86 @@
     (t
      (format t "~,2F ~A" val unit))))
 
+(defconstant +posix-epoch+
+  (encode-universal-time 0 0 0 1 1 1970 0))
+
+(defun posix-time-to-utime (time)
+  (+ time +posix-epoch+))
+
+(defun utime-to-posix-time (utime)
+  (- utime +posix-epoch+))
+
+;; Monthnames taken from net-telent-date to support lml2
+
+(defvar *monthnames*
+  '((1 . "January")
+    (2 . "February")
+    (3 . "March")
+    (4 . "April")
+    (5 . "May")
+    (6 . "June")
+    (7 . "July")
+    (8 . "August")
+    (9 . "September")
+    (10 . "October")
+    (11 . "November")
+    (12 . "December")))
+
+(defun monthname (stream arg colon-p at-p &optional width (mincol 0) (colinc 1) (minpad 0) (padchar #\Space))
+  "Print the name of the month (1=January) corresponding to ARG on STREAM.  This is intended for embedding in a FORMAT directive: WIDTH governs the number of characters of text printed, MINCOL, COLINC, MINPAD, PADCHAR work as for ~A"
+  (declare (ignore colon-p))
+  (let ((monthstring (cdr (assoc arg *monthnames*))))
+    (if (not monthstring) (return-from monthname nil))
+    (let ((truncate (if width (min width (length monthstring)) nil)))
+      (format stream
+              (if at-p "~V,V,V,V@A" "~V,V,V,VA")
+              mincol colinc minpad padchar
+              (subseq monthstring 0 truncate)))))
+
+(defconstant* +zellers-adj+ #(0 3 2 5 0 3 5 1 4 6 2 4))
+
+(defun day-of-week (year month day)
+  "Day of week calculation using Zeller's Congruence.
+Input: The year y, month m (1 ≤ m ≤ 12) and day d (1 ≤ d ≤ 31).
+Output: n - the day of the week (Sunday = 0, Saturday = 6)."
+
+  (when (< month 3)
+    (decf year))
+  (mod
+   (+ year (floor year 4) (- (floor year 100)) (floor year 400)
+      (aref +zellers-adj+ (1- month)) day)
+   7))
+
+;;;; Daylight Saving Time calculations
+
+;; Daylight Saving Time begins for most of the United States at 2
+;; a.m. on the first Sunday of April. Time reverts to standard time at
+;; 2 a.m. on the last Sunday of October. In the U.S., each time zone
+;; switches at a different time.
+
+;; In the European Union, Summer Time begins and ends at 1 am
+;; Universal Time (Greenwich Mean Time). It starts the last Sunday in
+;; March, and ends the last Sunday in October. In the EU, all time
+;; zones change at the same moment.
+
+;; Spring forward, Fall back
+;; During DST, clocks are turned forward an hour, effectively moving
+;; an hour of daylight from the morning to the evening.
+
+;; United States                  European Union
+
+;; Year  DST Begins DST Ends     Summertime     Summertime
+;;       at 2 a.m.  at 2 a.m.    period begins  period ends
+;;                               at 1 a.m. UT   at 1 a.m. UT
+;; ----------------------------------------------------------
+;; 2000  April 2   October 29    March 26       October 29
+;; 2001  April 1   October 28    March 25       October 28
+;; 2002  April 7   October 27    March 31       October 27
+;; 2003  April 6   October 26    March 30       October 26
+;; 2004  April 4   October 31    March 28       October 31
+;; 2005  April 3   October 30    March 27       October 30
+;; 2006  April 2   October 29    March 26       October 29
+;; 2007  April 1   October 28    March 25       October 28
+;; 2008  April 6   October 26    March 30       October 26
+
+