Index: openacs-4/packages/xotcl-core/tcl/ical-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xotcl-core/tcl/ical-procs.tcl,v
diff -u
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ openacs-4/packages/xotcl-core/tcl/ical-procs.tcl	2 Dec 2007 21:42:44 -0000	1.1
@@ -0,0 +1,60 @@
+ad_library {
+    Utility functions for ical data 
+    
+    @author neumann@wu-wien.ac.at
+    @creation-date July 20, 2005
+
+  Incomplete backport from my calendar extensions
+}
+
+namespace eval ::xo {
+  ::xotcl::Object ::xo::ical -ad_doc {
+    The Object ::calendar::ical provides the methods for 
+    importing and exporting single or multiple calendar items
+    in the ical format (see rfc 2445). Currently only the part
+    of ical is implemented, which is used by the mozilla
+    calendar (sunbird, or the xul-file for thunderbird or firefox).
+    
+    @author Gustaf Neumann
+  }
+
+
+  #
+  # conversion routines from and to the date formats used by ical
+  #
+  ical proc date_time_to_clock {date time utc} {
+    set year  [string range $date 0 3]
+    set month [string range $date 4 5]
+    set day   [string range $date 6 7]
+    set hour  [string range $time 0 1]
+    set min   [string range $time 2 3]
+    set sec   [string range $time 4 5]
+    set TZ [expr {$utc ? "GMT" : ""}]
+    return [clock scan "$year-$month-$day $hour:$min $TZ"]
+  }
+  ical proc clock_to_utc {seconds} {
+    clock format $seconds -format "%Y%m%dT%H%M%SZ" -gmt 1
+  }
+  ical proc clock_to_iso {seconds} {
+    clock format $seconds -format "%Y-%m-%dT%H:%M:%SZ" -gmt 1
+  }
+  ical proc clock_to_local_day {seconds} {
+    clock format $seconds -format "%Y%m%d"
+  }
+  ical proc clock_to_oacstime {seconds} {
+    clock format $seconds -format "%Y-%m-%d %H:%M" 
+  }
+  
+  ical ad_proc dates_valid_p {
+    -start_date:required
+    -end_date:required
+  } {
+    A sanity check that the start time is before the end time.
+    This is a rewrite of calendar::item::dates_valid_p, but
+    about 100 times faster.
+  } {
+    #my log "$start_date <= $end_date = [expr {[clock scan $start_date] <= [clock scan $end_date]}]"
+    expr {[clock scan $start_date] <= [clock scan $end_date]}
+  }
+  
+}
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