# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1454884520 -3600
# Node ID ed312d199bb75ff53a37cbeb31b091ddd93e02e3
# Parent  e55229d8df6d809be921b20c8a2d4a22110d0be3
Added support for duration formatting.

diff -r e55229d8df6d -r ed312d199bb7 imiptools/dates.py
--- a/imiptools/dates.py	Sun Jan 31 17:18:54 2016 +0100
+++ b/imiptools/dates.py	Sun Feb 07 23:35:20 2016 +0100
@@ -3,7 +3,7 @@
 """
 Date processing functions.
 
-Copyright (C) 2014, 2015 Paul Boddie <paul@boddie.org.uk>
+Copyright (C) 2014, 2015, 2016 Paul Boddie <paul@boddie.org.uk>
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -89,6 +89,19 @@
     else:
         return None
 
+def format_duration(td):
+
+    "Format the timedelta 'td' as an iCalendar-compatible string."
+
+    if not td:
+        return None
+    else:
+        day_portion = td.days and "%dD" % td.days or ""
+        time_portion = td.seconds and "T%dS" % td.seconds or ""
+        if not day_portion and not time_portion:
+            time_portion = "T0S"
+        return "P%s%s" % (day_portion, time_portion)
+
 # Parsing of datetime and related information.
 
 def get_datetime(value, attr=None):