From 90f99fd4c47a7a28b33e330e93628e4c3c71474a Mon Sep 17 00:00:00 2001
From: fawce <fawce@quantopian.com>
Date: Tue, 3 Jul 2012 17:34:15 -0400
Subject: [PATCH] added methods to convert epochs to/from days since the
 UNIX_EPOCH.

---
 zipline/utils/date_utils.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/zipline/utils/date_utils.py b/zipline/utils/date_utils.py
index b80ee867..a1fbfad1 100644
--- a/zipline/utils/date_utils.py
+++ b/zipline/utils/date_utils.py
@@ -70,7 +70,16 @@ class utcdatetime(datetime):
         dt = datetime.__new__(cls, *args, **kwargs)
         return dt
 
+def days_since_epoch(ms_since_epoch):
+    dt = UN_EPOCH(ms_since_epoch)
+    delta = dt - UNIX_EPOCH
+    return delta.days
 
+def epoch_from_days(days_since_epoch):
+    delta = timedelta(days=days_since_epoch)
+    dt = UNIX_EPOCH + delta
+    ms = EPOCH(dt)
+    return ms
 
 # Datetime Calculations
 # ---------------------