From 7bcd1596b04a6a2c971569c5fdfdc96ba9e61c8c Mon Sep 17 00:00:00 2001
From: arkdro <arkdro@gmail.com>
Date: Thu, 21 Feb 2013 00:07:14 +0400
Subject: [PATCH] add api to check whether the dst is active

---
 src/ezic.erl | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/ezic.erl b/src/ezic.erl
index 18ce7f0..c6612f0 100644
--- a/src/ezic.erl
+++ b/src/ezic.erl
@@ -5,6 +5,8 @@
 	 localtime/1
 	 , utc_to_local/2
 	 , local_to_utc/2
+	 , has_dst_utc/2
+	 , has_dst_local/2
 	]).
 
 
@@ -30,7 +32,11 @@ local_to_utc(LocalDatetime, TzName) ->
     local_to_utc_handleFlatzone(LocalDatetime, ezic_db:flatzone(NormalDatetime, TzName)).
     
 
+has_dst_utc(Datetime, TzName) ->
+    has_dst(Datetime, TzName, u).
 
+has_dst_local(Datetime, TzName) ->
+    has_dst(Datetime, TzName, w).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % PRIVATE
@@ -55,3 +61,14 @@ local_to_utc_handleFlatzone(LocalDatetime, #flatzone{offset=Offset, dstoffset=DS
     	, Offset, {0,0,0})
       , DSTOffset, {0,0,0}).
 
+has_dst(Datetime, TzName, Flag) ->
+    NormalDatetime = ezic_date:normalize(Datetime, Flag),
+    case ezic_db:flatzone(NormalDatetime, TzName) of
+        #flatzone{dstoffset={0,0,0}} ->
+            false;
+        #flatzone{dstoffset={_,_,_}} ->
+            true;
+        _ ->
+            false
+    end.
+