From 4931d2d41f40842016a22f4938f63d00b8aac5bf Mon Sep 17 00:00:00 2001
From: John Schember <john@nachtimwald.com>
Date: Sat, 25 Jun 2011 16:23:59 -0400
Subject: [PATCH] Fix Bug #801888: PalmDoc compression cannot compress empty
 string.

---
 src/calibre/ebooks/compression/palmdoc.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/calibre/ebooks/compression/palmdoc.py b/src/calibre/ebooks/compression/palmdoc.py
index 90dabcb5a8..6069777fab 100644
--- a/src/calibre/ebooks/compression/palmdoc.py
+++ b/src/calibre/ebooks/compression/palmdoc.py
@@ -17,6 +17,8 @@ def decompress_doc(data):
     return cPalmdoc.decompress(data)
 
 def compress_doc(data):
+    if not data:
+        return u''
     return cPalmdoc.compress(data)
 
 def test():