From 9ee7dc27e85f1d6e948210818a4b68082bf5792d Mon Sep 17 00:00:00 2001
From: Charles Haley <>
Date: Wed, 5 Jan 2011 19:21:17 +0000
Subject: [PATCH] Do slice stepping correctly

---
 src/calibre/library/caches.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/calibre/library/caches.py b/src/calibre/library/caches.py
index ada1ee0a77..2596b494bf 100644
--- a/src/calibre/library/caches.py
+++ b/src/calibre/library/caches.py
@@ -144,7 +144,9 @@ class CacheRow(list):
         if self._must_do:
             is_comp = False
             if isinstance(col, slice):
-                for c in range(col.start, col.stop):
+                start = 0 if col.start is None else col.start
+                step = 1 if col.stop is None else col.stop
+                for c in range(start, col.stop, step):
                     if c in self._composites:
                         is_comp = True
                         break