From: Robert Mast <beheerder@tekenbeetziekten.nl>
To: notmuch@notmuchmail.org
Subject: [PATCH] This patch is a little finger excercise for working with git.
	I found a piece of code that I didn't understand at first.
Date: Sun,  3 Feb 2013 19:51:31 +0100
Message-Id: <1359917491-17178-1-git-send-email-beheerder@tekenbeetziekten.nl>
Cc: Robert Mast <beheerder@tekenbeetziekten.nl>
Precedence: list

Reading it in detail I thought it allocated way too much memory and
didn't use the full size of the allocated unsigned ints for storing
bits.

Am I right, and is this the right way to patch code to notmuch?

---
 lib/query.cc |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/query.cc b/lib/query.cc
index e9c1a2d..046663a 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -43,8 +43,8 @@ struct _notmuch_doc_id_set {
     unsigned int bound;
 };
 
-#define DOCIDSET_WORD(bit) ((bit) / sizeof (unsigned int))
-#define DOCIDSET_BIT(bit) ((bit) % sizeof (unsigned int))
+#define DOCIDSET_WORD(bit) ((bit) / (sizeof (unsigned int) * CHAR_BIT))
+#define DOCIDSET_BIT(bit) ((bit) % (sizeof (unsigned int) * CHAR_BIT))
 
 struct visible _notmuch_threads {
     notmuch_query_t *query;
@@ -363,7 +363,7 @@ _notmuch_doc_id_set_init (void *ctx,
 
     for (unsigned int i = 0; i < arr->len; i++)
 	max = MAX(max, g_array_index (arr, unsigned int, i));
-    bitmap = talloc_zero_array (ctx, unsigned int, 1 + max / sizeof (*bitmap));
+    bitmap = talloc_zero_array (ctx, unsigned int, (DOCIDSET_WORD(max) + 1) * sizeof (*bitmap));
 
     if (bitmap == NULL)
 	return FALSE;
-- 
1.7.9.5