From 0e5b77af2c0f6253025afbdb77aff38a02e30602 Mon Sep 17 00:00:00 2001
From: Karsten Blees <karsten.blees@gmail.com>
Date: Sat, 7 Dec 2013 20:56:32 +0100
Subject: hashmap.h: make sure map entries are tightly packed

Extending 'struct hashmap_entry' with an int-sized member shouldn't waste
memory on 64-bit systems. This is already documented in api-hashmap.txt,
but needs '__attribute__((__packed__))' to work.

Reduces e.g.

 struct name_entry {
     struct hashmap_entry ent;
     int namelen;
     char *name;
 };

from 32 to 24 bytes.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 hashmap.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hashmap.h b/hashmap.h
index a816ad47b1..b64567bc17 100644
--- a/hashmap.h
+++ b/hashmap.h
@@ -15,7 +15,7 @@ extern unsigned int memihash(const void *buf, size_t len);
 
 /* data structures */
 
-struct hashmap_entry {
+struct __attribute__((__packed__)) hashmap_entry {
 	struct hashmap_entry *next;
 	unsigned int hash;
 };
-- 
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