[src/trunk]: src/lib/libc/db/hash If MAX_BSIZE == hashp->BSIZE (65536) then i...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8dedc7ce91c0
branches:  trunk
changeset: 341688:8dedc7ce91c0
user:      christos <christos%NetBSD.org@localhost>
date:      Wed Nov 18 00:23:39 2015 +0000

description:
If MAX_BSIZE == hashp->BSIZE (65536) then it does not fit in a short, and
we end up storing 0... This means that every entry needs a page. We store
MAX_BSIZE - 1 here, but it would be better to always store (avail - 1) here
so that we don't waste a byte and be consistent.

diffstat:

 lib/libc/db/hash/hash_page.c |  8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diffs (29 lines):

diff -r 392d53043d46 -r 8dedc7ce91c0 lib/libc/db/hash/hash_page.c
--- a/lib/libc/db/hash/hash_page.c      Tue Nov 17 22:01:39 2015 +0000
+++ b/lib/libc/db/hash/hash_page.c      Wed Nov 18 00:23:39 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: hash_page.c,v 1.26 2013/12/01 00:22:48 christos Exp $  */
+/*     $NetBSD: hash_page.c,v 1.27 2015/11/18 00:23:39 christos Exp $  */
 
 /*-
  * Copyright (c) 1990, 1993, 1994
@@ -37,7 +37,7 @@
 #endif
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: hash_page.c,v 1.26 2013/12/01 00:22:48 christos Exp $");
+__RCSID("$NetBSD: hash_page.c,v 1.27 2015/11/18 00:23:39 christos Exp $");
 
 /*
  * PACKAGE:  hashing
@@ -85,7 +85,9 @@
        temp = 3 * sizeof(uint16_t); \
        _DIAGASSERT((size_t)hashp->BSIZE >= temp); \
        ((uint16_t *)(void *)(P))[1] = (uint16_t)(hashp->BSIZE - temp); \
-       ((uint16_t *)(void *)(P))[2] = hashp->BSIZE; \
+       /* we should be really storing always length - 1 here... */ \
+       ((uint16_t *)(void *)(P))[2] = \
+           hashp->BSIZE == MAX_BSIZE ? MAX_BSIZE - 1 : hashp->BSIZE; \
 }
 
 /*