diff options
| author | Damien Miller <djm@cvs.openbsd.org> | 2008-03-15 04:57:51 +0000 |
|---|---|---|
| committer | Damien Miller <djm@cvs.openbsd.org> | 2008-03-15 04:57:51 +0000 |
| commit | e3e28c1165458f7a58667f74181afcae889fb357 (patch) | |
| tree | 12f47c3f86b9692ad7ced677edce3241f9fffee6 /usr.sbin | |
| parent | e5c77630f050400096e5727c1267923f6ca50c4d (diff) | |
Because the shuffle code initialisation is a specific case of shuffling
a set of incrementing integers (and not an arbitrary set of values) it
is possible to populate the array as we shuffle it in a single forward
pass. Clever optimisation from didickman AT gmail.com;
ok deraadt@ mcbride@
(same change as netinet/ip_id.c)
Diffstat (limited to 'usr.sbin')
| -rw-r--r-- | usr.sbin/bind/lib/isc/shuffle.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/usr.sbin/bind/lib/isc/shuffle.c b/usr.sbin/bind/lib/isc/shuffle.c index 5e8bb6f9529..0cdcdef6f9b 100644 --- a/usr.sbin/bind/lib/isc/shuffle.c +++ b/usr.sbin/bind/lib/isc/shuffle.c @@ -15,7 +15,7 @@ * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ -/* $OpenBSD: shuffle.c,v 1.2 2008/03/02 22:39:12 djm Exp $ */ +/* $OpenBSD: shuffle.c,v 1.3 2008/03/15 04:57:50 djm Exp $ */ #include <config.h> @@ -37,15 +37,11 @@ isc_shuffle_init(isc_shuffle_t *shuffle) REQUIRE(VALID_SHUFFLE(shuffle)); shuffle->isindex = 0; - for (i = 0; i < 65536; ++i) - shuffle->id_shuffle[i] = i; - - /* Initialize using a Durstenfeld shuffle */ - for (i = 65536; --i; ) { + /* Initialize using a Knuth shuffle */ + for (i = 0; i < 65536; ++i) { i2 = isc_random_uniform(i + 1); - r = shuffle->id_shuffle[i]; shuffle->id_shuffle[i] = shuffle->id_shuffle[i2]; - shuffle->id_shuffle[i2] = r; + shuffle->id_shuffle[i2] = i; } } |