diff options
Diffstat (limited to 'lib/erl_interface/src/registry/hash_dohash.c')
-rw-r--r-- | lib/erl_interface/src/registry/hash_dohash.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/lib/erl_interface/src/registry/hash_dohash.c b/lib/erl_interface/src/registry/hash_dohash.c new file mode 100644 index 0000000000..f672dce9b3 --- /dev/null +++ b/lib/erl_interface/src/registry/hash_dohash.c @@ -0,0 +1,45 @@ +/* + * %CopyrightBegin% + * + * Copyright Ericsson AB 1998-2009. All Rights Reserved. + * + * The contents of this file are subject to the Erlang Public License, + * Version 1.1, (the "License"); you may not use this file except in + * compliance with the License. You should have received a copy of the + * Erlang Public License along with this software. If not, it can be + * retrieved online at http://www.erlang.org/. + * + * Software distributed under the License is distributed on an "AS IS" + * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See + * the License for the specific language governing rights and limitations + * under the License. + * + * %CopyrightEnd% + * + + */ +#include "hash.h" + +/* This is hashpjw, from the dragon book */ +/* Note that this function is only used as a default hash function. + * All calls are made through the hash pointer in the tab structure. + * The only place this function is explicitly referenced is in + * hash_newtab(); Users can use hash_setfunc() to change the hash function. + */ +int ei_dohash(const char *key) +{ + const char *s; + unsigned h = 0; + unsigned g; + + for (s=key; *s; s++) { + h = (h << 4) + *s; + if ((g = (h & 0xf0000000))) { /* assumes 32-bit int */ + h = h^(g >> 24); + h = h^g; + } + } + return h; +} + + |