125b3c049e70834cf33790a28643ab058b507b35cBen Cheng/* Compute hash value for given string according to ELF standard. 225b3c049e70834cf33790a28643ab058b507b35cBen Cheng Copyright (C) 2006 Red Hat, Inc. 325b3c049e70834cf33790a28643ab058b507b35cBen Cheng This file is part of Red Hat elfutils. 425b3c049e70834cf33790a28643ab058b507b35cBen Cheng Written by Ulrich Drepper <drepper@redhat.com>, 1995. 525b3c049e70834cf33790a28643ab058b507b35cBen Cheng 625b3c049e70834cf33790a28643ab058b507b35cBen Cheng Red Hat elfutils is free software; you can redistribute it and/or modify 725b3c049e70834cf33790a28643ab058b507b35cBen Cheng it under the terms of the GNU General Public License as published by the 825b3c049e70834cf33790a28643ab058b507b35cBen Cheng Free Software Foundation; version 2 of the License. 925b3c049e70834cf33790a28643ab058b507b35cBen Cheng 1025b3c049e70834cf33790a28643ab058b507b35cBen Cheng Red Hat elfutils is distributed in the hope that it will be useful, but 1125b3c049e70834cf33790a28643ab058b507b35cBen Cheng WITHOUT ANY WARRANTY; without even the implied warranty of 1225b3c049e70834cf33790a28643ab058b507b35cBen Cheng MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 1325b3c049e70834cf33790a28643ab058b507b35cBen Cheng General Public License for more details. 1425b3c049e70834cf33790a28643ab058b507b35cBen Cheng 1525b3c049e70834cf33790a28643ab058b507b35cBen Cheng You should have received a copy of the GNU General Public License along 1625b3c049e70834cf33790a28643ab058b507b35cBen Cheng with Red Hat elfutils; if not, write to the Free Software Foundation, 1725b3c049e70834cf33790a28643ab058b507b35cBen Cheng Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 1825b3c049e70834cf33790a28643ab058b507b35cBen Cheng 1925b3c049e70834cf33790a28643ab058b507b35cBen Cheng In addition, as a special exception, Red Hat, Inc. gives You the 2025b3c049e70834cf33790a28643ab058b507b35cBen Cheng additional right to link the code of Red Hat elfutils with code licensed 2125b3c049e70834cf33790a28643ab058b507b35cBen Cheng under an Open Source Initiative certified open source license 2225b3c049e70834cf33790a28643ab058b507b35cBen Cheng (http://www.opensource.org/licenses/index.php) and to distribute linked 2325b3c049e70834cf33790a28643ab058b507b35cBen Cheng combinations including the two. Non-GPL Code permitted under this 2425b3c049e70834cf33790a28643ab058b507b35cBen Cheng exception must only link to the code of Red Hat elfutils through those 2525b3c049e70834cf33790a28643ab058b507b35cBen Cheng well defined interfaces identified in the file named EXCEPTION found in 2625b3c049e70834cf33790a28643ab058b507b35cBen Cheng the source code files (the "Approved Interfaces"). The files of Non-GPL 2725b3c049e70834cf33790a28643ab058b507b35cBen Cheng Code may instantiate templates or use macros or inline functions from 2825b3c049e70834cf33790a28643ab058b507b35cBen Cheng the Approved Interfaces without causing the resulting work to be covered 2925b3c049e70834cf33790a28643ab058b507b35cBen Cheng by the GNU General Public License. Only Red Hat, Inc. may make changes 3025b3c049e70834cf33790a28643ab058b507b35cBen Cheng or additions to the list of Approved Interfaces. Red Hat's grant of 3125b3c049e70834cf33790a28643ab058b507b35cBen Cheng this exception is conditioned upon your not adding any new exceptions. 3225b3c049e70834cf33790a28643ab058b507b35cBen Cheng If you wish to add a new Approved Interface or exception, please contact 3325b3c049e70834cf33790a28643ab058b507b35cBen Cheng Red Hat. You must obey the GNU General Public License in all respects 3425b3c049e70834cf33790a28643ab058b507b35cBen Cheng for all of the Red Hat elfutils code and other code used in conjunction 3525b3c049e70834cf33790a28643ab058b507b35cBen Cheng with Red Hat elfutils except the Non-GPL Code covered by this exception. 3625b3c049e70834cf33790a28643ab058b507b35cBen Cheng If you modify this file, you may extend this exception to your version 3725b3c049e70834cf33790a28643ab058b507b35cBen Cheng of the file, but you are not obligated to do so. If you do not wish to 3825b3c049e70834cf33790a28643ab058b507b35cBen Cheng provide this exception without modification, you must delete this 3925b3c049e70834cf33790a28643ab058b507b35cBen Cheng exception statement from your version and license this file solely under 4025b3c049e70834cf33790a28643ab058b507b35cBen Cheng the GPL without exception. 4125b3c049e70834cf33790a28643ab058b507b35cBen Cheng 4225b3c049e70834cf33790a28643ab058b507b35cBen Cheng Red Hat elfutils is an included package of the Open Invention Network. 4325b3c049e70834cf33790a28643ab058b507b35cBen Cheng An included package of the Open Invention Network is a package for which 4425b3c049e70834cf33790a28643ab058b507b35cBen Cheng Open Invention Network licensees cross-license their patents. No patent 4525b3c049e70834cf33790a28643ab058b507b35cBen Cheng license is granted, either expressly or impliedly, by designation as an 4625b3c049e70834cf33790a28643ab058b507b35cBen Cheng included package. Should you wish to participate in the Open Invention 4725b3c049e70834cf33790a28643ab058b507b35cBen Cheng Network licensing program, please visit www.openinventionnetwork.com 4825b3c049e70834cf33790a28643ab058b507b35cBen Cheng <http://www.openinventionnetwork.com>. */ 4925b3c049e70834cf33790a28643ab058b507b35cBen Cheng 5025b3c049e70834cf33790a28643ab058b507b35cBen Cheng#ifndef _DL_HASH_H 5125b3c049e70834cf33790a28643ab058b507b35cBen Cheng#define _DL_HASH_H 1 5225b3c049e70834cf33790a28643ab058b507b35cBen Cheng 5325b3c049e70834cf33790a28643ab058b507b35cBen Cheng 5425b3c049e70834cf33790a28643ab058b507b35cBen Cheng/* This is the hashing function specified by the ELF ABI. In the 5525b3c049e70834cf33790a28643ab058b507b35cBen Cheng first five operations no overflow is possible so we optimized it a 5625b3c049e70834cf33790a28643ab058b507b35cBen Cheng bit. */ 5725b3c049e70834cf33790a28643ab058b507b35cBen Chengstatic inline unsigned int 5825b3c049e70834cf33790a28643ab058b507b35cBen Cheng__attribute__ ((__pure__)) 5925b3c049e70834cf33790a28643ab058b507b35cBen Cheng_dl_elf_hash (const char *name) 6025b3c049e70834cf33790a28643ab058b507b35cBen Cheng{ 6125b3c049e70834cf33790a28643ab058b507b35cBen Cheng const unsigned char *iname = (const unsigned char *) name; 6225b3c049e70834cf33790a28643ab058b507b35cBen Cheng unsigned int hash = (unsigned int) *iname++; 6325b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (*iname != '\0') 6425b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 6525b3c049e70834cf33790a28643ab058b507b35cBen Cheng hash = (hash << 4) + (unsigned int) *iname++; 6625b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (*iname != '\0') 6725b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 6825b3c049e70834cf33790a28643ab058b507b35cBen Cheng hash = (hash << 4) + (unsigned int) *iname++; 6925b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (*iname != '\0') 7025b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 7125b3c049e70834cf33790a28643ab058b507b35cBen Cheng hash = (hash << 4) + (unsigned int) *iname++; 7225b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (*iname != '\0') 7325b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 7425b3c049e70834cf33790a28643ab058b507b35cBen Cheng hash = (hash << 4) + (unsigned int) *iname++; 7525b3c049e70834cf33790a28643ab058b507b35cBen Cheng while (*iname != '\0') 7625b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 7725b3c049e70834cf33790a28643ab058b507b35cBen Cheng unsigned int hi; 7825b3c049e70834cf33790a28643ab058b507b35cBen Cheng hash = (hash << 4) + (unsigned int) *iname++; 7925b3c049e70834cf33790a28643ab058b507b35cBen Cheng hi = hash & 0xf0000000; 8025b3c049e70834cf33790a28643ab058b507b35cBen Cheng 8125b3c049e70834cf33790a28643ab058b507b35cBen Cheng /* The algorithm specified in the ELF ABI is as 8225b3c049e70834cf33790a28643ab058b507b35cBen Cheng follows: 8325b3c049e70834cf33790a28643ab058b507b35cBen Cheng 8425b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (hi != 0) 8525b3c049e70834cf33790a28643ab058b507b35cBen Cheng hash ^= hi >> 24; 8625b3c049e70834cf33790a28643ab058b507b35cBen Cheng 8725b3c049e70834cf33790a28643ab058b507b35cBen Cheng hash &= ~hi; 8825b3c049e70834cf33790a28643ab058b507b35cBen Cheng 8925b3c049e70834cf33790a28643ab058b507b35cBen Cheng But the following is equivalent and a lot 9025b3c049e70834cf33790a28643ab058b507b35cBen Cheng faster, especially on modern processors. */ 9125b3c049e70834cf33790a28643ab058b507b35cBen Cheng 9225b3c049e70834cf33790a28643ab058b507b35cBen Cheng hash ^= hi; 9325b3c049e70834cf33790a28643ab058b507b35cBen Cheng hash ^= hi >> 24; 9425b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 9525b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 9625b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 9725b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 9825b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 9925b3c049e70834cf33790a28643ab058b507b35cBen Cheng return hash; 10025b3c049e70834cf33790a28643ab058b507b35cBen Cheng} 10125b3c049e70834cf33790a28643ab058b507b35cBen Cheng 10225b3c049e70834cf33790a28643ab058b507b35cBen Cheng#endif /* dl-hash.h */ 103