hashutil.java

这个是网络上下载的一个struct框架的程序

/*

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                   The Apache Software License, Version 1.1
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 Copyright (C) 1999-2002 The Apache Software Foundation. All rights reserved.

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 tion, are permitted provided that the following conditions are met:

 1. Redistributions of  source code must  retain the above copyright  notice,
    this list of conditions and the following disclaimer.

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    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.

 3. The end-user documentation included with the redistribution, if any, must
    include  the following  acknowledgment:  "This product includes  software
    developed  by the  Apache Software Foundation  (http://www.apache.org/)."
    Alternately, this  acknowledgment may  appear in the software itself,  if
    and wherever such third-party acknowledgments normally appear.

 4. The names "Apache Cocoon" and  "Apache Software Foundation" must  not  be
    used to  endorse or promote  products derived from  this software without
    prior written permission. For written permission, please contact
    [e-mail].

 5. Products  derived from this software may not  be called "Apache", nor may
    "Apache" appear  in their name,  without prior written permission  of the
    Apache Software Foundation.

 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 FITNESS  FOR A PARTICULAR  PURPOSE ARE  DISCLAIMED.  IN NO  EVENT SHALL  THE
 APACHE SOFTWARE  FOUNDATION  OR ITS CONTRIBUTORS  BE LIABLE FOR  ANY DIRECT,
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 (INCLUDING  NEGLIGENCE OR  OTHERWISE) ARISING IN  ANY WAY OUT OF THE  USE OF
 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 This software  consists of voluntary contributions made  by many individuals
 on  behalf of the Apache Software  Foundation and was  originally created by
 Stefano Mazzocchi  <[e-mail]>. For more  information on the Apache
 Software Foundation, please see <http://www.apache.org/>.

*/
package com.struts2.framework.util;

/**
 * A very efficient java hash algorithm, based on the BuzHash algoritm
 * by Robert Uzgalis (see http://www.serve.net/buz/hash.adt/java.000.html
 * for more information).
 * BuzHash is Copyright (c)1996 Robert Uzgalis, All Rights Reserved.
 * Used with kind permission of the author
 *
 * @author <a href="mailto:[e-mail]">Robert Uzgalis</a>
 * @author <a href="mailto:cziegeler@Carsten Ziegeler">Carsten Ziegeler</a>
 * @version CVS $Id: HashUtil.java,v 1.4 2002/02/22 07:03:57 cziegeler Exp $
 */
public final class HashUtil {


    private static long initial_hash = 0xe12398c6d9ae3b8aL; // initial values
    private static long hash_true = 0x851dcaa2656c6af4L; // are arbitrary
    private static long hash_false = 0x1af84a6b589285f7L; // 64-bit rands
    private static long mix_master[/* 0:255 */] = {
/* 000 */ 0x4476081a7043a46fL, 0x45768b8a6e7eac19L, 0xebd556c1cf055952L,
/* */ 0x72ed2da1bf010101L, 0x3ff2030b128e8a64L,
/* 005 */ 0xcbc330238adcfef2L, 0x737807fe42e20c6cL, 0x74dabaedb1095c58L,
/* */ 0x968f065c65361d67L, 0xd3f4018ac7a4b199L,
/* 010 */ 0x954b389b52f24df2L, 0x2f97a9d8d0549327L, 0xb9bea2b49a3b180fL,
/* */ 0xaf2f42536b21f2ebL, 0x85d991663cff1325L,
/* 015 */ 0xb9e1260207b575b9L, 0xf3ea88398a23b7e2L, 0xfaf8c83ffbd9091dL,
/* */ 0x4274fe90834dbdf9L, 0x3f20b157b68d6313L,
/* 020 */ 0x68b48972b6d06b93L, 0x694837b6eba548afL, 0xeecb51d1acc917c9L,
/* */ 0xf1c633f02dffbcfaL, 0xa6549ec9d301f3b5L,
/* 025 */ 0x451dc944f1663592L, 0x446d6acef6ce9e4fL, 0x1c8a5b3013206f02L,
/* */ 0x5908ca36f2dc50f7L, 0x4fd55d3f3e880a87L,
/* 030 */ 0xa03a8dbeabbf065dL, 0x3ccbbe078fabcb6dL, 0x1da53a259116f2d0L,
/* */ 0xfb27a96fcb9af152L, 0x50aba242e85aec09L,
/* 035 */ 0x24d4e414fc4fc987L, 0x83971844a9ce535eL, 0xc26a3fdeb849398eL,
/* */ 0xc2380d044d2e70d8L, 0xab418aa8ae19b18fL,
/* 040 */ 0xd95b6b9247d5ebeaL, 0x8b3b2171fdc60511L, 0xe15cd0ae3fcc44afL,
/* */ 0x5a4e27f914a68f17L, 0x377bd28ca09aafdcL,
/* 045 */ 0xbbeb9828594a3294L, 0x7c8df263ae1de1b9L, 0xba0a48a5fd1c1dd0L,
/* */ 0x57cc1b8818b98ee6L, 0x8c570975d357dabcL,
/* 050 */ 0x76bdcd6f2e8826aaL, 0x529b15b6ec4055f1L, 0x9147c7a54c34f8a9L,
/* */ 0x2f96a7728170e402L, 0xe46602f455eca72eL,
/* 055 */ 0x22834c4dd1bde03fL, 0x2644cf5a25e368ffL, 0x907c6de90b120f4aL,
/* */ 0xadfe8ba99028f728L, 0xa85199ae14df0433L,
/* 060 */ 0x2d749b946dd3601eL, 0x76e35457aa052772L, 0x90410bf6e427f736L,
/* */ 0x536ad04d13e35041L, 0x8cc0d76769b76914L,
/* 065 */ 0xae0249f6e3b3c01cL, 0x1bdfd075307d6fafL, 0xd8e04f70c221deccL,
/* */ 0x4ab23622a4281a5dL, 0x37a5613da2fcaba7L,
/* 070 */ 0x19a56203666d4a9fL, 0x158ffab502c4be93L, 0x0bee714e332ecb2fL,
/* */ 0x69b71a59f6f74ab0L, 0x0fc7fc622f1dfe8fL,
/* 075 */ 0x513966de7152a6f9L, 0xc16fae9cc2ea9be7L, 0xb66f0ac586c1899eL,
/* */ 0x11e124aee3bdefd7L, 0x86cf5a577512901bL,
/* 080 */ 0x33f33ba6994a1fbdL, 0xde6c4d1d3d47ff0dL, 0x6a99220dc6f78e66L,
/* */ 0x2dc06ca93e2d25d2L, 0x96413b520134d573L,
/* 085 */ 0xb4715ce8e1023afaL, 0xe6a75900c8c66c0aL, 0x6448f13ad54c12edL,
/* */ 0xb9057c28cf6689f0L, 0xf4023daf67f7677aL,
/* 090 */ 0x877c2650767b9867L, 0xb7ea587dcd5b2341L, 0xc048cf111733f9bcL,
/* */ 0x112012c15bc867bfL, 0xc95f52b1d9418811L,
/* 095 */ 0xa47e624ee7499083L, 0x26928606df9b12e8L, 0x5d020462ec3e0928L,
/* */ 0x8bbde651f6d08914L, 0xd5db83db758e524aL,
/* 100 */ 0x3105e355c000f455L, 0xdd7fe1b81a786c79L, 0x1f3a818c8e012db1L,
/* */ 0xd902de819d7b42faL, 0x4200e63325cda5f0L,
/* 105 */ 0x0e919cdc5fba9220L, 0x5360dd54605a11e1L, 0xa3182d0e6cb23e6cL,
/* */ 0x13ee462c1b483b87L, 0x1b1b6087b997ee22L,
/* 110 */ 0x81c36d0b877f7362L, 0xc24879932c1768d4L, 0x1faa756e1673f9adL,
/* */ 0x61651b24d11fe93dL, 0x30fe3d9304e1cde4L,
/* 115 */ 0x7be867c750747250L, 0x973e52c7005b5db6L, 0x75d6b699bbaf4817L,
/* */ 0x25d2a9e97379e196L, 0xe65fb599aca98701L,
/* 120 */ 0x6ac27960d24bde84L, 0xdfacc04c9fabbcb6L, 0xa46cd07f4a97882bL,
/* */ 0x652031d8e59a1fd8L, 0x1185bd967ec7ce10L,
/* 125 */ 0xfc9bd84c6780f244L, 0x0a0c59872f61b3ffL, 0x63885727a1c71c95L,
/* */ 0x5e88b4390b2d765cL, 0xf0005ccaf988514dL,
/* 130 */ 0x474e44280a98e840L, 0x32de151c1411bc42L, 0x2c4b86d5aa4482c2L,
/* */ 0xccd93deb2d9d47daL, 0x3743236ff128a622L,
/* 135 */ 0x42ed2f2635ba5647L, 0x99c74afd18962dbdL, 0x2d663bb870f6d242L,
/* */ 0x7912033bc7635d81L, 0xb442862f43753680L,
/* 140 */ 0x94b1a5400aeaab4cL, 0x5ce285fe810f2220L, 0xe8a7dbe565d9c0b1L,
/* */ 0x219131af78356c94L, 0x7b3a80d130f27e2fL,
/* 145 */ 0xbaa5d2859d16b440L, 0x821cfb6935771070L, 0xf68cfb6ee9bc2336L,
/* */ 0x18244132e935d2fdL, 0x2ed0bda1f4720cffL,
/* 150 */ 0x4ed48cdf6975173cL, 0xfd37a7a2520e2405L, 0x82c102b2a9e73ce2L,
/* */ 0xadac6517062623a7L, 0x5a1294d318e26104L,
/* 155 */ 0xea84fe65c0e4f061L, 0x4f96f8a9464cfee9L, 0x9831dff8ccdc534aL,
/* */ 0x4ca927cd0f192a14L, 0x030900b294b71649L,
/* 160 */ 0x644b263b9aeb0675L, 0xa601d4e34647e040L, 0x34d897eb397f1004L,
/* */ 0xa6101c37f4ec8dfcL, 0xc29d2a8bbfd0006bL,
/* 165 */ 0xc6b07df8c5b4ed0fL, 0xce1b7d92ba6bccbeL, 0xfa2f99442e03fe1bL,
/* */ 0xd8863e4c16f0b363L, 0x033b2cccc3392942L,
/* 170 */ 0x757dc33522d6cf9cL, 0xf07b1ff6ce55fec5L, 0x1569e75f09b40463L,
/* */ 0xfa33fa08f14a310bL, 0x6eb79aa27bbcf76bL,
/* 175 */ 0x157061207c249602L, 0x25e5a71fc4e99555L, 0x5df1fe93de625355L,
/* */ 0x235b56090c1aa55dL, 0xe51068613eaced91L,
/* 180 */ 0x45bd47b893b9ff1eL, 0x6595e1798d381f2dL, 0xc9b5848cbcdb5ba8L,
/* */ 0x65985146ff7792bcL, 0x4ab4a17bf05a19a0L,
/* 185 */ 0xfd94f4ca560ffb0cL, 0xcf9bad581a68fa68L, 0x92b4f0b502b1ce1aL,
/* */ 0xbcbec0769a610474L, 0x8dbd31ded1a0fecbL,
/* 190 */ 0xdd1f5ed9f90e8533L, 0x61c1e6a523f84d95L, 0xf24475f383c110c4L,
/* */ 0xdb2dffa66f90588dL, 0xac06d88e9ee04455L,
/* 195 */ 0xa215fc47c40504baL, 0x86d7caebfee93369L, 0x9eaec31985804099L,
/* */ 0x0fba2214abe5d01bL, 0x5a32975a4b3865d6L,
/* 200 */ 0x8cceebc98a5c108fL, 0x7e12c4589654f2dcL, 0xa49ad49fb0d19772L,
/* */ 0x3d142dd9c406152bL, 0x9f13589e7be2b8a5L,
/* 205 */ 0x5e8dbac1892967adL, 0xcc23b93a6308e597L, 0x1ef35f5fe874e16aL,
/* */ 0x63ae9cc08d2e274fL, 0x5bbabee56007fc05L,
/* 210 */ 0xabfd72994230fc39L, 0x9d71a13a99144de1L, 0xd9daf5aa8dcc89b3L,
/* */ 0xe145ec0514161bfdL, 0x143befc2498cd270L,
/* 215 */ 0xa8e192557dbbd9f8L, 0xcbeda2445628d7d0L, 0x997f0a93205d9ea4L,
/* */ 0x01014a97f214ebfaL, 0x70c026ffd1ebedafL,
/* 220 */ 0xf8737b1b3237002fL, 0x8afcbef3147e6e5eL, 0x0e1bb0684483ebd3L,
/* */ 0x4cbad70ae9b05aa6L, 0xd4a31f523517c363L,
/* 225 */ 0xdb0f057ae8e9e8a2L, 0x400894a919d89df6L, 0x6a626a9b62defab3L,
/* */ 0xf907fd7e14f4e201L, 0xe10e4a5657c48f3fL,
/* 230 */ 0xb17f9f54b8e6e5dcL, 0x6b9e69045fa6d27aL, 0x8b74b6a41dc3078eL,
/* */ 0x027954d45ca367f9L, 0xd07207b8fdcbb7ccL,
/* 235 */ 0xf397c47d2f36414bL, 0x05e4e8b11d3a034fL, 0x36adb3f7122d654fL,
/* */ 0x607d9540eb336078L, 0xb639118e3a8b9600L,
/* 240 */ 0xd0a406770b5f1484L, 0x3cbee8213ccfb7c6L, 0x467967bb2ff89cf1L,
/* */ 0xb115fe29609919a6L, 0xba740e6ffa83287eL,
/* 245 */ 0xb4e51be9b694b7cdL, 0xc9a081c677df5aeaL, 0x2e1fbcd8944508ccL,
/* */ 0xf626e7895581fbb8L, 0x3ce6e9b5728a05cbL,
/* 250 */ 0x46e87f2664a31712L, 0x8c1dc526c2f6acfaL, 0x7b4826726e560b10L,
/* */ 0x2966e0099d8d7ce1L, 0xbb0dd5240d2b2adeL, 0x0d527cc60bbaa936L
};


    /**
     * Move the bits in an integer long into a StringBuffer without
     * conversion, then hash the string buffer, returning a long.
     */
    private static long lhv (long arg) {
        // Hash a long
        StringBuffer tmp = new StringBuffer(4);
        long aval = arg;

        tmp.setLength(4);
        for ( int i=0; i<4; ++i, aval >>>= 16 )
            tmp.setCharAt( i, (char) aval);

        return buzhash( tmp );
    }


    /**
     * This is buzhash the hash function on which most other Hash methods
     * are built.
     */
    private static long buzhash (StringBuffer arg) {
        /* Hash StringBuffer */
        long h = initial_hash;
        for ( int i=0; i<arg.length(); ++i )
            h = (h<<1) ^ (h>>>63) ^
                mix_master[ ( arg.charAt(i) ^ (arg.charAt(i)>>>8) ) & 0xff ];
        return h;
    }

    /**
     * This is buzhash the hash function on which most other Hash methods
     * are built.
     */
    private static long buzhash (String arg) {
        /* Hash StringBuffer */
        long h = initial_hash;
        for ( int i=0; i<arg.length(); ++i )
            h = (h<<1) ^ (h>>>63) ^
                mix_master[ ( arg.charAt(i) ^ (arg.charAt(i)>>>8) ) & 0xff ];
        return h;
    }

    /**
     * Hash a String.
     *
     * @param arg The String to be hashed
     * @return The hash for the input.
     */
    public static long hash(String arg) {
        // Make Hash from String
        return buzhash( arg );
    }

    /**
     * Hash a String.
     *
     * @param arg The String represented by the StringBuffer to be hashed
     * @return The hash for the input.
     */
    public static long hash(StringBuffer arg) {
        // Make Hash from StringBuffer
        return buzhash( arg );
    }

}