1 /* 2 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 package sun.jvm.hotspot.utilities; 26 27 import java.util.*; 28 import sun.jvm.hotspot.debugger.*; 29 import sun.jvm.hotspot.types.*; 30 import sun.jvm.hotspot.oops.*; 31 import sun.jvm.hotspot.runtime.*; 32 33 public class Hashtable extends BasicHashtable { 34 static { 35 VM.registerVMInitializedObserver(new Observer() { 36 public void update(Observable o, Object data) { 37 initialize(VM.getVM().getTypeDataBase()); 38 } 39 }); 40 } 41 42 private static synchronized void initialize(TypeDataBase db) { 43 // just to confirm that type exists 44 Type type = db.lookupType("IntptrHashtable"); 45 } 46 47 // derived class may return Class<? extends HashtableEntry> 48 protected Class getHashtableEntryClass() { 49 return HashtableEntry.class; 50 } 51 52 public long computeHash(Symbol name) { 53 return name.identityHash(); 54 } 55 56 public int hashToIndex(long fullHash) { 57 return (int) (fullHash % tableSize()); 58 } 59 60 public Hashtable(Address addr) { 61 super(addr); 62 } 63 64 // VM's Hashtable::hash_symbol 65 protected static long hashSymbol(byte[] buf) { 66 long h = 0; 67 int s = 0; 68 int len = buf.length; 69 while (len-- > 0) { 70 h = 31*h + (0xFFL & buf[s]); 71 s++; 72 } 73 return h & 0xFFFFFFFFL; 74 } 75 }