Mercurial > jdk8-mips64-public > langtools / file revision

 /*

  * Copyright 1999-2008 Sun Microsystems, Inc.  All Rights Reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Sun designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Sun in the LICENSE file that accompanied this code.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  */

 package com.sun.tools.javac.util;

 import java.lang.ref.WeakReference;

 /**

  * Implementation of Name.Table that stores names in individual arrays

  * using weak references. It is recommended for use when a single shared

  * byte array is unsuitable.

  *

  *  <p><b>This is NOT part of any API supported by Sun Microsystems.  If

  *  you write code that depends on this, you do so at your own risk.

  *  This code and its internal interfaces are subject to change or

  *  deletion without notice.</b>

  */

 public class UnsharedNameTable extends Name.Table {

     static public Name.Table create(Names names) {

         return new UnsharedNameTable(names);

     }

     static class HashEntry extends WeakReference<NameImpl> {

         HashEntry next;

         HashEntry(NameImpl referent) {

             super(referent);

         }

     }

     /** The hash table for names.

      */

     private HashEntry[] hashes = null;

     /** The mask to be used for hashing

      */

     private int hashMask;

     /** Index counter for names in this table.

      */

     public int index;

     /** Allocator

      *  @param names The main name table

      *  @param hashSize the (constant) size to be used for the hash table

      *                  needs to be a power of two.

      */

     public UnsharedNameTable(Names names, int hashSize) {

         super(names);

         hashMask = hashSize - 1;

         hashes = new HashEntry[hashSize];

     }

     public UnsharedNameTable(Names names) {

         this(names, 0x8000);

     }

     @Override

     public Name fromChars(char[] cs, int start, int len) {

         byte[] name = new byte[len * 3];

         int nbytes = Convert.chars2utf(cs, start, name, 0, len);

         return fromUtf(name, 0, nbytes);

     }

     @Override

     public Name fromUtf(byte[] cs, int start, int len) {

         int h = hashValue(cs, start, len) & hashMask;

         HashEntry element = hashes[h];

         NameImpl n = null;

         HashEntry previousNonNullTableEntry = null;

         HashEntry firstTableEntry = element;

         while (element != null) {

             if (element == null) {

                 break;

             }

             n = element.get();

             if (n == null) {

                 if (firstTableEntry == element) {

                     hashes[h] = firstTableEntry = element.next;

                 }

                 else {

                     assert previousNonNullTableEntry != null : "previousNonNullTableEntry cannot be null here.";

                     previousNonNullTableEntry.next = element.next;

                 }

             }

             else {

                 if (n.getByteLength() == len && equals(n.bytes, 0, cs, start, len)) {

                     return n;

                 }

                 previousNonNullTableEntry = element;

             }

             element = element.next;

         }

         byte[] bytes = new byte[len];

         System.arraycopy(cs, start, bytes, 0, len);

         n = new NameImpl(this, bytes, index++);

         System.arraycopy(cs, start, n.bytes, 0, len);

         HashEntry newEntry = new HashEntry(n);

         if (previousNonNullTableEntry == null) { // We are not the first name with that hashCode.

             hashes[h] = newEntry;

         }

         else {

             assert previousNonNullTableEntry.next == null : "previousNonNullTableEntry.next must be null.";

             previousNonNullTableEntry.next = newEntry;

         }

         return n;

     }

     @Override

     public void dispose() {

         hashes = null;

     }

     static class NameImpl extends Name {

         NameImpl(UnsharedNameTable table, byte[] bytes, int index) {

             super(table);

             this.bytes = bytes;

             this.index = index;

         }

         final byte[] bytes;

         final int index;

         @Override

         public int getIndex() {

             return index;

         }

         @Override

         public int getByteLength() {

             return bytes.length;

         }

         @Override

         public byte getByteAt(int i) {

             return bytes[i];

         }

         @Override

         public byte[] getByteArray() {

             return bytes;

         }

         @Override

         public int getByteOffset() {

             return 0;

         }

     }

 }