| /* |
| * Copyright (c) 1999, 2012, Oracle and/or its affiliates. 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.tools.javac.util; |
| |
| import java.lang.ref.SoftReference; |
| |
| /** |
| * Implementation of Name.Table that stores all names in a single shared |
| * byte array, expanding it as needed. This avoids the overhead incurred |
| * by using an array of bytes for each name. |
| * |
| * <p><b>This is NOT part of any supported API. |
| * 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 SharedNameTable extends Name.Table { |
| // maintain a freelist of recently used name tables for reuse. |
| private static List<SoftReference<SharedNameTable>> freelist = List.nil(); |
| |
| static public synchronized SharedNameTable create(Names names) { |
| while (freelist.nonEmpty()) { |
| SharedNameTable t = freelist.head.get(); |
| freelist = freelist.tail; |
| if (t != null) { |
| return t; |
| } |
| } |
| return new SharedNameTable(names); |
| } |
| |
| static private synchronized void dispose(SharedNameTable t) { |
| freelist = freelist.prepend(new SoftReference<>(t)); |
| } |
| |
| /** The hash table for names. |
| */ |
| private NameImpl[] hashes; |
| |
| /** The shared byte array holding all encountered names. |
| */ |
| public byte[] bytes; |
| |
| /** The mask to be used for hashing |
| */ |
| private int hashMask; |
| |
| /** The number of filled bytes in `names'. |
| */ |
| private int nc = 0; |
| |
| /** 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. |
| * @param nameSize the initial size of the name table. |
| */ |
| public SharedNameTable(Names names, int hashSize, int nameSize) { |
| super(names); |
| hashMask = hashSize - 1; |
| hashes = new NameImpl[hashSize]; |
| bytes = new byte[nameSize]; |
| |
| } |
| |
| public SharedNameTable(Names names) { |
| this(names, 0x8000, 0x20000); |
| } |
| |
| @Override |
| public Name fromChars(char[] cs, int start, int len) { |
| int nc = this.nc; |
| byte[] bytes = this.bytes = ArrayUtils.ensureCapacity(this.bytes, nc + len * 3); |
| int nbytes = Convert.chars2utf(cs, start, bytes, nc, len) - nc; |
| int h = hashValue(bytes, nc, nbytes) & hashMask; |
| NameImpl n = hashes[h]; |
| while (n != null && |
| (n.getByteLength() != nbytes || |
| !equals(bytes, n.index, bytes, nc, nbytes))) { |
| n = n.next; |
| } |
| if (n == null) { |
| n = new NameImpl(this); |
| n.index = nc; |
| n.length = nbytes; |
| n.next = hashes[h]; |
| hashes[h] = n; |
| this.nc = nc + nbytes; |
| if (nbytes == 0) { |
| this.nc++; |
| } |
| } |
| return n; |
| } |
| |
| @Override |
| public Name fromUtf(byte[] cs, int start, int len) { |
| int h = hashValue(cs, start, len) & hashMask; |
| NameImpl n = hashes[h]; |
| byte[] names = this.bytes; |
| while (n != null && |
| (n.getByteLength() != len || !equals(names, n.index, cs, start, len))) { |
| n = n.next; |
| } |
| if (n == null) { |
| int nc = this.nc; |
| names = this.bytes = ArrayUtils.ensureCapacity(names, nc + len); |
| System.arraycopy(cs, start, names, nc, len); |
| n = new NameImpl(this); |
| n.index = nc; |
| n.length = len; |
| n.next = hashes[h]; |
| hashes[h] = n; |
| this.nc = nc + len; |
| if (len == 0) { |
| this.nc++; |
| } |
| } |
| return n; |
| } |
| |
| @Override |
| public void dispose() { |
| dispose(this); |
| } |
| |
| static class NameImpl extends Name { |
| /** The next name occupying the same hash bucket. |
| */ |
| NameImpl next; |
| |
| /** The index where the bytes of this name are stored in the global name |
| * buffer `byte'. |
| */ |
| int index; |
| |
| /** The number of bytes in this name. |
| */ |
| int length; |
| |
| NameImpl(SharedNameTable table) { |
| super(table); |
| } |
| |
| @Override |
| public int getIndex() { |
| return index; |
| } |
| |
| @Override |
| public int getByteLength() { |
| return length; |
| } |
| |
| @Override |
| public byte getByteAt(int i) { |
| return getByteArray()[index + i]; |
| } |
| |
| @Override |
| public byte[] getByteArray() { |
| return ((SharedNameTable) table).bytes; |
| } |
| |
| @Override |
| public int getByteOffset() { |
| return index; |
| } |
| |
| /** Return the hash value of this name. |
| */ |
| public int hashCode() { |
| return index; |
| } |
| |
| /** Is this name equal to other? |
| */ |
| public boolean equals(Object other) { |
| if (other instanceof Name) |
| return |
| table == ((Name)other).table && index == ((Name) other).getIndex(); |
| else return false; |
| } |
| |
| } |
| |
| } |