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src/share/classes/com/sun/tools/javac/util/SharedNameTable.java@93012e2a5d1d (annotated)

src/share/classes/com/sun/tools/javac/util/SharedNameTable.java

Sat, 07 Nov 2020 10:30:02 +0800

author

aoqi

date

Sat, 07 Nov 2020 10:30:02 +0800

changeset 3938

93012e2a5d1d

parent 2525

2eb010b6cb22

permissions

-rw-r--r--

Added tag mips-jdk8u275-b01 for changeset eb6ee6a5f2fe

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation. Oracle designates this
aoqi@0	8	* particular file as subject to the "Classpath" exception as provided
aoqi@0	9	* by Oracle in the LICENSE file that accompanied this code.
aoqi@0	10	*
aoqi@0	11	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	12	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	13	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	14	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	15	* accompanied this code).
aoqi@0	16	*
aoqi@0	17	* You should have received a copy of the GNU General Public License version
aoqi@0	18	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	19	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	20	*
aoqi@0	21	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	22	* or visit www.oracle.com if you need additional information or have any
aoqi@0	23	* questions.
aoqi@0	24	*/
aoqi@0	25
aoqi@0	26	package com.sun.tools.javac.util;
aoqi@0	27
aoqi@0	28	import java.lang.ref.SoftReference;
aoqi@0	29
aoqi@0	30	/**
aoqi@0	31	* Implementation of Name.Table that stores all names in a single shared
aoqi@0	32	* byte array, expanding it as needed. This avoids the overhead incurred
aoqi@0	33	* by using an array of bytes for each name.
aoqi@0	34	*
aoqi@0	35	* <p><b>This is NOT part of any supported API.
aoqi@0	36	* If you write code that depends on this, you do so at your own risk.
aoqi@0	37	* This code and its internal interfaces are subject to change or
aoqi@0	38	* deletion without notice.</b>
aoqi@0	39	*/
aoqi@0	40	public class SharedNameTable extends Name.Table {
aoqi@0	41	// maintain a freelist of recently used name tables for reuse.
aoqi@0	42	private static List<SoftReference<SharedNameTable>> freelist = List.nil();
aoqi@0	43
aoqi@0	44	static public synchronized SharedNameTable create(Names names) {
aoqi@0	45	while (freelist.nonEmpty()) {
aoqi@0	46	SharedNameTable t = freelist.head.get();
aoqi@0	47	freelist = freelist.tail;
aoqi@0	48	if (t != null) {
aoqi@0	49	return t;
aoqi@0	50	}
aoqi@0	51	}
aoqi@0	52	return new SharedNameTable(names);
aoqi@0	53	}
aoqi@0	54
aoqi@0	55	static private synchronized void dispose(SharedNameTable t) {
aoqi@0	56	freelist = freelist.prepend(new SoftReference<SharedNameTable>(t));
aoqi@0	57	}
aoqi@0	58
aoqi@0	59	/** The hash table for names.
aoqi@0	60	*/
aoqi@0	61	private NameImpl[] hashes;
aoqi@0	62
aoqi@0	63	/** The shared byte array holding all encountered names.
aoqi@0	64	*/
aoqi@0	65	public byte[] bytes;
aoqi@0	66
aoqi@0	67	/** The mask to be used for hashing
aoqi@0	68	*/
aoqi@0	69	private int hashMask;
aoqi@0	70
aoqi@0	71	/** The number of filled bytes in `names'.
aoqi@0	72	*/
aoqi@0	73	private int nc = 0;
aoqi@0	74
aoqi@0	75	/** Allocator
aoqi@0	76	* @param names The main name table
aoqi@0	77	* @param hashSize the (constant) size to be used for the hash table
aoqi@0	78	* needs to be a power of two.
aoqi@0	79	* @param nameSize the initial size of the name table.
aoqi@0	80	*/
aoqi@0	81	public SharedNameTable(Names names, int hashSize, int nameSize) {
aoqi@0	82	super(names);
aoqi@0	83	hashMask = hashSize - 1;
aoqi@0	84	hashes = new NameImpl[hashSize];
aoqi@0	85	bytes = new byte[nameSize];
aoqi@0	86
aoqi@0	87	}
aoqi@0	88
aoqi@0	89	public SharedNameTable(Names names) {
aoqi@0	90	this(names, 0x8000, 0x20000);
aoqi@0	91	}
aoqi@0	92
aoqi@0	93	@Override
aoqi@0	94	public Name fromChars(char[] cs, int start, int len) {
aoqi@0	95	int nc = this.nc;
aoqi@0	96	byte[] bytes = this.bytes = ArrayUtils.ensureCapacity(this.bytes, nc + len * 3);
aoqi@0	97	int nbytes = Convert.chars2utf(cs, start, bytes, nc, len) - nc;
aoqi@0	98	int h = hashValue(bytes, nc, nbytes) & hashMask;
aoqi@0	99	NameImpl n = hashes[h];
aoqi@0	100	while (n != null &&
aoqi@0	101	(n.getByteLength() != nbytes ||
aoqi@0	102	!equals(bytes, n.index, bytes, nc, nbytes))) {
aoqi@0	103	n = n.next;
aoqi@0	104	}
aoqi@0	105	if (n == null) {
aoqi@0	106	n = new NameImpl(this);
aoqi@0	107	n.index = nc;
aoqi@0	108	n.length = nbytes;
aoqi@0	109	n.next = hashes[h];
aoqi@0	110	hashes[h] = n;
aoqi@0	111	this.nc = nc + nbytes;
aoqi@0	112	if (nbytes == 0) {
aoqi@0	113	this.nc++;
aoqi@0	114	}
aoqi@0	115	}
aoqi@0	116	return n;
aoqi@0	117	}
aoqi@0	118
aoqi@0	119	@Override
aoqi@0	120	public Name fromUtf(byte[] cs, int start, int len) {
aoqi@0	121	int h = hashValue(cs, start, len) & hashMask;
aoqi@0	122	NameImpl n = hashes[h];
aoqi@0	123	byte[] names = this.bytes;
aoqi@0	124	while (n != null &&
aoqi@0	125	(n.getByteLength() != len || !equals(names, n.index, cs, start, len))) {
aoqi@0	126	n = n.next;
aoqi@0	127	}
aoqi@0	128	if (n == null) {
aoqi@0	129	int nc = this.nc;
aoqi@0	130	names = this.bytes = ArrayUtils.ensureCapacity(names, nc + len);
aoqi@0	131	System.arraycopy(cs, start, names, nc, len);
aoqi@0	132	n = new NameImpl(this);
aoqi@0	133	n.index = nc;
aoqi@0	134	n.length = len;
aoqi@0	135	n.next = hashes[h];
aoqi@0	136	hashes[h] = n;
aoqi@0	137	this.nc = nc + len;
aoqi@0	138	if (len == 0) {
aoqi@0	139	this.nc++;
aoqi@0	140	}
aoqi@0	141	}
aoqi@0	142	return n;
aoqi@0	143	}
aoqi@0	144
aoqi@0	145	@Override
aoqi@0	146	public void dispose() {
aoqi@0	147	dispose(this);
aoqi@0	148	}
aoqi@0	149
aoqi@0	150	static class NameImpl extends Name {
aoqi@0	151	/** The next name occupying the same hash bucket.
aoqi@0	152	*/
aoqi@0	153	NameImpl next;
aoqi@0	154
aoqi@0	155	/** The index where the bytes of this name are stored in the global name
aoqi@0	156	* buffer `byte'.
aoqi@0	157	*/
aoqi@0	158	int index;
aoqi@0	159
aoqi@0	160	/** The number of bytes in this name.
aoqi@0	161	*/
aoqi@0	162	int length;
aoqi@0	163
aoqi@0	164	NameImpl(SharedNameTable table) {
aoqi@0	165	super(table);
aoqi@0	166	}
aoqi@0	167
aoqi@0	168	@Override
aoqi@0	169	public int getIndex() {
aoqi@0	170	return index;
aoqi@0	171	}
aoqi@0	172
aoqi@0	173	@Override
aoqi@0	174	public int getByteLength() {
aoqi@0	175	return length;
aoqi@0	176	}
aoqi@0	177
aoqi@0	178	@Override
aoqi@0	179	public byte getByteAt(int i) {
aoqi@0	180	return getByteArray()[index + i];
aoqi@0	181	}
aoqi@0	182
aoqi@0	183	@Override
aoqi@0	184	public byte[] getByteArray() {
aoqi@0	185	return ((SharedNameTable) table).bytes;
aoqi@0	186	}
aoqi@0	187
aoqi@0	188	@Override
aoqi@0	189	public int getByteOffset() {
aoqi@0	190	return index;
aoqi@0	191	}
aoqi@0	192
aoqi@0	193	/** Return the hash value of this name.
aoqi@0	194	*/
aoqi@0	195	public int hashCode() {
aoqi@0	196	return index;
aoqi@0	197	}
aoqi@0	198
aoqi@0	199	/** Is this name equal to other?
aoqi@0	200	*/
aoqi@0	201	public boolean equals(Object other) {
aoqi@0	202	if (other instanceof Name)
aoqi@0	203	return
aoqi@0	204	table == ((Name)other).table && index == ((Name) other).getIndex();
aoqi@0	205	else return false;
aoqi@0	206	}
aoqi@0	207
aoqi@0	208	}
aoqi@0	209
aoqi@0	210	}