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

comparison: src/share/classes/com/sun/tools/javac/util/UnsharedNameTable.java

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

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1 /*
2 * Copyright (c) 1999, 2013, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.tools.javac.util;
27
28 import java.lang.ref.WeakReference;
29
30 /**
31 * Implementation of Name.Table that stores names in individual arrays
32 * using weak references. It is recommended for use when a single shared
33 * byte array is unsuitable.
34 *
35 * <p><b>This is NOT part of any supported API.
36 * If you write code that depends on this, you do so at your own risk.
37 * This code and its internal interfaces are subject to change or
38 * deletion without notice.</b>
39 */
40 public class UnsharedNameTable extends Name.Table {
41 static public Name.Table create(Names names) {
42 return new UnsharedNameTable(names);
43 }
44
45 static class HashEntry extends WeakReference<NameImpl> {
46 HashEntry next;
47 HashEntry(NameImpl referent) {
48 super(referent);
49 }
50 }
51
52 /** The hash table for names.
53 */
54 private HashEntry[] hashes = null;
55
56 /** The mask to be used for hashing
57 */
58 private int hashMask;
59
60 /** Index counter for names in this table.
61 */
62 public int index;
63
64 /** Allocator
65 * @param names The main name table
66 * @param hashSize the (constant) size to be used for the hash table
67 * needs to be a power of two.
68 */
69 public UnsharedNameTable(Names names, int hashSize) {
70 super(names);
71 hashMask = hashSize - 1;
72 hashes = new HashEntry[hashSize];
73 }
74
75 public UnsharedNameTable(Names names) {
76 this(names, 0x8000);
77 }
78
79
80 @Override
81 public Name fromChars(char[] cs, int start, int len) {
82 byte[] name = new byte[len * 3];
83 int nbytes = Convert.chars2utf(cs, start, name, 0, len);
84 return fromUtf(name, 0, nbytes);
85 }
86
87 @Override
88 public Name fromUtf(byte[] cs, int start, int len) {
89 int h = hashValue(cs, start, len) & hashMask;
90
91 HashEntry element = hashes[h];
92
93 NameImpl n = null;
94
95 HashEntry previousNonNullTableEntry = null;
96 HashEntry firstTableEntry = element;
97
98 while (element != null) {
99 if (element == null) {
100 break;
101 }
102
103 n = element.get();
104
105 if (n == null) {
106 if (firstTableEntry == element) {
107 hashes[h] = firstTableEntry = element.next;
108 }
109 else {
110 Assert.checkNonNull(previousNonNullTableEntry, "previousNonNullTableEntry cannot be null here.");
111 previousNonNullTableEntry.next = element.next;
112 }
113 }
114 else {
115 if (n.getByteLength() == len && equals(n.bytes, 0, cs, start, len)) {
116 return n;
117 }
118 previousNonNullTableEntry = element;
119 }
120
121 element = element.next;
122 }
123
124 byte[] bytes = new byte[len];
125 System.arraycopy(cs, start, bytes, 0, len);
126 n = new NameImpl(this, bytes, index++);
127
128 HashEntry newEntry = new HashEntry(n);
129
130 if (previousNonNullTableEntry == null) { // We are not the first name with that hashCode.
131 hashes[h] = newEntry;
132 }
133 else {
134 Assert.checkNull(previousNonNullTableEntry.next, "previousNonNullTableEntry.next must be null.");
135 previousNonNullTableEntry.next = newEntry;
136 }
137
138 return n;
139 }
140
141 @Override
142 public void dispose() {
143 hashes = null;
144 }
145
146 static class NameImpl extends Name {
147 NameImpl(UnsharedNameTable table, byte[] bytes, int index) {
148 super(table);
149 this.bytes = bytes;
150 this.index = index;
151 }
152
153 final byte[] bytes;
154 final int index;
155
156 @Override
157 public int getIndex() {
158 return index;
159 }
160
161 @Override
162 public int getByteLength() {
163 return bytes.length;
164 }
165
166 @Override
167 public byte getByteAt(int i) {
168 return bytes[i];
169 }
170
171 @Override
172 public byte[] getByteArray() {
173 return bytes;
174 }
175
176 @Override
177 public int getByteOffset() {
178 return 0;
179 }
180
181 }
182
183 }

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