1 /*
2 * Copyright (c) 2010, 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 jdk.nashorn.internal.runtime.arrays;
27
28 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
29 import java.lang.reflect.Array;
30 import jdk.nashorn.internal.runtime.BitVector;
31
32 /**
33 * This filter handles the deletion of array elements.
34 */
35 final class DeletedArrayFilter extends ArrayFilter {
36 /** Bit vector tracking deletions. */
37 private final BitVector deleted;
38
39 DeletedArrayFilter(final ArrayData underlying) {
40 super(underlying);
41 this.deleted = new BitVector(underlying.length());
42 }
43
44 @Override
45 public ArrayData copy() {
46 final DeletedArrayFilter copy = new DeletedArrayFilter(underlying.copy());
47 copy.getDeleted().copy(deleted);
48 return copy;
49 }
50
51 @Override
52 public Object[] asObjectArray() {
53 final Object[] value = super.asObjectArray();
54
55 for (int i = 0; i < value.length; i++) {
56 if (deleted.isSet(i)) {
57 value[i] = UNDEFINED;
58 }
59 }
60
61 return value;
62 }
63
64 @Override
65 public Object asArrayOfType(final Class<?> componentType) {
66 final Object value = super.asArrayOfType(componentType);
67 final Object undefValue = convertUndefinedValue(componentType);
68 final int l = Array.getLength(value);
69 for (int i = 0; i < l; i++) {
70 if (deleted.isSet(i)) {
71 Array.set(value, i, undefValue);
72 }
73 }
74
75 return value;
76 }
77
78 @Override
79 public void shiftLeft(final int by) {
80 super.shiftLeft(by);
81 deleted.shiftLeft(by, length());
82 }
83
84 @Override
85 public ArrayData shiftRight(final int by) {
86 super.shiftRight(by);
87 deleted.shiftRight(by, length());
88 return this;
89 }
90
91 @Override
92 public ArrayData ensure(final long safeIndex) {
93 if (safeIndex >= SparseArrayData.MAX_DENSE_LENGTH && safeIndex >= length()) {
94 return new SparseArrayData(this, safeIndex + 1);
95 }
96
97 super.ensure(safeIndex);
98 deleted.resize(length());
99
100 return this;
101 }
102
103 @Override
104 public ArrayData shrink(final long newLength) {
105 super.shrink(newLength);
106 deleted.resize(length());
107 return this;
108 }
109
110 @Override
111 public ArrayData set(final int index, final Object value, final boolean strict) {
112 deleted.clear(ArrayIndex.toLongIndex(index));
113 return super.set(index, value, strict);
114 }
115
116 @Override
117 public ArrayData set(final int index, final int value, final boolean strict) {
118 deleted.clear(ArrayIndex.toLongIndex(index));
119 return super.set(index, value, strict);
120 }
121
122 @Override
123 public ArrayData set(final int index, final double value, final boolean strict) {
124 deleted.clear(ArrayIndex.toLongIndex(index));
125 return super.set(index, value, strict);
126 }
127
128 @Override
129 public boolean has(final int index) {
130 return super.has(index) && deleted.isClear(ArrayIndex.toLongIndex(index));
131 }
132
133 @Override
134 public ArrayData delete(final int index) {
135 final long longIndex = ArrayIndex.toLongIndex(index);
136 assert longIndex >= 0 && longIndex < length();
137 deleted.set(longIndex);
138 underlying.setEmpty(index);
139 return this;
140 }
141
142 @Override
143 public ArrayData delete(final long fromIndex, final long toIndex) {
144 assert fromIndex >= 0 && fromIndex <= toIndex && toIndex < length();
145 deleted.setRange(fromIndex, toIndex + 1);
146 underlying.setEmpty(fromIndex, toIndex);
147 return this;
148 }
149
150 @Override
151 public Object pop() {
152 final long index = length() - 1;
153
154 if (super.has((int)index)) {
155 final boolean isDeleted = deleted.isSet(index);
156 final Object value = super.pop();
157
158 return isDeleted ? UNDEFINED : value;
159 }
160
161 return super.pop();
162 }
163
164 @Override
165 public ArrayData slice(final long from, final long to) {
166 final ArrayData newArray = underlying.slice(from, to);
167 final DeletedArrayFilter newFilter = new DeletedArrayFilter(newArray);
168 newFilter.getDeleted().copy(deleted);
169 newFilter.getDeleted().shiftLeft(from, newFilter.length());
170
171 return newFilter;
172 }
173
174 private BitVector getDeleted() {
175 return deleted;
176 }
177 }