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 java.lang.reflect.Array; 29 import jdk.nashorn.internal.runtime.ScriptRuntime; 30 31 /** 32 * This filter handles the deletion of array elements. 33 */ 34 final class DeletedRangeArrayFilter extends ArrayFilter { 35 /** Range (inclusive) tracking deletions */ 36 private long lo, hi; 37 38 DeletedRangeArrayFilter(final ArrayData underlying, final long lo, final long hi) { 39 super(maybeSparse(underlying, hi)); 40 this.lo = lo; 41 this.hi = hi; 42 } 43 44 private static ArrayData maybeSparse(final ArrayData underlying, final long hi) { 45 if (hi < SparseArrayData.MAX_DENSE_LENGTH || underlying instanceof SparseArrayData) { 46 return underlying; 47 } 48 return new SparseArrayData(underlying, underlying.length()); 49 } 50 51 private boolean isEmpty() { 52 return lo > hi; 53 } 54 55 private boolean isDeleted(final int index) { 56 final long longIndex = ArrayIndex.toLongIndex(index); 57 return lo <= longIndex && longIndex <= hi; 58 } 59 60 @Override 61 public ArrayData copy() { 62 return new DeletedRangeArrayFilter(underlying.copy(), lo, hi); 63 } 64 65 @Override 66 public Object[] asObjectArray() { 67 final Object[] value = super.asObjectArray(); 68 69 if (lo < Integer.MAX_VALUE) { 70 final int end = (int)Math.min(hi + 1, Integer.MAX_VALUE); 71 for (int i = (int)lo; i < end; i++) { 72 value[i] = ScriptRuntime.UNDEFINED; 73 } 74 } 75 76 return value; 77 } 78 79 @Override 80 public Object asArrayOfType(final Class<?> componentType) { 81 final Object value = super.asArrayOfType(componentType); 82 final Object undefValue = convertUndefinedValue(componentType); 83 84 if (lo < Integer.MAX_VALUE) { 85 final int end = (int)Math.min(hi + 1, Integer.MAX_VALUE); 86 for (int i = (int)lo; i < end; i++) { 87 Array.set(value, i, undefValue); 88 } 89 } 90 91 return value; 92 } 93 94 @Override 95 public ArrayData ensure(final long safeIndex) { 96 if (safeIndex >= SparseArrayData.MAX_DENSE_LENGTH && safeIndex >= length()) { 97 return new SparseArrayData(this, safeIndex + 1); 98 } 99 100 return super.ensure(safeIndex); 101 } 102 103 @Override 104 public ArrayData shiftLeft(final int by) { 105 super.shiftLeft(by); 106 lo = Math.max(0, lo - by); 107 hi = Math.max(-1, hi - by); 108 109 return isEmpty() ? getUnderlying() : this; 110 } 111 112 @Override 113 public ArrayData shiftRight(final int by) { 114 super.shiftRight(by); 115 final long len = length(); 116 lo = Math.min(len, lo + by); 117 hi = Math.min(len - 1, hi + by); 118 119 return isEmpty() ? getUnderlying() : this; 120 } 121 122 @Override 123 public ArrayData shrink(final long newLength) { 124 super.shrink(newLength); 125 lo = Math.min(newLength, lo); 126 hi = Math.min(newLength - 1, hi); 127 128 return isEmpty() ? getUnderlying() : this; 129 } 130 131 @Override 132 public ArrayData set(final int index, final Object value, final boolean strict) { 133 final long longIndex = ArrayIndex.toLongIndex(index); 134 if (longIndex < lo || longIndex > hi) { 135 return super.set(index, value, strict); 136 } else if (longIndex > lo && longIndex < hi) { 137 return getDeletedArrayFilter().set(index, value, strict); 138 } 139 if (longIndex == lo) { 140 lo++; 141 } else { 142 assert longIndex == hi; 143 hi--; 144 } 145 146 return isEmpty() ? getUnderlying().set(index, value, strict) : super.set(index, value, strict); 147 } 148 149 @Override 150 public ArrayData set(final int index, final int value, final boolean strict) { 151 final long longIndex = ArrayIndex.toLongIndex(index); 152 if (longIndex < lo || longIndex > hi) { 153 return super.set(index, value, strict); 154 } else if (longIndex > lo && longIndex < hi) { 155 return getDeletedArrayFilter().set(index, value, strict); 156 } 157 if (longIndex == lo) { 158 lo++; 159 } else { 160 assert longIndex == hi; 161 hi--; 162 } 163 164 return isEmpty() ? getUnderlying().set(index, value, strict) : super.set(index, value, strict); 165 } 166 167 @Override 168 public ArrayData set(final int index, final double value, final boolean strict) { 169 final long longIndex = ArrayIndex.toLongIndex(index); 170 if (longIndex < lo || longIndex > hi) { 171 return super.set(index, value, strict); 172 } else if (longIndex > lo && longIndex < hi) { 173 return getDeletedArrayFilter().set(index, value, strict); 174 } 175 if (longIndex == lo) { 176 lo++; 177 } else { 178 assert longIndex == hi; 179 hi--; 180 } 181 182 return isEmpty() ? getUnderlying().set(index, value, strict) : super.set(index, value, strict); 183 } 184 185 @Override 186 public boolean has(final int index) { 187 return super.has(index) && !isDeleted(index); 188 } 189 190 private ArrayData getDeletedArrayFilter() { 191 final ArrayData deleteFilter = new DeletedArrayFilter(getUnderlying()); 192 deleteFilter.delete(lo, hi); 193 return deleteFilter; 194 } 195 196 @Override 197 public ArrayData delete(final int index) { 198 final long longIndex = ArrayIndex.toLongIndex(index); 199 underlying.setEmpty(index); 200 201 if (longIndex + 1 == lo) { 202 lo = longIndex; 203 } else if (longIndex - 1 == hi) { 204 hi = longIndex; 205 } else if (longIndex < lo || hi < longIndex) { 206 return getDeletedArrayFilter().delete(index); 207 } 208 209 return this; 210 } 211 212 @Override 213 public ArrayData delete(final long fromIndex, final long toIndex) { 214 if (fromIndex > hi + 1 || toIndex < lo - 1) { 215 return getDeletedArrayFilter().delete(fromIndex, toIndex); 216 } 217 lo = Math.min(fromIndex, lo); 218 hi = Math.max(toIndex, hi); 219 underlying.setEmpty(lo, hi); 220 return this; 221 } 222 223 @Override 224 public Object pop() { 225 final int index = (int)length() - 1; 226 if (super.has(index)) { 227 final boolean isDeleted = isDeleted(index); 228 final Object value = super.pop(); 229 230 lo = Math.min(index + 1, lo); 231 hi = Math.min(index, hi); 232 return isDeleted ? ScriptRuntime.UNDEFINED : value; 233 } 234 235 return super.pop(); 236 } 237 238 @Override 239 public ArrayData slice(final long from, final long to) { 240 return new DeletedRangeArrayFilter(underlying.slice(from, to), Math.max(0, lo - from), Math.max(0, hi - from)); 241 } 242 }