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-rw-r--r--src/jdk/nashorn/internal/runtime/ConsString.java139
1 files changed, 0 insertions, 139 deletions
diff --git a/src/jdk/nashorn/internal/runtime/ConsString.java b/src/jdk/nashorn/internal/runtime/ConsString.java
deleted file mode 100644
index 2c6bece8..00000000
--- a/src/jdk/nashorn/internal/runtime/ConsString.java
+++ /dev/null
@@ -1,139 +0,0 @@
-/*
- * Copyright (c) 2010, 2013, 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 jdk.nashorn.internal.runtime;
-
-import static jdk.nashorn.internal.runtime.JSType.isString;
-
-import java.util.ArrayDeque;
-import java.util.Deque;
-
-/**
- * This class represents a string composed of two parts which may themselves be
- * instances of <tt>ConsString</tt> or {@link String}. Copying of characters to
- * a proper string is delayed until it becomes necessary.
- */
-public final class ConsString implements CharSequence {
-
- private CharSequence left, right;
- private final int length;
- private volatile int state = STATE_NEW;
-
- private final static int STATE_NEW = 0;
- private final static int STATE_THRESHOLD = 2;
- private final static int STATE_FLATTENED = -1;
-
- /**
- * Constructor
- *
- * Takes two {@link CharSequence} instances that, concatenated, forms this {@code ConsString}
- *
- * @param left left char sequence
- * @param right right char sequence
- */
- public ConsString(final CharSequence left, final CharSequence right) {
- assert isString(left);
- assert isString(right);
- this.left = left;
- this.right = right;
- length = left.length() + right.length();
- if (length < 0) {
- throw new IllegalArgumentException("too big concatenated String");
- }
- }
-
- @Override
- public String toString() {
- return (String) flattened(true);
- }
-
- @Override
- public int length() {
- return length;
- }
-
- @Override
- public char charAt(final int index) {
- return flattened(true).charAt(index);
- }
-
- @Override
- public CharSequence subSequence(final int start, final int end) {
- return flattened(true).subSequence(start, end);
- }
-
- /**
- * Returns the components of this ConsString as a {@code CharSequence} array with two elements.
- * The elements will be either {@code Strings} or other {@code ConsStrings}.
- * @return CharSequence array of length 2
- */
- public synchronized CharSequence[] getComponents() {
- return new CharSequence[] { left, right };
- }
-
- private CharSequence flattened(final boolean flattenNested) {
- if (state != STATE_FLATTENED) {
- flatten(flattenNested);
- }
- return left;
- }
-
- private synchronized void flatten(final boolean flattenNested) {
- // We use iterative traversal as recursion may exceed the stack size limit.
- final char[] chars = new char[length];
- int pos = length;
- // Strings are most often composed by appending to the end, which causes ConsStrings
- // to be very unbalanced, with mostly single string elements on the right and a long
- // linear list on the left. Traversing from right to left helps to keep the stack small
- // in this scenario.
- final Deque<CharSequence> stack = new ArrayDeque<>();
- stack.addFirst(left);
- CharSequence cs = right;
-
- do {
- if (cs instanceof ConsString) {
- final ConsString cons = (ConsString) cs;
- // Count the times a cons-string is traversed as part of other cons-strings being flattened.
- // If it crosses a threshold we flatten the nested cons-string internally.
- if (cons.state == STATE_FLATTENED || (flattenNested && ++cons.state >= STATE_THRESHOLD)) {
- cs = cons.flattened(false);
- } else {
- stack.addFirst(cons.left);
- cs = cons.right;
- }
- } else {
- final String str = (String) cs;
- pos -= str.length();
- str.getChars(0, str.length(), chars, pos);
- cs = stack.isEmpty() ? null : stack.pollFirst();
- }
- } while (cs != null);
-
- left = new String(chars);
- right = "";
- state = STATE_FLATTENED;
- }
-
-}