--- /dev/null
+/*******************************************************************************
+ * Copyright (c) 2000, 2004 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Common Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v10.html
+ *
+ * Contributors:
+ * IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.jdt.internal.compiler.codegen;
+
+import org.eclipse.jdt.core.compiler.CharOperation;
+
+public class CharArrayCache {
+ // to avoid using Enumerations, walk the individual tables skipping nulls
+ public char[] keyTable[];
+ public int valueTable[];
+ int elementSize; // number of elements in the table
+ int threshold;
+/**
+ * Constructs a new, empty hashtable. A default capacity is used.
+ * Note that the hashtable will automatically grow when it gets full.
+ */
+public CharArrayCache() {
+ this(13);
+}
+/**
+ * Constructs a new, empty hashtable with the specified initial
+ * capacity.
+ * @param initialCapacity int
+ * the initial number of buckets
+ */
+public CharArrayCache(int initialCapacity) {
+ this.elementSize = 0;
+ this.threshold = (int) (initialCapacity * 0.66f);
+ this.keyTable = new char[initialCapacity][];
+ this.valueTable = new int[initialCapacity];
+}
+/**
+ * Clears the hash table so that it has no more elements in it.
+ */
+public void clear() {
+ for (int i = keyTable.length; --i >= 0;) {
+ keyTable[i] = null;
+ valueTable[i] = 0;
+ }
+ elementSize = 0;
+}
+/** Returns true if the collection contains an element for the key.
+ *
+ * @param key char[] the key that we are looking for
+ * @return boolean
+ */
+public boolean containsKey(char[] key) {
+ int index = hashCodeChar(key);
+ while (keyTable[index] != null) {
+ if (CharOperation.equals(keyTable[index], key))
+ return true;
+ index = (index + 1) % keyTable.length;
+ }
+ return false;
+}
+/** Gets the object associated with the specified key in the
+ * hashtable.
+ * @param key <CODE>char[]</CODE> the specified key
+ * @return int the element for the key or -1 if the key is not
+ * defined in the hash table.
+ */
+public int get(char[] key) {
+ int index = hashCodeChar(key);
+ while (keyTable[index] != null) {
+ if (CharOperation.equals(keyTable[index], key))
+ return valueTable[index];
+ index = (index + 1) % keyTable.length;
+ }
+ return -1;
+}
+private int hashCodeChar(char[] val) {
+ int length = val.length;
+ int hash = 0;
+ int n = 2; // number of characters skipped
+ for (int i = 0; i < length; i += n) {
+ hash += val[i];
+ }
+ return (hash & 0x7FFFFFFF) % keyTable.length;
+}
+/**
+ * Puts the specified element into the hashtable, using the specified
+ * key. The element may be retrieved by doing a get() with the same key.
+ * The key and the element cannot be null.
+ *
+ * @param key <CODE>Object</CODE> the specified key in the hashtable
+ * @param value <CODE>int</CODE> the specified element
+ * @return int the old value of the key, or -1 if it did not have one.
+ */
+public int put(char[] key, int value) {
+ int index = hashCodeChar(key);
+ while (keyTable[index] != null) {
+ if (CharOperation.equals(keyTable[index], key))
+ return valueTable[index] = value;
+ index = (index + 1) % keyTable.length;
+ }
+ keyTable[index] = key;
+ valueTable[index] = value;
+
+ // assumes the threshold is never equal to the size of the table
+ if (++elementSize > threshold)
+ rehash();
+ return value;
+}
+/**
+ * Rehashes the content of the table into a bigger table.
+ * This method is called automatically when the hashtable's
+ * size exceeds the threshold.
+ */
+private void rehash() {
+ CharArrayCache newHashtable = new CharArrayCache(keyTable.length * 2);
+ for (int i = keyTable.length; --i >= 0;)
+ if (keyTable[i] != null)
+ newHashtable.put(keyTable[i], valueTable[i]);
+
+ this.keyTable = newHashtable.keyTable;
+ this.valueTable = newHashtable.valueTable;
+ this.threshold = newHashtable.threshold;
+}
+/** Remove the object associated with the specified key in the
+ * hashtable.
+ * @param key <CODE>char[]</CODE> the specified key
+ */
+public void remove(char[] key) {
+ int index = hashCodeChar(key);
+ while (keyTable[index] != null) {
+ if (CharOperation.equals(keyTable[index], key)) {
+ valueTable[index] = 0;
+ keyTable[index] = null;
+ return;
+ }
+ index = (index + 1) % keyTable.length;
+ }
+}
+/**
+ * Returns the key corresponding to the value. Returns null if the
+ * receiver doesn't contain the value.
+ * @param value int the value that we are looking for
+ * @return Object
+ */
+public char[] returnKeyFor(int value) {
+ for (int i = keyTable.length; i-- > 0;) {
+ if (valueTable[i] == value) {
+ return keyTable[i];
+ }
+ }
+ return null;
+}
+/**
+ * Returns the number of elements contained in the hashtable.
+ *
+ * @return <CODE>int</CODE> The size of the table
+ */
+public int size() {
+ return elementSize;
+}
+/**
+ * Converts to a rather lengthy String.
+ *
+ * return String the ascii representation of the receiver
+ */
+public String toString() {
+ int max = size();
+ StringBuffer buf = new StringBuffer();
+ buf.append("{"); //$NON-NLS-1$
+ for (int i = 0; i < max; ++i) {
+ if (keyTable[i] != null) {
+ buf.append(keyTable[i]).append("->").append(valueTable[i]); //$NON-NLS-1$
+ }
+ if (i < max) {
+ buf.append(", "); //$NON-NLS-1$
+ }
+ }
+ buf.append("}"); //$NON-NLS-1$
+ return buf.toString();
+}
+}
projects / org.ibex.tool.git / blobdiff