removed Makefile; lifted repo/org.ibex.tool/src/ to src/

[org.ibex.tool.git] / src / org / eclipse / jdt / internal / compiler / codegen / ObjectCache.java

diff --git a/src/org/eclipse/jdt/internal/compiler/codegen/ObjectCache.java b/src/org/eclipse/jdt/internal/compiler/codegen/ObjectCache.java
new file mode 100644 (file)
index 0000000..a1ff0eb
--- /dev/null
+++ b/src/org/eclipse/jdt/internal/compiler/codegen/ObjectCache.java
@@ -0,0 +1,152 @@
+/*******************************************************************************
+ * 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;
+
+public class ObjectCache {
+       public Object keyTable[];
+       public int valueTable[];
+       int elementSize;
+       int threshold;
+/**
+ * Constructs a new, empty hashtable. A default capacity is used.
+ * Note that the hashtable will automatically grow when it gets full.
+ */
+public ObjectCache() {
+       this(13);
+}
+/**
+ * Constructs a new, empty hashtable with the specified initial
+ * capacity.
+ * @param initialCapacity int
+ *  the initial number of buckets
+ */
+public ObjectCache(int initialCapacity) {
+       this.elementSize = 0;
+       this.threshold = (int) (initialCapacity * 0.66f);
+       this.keyTable = new Object[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(Object key) {
+       int index = hashCode(key);
+       while (keyTable[index] != null) {
+               if (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(Object key) {
+       int index = hashCode(key);
+       while (keyTable[index] != null) {
+               if (keyTable[index] == key)
+                       return valueTable[index];
+               index = (index + 1) % keyTable.length;
+       }
+       return -1;
+}
+/**
+ * Return the hashcode for the key parameter
+ *
+ * @param key org.eclipse.jdt.internal.compiler.lookup.MethodBinding
+ * @return int
+ */
+public int hashCode(Object key) {
+       return (key.hashCode() & 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(Object key, int value) { 
+       int index = hashCode(key);
+       while (keyTable[index] != null) {
+               if (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() {
+       ObjectCache newHashtable = new ObjectCache(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;
+}
+/**
+ * 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();
+}
+}