Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.scenegraph / src / gnu / trove / TPrimitiveHash.java

diff --git a/bundles/org.simantics.scenegraph/src/gnu/trove/TPrimitiveHash.java b/bundles/org.simantics.scenegraph/src/gnu/trove/TPrimitiveHash.java
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+///////////////////////////////////////////////////////////////////////////////
+// Copyright (c) 2001, Eric D. Friedman All Rights Reserved.
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library 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 for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+///////////////////////////////////////////////////////////////////////////////
+
+package gnu.trove;
+
+/**
+ * The base class for hashtables of primitive values.  Since there is
+ * no notion of object equality for primitives, it isn't possible to
+ * use a `REMOVED' object to track deletions in an open-addressed table.
+ * So, we have to resort to using a parallel `bookkeeping' array of bytes,
+ * in which flags can be set to indicate that a particular slot in the
+ * hash table is FREE, FULL, or REMOVED.
+ *
+ * Created: Fri Jan 11 18:55:16 2002
+ *
+ * @author Eric D. Friedman
+ * @version $Id: TPrimitiveHash.java,v 1.5 2008/10/08 16:39:10 robeden Exp $
+ */
+
+abstract public class TPrimitiveHash extends THash  {
+    /** flags indicating whether each position in the hash is
+     * FREE, FULL, or REMOVED */
+    protected transient byte[] _states;
+
+    /* constants used for state flags */
+
+    /** flag indicating that a slot in the hashtable is available */
+    protected static final byte FREE = 0;
+
+    /** flag indicating that a slot in the hashtable is occupied */
+    protected static final byte FULL = 1;
+
+    /** flag indicating that the value of a slot in the hashtable 
+     * was deleted */
+    protected static final byte REMOVED = 2;
+
+    /**
+     * Creates a new <code>THash</code> instance with the default
+     * capacity and load factor.
+     */
+    public TPrimitiveHash() {
+        super();
+    }
+
+    /**
+     * Creates a new <code>TPrimitiveHash</code> instance with a prime
+     * capacity at or near the specified capacity and with the default
+     * load factor.
+     *
+     * @param initialCapacity an <code>int</code> value
+     */
+    public TPrimitiveHash(int initialCapacity) {
+        this(initialCapacity, DEFAULT_LOAD_FACTOR);
+    }
+
+    /**
+     * Creates a new <code>TPrimitiveHash</code> instance with a prime
+     * capacity at or near the minimum needed to hold
+     * <tt>initialCapacity<tt> elements with load factor
+     * <tt>loadFactor</tt> without triggering a rehash.
+     *
+     * @param initialCapacity an <code>int</code> value
+     * @param loadFactor a <code>float</code> value
+     */
+    public TPrimitiveHash(int initialCapacity, float loadFactor) {
+        super();
+        _loadFactor = loadFactor;
+        setUp(HashFunctions.fastCeil(initialCapacity / loadFactor));
+    }
+
+    public Object clone() {
+        TPrimitiveHash h = (TPrimitiveHash)super.clone();
+        h._states = (byte[])this._states.clone();
+        return h;
+    }
+
+    /**
+     * Returns the capacity of the hash table.  This is the true
+     * physical capacity, without adjusting for the load factor.
+     *
+     * @return the physical capacity of the hash table.
+     */
+    protected int capacity() {
+        return _states.length;
+    }
+
+    /**
+     * Delete the record at <tt>index</tt>.
+     *
+     * @param index an <code>int</code> value
+     */
+    protected void removeAt(int index) {
+        _states[index] = REMOVED;
+        super.removeAt(index);
+    }
+
+    /**
+     * initializes the hashtable to a prime capacity which is at least
+     * <tt>initialCapacity + 1</tt>.  
+     *
+     * @param initialCapacity an <code>int</code> value
+     * @return the actual capacity chosen
+     */
+    protected int setUp(int initialCapacity) {
+        int capacity;
+
+        capacity = super.setUp(initialCapacity);
+        _states = new byte[capacity];
+        return capacity;
+    }
+} // TPrimitiveHash