01: /*
02: * Primitive Collections for Java.
03: * Copyright (C) 2002, 2003 Søren Bak
04: *
05: * This library is free software; you can redistribute it and/or
06: * modify it under the terms of the GNU Lesser General Public
07: * License as published by the Free Software Foundation; either
08: * version 2.1 of the License, or (at your option) any later version.
09: *
10: * This library is distributed in the hope that it will be useful,
11: * but WITHOUT ANY WARRANTY; without even the implied warranty of
12: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13: * Lesser General Public License for more details.
14: *
15: * You should have received a copy of the GNU Lesser General Public
16: * License along with this library; if not, write to the Free Software
17: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18: */
19: package bak.pcj.hash;
20:
21: import java.io.Serializable;
22:
23: /**
24: * This class provides a default hash function for
25: * double values. It has been derived from the Java library and
26: * is known to work well in the general case.
27: *
28: * @see Double#hashCode()
29: *
30: * @serial exclude
31: * @author Søren Bak
32: * @version 1.2 2003/5/3
33: * @since 1.0
34: */
35: public class DefaultDoubleHashFunction implements DoubleHashFunction,
36: Serializable {
37:
38: /** Default instance of this hash function. */
39: public static final DoubleHashFunction INSTANCE = new DefaultDoubleHashFunction();
40:
41: /** Default constructor to be invoked by sub-classes. */
42: protected DefaultDoubleHashFunction() {
43: }
44:
45: public int hash(double v) {
46: long longhash = Double.doubleToLongBits(v);
47: return (int) (longhash ^ (longhash >>> 32));
48: }
49:
50: }
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