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Java > Open Source Codes > org > armedbear > lisp > float_sign


1 /*
2  * float_sign.java
3  *
4  * Copyright (C) 2004 Peter Graves
5  * $Id: float_sign.java,v 1.1 2004/06/06 19:31:53 piso Exp $
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * as published by the Free Software Foundation; either version 2
10  * of the License, or (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20  */

21
22 package org.armedbear.lisp;
23
24 public final class float_sign extends Primitive
25 {
26     private float_sign()
27     {
28         super("float-sign", "float-1 &optional float-2");
29     }
30
31     public LispObject execute(LispObject arg) throws ConditionThrowable
32     {
33         try {
34             double d = ((LispFloat)arg).value;
35             long bits = Double.doubleToRawLongBits(d);
36             return bits < 0 ? LispFloat.MINUS_ONE : LispFloat.ONE;
37         }
38         catch (ClassCastException JavaDoc e) {
39             return signal(new TypeError(arg, Symbol.FLOAT));
40         }
41     }
42
43     public LispObject execute(LispObject first, LispObject second)
44         throws ConditionThrowable
45     {
46         double d1, d2;
47         try {
48             d1 = ((LispFloat)first).value;
49         }
50         catch (ClassCastException JavaDoc e) {
51             return signal(new TypeError(first, Symbol.FLOAT));
52         }
53         try {
54             d2 = Math.abs(((LispFloat)second).value);
55         }
56         catch (ClassCastException JavaDoc e) {
57             return signal(new TypeError(second, Symbol.FLOAT));
58         }
59         long bits = Double.doubleToRawLongBits(d1);
60         return bits < 0 ? new LispFloat(-d2) : new LispFloat(d2);
61     }
62
63     private static final Primitive FLOAT_SIGN = new float_sign();
64 }
65
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