01: /*
02: * logeqv.java
03: *
04: * Copyright (C) 2003 Peter Graves
05: * $Id: logeqv.java,v 1.6 2003/11/15 11:03:35 beedlem Exp $
06: *
07: * This program is free software; you can redistribute it and/or
08: * modify it under the terms of the GNU General Public License
09: * 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: import java.math.BigInteger;
25:
26: // ### logeqv
27: // logeqv &rest integers => result-integer
28: // equivalence (exclusive nor)
29: public final class logeqv extends Primitive {
30: private logeqv() {
31: super ("logeqv");
32: }
33:
34: public LispObject execute() {
35: return Fixnum.MINUS_ONE;
36: }
37:
38: public LispObject execute(LispObject arg) throws ConditionThrowable {
39: if (arg instanceof Fixnum)
40: return arg;
41: if (arg instanceof Bignum)
42: return arg;
43: throw new ConditionThrowable(new TypeError(arg, "integer"));
44: }
45:
46: public LispObject execute(LispObject[] args)
47: throws ConditionThrowable {
48: BigInteger result = null;
49: for (int i = 0; i < args.length; i++) {
50: LispObject arg = args[i];
51: BigInteger n;
52: if (arg instanceof Fixnum)
53: n = ((Fixnum) arg).getBigInteger();
54: else if (arg instanceof Bignum)
55: n = ((Bignum) arg).getValue();
56: else
57: throw new ConditionThrowable(new TypeError(arg,
58: "integer"));
59: if (result == null)
60: result = n;
61: else
62: result = result.xor(n).not();
63: }
64: return number(result);
65: }
66:
67: private static final logeqv LOGEQV = new logeqv();
68: }
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