01: /* Soot - a J*va Optimization Framework
02: * Copyright (C) 2003 Ondrej Lhotak
03: *
04: * This library is free software; you can redistribute it and/or
05: * modify it under the terms of the GNU Lesser General Public
06: * License as published by the Free Software Foundation; either
07: * version 2.1 of the License, or (at your option) any later version.
08: *
09: * This library is distributed in the hope that it will be useful,
10: * but WITHOUT ANY WARRANTY; without even the implied warranty of
11: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12: * Lesser General Public License for more details.
13: *
14: * You should have received a copy of the GNU Lesser General Public
15: * License along with this library; if not, write to the
16: * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17: * Boston, MA 02111-1307, USA.
18: */
19:
20: package soot.util;
21:
22: import soot.*;
23:
24: public final class SharedBitSetCache {
25: public SharedBitSetCache(Singletons.Global g) {
26: }
27:
28: public static SharedBitSetCache v() {
29: return G.v().soot_util_SharedBitSetCache();
30: }
31:
32: public static final int size = 32749; // a nice prime about 32k
33:
34: public BitVector[] cache = new BitVector[size];
35: public BitVector[] orAndAndNotCache = new BitVector[size];
36:
37: public BitVector canonicalize(BitVector set) {
38: int hash = set.hashCode();
39: if (hash < 0)
40: hash = -hash;
41: hash %= size;
42: if (cache[hash] == null || !cache[hash].equals(set)) {
43: return cache[hash] = set;
44: }
45: return cache[hash];
46: }
47: }
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