1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.dx.ssa;
18
19import com.android.dx.rop.code.RegisterSpec;
20import com.android.dx.rop.code.RegisterSpecList;
21import com.android.dx.util.ToHuman;
22
23/**
24 * Represents a mapping between two register numbering schemes.
25 * Subclasses of this may be mutable, and as such the mapping provided
26 * is only valid for the lifetime of the method call in which
27 * instances of this class are passed.
28 */
29public abstract class RegisterMapper {
30    /**
31     * Gets the count of registers (really, the total register width, since
32     * category width is counted) in the new namespace.
33     * @return >= 0 width of new namespace.
34     */
35    public abstract int getNewRegisterCount();
36
37    /**
38     * @param registerSpec old register
39     * @return register in new space
40     */
41    public abstract RegisterSpec map(RegisterSpec registerSpec);
42
43    /**
44     *
45     * @param sources old register list
46     * @return new mapped register list, or old if nothing has changed.
47     */
48    public final RegisterSpecList map(RegisterSpecList sources) {
49        int sz = sources.size();
50        RegisterSpecList newSources = new RegisterSpecList(sz);
51
52        for (int i = 0; i < sz; i++) {
53            newSources.set(i, map(sources.get(i)));
54        }
55
56        newSources.setImmutable();
57
58        // Return the old sources if nothing has changed.
59        return newSources.equals(sources) ? sources : newSources;
60    }
61}
62