1/*
2 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23package jdk.vm.ci.code;
24
25import java.util.Arrays;
26import java.util.Collection;
27import java.util.Collections;
28import java.util.Iterator;
29import java.util.List;
30
31/**
32 * An immutable ordered list of registers. Only required because Java lacks immutable arrays.
33 */
34public final class RegisterArray implements Iterable<Register> {
35
36    private final Register[] registers;
37    private int hash;
38
39    public RegisterArray(Register... registers) {
40        this.registers = registers;
41    }
42
43    public RegisterArray(Collection<Register> registers) {
44        this.registers = registers.toArray(new Register[registers.size()]);
45    }
46
47    /**
48     * Gets the number of registers.
49     */
50    public int size() {
51        return registers.length;
52    }
53
54    /**
55     * Gets the register at a given index.
56     *
57     * @param index the index of the register to retrieve
58     */
59    public Register get(int index) {
60        return registers[index];
61    }
62
63    public void addTo(Collection<Register> collection) {
64        collection.addAll(Arrays.asList(registers));
65    }
66
67    /**
68     * Gets an immutable view of the registers as a list.
69     */
70    public List<Register> asList() {
71        return Collections.unmodifiableList(Arrays.asList(registers));
72    }
73
74    /**
75     * Gets a copy of the registers as an array.
76     */
77    public Register[] toArray() {
78        return registers.clone();
79    }
80
81    public Iterator<Register> iterator() {
82        return Arrays.asList(registers).iterator();
83    }
84
85    @Override
86    public int hashCode() {
87        if (hash == 0 && registers.length > 0) {
88            hash = Arrays.hashCode(registers);
89        }
90        return hash;
91    }
92
93    @Override
94    public boolean equals(Object obj) {
95        if (obj instanceof RegisterArray) {
96            return Arrays.equals(registers, ((RegisterArray) obj).registers);
97        }
98        return false;
99    }
100
101    @Override
102    public String toString() {
103        return Arrays.toString(registers);
104    }
105}
106