FixedRange.java revision 12651:6ef01bd40ce2 
11854Swollman/*
250476Speter * Copyright (c) 2015, 2015, Oracle and/or its affiliates. All rights reserved.
31573Srgrimes * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4156813Sru *
5156813Sru * This code is free software; you can redistribute it and/or modify it
6313603Sngie * under the terms of the GNU General Public License version 2 only, as
7117675Smarkm * published by the Free Software Foundation.
8117675Smarkm *
981961Smarkm * This code is distributed in the hope that it will be useful, but WITHOUT
1074928Sru * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11136910Sru * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
1274928Sru * version 2 for more details (a copy is included in the LICENSE file that
1381961Smarkm * accompanied this code).
14117675Smarkm *
151573Srgrimes * You should have received a copy of the GNU General Public License version
16189092Sed * 2 along with this work; if not, write to the Free Software Foundation,
1787147Smarkm * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18117973Smarkm *
19156813Sru * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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22160854Syar */
23160854Syarpackage org.graalvm.compiler.lir.alloc.trace.lsra;
24156813Sru
25117675Smarkm/**
26323043Scy * Represents a range of integers from a start (inclusive) to an end (exclusive).
27117675Smarkm */
28117675Smarkmfinal class FixedRange {
2987147Smarkm
30117675Smarkm    public static final FixedRange EndMarker = new FixedRange(Integer.MAX_VALUE, Integer.MAX_VALUE, null);
31117675Smarkm
32117675Smarkm    /**
3387147Smarkm     * The start of the range, inclusive.
34     */
35    public int from;
36
37    /**
38     * The end of the range, exclusive.
39     */
40    public int to;
41
42    /**
43     * A link to allow the range to be put into a singly linked list.
44     */
45    public FixedRange next;
46
47    boolean intersects(TraceInterval i) {
48        return intersectsAt(i) != -1;
49    }
50
51    /**
52     * Creates a new range.
53     *
54     * @param from the start of the range, inclusive
55     * @param to the end of the range, exclusive
56     * @param next link to the next range in a linked list
57     */
58    FixedRange(int from, int to, FixedRange next) {
59        this.from = from;
60        this.to = to;
61        this.next = next;
62    }
63
64    int intersectsAt(TraceInterval other) {
65        FixedRange range = this;
66        assert other != null : "null ranges not allowed";
67        assert range != EndMarker && other != TraceInterval.EndMarker : "empty ranges not allowed";
68        int intervalFrom = other.from();
69        int intervalTo = other.to();
70
71        do {
72            if (range.from < intervalFrom) {
73                if (range.to <= intervalFrom) {
74                    range = range.next;
75                    if (range == EndMarker) {
76                        return -1;
77                    }
78                } else {
79                    return intervalFrom;
80                }
81            } else {
82                if (intervalFrom < range.from) {
83                    if (intervalTo <= range.from) {
84                        return -1;
85                    }
86                    return range.from;
87                } else {
88                    assert range.from == intervalFrom;
89                    if (range.from == range.to) {
90                        range = range.next;
91                        if (range == EndMarker) {
92                            return -1;
93                        }
94                    } else {
95                        if (intervalFrom == intervalTo) {
96                            return -1;
97                        }
98                        return range.from;
99                    }
100                }
101            }
102        } while (true);
103    }
104
105    @Override
106    public String toString() {
107        return "[" + from + ", " + to + "]";
108    }
109}
110