1 /* 2 * Copyright (c) 2009, 2011, 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 */ 23 package org.graalvm.compiler.lir.alloc.lsra; 24 25 /** 26 * Represents a range of integers from a start (inclusive) to an end (exclusive. 27 */ 28 public final class Range { 29 30 public static final Range EndMarker = new Range(Integer.MAX_VALUE, Integer.MAX_VALUE, null); 31 32 /** 33 * 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 Range next; 46 47 boolean intersects(Range r) { 48 return intersectsAt(r) != -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 Range(int from, int to, Range next) { 59 this.from = from; 60 this.to = to; 61 this.next = next; 62 } 63 64 int intersectsAt(Range other) { 65 Range r1 = this; 66 Range r2 = other; 67 68 assert r2 != null : "null ranges not allowed"; 69 assert r1 != EndMarker && r2 != EndMarker : "empty ranges not allowed"; 70 71 do { 72 if (r1.from < r2.from) { 73 if (r1.to <= r2.from) { 74 r1 = r1.next; 75 if (r1 == EndMarker) { 76 return -1; 77 } 78 } else { 79 return r2.from; 80 } 81 } else { 82 if (r2.from < r1.from) { 83 if (r2.to <= r1.from) { 84 r2 = r2.next; 85 if (r2 == EndMarker) { 86 return -1; 87 } 88 } else { 89 return r1.from; 90 } 91 } else { // r1.from() == r2.from() 92 if (r1.from == r1.to) { 93 r1 = r1.next; 94 if (r1 == EndMarker) { 95 return -1; 96 } 97 } else { 98 if (r2.from == r2.to) { 99 r2 = r2.next; 100 if (r2 == EndMarker) { 101 return -1; 102 } 103 } else { 104 return r1.from; 105 } 106 } 107 } 108 } 109 } while (true); 110 } 111 112 @Override 113 public String toString() { 114 return "[" + from + ", " + to + "]"; 115 } 116 }