1 /*
2  * Copyright (c) 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 jdk.vm.ci.meta;
24 
25 /**
26  * Maps bytecode indexes to source line numbers.
27  *
28  * @see "https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.12"
29  */
30 public class LineNumberTable {
31 
32     private final int[] lineNumbers;
33     private final int[] bcis;
34 
35     /**
36      *
37      * @param lineNumbers an array of source line numbers. This array is now owned by this object
38      *            and should not be mutated by the caller.
39      * @param bcis an array of bytecode indexes the same length at {@code lineNumbers} whose entries
40      *            are sorted in ascending order. This array is now owned by this object and must not
41      *            be mutated by the caller.
42      */
43     @SuppressFBWarnings(value = "EI_EXPOSE_REP2", justification = "caller transfers ownership of `lineNumbers` and `bcis`")
LineNumberTable(int[] lineNumbers, int[] bcis)44     public LineNumberTable(int[] lineNumbers, int[] bcis) {
45         assert bcis.length == lineNumbers.length;
46         this.lineNumbers = lineNumbers;
47         this.bcis = bcis;
48     }
49 
50     /**
51      * Gets a source line number for bytecode index {@code atBci}.
52      */
getLineNumber(int atBci)53     public int getLineNumber(int atBci) {
54         for (int i = 0; i < this.bcis.length - 1; i++) {
55             if (this.bcis[i] <= atBci && atBci < this.bcis[i + 1]) {
56                 return lineNumbers[i];
57             }
58         }
59         return lineNumbers[lineNumbers.length - 1];
60     }
61 
62     /**
63      * Gets a copy of the array of line numbers that was passed to this object's constructor.
64      */
getLineNumbers()65     public int[] getLineNumbers() {
66         return lineNumbers.clone();
67     }
68 
69     /**
70      * Gets a copy of the array of bytecode indexes that was passed to this object's constructor.
71      */
getBcis()72     public int[] getBcis() {
73         return bcis.clone();
74     }
75 }
76