1 ///////////////////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3 // Copyright (C) 2001-2024 the original author or authors.
4 //
5 // This library is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU Lesser General Public
7 // License as published by the Free Software Foundation; either
8 // version 2.1 of the License, or (at your option) any later version.
9 //
10 // This library is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // Lesser General Public License for more details.
14 //
15 // You should have received a copy of the GNU Lesser General Public
16 // License along with this library; if not, write to the Free Software
17 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 ///////////////////////////////////////////////////////////////////////////////////////////////
19
20 package com.puppycrawl.tools.checkstyle.grammar;
21
22 import org.antlr.v4.runtime.CharStream;
23 import org.antlr.v4.runtime.Lexer;
24 import org.antlr.v4.runtime.atn.ATN;
25 import org.antlr.v4.runtime.atn.LexerATNSimulator;
26 import org.antlr.v4.runtime.atn.PredictionContextCache;
27 import org.antlr.v4.runtime.dfa.DFA;
28
29 /**
30 * Extends the LexerATNSimulator class in order to override
31 * the 'consume()' method so that we can handle '\r' line
32 * endings (pre-OSX macOS line endings) correctly in the
33 * ANTLR lexer.
34 */
35 public class CrAwareLexerSimulator extends LexerATNSimulator {
36
37 /**
38 * Constructs a CrAwareLexerSimulator to interpret the input
39 * from the lexer.
40 *
41 * @param lexer the current lexer
42 * @param augmented the augmented transition network
43 * @param decisionToDfa the DFA to store our states in
44 * @param sharedContextCache cache of PredictionContext objects
45 */
46 public CrAwareLexerSimulator(Lexer lexer, ATN augmented,
47 DFA[] decisionToDfa,
48 PredictionContextCache sharedContextCache) {
49 super(lexer, augmented, decisionToDfa, sharedContextCache);
50 }
51
52 /**
53 * Overrides the 'consume()' method to add support for
54 * '\r' (carriage return) line endings.
55 *
56 * @param input the Character stream of the file we are parsing
57 */
58 @Override
59 public void consume(CharStream input) {
60 final int currentChar = input.LA(1);
61 if (currentChar == '\n') {
62 line++;
63 charPositionInLine = 0;
64 }
65 else if (currentChar == '\r') {
66 final int nextChar = input.LA(2);
67 if (nextChar != '\n') {
68 line++;
69 charPositionInLine = 0;
70 }
71 }
72 else {
73 charPositionInLine++;
74 }
75 input.consume();
76 }
77 }