138 lines
4.2 KiB
Java
138 lines
4.2 KiB
Java
/*
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* Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package com.sun.tools.javac.parser;
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import java.nio.*;
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import java.util.List;
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import java.util.ArrayList;
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import com.sun.tools.javac.util.Position.LineMap;
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import com.sun.tools.javac.parser.JavaTokenizer.*;
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import static com.sun.tools.javac.parser.Tokens.*;
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/** The lexical analyzer maps an input stream consisting of
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* ASCII characters and Unicode escapes into a token sequence.
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*
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* <p><b>This is NOT part of any supported API.
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* If you write code that depends on this, you do so at your own risk.
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* This code and its internal interfaces are subject to change or
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* deletion without notice.</b>
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*/
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public class Scanner implements Lexer {
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private Tokens tokens;
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/** The token, set by nextToken().
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*/
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private Token token;
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/** The previous token, set by nextToken().
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*/
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private Token prevToken;
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/** Buffer of saved tokens (used during lookahead)
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*/
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private List<Token> savedTokens = new ArrayList<Token>();
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private JavaTokenizer tokenizer;
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/**
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* Create a scanner from the input array. This method might
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* modify the array. To avoid copying the input array, ensure
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* that {@code inputLength < input.length} or
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* {@code input[input.length -1]} is a white space character.
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*
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* @param fac the factory which created this Scanner
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* @param buf the input, might be modified
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* Must be positive and less than or equal to input.length.
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*/
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protected Scanner(ScannerFactory fac, CharBuffer buf) {
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this(fac, new JavaTokenizer(fac, buf));
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}
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protected Scanner(ScannerFactory fac, char[] buf, int inputLength) {
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this(fac, new JavaTokenizer(fac, buf, inputLength));
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}
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protected Scanner(ScannerFactory fac, JavaTokenizer tokenizer) {
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this.tokenizer = tokenizer;
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tokens = fac.tokens;
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token = prevToken = DUMMY;
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}
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public Token token() {
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return token(0);
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}
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public Token token(int lookahead) {
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if (lookahead == 0) {
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return token;
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} else {
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ensureLookahead(lookahead);
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return savedTokens.get(lookahead - 1);
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}
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}
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//where
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private void ensureLookahead(int lookahead) {
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for (int i = savedTokens.size() ; i < lookahead ; i ++) {
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savedTokens.add(tokenizer.readToken());
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}
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}
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public Token prevToken() {
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return prevToken;
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}
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public void nextToken() {
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prevToken = token;
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if (!savedTokens.isEmpty()) {
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token = savedTokens.remove(0);
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} else {
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token = tokenizer.readToken();
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}
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}
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public Token split() {
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Token[] splitTokens = token.split(tokens);
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prevToken = splitTokens[0];
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token = splitTokens[1];
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return token;
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}
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public LineMap getLineMap() {
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return tokenizer.getLineMap();
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}
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public int errPos() {
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return tokenizer.errPos();
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}
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public void errPos(int pos) {
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tokenizer.errPos(pos);
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}
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}
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