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