duke@1: /*
jjg@1358:  * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.
duke@1:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1:  *
duke@1:  * This code is free software; you can redistribute it and/or modify it
duke@1:  * under the terms of the GNU General Public License version 2 only, as
ohair@554:  * published by the Free Software Foundation.  Oracle designates this
duke@1:  * particular file as subject to the "Classpath" exception as provided
ohair@554:  * by Oracle in the LICENSE file that accompanied this code.
duke@1:  *
duke@1:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@1:  * version 2 for more details (a copy is included in the LICENSE file that
duke@1:  * accompanied this code).
duke@1:  *
duke@1:  * You should have received a copy of the GNU General Public License version
duke@1:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@1:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1:  *
ohair@554:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554:  * or visit www.oracle.com if you need additional information or have any
ohair@554:  * questions.
duke@1:  */
duke@1: 
duke@1: package com.sun.tools.javac.parser;
duke@1: 
duke@1: import java.nio.*;
mcimadamore@1144: import java.util.List;
mcimadamore@1144: import java.util.ArrayList;
duke@1: 
mcimadamore@1113: import com.sun.tools.javac.util.Position.LineMap;
mcimadamore@1113: import com.sun.tools.javac.parser.JavaTokenizer.*;
duke@1: 
mcimadamore@1113: import static com.sun.tools.javac.parser.Tokens.*;
duke@1: 
duke@1: /** The lexical analyzer maps an input stream consisting of
duke@1:  *  ASCII characters and Unicode escapes into a token sequence.
duke@1:  *
jjg@581:  *  <p><b>This is NOT part of any supported API.
jjg@581:  *  If you write code that depends on this, you do so at your own risk.
duke@1:  *  This code and its internal interfaces are subject to change or
duke@1:  *  deletion without notice.</b>
duke@1:  */
duke@1: public class Scanner implements Lexer {
duke@1: 
mcimadamore@1113:     private Tokens tokens;
duke@1: 
duke@1:     /** The token, set by nextToken().
duke@1:      */
duke@1:     private Token token;
duke@1: 
mcimadamore@1113:     /** The previous token, set by nextToken().
duke@1:      */
mcimadamore@1113:     private Token prevToken;
duke@1: 
mcimadamore@1144:     /** Buffer of saved tokens (used during lookahead)
mcimadamore@1144:      */
mcimadamore@1144:     private List<Token> savedTokens = new ArrayList<Token>();
mcimadamore@1144: 
mcimadamore@1113:     private JavaTokenizer tokenizer;
duke@1:     /**
duke@1:      * Create a scanner from the input array.  This method might
duke@1:      * modify the array.  To avoid copying the input array, ensure
duke@1:      * that {@code inputLength < input.length} or
duke@1:      * {@code input[input.length -1]} is a white space character.
duke@1:      *
duke@1:      * @param fac the factory which created this Scanner
jjg@1358:      * @param buf the input, might be modified
duke@1:      * Must be positive and less than or equal to input.length.
duke@1:      */
mcimadamore@1113:     protected Scanner(ScannerFactory fac, CharBuffer buf) {
mcimadamore@1113:         this(fac, new JavaTokenizer(fac, buf));
duke@1:     }
duke@1: 
mcimadamore@1113:     protected Scanner(ScannerFactory fac, char[] buf, int inputLength) {
mcimadamore@1113:         this(fac, new JavaTokenizer(fac, buf, inputLength));
duke@1:     }
duke@1: 
mcimadamore@1113:     protected Scanner(ScannerFactory fac, JavaTokenizer tokenizer) {
mcimadamore@1113:         this.tokenizer = tokenizer;
mcimadamore@1113:         tokens = fac.tokens;
mcimadamore@1113:         token = prevToken = DUMMY;
duke@1:     }
duke@1: 
duke@1:     public Token token() {
mcimadamore@1144:         return token(0);
duke@1:     }
duke@1: 
mcimadamore@1144:     public Token token(int lookahead) {
mcimadamore@1144:         if (lookahead == 0) {
mcimadamore@1144:             return token;
mcimadamore@1144:         } else {
mcimadamore@1144:             ensureLookahead(lookahead);
mcimadamore@1144:             return savedTokens.get(lookahead - 1);
mcimadamore@1144:         }
mcimadamore@1144:     }
mcimadamore@1144:     //where
mcimadamore@1144:         private void ensureLookahead(int lookahead) {
mcimadamore@1144:             for (int i = savedTokens.size() ; i < lookahead ; i ++) {
mcimadamore@1144:                 savedTokens.add(tokenizer.readToken());
mcimadamore@1144:             }
mcimadamore@1144:         }
mcimadamore@1144: 
mcimadamore@1113:     public Token prevToken() {
mcimadamore@1113:         return prevToken;
duke@1:     }
duke@1: 
mcimadamore@1113:     public void nextToken() {
mcimadamore@1113:         prevToken = token;
mcimadamore@1144:         if (!savedTokens.isEmpty()) {
mcimadamore@1144:             token = savedTokens.remove(0);
mcimadamore@1144:         } else {
mcimadamore@1144:             token = tokenizer.readToken();
mcimadamore@1144:         }
duke@1:     }
duke@1: 
mcimadamore@1113:     public Token split() {
mcimadamore@1113:         Token[] splitTokens = token.split(tokens);
mcimadamore@1113:         prevToken = splitTokens[0];
mcimadamore@1113:         token = splitTokens[1];
mcimadamore@1113:         return token;
duke@1:     }
duke@1: 
mcimadamore@1113:     public LineMap getLineMap() {
mcimadamore@1113:         return tokenizer.getLineMap();
duke@1:     }
duke@1: 
duke@1:     public int errPos() {
mcimadamore@1113:         return tokenizer.errPos();
duke@1:     }
duke@1: 
duke@1:     public void errPos(int pos) {
mcimadamore@1113:         tokenizer.errPos(pos);
duke@1:     }
duke@1: }