jdk8-mips64-public/langtools: src/share/classes/com/sun/tools/javac/parser/Scanner.java@c46e0c9940d6

     1 /*

     2  * Copyright (c) 1999, 2012, 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.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    26 package com.sun.tools.javac.parser;

    28 import java.nio.*;

    29 import java.util.List;

    30 import java.util.ArrayList;

    32 import com.sun.tools.javac.util.Position.LineMap;

    33 import com.sun.tools.javac.parser.JavaTokenizer.*;

    35 import static com.sun.tools.javac.parser.Tokens.*;

    37 /** The lexical analyzer maps an input stream consisting of

    38  *  ASCII characters and Unicode escapes into a token sequence.

    39  *

    40  *  <p><b>This is NOT part of any supported API.

    41  *  If you write code that depends on this, you do so at your own risk.

    42  *  This code and its internal interfaces are subject to change or

    43  *  deletion without notice.</b>

    44  */

    45 public class Scanner implements Lexer {

    47     private Tokens tokens;

    49     /** The token, set by nextToken().

    50      */

    51     private Token token;

    53     /** The previous token, set by nextToken().

    54      */

    55     private Token prevToken;

    57     /** Buffer of saved tokens (used during lookahead)

    58      */

    59     private List<Token> savedTokens = new ArrayList<Token>();

    61     private JavaTokenizer tokenizer;

    62     /**

    63      * Create a scanner from the input array.  This method might

    64      * modify the array.  To avoid copying the input array, ensure

    65      * that {@code inputLength < input.length} or

    66      * {@code input[input.length -1]} is a white space character.

    67      *

    68      * @param fac the factory which created this Scanner

    69      * @param buf the input, might be modified

    70      * Must be positive and less than or equal to input.length.

    71      */

    72     protected Scanner(ScannerFactory fac, CharBuffer buf) {

    73         this(fac, new JavaTokenizer(fac, buf));

    74     }

    76     protected Scanner(ScannerFactory fac, char[] buf, int inputLength) {

    77         this(fac, new JavaTokenizer(fac, buf, inputLength));

    78     }

    80     protected Scanner(ScannerFactory fac, JavaTokenizer tokenizer) {

    81         this.tokenizer = tokenizer;

    82         tokens = fac.tokens;

    83         token = prevToken = DUMMY;

    84     }

    86     public Token token() {

    87         return token(0);

    88     }

    90     public Token token(int lookahead) {

    91         if (lookahead == 0) {

    92             return token;

    93         } else {

    94             ensureLookahead(lookahead);

    95             return savedTokens.get(lookahead - 1);

    96         }

    97     }

    98     //where

    99         private void ensureLookahead(int lookahead) {

   100             for (int i = savedTokens.size() ; i < lookahead ; i ++) {

   101                 savedTokens.add(tokenizer.readToken());

   102             }

   103         }

   105     public Token prevToken() {

   106         return prevToken;

   107     }

   109     public void nextToken() {

   110         prevToken = token;

   111         if (!savedTokens.isEmpty()) {

   112             token = savedTokens.remove(0);

   113         } else {

   114             token = tokenizer.readToken();

   115         }

   116     }

   118     public Token split() {

   119         Token[] splitTokens = token.split(tokens);

   120         prevToken = splitTokens[0];

   121         token = splitTokens[1];

   122         return token;

   123     }

   125     public LineMap getLineMap() {

   126         return tokenizer.getLineMap();

   127     }

   129     public int errPos() {

   130         return tokenizer.errPos();

   131     }

   133     public void errPos(int pos) {

   134         tokenizer.errPos(pos);

   135     }

   136 }

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