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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
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 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common
 * Development and Distribution License("CDDL") (collectively, the
 * "License"). You may not use this file except in compliance with the
 * License. You can obtain a copy of the License at
 * http://www.netbeans.org/cddl-gplv2.html
 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
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 * Notice in each file and include the License file at
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 * particular file as subject to the "Classpath" exception as provided
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 * accompanied this code. If applicable, add the following below the
 * License Header, with the fields enclosed by brackets [] replaced by
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 *
 * The Original Software is NetBeans. The Initial Developer of the Original
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 *
 * If you wish your version of this file to be governed by only the CDDL
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 * "[Contributor] elects to include this software in this distribution
 * under the [CDDL or GPL Version 2] license." If you do not indicate a
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 * your version of this file under either the CDDL, the GPL Version 2 or
 * to extend the choice of license to its licensees as provided above.
 * However, if you add GPL Version 2 code and therefore, elected the GPL
 * Version 2 license, then the option applies only if the new code is
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package org.netbeans.modules.languages.diff;

import org.netbeans.api.lexer.Token;
import org.netbeans.spi.lexer.Lexer;
import org.netbeans.spi.lexer.LexerInput;
import org.netbeans.spi.lexer.LexerRestartInfo;


/**
 *
 * @author Jan Jancura
 */
class DiffLexer implements Lexer<DiffTokenId> {

    private LexerRestartInfo<DiffTokenId> info;

    DiffLexer (LexerRestartInfo<DiffTokenId> info) {
        this.info = info;
    }

    public Token<DiffTokenId> nextToken () {
        LexerInput input = info.input ();
        int i = input.read ();
        switch (i) {
            case LexerInput.EOF:
                return null;
            case 'I':
                if (read ("ndex:", input)) 
                    return info.tokenFactory ().createToken (DiffTokenId.INDEX);
                return info.tokenFactory ().createToken (DiffTokenId.PLAIN);
            case '=':
                if (read ("==", input))
                    return info.tokenFactory ().createToken (DiffTokenId.HEADER);
                return info.tokenFactory ().createToken (DiffTokenId.PLAIN);
            case '-':
                if (read ("--", input))
                    return info.tokenFactory ().createToken (DiffTokenId.HEADER);
                return info.tokenFactory ().createToken (DiffTokenId.REMOVED);
            case '+':
                if (read ("++", input))
                    return info.tokenFactory ().createToken (DiffTokenId.HEADER);
                return info.tokenFactory ().createToken (DiffTokenId.ADDED);
            case 'd':
                if (read ("iff", input))
                    return info.tokenFactory ().createToken (DiffTokenId.HEADER);
                return info.tokenFactory ().createToken (DiffTokenId.PLAIN);
            case 'r':
                if (read ("etrieving", input))
                    return info.tokenFactory ().createToken (DiffTokenId.HEADER);
                return info.tokenFactory ().createToken (DiffTokenId.PLAIN);
            case '@':
                if (read ("@", input))
                    return info.tokenFactory ().createToken (DiffTokenId.HEADER);
                return info.tokenFactory ().createToken (DiffTokenId.PLAIN);
            case 'R':
                if (read ("CS file:", input))
                    return info.tokenFactory ().createToken (DiffTokenId.HEADER);
                return info.tokenFactory ().createToken (DiffTokenId.PLAIN);
            case '>':
                read ("", input);
                return info.tokenFactory ().createToken (DiffTokenId.ADDED);
            case '<':
                read ("", input);
                return info.tokenFactory ().createToken (DiffTokenId.REMOVED);
            default:
                read ("", input);
                return info.tokenFactory ().createToken (DiffTokenId.PLAIN);
        }
    }

    private static boolean read (String text, LexerInput input) {
        boolean result = true;
        for (int i = 0; i < text.length (); i++) {
            int c;
            if (text.charAt (i) != (c = input.read ())) {
                result = false;
                if (c == '\n' || c == '\r') {
                    input.backup(1);
                }
                break;
            }
        }
        int i = input.read ();
        while (
            i != '\n' &&
            i != '\r' &&
            i != LexerInput.EOF
        ) {
            i = input.read ();
        }
        while (
            i != LexerInput.EOF &&
            (i == '\n' ||
             i == '\r')
        ) {
            i = input.read ();
        }
        if (i != LexerInput.EOF)
            input.backup (1);
        return result;
    }

    public Object state () {
        return null;
    }

    public void release () {
    }
}


