/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

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

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

 *

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

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

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

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

 * accompanied this code).

 *

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

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

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

 *

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

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package com.sun.xml.internal.stream.writers;

import java.io.FileWriter;

import java.io.IOException;

import java.io.OutputStreamWriter;

import java.io.Writer;

import java.nio.charset.Charset;

import java.nio.charset.CharsetEncoder;

/**

 * Implements common xml writer functions.

 *

 * @author Neeraj Bajaj,K.Venugopal Sun Microsystems.

 */

public class WriterUtility {

    public static final String START_COMMENT = "<!--";

    public static final String END_COMMENT = "-->";

    public static final String DEFAULT_ENCODING = " encoding=\"utf-8\"";

    public static final String DEFAULT_XMLDECL ="<?xml version=\"1.0\" ?>";

    public static final String DEFAULT_XML_VERSION ="1.0";

    public static final char CLOSE_START_TAG = '>';

    public static final char OPEN_START_TAG = '<';

    public static final String OPEN_END_TAG ="</";

    public static final char CLOSE_END_TAG = '>';

    public static final String START_CDATA = "<![CDATA[";

    public static final String END_CDATA = "]]>";

    public static final String CLOSE_EMPTY_ELEMENT = "/>";

    public static final String SPACE = " ";

    public static final String UTF_8 = "utf-8";

    static final boolean DEBUG_XML_CONTENT = false;

    /**XXX: This feature is only used when writing element content values.

     * default value is 'true' however, if the feature is set to false

     * characters wont be escaped.

     * This feature has no effect when writing Attribute values, character would still be escaped.

     * I can't think of any reason why this would be useful when writing attribute values.

     * However, this can be reconsidered if there is any usecase.

     */

    boolean fEscapeCharacters = true ;

    /** Writer object*/

    Writer fWriter = null;

    //CharsetEncoder

    CharsetEncoder fEncoder ;

    public WriterUtility(){

        fEncoder = getDefaultEncoder();

    }

    /** Creates a new instance of WriterUtility */

    public WriterUtility(Writer writer) {

        fWriter = writer;

        if(writer instanceof OutputStreamWriter){

            String charset = ((OutputStreamWriter)writer).getEncoding();

            if(charset != null){

                fEncoder = Charset.forName(charset).newEncoder();

            }

        }else if(writer instanceof FileWriter){

            String charset = ((FileWriter)writer).getEncoding();

            if(charset != null){

                fEncoder = Charset.forName(charset).newEncoder();

            }

        }

        else{

            //attempt to retreive default fEncoderoder

            fEncoder = getDefaultEncoder();

        }

    }

    /**

     * sets the writer object

     * @param writer file to write into

     */

    public void  setWriter(Writer writer){

        fWriter = writer;

    }

    public void setEscapeCharacters(boolean escape){

        fEscapeCharacters = escape ;

    }

    public boolean getEscapeCharacters(){

        return fEscapeCharacters;

    }

    /**

     * writes xml content (characters and element content

     * @param content

     */

    public void writeXMLContent(char[] content, int start, int length) throws IOException{

        writeXMLContent(content, start, length, getEscapeCharacters());

    }

    /**

     * writes xml content (characters and element content

     * @param content

     */

    private void writeXMLContent(char[] content, int start, int length, boolean escapeCharacter) throws IOException{

        if(DEBUG_XML_CONTENT){

            System.out.println("content to write is " + new String(content, start, length));

        }

        int index;

        char ch;

        int sc;

        final int end = start + length ;

        //define startWritePos to track the position from where the character array data needs to be written

        //initialize this variable to start pos. indicating that no data has been written

        int startWritePos = start;

        for ( index = start ; index < end ; index++ ) {

            ch = content[ index ];

            if(fEncoder != null && !fEncoder.canEncode(ch)){

                //- write the data to the point we get this character

                fWriter.write(content, startWritePos, index - startWritePos );

                //escape this character

                fWriter.write( "&#x" );

                fWriter.write(Integer.toHexString(ch));

                fWriter.write( ';' );

                //increase the startWritePos by 1 indicating that next write should start from

                //one position ahead

                startWritePos = index + 1;

            }

            if(DEBUG_XML_CONTENT){

                System.out.println("startWritePos = " + startWritePos);

                System.out.println("index = " + index);

                System.out.println("start = " + start);

                System.out.println("end = " + end);

            }

            switch(ch){

                case '<' :{

                    if(escapeCharacter){

                        //this character needs to be escaped, write the data from the last write pos

                        fWriter.write(content, startWritePos, index - startWritePos);

                        fWriter.write("<");

                        if(DEBUG_XML_CONTENT){

                            System.out.print(new String(content, startWritePos, index - startWritePos));

                            System.out.println("<");

                        }

                        //increase the startWritePos by 1 indicating that next write should start from

                        //one position ahead

                        startWritePos = index + 1;

                    }

                    break;

                }

                case '&' :{

                    if(escapeCharacter){

                        //this character needs to be escaped, write the data from the last write pos

                        fWriter.write(content, startWritePos, index - startWritePos);

                        fWriter.write("&");

                        if(DEBUG_XML_CONTENT){

                            System.out.print(new String(content,startWritePos, index - startWritePos));

                            System.out.println("&");

                        }

                        //increase the startWritePos by 1 indicating that next write should start from

                        //one position ahead

                        startWritePos = index + 1;

                    }

                    break;

                }

                case '>': {

                    if(escapeCharacter){

                        //this character needs to be escaped, write the data from the last write pos

                        fWriter.write(content, startWritePos, index - startWritePos);

                        fWriter.write(">");

                        if(DEBUG_XML_CONTENT){

                            System.out.print(new String(content,startWritePos, index - startWritePos));

                            System.out.println(">");

                        }

                        //increase the startWritePos by 1 indicating that next write should start from

                        //one position ahead

                        startWritePos = index + 1;

                    }

                    break;

                }

            }

        }

        if(DEBUG_XML_CONTENT){

            System.out.println("out of the loop, writing " + new String(content, startWritePos, end - startWritePos));

        }

        //write any pending data

        fWriter.write(content, startWritePos, end - startWritePos);

    }

    /**

     * writes xml content (characters and element content

     * @param content

     */

    public void writeXMLContent(String content) throws IOException{

        if(content == null || content.length() == 0) return ;

        writeXMLContent(content.toCharArray(), 0, content.length());

    }

    /**

     * Write Attribute value to the underlying stream.

     *

     * @param value

     */

    public void  writeXMLAttributeValue(String value)throws IOException{

        writeXMLContent(value.toCharArray(), 0, value.length(), true);

    }

    private CharsetEncoder getDefaultEncoder(){

        try{

            String encoding = SecuritySupport.getSystemProperty("file.encoding");

            if(encoding != null){

                return Charset.forName(encoding).newEncoder();

            }

        }

        catch(Exception ex){

            //for any exception thrown , catch and continue

        }

        return null;

    }

}