/*

 * 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.tools.internal.xjc.reader.internalizer;

import com.sun.xml.internal.bind.WhiteSpaceProcessor;

import org.xml.sax.Attributes;

import org.xml.sax.ContentHandler;

import org.xml.sax.EntityResolver;

import org.xml.sax.ErrorHandler;

import org.xml.sax.SAXException;

import org.xml.sax.XMLReader;

import org.xml.sax.helpers.XMLFilterImpl;

/**

 * Strips ignorable whitespace from SAX event stream.

 *

 * <p>

 * This filter works only when the event stream doesn't

 * contain any mixed content.

 *

 * @author

 *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)

 */

class WhitespaceStripper extends XMLFilterImpl {

    private int state = 0;

    private char[] buf = new char[1024];

    private int bufLen = 0;

    private static final int AFTER_START_ELEMENT = 1;

    private static final int AFTER_END_ELEMENT = 2;

    public WhitespaceStripper(XMLReader reader) {

        setParent(reader);

    }

    public WhitespaceStripper(ContentHandler handler,ErrorHandler eh,EntityResolver er) {

        setContentHandler(handler);

        if(eh!=null)    setErrorHandler(eh);

        if(er!=null)    setEntityResolver(er);

    }

    public void characters(char[] ch, int start, int length) throws SAXException {

        switch(state) {

        case AFTER_START_ELEMENT:

            // we have to store the characters here, even if it consists entirely

            // of whitespaces. This is because successive characters event might

            // include non-whitespace char, in which case all the whitespaces in

            // this event may suddenly become significant.

            if( bufLen+length>buf.length ) {

                // reallocate buffer

                char[] newBuf = new char[Math.max(bufLen+length,buf.length*2)];

                System.arraycopy(buf,0,newBuf,0,bufLen);

                buf = newBuf;

            }

            System.arraycopy(ch,start,buf,bufLen,length);

            bufLen += length;

            break;

        case AFTER_END_ELEMENT:

            // check if this is ignorable.

            int len = start+length;

            for( int i=start; i<len; i++ )

                if( !WhiteSpaceProcessor.isWhiteSpace(ch[i]) ) {

                    super.characters(ch, start, length);

                    return;

                }

            // if it's entirely whitespace, ignore it.

            break;

        }

    }

    public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {

        processPendingText();

        super.startElement(uri, localName, qName, atts);

        state = AFTER_START_ELEMENT;

        bufLen = 0;

    }

    public void endElement(String uri, String localName, String qName) throws SAXException {

        processPendingText();

        super.endElement(uri, localName, qName);

        state = AFTER_END_ELEMENT;

    }

    /**

     * Forwars the buffered characters if it contains any non-whitespace

     * character.

     */

    private void processPendingText() throws SAXException {

        if(state==AFTER_START_ELEMENT) {

            for( int i=bufLen-1; i>=0; i-- )

                if( !WhiteSpaceProcessor.isWhiteSpace(buf[i]) ) {

                    super.characters(buf, 0, bufLen);

                    return;

               }

        }

    }

    public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException {

        // ignore completely.

    }

}