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A slightly adapted version of Xerces 2.11.0 to allow the XMLStringBuffer responsible for XML attribute scanning to start larger and thus avoid extended appending times. The initial buffer size is controlled by settting the system property julielab.xerces.attributebuffersize (also available as constant XMLScanner#ATTRIBUTE_BUFFER_SIZE).

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.xml.serialize;

import java.io.UnsupportedEncodingException;
import java.util.Hashtable;
import java.util.Locale;

import org.apache.xerces.util.EncodingMap;

/**
 * Provides information about encodings. Depends on the Java runtime
 * to provides writers for the different encodings, but can be used
 * to override encoding names and provide the last printable character
 * for each encoding.
 *
 * @deprecated This class was deprecated in Xerces 2.9.0. It is recommended 
 * that new applications use the DOM Level 3 LSSerializer or JAXP's Transformation 
 * API for XML (TrAX) for serializing XML. See the Xerces documentation for more 
 * information.
 * @version $Id: Encodings.java 476047 2006-11-17 04:27:45Z mrglavas $
 * @author Assaf Arkin
 */
public class Encodings
{


    /**
     * The last printable character for unknown encodings.
     */
    static final int DEFAULT_LAST_PRINTABLE = 0x7F;

    // last printable character for Unicode-compatible encodings
    static final int LAST_PRINTABLE_UNICODE = 0xffff;
    // unicode-compliant encodings; can express plane 0
    static final String[] UNICODE_ENCODINGS = {
        "Unicode", "UnicodeBig", "UnicodeLittle", "GB2312", "UTF8", "UTF-16",
    };
    // default (Java) encoding if none supplied:
    static final String DEFAULT_ENCODING = "UTF8";

    // note that the size of this Hashtable
    // is bounded by the number of encodings recognized by EncodingMap;
    // therefore it poses no static mutability risk.
    static Hashtable _encodings = new Hashtable();

    /**
     * @param encoding a MIME charset name, or null.
     */
    static EncodingInfo getEncodingInfo(String encoding, boolean allowJavaNames) throws UnsupportedEncodingException {
        EncodingInfo eInfo = null;
        if (encoding == null) {
            if((eInfo = (EncodingInfo)_encodings.get(DEFAULT_ENCODING)) != null) 
                return eInfo;
            eInfo = new EncodingInfo(EncodingMap.getJava2IANAMapping(DEFAULT_ENCODING), DEFAULT_ENCODING, LAST_PRINTABLE_UNICODE);
            _encodings.put(DEFAULT_ENCODING, eInfo);
            return eInfo;
        }
        // need to convert it to upper case:
        encoding = encoding.toUpperCase(Locale.ENGLISH);
        String jName = EncodingMap.getIANA2JavaMapping(encoding);
        if (jName == null) {
            // see if the encoding passed in is a Java encoding name.
            if (allowJavaNames) {
                EncodingInfo.testJavaEncodingName(encoding);
                if ((eInfo = (EncodingInfo)_encodings.get(encoding)) != null) 
                    return eInfo;
                // is it known to be unicode-compliant?
                int i = 0;
                for(; i