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/*
 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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 jdk8u.jaxp.org.apache.xml.external.serialize;


import jdk8u.jaxp.org.apache.xerces.external.util.EncodingMap;
import java.io.UnsupportedEncodingException;
import java.util.Locale;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;


/**
 * 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.
 *
 * @author Assaf Arkin
 */
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 Map
    // is bounded by the number of encodings recognized by EncodingMap;
    // therefore it poses no static mutability risk.
    private static final Map _encodings = new ConcurrentHashMap();

    /**
     * @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 = _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 = _encodings.get(encoding)) != null)
                    return eInfo;
                // is it known to be unicode-compliant?
                int i=0;
                for(; i