/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 1999-2002,2004 The Apache Software Foundation.

 *

 * Licensed 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 com.sun.org.apache.xml.internal.serialize;

import java.io.UnsupportedEncodingException;

import java.util.Hashtable;

import java.util.Locale;

import com.sun.org.apache.xerces.internal.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.

 *

 * @author <a href="mailto:arkin@intalio.com">Assaf Arkin</a>

 */

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<UNICODE_ENCODINGS.length; i++) {

                    if(UNICODE_ENCODINGS[i].equalsIgnoreCase(encoding)) {

                        eInfo = new EncodingInfo(EncodingMap.getJava2IANAMapping(encoding), encoding, LAST_PRINTABLE_UNICODE);

                        break;

                    }

                }

                if(i == UNICODE_ENCODINGS.length) {

                    eInfo = new EncodingInfo(EncodingMap.getJava2IANAMapping(encoding), encoding, DEFAULT_LAST_PRINTABLE);

                }

                _encodings.put(encoding, eInfo);

                return eInfo;

            } else {

                throw new UnsupportedEncodingException(encoding);

            }

        }

        if ((eInfo = (EncodingInfo)_encodings.get(jName)) != null)

            return eInfo;

        // have to create one...

        // is it known to be unicode-compliant?

        int i=0;

        for(; i<UNICODE_ENCODINGS.length; i++) {

            if(UNICODE_ENCODINGS[i].equalsIgnoreCase(jName)) {

                eInfo = new EncodingInfo(encoding, jName, LAST_PRINTABLE_UNICODE);

                break;

            }

        }

        if(i == UNICODE_ENCODINGS.length) {

            eInfo = new EncodingInfo(encoding, jName, DEFAULT_LAST_PRINTABLE);

        }

        _encodings.put(jName, eInfo);

        return eInfo;

    }

    static final String JIS_DANGER_CHARS

    = "\\\u007e\u007f\u00a2\u00a3\u00a5\u00ac"

    +"\u2014\u2015\u2016\u2026\u203e\u203e\u2225\u222f\u301c"

    +"\uff3c\uff5e\uffe0\uffe1\uffe2\uffe3";

}