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Apache Commons Compress defines an API for working with compression and archive formats. These include bzip2, gzip, pack200, LZMA, XZ, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4, Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.

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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.commons.compress.archivers.zip;

import java.io.IOException;
import java.nio.ByteBuffer;

/**
 * A fallback ZipEncoding, which uses a java.io means to encode names.
 *
 * This implementation is not suitable for encodings other than
 * utf-8, because java.io encodes unmappable character as question
 * marks leading to unreadable ZIP entries on some operating
 * systems.
 * 
 * Furthermore this implementation is unable to tell whether a
 * given name can be safely encoded or not.
 * 
 * This implementation acts as a last resort implementation, when
 * neither {@link Simple8BitZipEnoding} nor {@link NioZipEncoding} is
 * available.
 * 
 * The methods of this class are reentrant.
 * @Immutable
 */
class FallbackZipEncoding implements ZipEncoding {
    private final String charset;

    /**
     * Construct a fallback zip encoding, which uses the platform's
     * default charset.
     */
    public FallbackZipEncoding() {
        this.charset = null;
    }

    /**
     * Construct a fallback zip encoding, which uses the given charset.
     * 
     * @param charset The name of the charset or {@code null} for
     *                the platform's default character set.
     */
    public FallbackZipEncoding(String charset) {
        this.charset = charset;
    }

    /**
     * @see
     * org.apache.commons.compress.archivers.zip.ZipEncoding#canEncode(java.lang.String)
     */
    public boolean canEncode(String name) {
        return true;
    }

    /**
     * @see
     * org.apache.commons.compress.archivers.zip.ZipEncoding#encode(java.lang.String)
     */
    public ByteBuffer encode(String name) throws IOException {
        if (this.charset == null) { // i.e. use default charset, see no-args constructor
            return ByteBuffer.wrap(name.getBytes());
        } else {
            return ByteBuffer.wrap(name.getBytes(this.charset));
        }
    }

    /**
     * @see
     * org.apache.commons.compress.archivers.zip.ZipEncoding#decode(byte[])
     */
    public String decode(byte[] data) throws IOException {
        if (this.charset == null) { // i.e. use default charset, see no-args constructor
            return new String(data);
        } else {
            return new String(data,this.charset);
        }
    }
}