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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;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;

/**
 * A ZipEncoding, which uses a java.nio {@link
 * java.nio.charset.Charset Charset} to encode names.
 *
 * This implementation works for all cases under java-1.5 or
 * later. However, in java-1.4, some charsets don't have a java.nio
 * implementation, most notably the default ZIP encoding Cp437.
 * 
 * The methods of this class are reentrant.
 * @Immutable
 */
class NioZipEncoding implements ZipEncoding {
    private final Charset charset;

    /**
     * Construct an NIO based zip encoding, which wraps the given
     * charset.
     * 
     * @param charset The NIO charset to wrap.
     */
    public NioZipEncoding(Charset charset) {
        this.charset = charset;
    }

    /**
     * @see
     * org.apache.commons.compress.archivers.zip.ZipEncoding#canEncode(java.lang.String)
     */
    public boolean canEncode(String name) {
        CharsetEncoder enc = this.charset.newEncoder();
        enc.onMalformedInput(CodingErrorAction.REPORT);
        enc.onUnmappableCharacter(CodingErrorAction.REPORT);

        return enc.canEncode(name);
    }

    /**
     * @see
     * org.apache.commons.compress.archivers.zip.ZipEncoding#encode(java.lang.String)
     */
    public ByteBuffer encode(String name) {
        CharsetEncoder enc = this.charset.newEncoder();

        enc.onMalformedInput(CodingErrorAction.REPORT);
        enc.onUnmappableCharacter(CodingErrorAction.REPORT);

        CharBuffer cb = CharBuffer.wrap(name);
        ByteBuffer out = ByteBuffer.allocate(name.length()
                                             + (name.length() + 1) / 2);

        while (cb.remaining() > 0) {
            CoderResult res = enc.encode(cb, out,true);

            if (res.isUnmappable() || res.isMalformed()) {

                // write the unmappable characters in utf-16
                // pseudo-URL encoding style to ByteBuffer.
                if (res.length() * 6 > out.remaining()) {
                    out = ZipEncodingHelper.growBuffer(out, out.position()
                                                       + res.length() * 6);
                }

                for (int i=0; i