/*
 *  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.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.Closeable;
import java.io.EOFException;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.SequenceInputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
import java.nio.channels.SeekableByteChannel;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.OpenOption;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.EnumSet;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.zip.Inflater;
import java.util.zip.ZipException;

import org.apache.commons.compress.archivers.EntryStreamOffsets;
import org.apache.commons.compress.compressors.bzip2.BZip2CompressorInputStream;
import org.apache.commons.compress.compressors.deflate64.Deflate64CompressorInputStream;
import org.apache.commons.compress.utils.BoundedArchiveInputStream;
import org.apache.commons.compress.utils.BoundedSeekableByteChannelInputStream;
import org.apache.commons.compress.utils.IOUtils;
import org.apache.commons.compress.utils.InputStreamStatistics;
import org.apache.commons.compress.utils.SeekableInMemoryByteChannel;
import org.apache.commons.io.Charsets;
import org.apache.commons.io.FilenameUtils;
import org.apache.commons.io.build.AbstractOrigin.ByteArrayOrigin;
import org.apache.commons.io.build.AbstractStreamBuilder;
import org.apache.commons.io.input.CountingInputStream;

/**
 * Replacement for {@link java.util.zip.ZipFile}.
 * <p>
 * This class adds support for file name encodings other than UTF-8 (which is required to work on ZIP files created by native ZIP tools and is able to skip a
 * preamble like the one found in self extracting archives. Furthermore it returns instances of
 * {@code org.apache.commons.compress.archivers.zip.ZipArchiveEntry} instead of {@link java.util.zip.ZipEntry}.
 * </p>
 * <p>
 * It doesn't extend {@link java.util.zip.ZipFile} as it would have to reimplement all methods anyway. Like {@link java.util.zip.ZipFile}, it uses
 * SeekableByteChannel under the covers and supports compressed and uncompressed entries. As of Apache Commons Compress 1.3 it also transparently supports Zip64
 * extensions and thus individual entries and archives larger than 4 GB or with more than 65,536 entries.
 * </p>
 * <p>
 * The method signatures mimic the ones of {@link java.util.zip.ZipFile}, with a couple of exceptions:
 * </p>
 * <ul>
 * <li>There is no getName method.</li>
 * <li>entries has been renamed to getEntries.</li>
 * <li>getEntries and getEntry return {@code org.apache.commons.compress.archivers.zip.ZipArchiveEntry} instances.</li>
 * <li>close is allowed to throw IOException.</li>
 * </ul>
 */
public class ZipFile implements Closeable {

    /**
     * Lock-free implementation of BoundedInputStream. The implementation uses positioned reads on the underlying archive file channel and therefore performs
     * significantly faster in concurrent environment.
     */
    private static class BoundedFileChannelInputStream extends BoundedArchiveInputStream {
        private final FileChannel archive;

        BoundedFileChannelInputStream(final long start, final long remaining, final FileChannel archive) {
            super(start, remaining);
            this.archive = archive;
        }

        @Override
        protected int read(final long pos, final ByteBuffer buf) throws IOException {
            final int read = archive.read(buf, pos);
            buf.flip();
            return read;
        }
    }

    /**
     * Builds new {@link ZipFile} instances.
     * <p>
     * The channel will be opened for reading, assuming the specified encoding for file names.
     * </p>
     * <p>
     * See {@link org.apache.commons.compress.utils.SeekableInMemoryByteChannel} to read from an in-memory archive.
     * </p>
     * <p>
     * By default the central directory record and all local file headers of the archive will be read immediately which may take a considerable amount of time
     * when the archive is big. The {@code ignoreLocalFileHeader} parameter can be set to {@code true} which restricts parsing to the central directory.
     * Unfortunately the local file header may contain information not present inside of the central directory which will not be available when the argument is
     * set to {@code true}. This includes the content of the Unicode extra field, so setting {@code
     * ignoreLocalFileHeader} to {@code true} means {@code useUnicodeExtraFields} will be ignored effectively.
     * </p>
     *
     * @since 1.26.0
     */
    public static class Builder extends AbstractStreamBuilder<ZipFile, Builder> {

        static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;

        private SeekableByteChannel seekableByteChannel;
        private boolean useUnicodeExtraFields = true;
        private boolean ignoreLocalFileHeader;
        private long maxNumberOfDisks = 1;

        public Builder() {
            setCharset(DEFAULT_CHARSET);
            setCharsetDefault(DEFAULT_CHARSET);
        }

        @SuppressWarnings("resource") // caller closes
        @Override
        public ZipFile get() throws IOException {
            final SeekableByteChannel actualChannel;
            final String actualDescription;
            if (seekableByteChannel != null) {
                actualChannel = seekableByteChannel;
                actualDescription = actualChannel.getClass().getSimpleName();
            } else if (checkOrigin() instanceof ByteArrayOrigin) {
                actualChannel = new SeekableInMemoryByteChannel(checkOrigin().getByteArray());
                actualDescription = actualChannel.getClass().getSimpleName();
            } else {
                OpenOption[] openOptions = getOpenOptions();
                if (openOptions.length == 0) {
                    openOptions = new OpenOption[] { StandardOpenOption.READ };
                }
                final Path path = getPath();
                actualChannel = openZipChannel(path, maxNumberOfDisks, openOptions);
                actualDescription = path.toString();
            }
            final boolean closeOnError = seekableByteChannel != null;
            return new ZipFile(actualChannel, actualDescription, getCharset(), useUnicodeExtraFields, closeOnError, ignoreLocalFileHeader);
        }

        /**
         * Sets whether to ignore information stored inside the local file header.
         *
         * @param ignoreLocalFileHeader whether to ignore information stored inside.
         * @return this.
         */
        public Builder setIgnoreLocalFileHeader(final boolean ignoreLocalFileHeader) {
            this.ignoreLocalFileHeader = ignoreLocalFileHeader;
            return this;
        }

        /**
         * Sets max number of multi archive disks, default is 1 (no multi archive).
         *
         * @param maxNumberOfDisks max number of multi archive disks.
         *
         * @return this.
         */
        public Builder setMaxNumberOfDisks(final long maxNumberOfDisks) {
            this.maxNumberOfDisks = maxNumberOfDisks;
            return this;
        }

        /**
         * The actual channel, overrides any other input aspects like a File, Path, and so on.
         *
         * @param seekableByteChannel The actual channel.
         * @return this.
         */
        public Builder setSeekableByteChannel(final SeekableByteChannel seekableByteChannel) {
            this.seekableByteChannel = seekableByteChannel;
            return this;
        }

        /**
         * Sets whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.
         *
         * @param useUnicodeExtraFields whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.
         * @return this.
         */
        public Builder setUseUnicodeExtraFields(final boolean useUnicodeExtraFields) {
            this.useUnicodeExtraFields = useUnicodeExtraFields;
            return this;
        }

    }

    /**
     * Extends ZipArchiveEntry to store the offset within the archive.
     */
    private static final class Entry extends ZipArchiveEntry {

        @Override
        public boolean equals(final Object other) {
            if (super.equals(other)) {
                // super.equals would return false if other were not an Entry
                final Entry otherEntry = (Entry) other;
                return getLocalHeaderOffset() == otherEntry.getLocalHeaderOffset() && super.getDataOffset() == otherEntry.getDataOffset()
                        && super.getDiskNumberStart() == otherEntry.getDiskNumberStart();
            }
            return false;
        }

        @Override
        public int hashCode() {
            return 3 * super.hashCode() + (int) getLocalHeaderOffset() + (int) (getLocalHeaderOffset() >> 32);
        }
    }

    private static final class NameAndComment {
        private final byte[] name;
        private final byte[] comment;

        private NameAndComment(final byte[] name, final byte[] comment) {
            this.name = name;
            this.comment = comment;
        }
    }

    private static final class StoredStatisticsStream extends CountingInputStream implements InputStreamStatistics {
        StoredStatisticsStream(final InputStream in) {
            super(in);
        }

        @Override
        public long getCompressedCount() {
            return super.getByteCount();
        }

        @Override
        public long getUncompressedCount() {
            return getCompressedCount();
        }
    }

    private static final String DEFAULT_CHARSET_NAME = StandardCharsets.UTF_8.name();

    private static final EnumSet<StandardOpenOption> READ = EnumSet.of(StandardOpenOption.READ);

    private static final int HASH_SIZE = 509;
    static final int NIBLET_MASK = 0x0f;
    static final int BYTE_SHIFT = 8;
    private static final int POS_0 = 0;
    private static final int POS_1 = 1;
    private static final int POS_2 = 2;
    private static final int POS_3 = 3;
    private static final byte[] ONE_ZERO_BYTE = new byte[1];

    /**
     * Length of a "central directory" entry structure without file name, extra fields or comment.
     */
    private static final int CFH_LEN =
    // @formatter:off
        /* version made by                 */ ZipConstants.SHORT
        /* version needed to extract       */ + ZipConstants.SHORT
        /* general purpose bit flag        */ + ZipConstants.SHORT
        /* compression method              */ + ZipConstants.SHORT
        /* last mod file time              */ + ZipConstants.SHORT
        /* last mod file date              */ + ZipConstants.SHORT
        /* crc-32                          */ + ZipConstants.WORD
        /* compressed size                 */ + ZipConstants.WORD
        /* uncompressed size               */ + ZipConstants.WORD
        /* file name length                */ + ZipConstants. SHORT
        /* extra field length              */ + ZipConstants.SHORT
        /* file comment length             */ + ZipConstants.SHORT
        /* disk number start               */ + ZipConstants.SHORT
        /* internal file attributes        */ + ZipConstants.SHORT
        /* external file attributes        */ + ZipConstants.WORD
        /* relative offset of local header */ + ZipConstants.WORD;
    // @formatter:on

    private static final long CFH_SIG = ZipLong.getValue(ZipArchiveOutputStream.CFH_SIG);

    /**
     * Length of the "End of central directory record" - which is supposed to be the last structure of the archive - without file comment.
     */
    static final int MIN_EOCD_SIZE =
    // @formatter:off
        /* end of central dir signature    */ ZipConstants.WORD
        /* number of this disk             */ + ZipConstants.SHORT
        /* number of the disk with the     */
        /* start of the central directory  */ + ZipConstants.SHORT
        /* total number of entries in      */
        /* the central dir on this disk    */ + ZipConstants.SHORT
        /* total number of entries in      */
        /* the central dir                 */ + ZipConstants.SHORT
        /* size of the central directory   */ + ZipConstants.WORD
        /* offset of start of central      */
        /* directory with respect to       */
        /* the starting disk number        */ + ZipConstants.WORD
        /* ZIP file comment length         */ + ZipConstants.SHORT;
    // @formatter:on

    /**
     * Maximum length of the "End of central directory record" with a file comment.
     */
    private static final int MAX_EOCD_SIZE = MIN_EOCD_SIZE
    // @formatter:off
        /* maximum length of ZIP file comment */ + ZipConstants.ZIP64_MAGIC_SHORT;
    // @formatter:on

    /**
     * Offset of the field that holds the location of the length of the central directory inside the "End of central directory record" relative to the start of
     * the "End of central directory record".
     */
    private static final int CFD_LENGTH_OFFSET =
    // @formatter:off
        /* end of central dir signature    */ ZipConstants.WORD
        /* number of this disk             */ + ZipConstants.SHORT
        /* number of the disk with the     */
        /* start of the central directory  */ + ZipConstants.SHORT
        /* total number of entries in      */
        /* the central dir on this disk    */ + ZipConstants.SHORT
        /* total number of entries in      */
        /* the central dir                 */ + ZipConstants.SHORT;
    // @formatter:on

    /**
     * Offset of the field that holds the disk number of the first central directory entry inside the "End of central directory record" relative to the start of
     * the "End of central directory record".
     */
    private static final int CFD_DISK_OFFSET =
    // @formatter:off
            /* end of central dir signature    */ ZipConstants.WORD
            /* number of this disk             */ + ZipConstants.SHORT;
    // @formatter:on

    /**
     * Offset of the field that holds the location of the first central directory entry inside the "End of central directory record" relative to the "number of
     * the disk with the start of the central directory".
     */
    private static final int CFD_LOCATOR_RELATIVE_OFFSET =
    // @formatter:off
            /* total number of entries in      */
            /* the central dir on this disk    */ + ZipConstants.SHORT
            /* total number of entries in      */
            /* the central dir                 */ + ZipConstants.SHORT
            /* size of the central directory   */ + ZipConstants.WORD;
    // @formatter:on

    /**
     * Length of the "Zip64 end of central directory locator" - which should be right in front of the "end of central directory record" if one is present at
     * all.
     */
    private static final int ZIP64_EOCDL_LENGTH =
    // @formatter:off
        /* zip64 end of central dir locator sig */ ZipConstants.WORD
        /* number of the disk with the start    */
        /* start of the zip64 end of            */
        /* central directory                    */ + ZipConstants.WORD
        /* relative offset of the zip64         */
        /* end of central directory record      */ + ZipConstants.DWORD
        /* total number of disks                */ + ZipConstants.WORD;
    // @formatter:on

    /**
     * Offset of the field that holds the location of the "Zip64 end of central directory record" inside the "Zip64 end of central directory locator" relative
     * to the start of the "Zip64 end of central directory locator".
     */
    private static final int ZIP64_EOCDL_LOCATOR_OFFSET =
    // @formatter:off
        /* zip64 end of central dir locator sig */ ZipConstants.WORD
        /* number of the disk with the start    */
        /* start of the zip64 end of            */
        /* central directory                    */ + ZipConstants.WORD;
    // @formatter:on

    /**
     * Offset of the field that holds the location of the first central directory entry inside the "Zip64 end of central directory record" relative to the start
     * of the "Zip64 end of central directory record".
     */
    private static final int ZIP64_EOCD_CFD_LOCATOR_OFFSET =
    // @formatter:off
        /* zip64 end of central dir        */
        /* signature                       */ ZipConstants.WORD
        /* size of zip64 end of central    */
        /* directory record                */ + ZipConstants.DWORD
        /* version made by                 */ + ZipConstants.SHORT
        /* version needed to extract       */ + ZipConstants.SHORT
        /* number of this disk             */ + ZipConstants.WORD
        /* number of the disk with the     */
        /* start of the central directory  */ + ZipConstants.WORD
        /* total number of entries in the  */
        /* central directory on this disk  */ + ZipConstants.DWORD
        /* total number of entries in the  */
        /* central directory               */ + ZipConstants.DWORD
        /* size of the central directory   */ + ZipConstants.DWORD;
    // @formatter:on

    /**
     * Offset of the field that holds the disk number of the first central directory entry inside the "Zip64 end of central directory record" relative to the
     * start of the "Zip64 end of central directory record".
     */
    private static final int ZIP64_EOCD_CFD_DISK_OFFSET =
    // @formatter:off
            /* zip64 end of central dir        */
            /* signature                       */ ZipConstants.WORD
            /* size of zip64 end of central    */
            /* directory record                */ + ZipConstants.DWORD
            /* version made by                 */ + ZipConstants.SHORT
            /* version needed to extract       */ + ZipConstants.SHORT
            /* number of this disk             */ + ZipConstants.WORD;
    // @formatter:on

    /**
     * Offset of the field that holds the location of the first central directory entry inside the "Zip64 end of central directory record" relative to the
     * "number of the disk with the start of the central directory".
     */
    private static final int ZIP64_EOCD_CFD_LOCATOR_RELATIVE_OFFSET =
    // @formatter:off
            /* total number of entries in the  */
            /* central directory on this disk  */ ZipConstants.DWORD
            /* total number of entries in the  */
            /* central directory               */ + ZipConstants.DWORD
            /* size of the central directory   */ + ZipConstants.DWORD;
    // @formatter:on

    /**
     * Number of bytes in local file header up to the &quot;length of file name&quot; entry.
     */
    private static final long LFH_OFFSET_FOR_FILENAME_LENGTH =
    // @formatter:off
        /* local file header signature     */ ZipConstants.WORD
        /* version needed to extract       */ + ZipConstants.SHORT
        /* general purpose bit flag        */ + ZipConstants.SHORT
        /* compression method              */ + ZipConstants.SHORT
        /* last mod file time              */ + ZipConstants.SHORT
        /* last mod file date              */ + ZipConstants.SHORT
        /* crc-32                          */ + ZipConstants.WORD
        /* compressed size                 */ + ZipConstants.WORD
        /* uncompressed size               */ + (long) ZipConstants.WORD;
    // @formatter:on

    /**
     * Compares two ZipArchiveEntries based on their offset within the archive.
     * <p>
     * Won't return any meaningful results if one of the entries isn't part of the archive at all.
     * </p>
     *
     * @since 1.1
     */
    private static final Comparator<ZipArchiveEntry> offsetComparator = Comparator.comparingLong(ZipArchiveEntry::getDiskNumberStart)
            .thenComparingLong(ZipArchiveEntry::getLocalHeaderOffset);

    /**
     * Creates a new Builder.
     *
     * @return a new Builder.
     * @since 1.26.0
     */
    public static Builder builder() {
        return new Builder();
    }

    /**
     * Closes a ZIP file quietly; throwing no IOException, does nothing on null input.
     *
     * @param zipFile file to close, can be null
     */
    public static void closeQuietly(final ZipFile zipFile) {
        org.apache.commons.io.IOUtils.closeQuietly(zipFile);
    }

    /**
     * Creates a new SeekableByteChannel for reading.
     *
     * @param path the path to the file to open or create
     * @return a new seekable byte channel
     * @throws IOException if an I/O error occurs
     */
    private static SeekableByteChannel newReadByteChannel(final Path path) throws IOException {
        return Files.newByteChannel(path, READ);
    }

    private static SeekableByteChannel openZipChannel(final Path path, final long maxNumberOfDisks, final OpenOption[] openOptions) throws IOException {
        final FileChannel channel = FileChannel.open(path, StandardOpenOption.READ);
        final List<FileChannel> channels = new ArrayList<>();
        try {
            final boolean is64 = positionAtEndOfCentralDirectoryRecord(channel);
            long numberOfDisks;
            if (is64) {
                channel.position(channel.position() + ZipConstants.WORD + ZipConstants.WORD + ZipConstants.DWORD);
                final ByteBuffer buf = ByteBuffer.allocate(ZipConstants.WORD);
                buf.order(ByteOrder.LITTLE_ENDIAN);
                IOUtils.readFully(channel, buf);
                buf.flip();
                numberOfDisks = buf.getInt() & 0xffffffffL;
            } else {
                channel.position(channel.position() + ZipConstants.WORD);
                final ByteBuffer buf = ByteBuffer.allocate(ZipConstants.SHORT);
                buf.order(ByteOrder.LITTLE_ENDIAN);
                IOUtils.readFully(channel, buf);
                buf.flip();
                numberOfDisks = (buf.getShort() & 0xffff) + 1;
            }
            if (numberOfDisks > Math.min(maxNumberOfDisks, Integer.MAX_VALUE)) {
                throw new IOException("Too many disks for zip archive, max=" + Math.min(maxNumberOfDisks, Integer.MAX_VALUE) + " actual=" + numberOfDisks);
            }

            if (numberOfDisks <= 1) {
                return channel;
            }
            channel.close();

            final Path parent = path.getParent();
            final String basename = FilenameUtils.removeExtension(path.getFileName().toString());

            return ZipSplitReadOnlySeekableByteChannel.forPaths(IntStream.range(0, (int) numberOfDisks).mapToObj(i -> {
                if (i == numberOfDisks - 1) {
                    return path;
                }
                final Path lowercase = parent.resolve(String.format("%s.z%02d", basename, i + 1));
                if (Files.exists(lowercase)) {
                    return lowercase;
                }
                final Path uppercase = parent.resolve(String.format("%s.Z%02d", basename, i + 1));
                if (Files.exists(uppercase)) {
                    return uppercase;
                }
                return lowercase;
            }).collect(Collectors.toList()), openOptions);
        } catch (final Throwable ex) {
            org.apache.commons.io.IOUtils.closeQuietly(channel);
            channels.forEach(org.apache.commons.io.IOUtils::closeQuietly);
            throw ex;
        }
    }

    /**
     * Searches for the and positions the stream at the start of the &quot;End of central dir record&quot;.
     *
     * @return true if it's Zip64 end of central directory or false if it's Zip32
     */
    private static boolean positionAtEndOfCentralDirectoryRecord(final SeekableByteChannel channel) throws IOException {
        final boolean found = tryToLocateSignature(channel, MIN_EOCD_SIZE, MAX_EOCD_SIZE, ZipArchiveOutputStream.EOCD_SIG);
        if (!found) {
            throw new ZipException("Archive is not a ZIP archive");
        }
        boolean found64 = false;
        final long position = channel.position();
        if (position > ZIP64_EOCDL_LENGTH) {
            final ByteBuffer wordBuf = ByteBuffer.allocate(4);
            channel.position(channel.position() - ZIP64_EOCDL_LENGTH);
            wordBuf.rewind();
            IOUtils.readFully(channel, wordBuf);
            wordBuf.flip();
            found64 = wordBuf.equals(ByteBuffer.wrap(ZipArchiveOutputStream.ZIP64_EOCD_LOC_SIG));
            if (!found64) {
                channel.position(position);
            } else {
                channel.position(channel.position() - ZipConstants.WORD);
            }
        }

        return found64;
    }

    /**
     * Searches the archive backwards from minDistance to maxDistance for the given signature, positions the RandomaccessFile right at the signature if it has
     * been found.
     */
    private static boolean tryToLocateSignature(final SeekableByteChannel channel, final long minDistanceFromEnd, final long maxDistanceFromEnd,
            final byte[] sig) throws IOException {
        final ByteBuffer wordBuf = ByteBuffer.allocate(ZipConstants.WORD);
        boolean found = false;
        long off = channel.size() - minDistanceFromEnd;
        final long stopSearching = Math.max(0L, channel.size() - maxDistanceFromEnd);
        if (off >= 0) {
            for (; off >= stopSearching; off--) {
                channel.position(off);
                try {
                    wordBuf.rewind();
                    IOUtils.readFully(channel, wordBuf);
                    wordBuf.flip();
                } catch (final EOFException ex) { // NOSONAR
                    break;
                }
                int curr = wordBuf.get();
                if (curr == sig[POS_0]) {
                    curr = wordBuf.get();
                    if (curr == sig[POS_1]) {
                        curr = wordBuf.get();
                        if (curr == sig[POS_2]) {
                            curr = wordBuf.get();
                            if (curr == sig[POS_3]) {
                                found = true;
                                break;
                            }
                        }
                    }
                }
            }
        }
        if (found) {
            channel.position(off);
        }
        return found;
    }

    /**
     * List of entries in the order they appear inside the central directory.
     */
    private final List<ZipArchiveEntry> entries = new LinkedList<>();

    /**
     * Maps String to list of ZipArchiveEntrys, name -> actual entries.
     */
    private final Map<String, LinkedList<ZipArchiveEntry>> nameMap = new HashMap<>(HASH_SIZE);

    /**
     * The encoding to use for file names and the file comment.
     * <p>
     * For a list of possible values see <a href="Supported Encodings">https://docs.oracle.com/javase/8/docs/technotes/guides/intl/encoding.doc.html</a>.
     * Defaults to UTF-8.
     * </p>
     */
    private final Charset encoding;

    /**
     * The ZIP encoding to use for file names and the file comment.
     */
    private final ZipEncoding zipEncoding;

    /**
     * The actual data source.
     */
    private final SeekableByteChannel archive;

    /**
     * Whether to look for and use Unicode extra fields.
     */
    private final boolean useUnicodeExtraFields;

    /**
     * Whether the file is closed.
     */
    private volatile boolean closed = true;

    /**
     * Whether the ZIP archive is a split ZIP archive
     */
    private final boolean isSplitZipArchive;

    // cached buffers - must only be used locally in the class (COMPRESS-172 - reduce garbage collection)
    private final byte[] dwordBuf = new byte[ZipConstants.DWORD];

    private final byte[] wordBuf = new byte[ZipConstants.WORD];

    private final byte[] cfhBuf = new byte[CFH_LEN];

    private final byte[] shortBuf = new byte[ZipConstants.SHORT];

    private final ByteBuffer dwordBbuf = ByteBuffer.wrap(dwordBuf);

    private final ByteBuffer wordBbuf = ByteBuffer.wrap(wordBuf);

    private final ByteBuffer cfhBbuf = ByteBuffer.wrap(cfhBuf);

    private final ByteBuffer shortBbuf = ByteBuffer.wrap(shortBuf);

    private long centralDirectoryStartDiskNumber, centralDirectoryStartRelativeOffset;

    private long centralDirectoryStartOffset;

    private long firstLocalFileHeaderOffset;

    /**
     * Opens the given file for reading, assuming "UTF8" for file names.
     *
     * @param file the archive.
     *
     * @throws IOException if an error occurs while reading the file.
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final File file) throws IOException {
        this(file, DEFAULT_CHARSET_NAME);
    }

    /**
     * Opens the given file for reading, assuming the specified encoding for file names and scanning for Unicode extra fields.
     *
     * @param file     the archive.
     * @param encoding the encoding to use for file names, use null for the platform's default encoding
     * @throws IOException if an error occurs while reading the file.
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final File file, final String encoding) throws IOException {
        this(file.toPath(), encoding, true);
    }

    /**
     * Opens the given file for reading, assuming the specified encoding for file names.
     *
     * @param file                  the archive.
     * @param encoding              the encoding to use for file names, use null for the platform's default encoding
     * @param useUnicodeExtraFields whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.
     * @throws IOException if an error occurs while reading the file.
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final File file, final String encoding, final boolean useUnicodeExtraFields) throws IOException {
        this(file.toPath(), encoding, useUnicodeExtraFields, false);
    }

    /**
     * Opens the given file for reading, assuming the specified encoding for file names.
     * <p>
     * By default the central directory record and all local file headers of the archive will be read immediately which may take a considerable amount of time
     * when the archive is big. The {@code ignoreLocalFileHeader} parameter can be set to {@code true} which restricts parsing to the central directory.
     * Unfortunately the local file header may contain information not present inside of the central directory which will not be available when the argument is
     * set to {@code true}. This includes the content of the Unicode extra field, so setting {@code
     * ignoreLocalFileHeader} to {@code true} means {@code useUnicodeExtraFields} will be ignored effectively.
     * </p>
     *
     * @param file                  the archive.
     * @param encoding              the encoding to use for file names, use null for the platform's default encoding
     * @param useUnicodeExtraFields whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.
     * @param ignoreLocalFileHeader whether to ignore information stored inside the local file header (see the notes in this method's Javadoc)
     * @throws IOException if an error occurs while reading the file.
     * @since 1.19
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    @SuppressWarnings("resource") // Caller closes
    public ZipFile(final File file, final String encoding, final boolean useUnicodeExtraFields, final boolean ignoreLocalFileHeader) throws IOException {
        this(newReadByteChannel(file.toPath()), file.getAbsolutePath(), encoding, useUnicodeExtraFields, true, ignoreLocalFileHeader);
    }

    /**
     * Opens the given path for reading, assuming "UTF-8" for file names.
     *
     * @param path path to the archive.
     * @throws IOException if an error occurs while reading the file.
     * @since 1.22
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final Path path) throws IOException {
        this(path, DEFAULT_CHARSET_NAME);
    }

    /**
     * Opens the given path for reading, assuming the specified encoding for file names and scanning for Unicode extra fields.
     *
     * @param path     path to the archive.
     * @param encoding the encoding to use for file names, use null for the platform's default encoding
     * @throws IOException if an error occurs while reading the file.
     * @since 1.22
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final Path path, final String encoding) throws IOException {
        this(path, encoding, true);
    }

    /**
     * Opens the given path for reading, assuming the specified encoding for file names.
     *
     * @param path                  path to the archive.
     * @param encoding              the encoding to use for file names, use null for the platform's default encoding
     * @param useUnicodeExtraFields whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.
     * @throws IOException if an error occurs while reading the file.
     * @since 1.22
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final Path path, final String encoding, final boolean useUnicodeExtraFields) throws IOException {
        this(path, encoding, useUnicodeExtraFields, false);
    }

    /**
     * Opens the given path for reading, assuming the specified encoding for file names.
     * <p>
     * By default the central directory record and all local file headers of the archive will be read immediately which may take a considerable amount of time
     * when the archive is big. The {@code ignoreLocalFileHeader} parameter can be set to {@code true} which restricts parsing to the central directory.
     * Unfortunately the local file header may contain information not present inside of the central directory which will not be available when the argument is
     * set to {@code true}. This includes the content of the Unicode extra field, so setting {@code
     * ignoreLocalFileHeader} to {@code true} means {@code useUnicodeExtraFields} will be ignored effectively.
     * </p>
     *
     * @param path                  path to the archive.
     * @param encoding              the encoding to use for file names, use null for the platform's default encoding
     * @param useUnicodeExtraFields whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.
     * @param ignoreLocalFileHeader whether to ignore information stored inside the local file header (see the notes in this method's Javadoc)
     * @throws IOException if an error occurs while reading the file.
     * @since 1.22
     * @deprecated Use {@link Builder#get()}.
     */
    @SuppressWarnings("resource") // Caller closes
    @Deprecated
    public ZipFile(final Path path, final String encoding, final boolean useUnicodeExtraFields, final boolean ignoreLocalFileHeader) throws IOException {
        this(newReadByteChannel(path), path.toAbsolutePath().toString(), encoding, useUnicodeExtraFields, true, ignoreLocalFileHeader);
    }

    /**
     * Opens the given channel for reading, assuming "UTF-8" for file names.
     * <p>
     * {@link org.apache.commons.compress.utils.SeekableInMemoryByteChannel} allows you to read from an in-memory archive.
     * </p>
     *
     * @param channel the archive.
     *
     * @throws IOException if an error occurs while reading the file.
     * @since 1.13
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final SeekableByteChannel channel) throws IOException {
        this(channel, "a SeekableByteChannel", DEFAULT_CHARSET_NAME, true);
    }

    /**
     * Opens the given channel for reading, assuming the specified encoding for file names.
     * <p>
     * {@link org.apache.commons.compress.utils.SeekableInMemoryByteChannel} allows you to read from an in-memory archive.
     * </p>
     *
     * @param channel  the archive.
     * @param encoding the encoding to use for file names, use null for the platform's default encoding
     * @throws IOException if an error occurs while reading the file.
     * @since 1.13
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final SeekableByteChannel channel, final String encoding) throws IOException {
        this(channel, "a SeekableByteChannel", encoding, true);
    }

    private ZipFile(final SeekableByteChannel channel, final String channelDescription, final Charset encoding, final boolean useUnicodeExtraFields,
            final boolean closeOnError, final boolean ignoreLocalFileHeader) throws IOException {
        this.isSplitZipArchive = channel instanceof ZipSplitReadOnlySeekableByteChannel;
        this.encoding = Charsets.toCharset(encoding, Builder.DEFAULT_CHARSET);
        this.zipEncoding = ZipEncodingHelper.getZipEncoding(encoding);
        this.useUnicodeExtraFields = useUnicodeExtraFields;
        this.archive = channel;
        boolean success = false;
        try {
            final Map<ZipArchiveEntry, NameAndComment> entriesWithoutUTF8Flag = populateFromCentralDirectory();
            if (!ignoreLocalFileHeader) {
                resolveLocalFileHeaderData(entriesWithoutUTF8Flag);
            }
            fillNameMap();
            success = true;
        } catch (final IOException e) {
            throw new IOException("Error reading Zip content from " + channelDescription, e);
        } finally {
            this.closed = !success;
            if (!success && closeOnError) {
                org.apache.commons.io.IOUtils.closeQuietly(archive);
            }
        }
    }

    /**
     * Opens the given channel for reading, assuming the specified encoding for file names.
     * <p>
     * {@link org.apache.commons.compress.utils.SeekableInMemoryByteChannel} allows you to read from an in-memory archive.
     * </p>
     *
     * @param channel               the archive.
     * @param channelDescription    description of the archive, used for error messages only.
     * @param encoding              the encoding to use for file names, use null for the platform's default encoding
     * @param useUnicodeExtraFields whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.
     * @throws IOException if an error occurs while reading the file.
     * @since 1.13
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final SeekableByteChannel channel, final String channelDescription, final String encoding, final boolean useUnicodeExtraFields)
            throws IOException {
        this(channel, channelDescription, encoding, useUnicodeExtraFields, false, false);
    }

    /**
     * Opens the given channel for reading, assuming the specified encoding for file names.
     * <p>
     * {@link org.apache.commons.compress.utils.SeekableInMemoryByteChannel} allows you to read from an in-memory archive.
     * </p>
     * <p>
     * By default the central directory record and all local file headers of the archive will be read immediately which may take a considerable amount of time
     * when the archive is big. The {@code ignoreLocalFileHeader} parameter can be set to {@code true} which restricts parsing to the central directory.
     * Unfortunately the local file header may contain information not present inside of the central directory which will not be available when the argument is
     * set to {@code true}. This includes the content of the Unicode extra field, so setting {@code
     * ignoreLocalFileHeader} to {@code true} means {@code useUnicodeExtraFields} will be ignored effectively.
     * </p>
     *
     * @param channel               the archive.
     * @param channelDescription    description of the archive, used for error messages only.
     * @param encoding              the encoding to use for file names, use null for the platform's default encoding
     * @param useUnicodeExtraFields whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.
     * @param ignoreLocalFileHeader whether to ignore information stored inside the local file header (see the notes in this method's Javadoc)
     * @throws IOException if an error occurs while reading the file.
     * @since 1.19
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final SeekableByteChannel channel, final String channelDescription, final String encoding, final boolean useUnicodeExtraFields,
            final boolean ignoreLocalFileHeader) throws IOException {
        this(channel, channelDescription, encoding, useUnicodeExtraFields, false, ignoreLocalFileHeader);
    }

    private ZipFile(final SeekableByteChannel channel, final String channelDescription, final String encoding, final boolean useUnicodeExtraFields,
            final boolean closeOnError, final boolean ignoreLocalFileHeader) throws IOException {
        this(channel, channelDescription, Charsets.toCharset(encoding), useUnicodeExtraFields, closeOnError, ignoreLocalFileHeader);
    }

    /**
     * Opens the given file for reading, assuming "UTF-8".
     *
     * @param name name of the archive.
     * @throws IOException if an error occurs while reading the file.
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final String name) throws IOException {
        this(new File(name).toPath(), DEFAULT_CHARSET_NAME);
    }

    /**
     * Opens the given file for reading, assuming the specified encoding for file names, scanning unicode extra fields.
     *
     * @param name     name of the archive.
     * @param encoding the encoding to use for file names, use null for the platform's default encoding
     * @throws IOException if an error occurs while reading the file.
     * @deprecated Use {@link Builder#get()}.
     */
    @Deprecated
    public ZipFile(final String name, final String encoding) throws IOException {
        this(new File(name).toPath(), encoding, true);
    }

    /**
     * Whether this class is able to read the given entry.
     * <p>
     * May return false if it is set up to use encryption or a compression method that hasn't been implemented yet.
     * </p>
     *
     * @since 1.1
     * @param entry the entry
     * @return whether this class is able to read the given entry.
     */
    public boolean canReadEntryData(final ZipArchiveEntry entry) {
        return ZipUtil.canHandleEntryData(entry);
    }

    /**
     * Closes the archive.
     *
     * @throws IOException if an error occurs closing the archive.
     */
    @Override
    public void close() throws IOException {
        // this flag is only written here and read in finalize() which
        // can never be run in parallel.
        // no synchronization needed.
        closed = true;
        archive.close();
    }

    /**
     * Transfer selected entries from this ZIP file to a given #ZipArchiveOutputStream. Compression and all other attributes will be as in this file.
     * <p>
     * This method transfers entries based on the central directory of the ZIP file.
     * </p>
     *
     * @param target    The zipArchiveOutputStream to write the entries to
     * @param predicate A predicate that selects which entries to write
     * @throws IOException on error
     */
    public void copyRawEntries(final ZipArchiveOutputStream target, final ZipArchiveEntryPredicate predicate) throws IOException {
        final Enumeration<ZipArchiveEntry> src = getEntriesInPhysicalOrder();
        while (src.hasMoreElements()) {
            final ZipArchiveEntry entry = src.nextElement();
            if (predicate.test(entry)) {
                target.addRawArchiveEntry(entry, getRawInputStream(entry));
            }
        }
    }

    /**
     * Creates new BoundedInputStream, according to implementation of underlying archive channel.
     */
    private BoundedArchiveInputStream createBoundedInputStream(final long start, final long remaining) {
        if (start < 0 || remaining < 0 || start + remaining < start) {
            throw new IllegalArgumentException("Corrupted archive, stream boundaries" + " are out of range");
        }
        return archive instanceof FileChannel ? new BoundedFileChannelInputStream(start, remaining, (FileChannel) archive)
                : new BoundedSeekableByteChannelInputStream(start, remaining, archive);
    }

    private void fillNameMap() {
        entries.forEach(ze -> {
            // entries are filled in populateFromCentralDirectory and
            // never modified
            final String name = ze.getName();
            final LinkedList<ZipArchiveEntry> entriesOfThatName = nameMap.computeIfAbsent(name, k -> new LinkedList<>());
            entriesOfThatName.addLast(ze);
        });
    }

    /**
     * Ensures that the close method of this ZIP file is called when there are no more references to it.
     *
     * @see #close()
     */
    @Override
    protected void finalize() throws Throwable {
        try {
            if (!closed) {
                close();
            }
        } finally {
            super.finalize();
        }
    }

    /**
     * Gets an InputStream for reading the content before the first local file header.
     *
     * @return null if there is no content before the first local file header. Otherwise, returns a stream to read the content before the first local file
     *         header.
     * @since 1.23
     */
    public InputStream getContentBeforeFirstLocalFileHeader() {
        return firstLocalFileHeaderOffset == 0 ? null : createBoundedInputStream(0, firstLocalFileHeaderOffset);
    }

    private long getDataOffset(final ZipArchiveEntry ze) throws IOException {
        final long s = ze.getDataOffset();
        if (s == EntryStreamOffsets.OFFSET_UNKNOWN) {
            setDataOffset(ze);
            return ze.getDataOffset();
        }
        return s;
    }

    /**
     * Gets the encoding to use for file names and the file comment.
     *
     * @return null if using the platform's default character encoding.
     */
    public String getEncoding() {
        return encoding.name();
    }

    /**
     * Gets all entries.
     * <p>
     * Entries will be returned in the same order they appear within the archive's central directory.
     * </p>
     *
     * @return all entries as {@link ZipArchiveEntry} instances
     */
    public Enumeration<ZipArchiveEntry> getEntries() {
        return Collections.enumeration(entries);
    }

    /**
     * Gets all named entries in the same order they appear within the archive's central directory.
     *
     * @param name name of the entry.
     * @return the Iterable&lt;ZipArchiveEntry&gt; corresponding to the given name
     * @since 1.6
     */
    public Iterable<ZipArchiveEntry> getEntries(final String name) {
        return nameMap.getOrDefault(name, ZipArchiveEntry.EMPTY_LINKED_LIST);
    }

    /**
     * Gets all entries in physical order.
     * <p>
     * Entries will be returned in the same order their contents appear within the archive.
     * </p>
     *
     * @return all entries as {@link ZipArchiveEntry} instances
     *
     * @since 1.1
     */
    public Enumeration<ZipArchiveEntry> getEntriesInPhysicalOrder() {
        final ZipArchiveEntry[] allEntries = entries.toArray(ZipArchiveEntry.EMPTY_ARRAY);
        return Collections.enumeration(Arrays.asList(sortByOffset(allEntries)));
    }

    /**
     * Gets all named entries in the same order their contents appear within the archive.
     *
     * @param name name of the entry.
     * @return the Iterable&lt;ZipArchiveEntry&gt; corresponding to the given name
     * @since 1.6
     */
    public Iterable<ZipArchiveEntry> getEntriesInPhysicalOrder(final String name) {
        final LinkedList<ZipArchiveEntry> linkedList = nameMap.getOrDefault(name, ZipArchiveEntry.EMPTY_LINKED_LIST);
        return Arrays.asList(sortByOffset(linkedList.toArray(ZipArchiveEntry.EMPTY_ARRAY)));
    }

    /**
     * Gets a named entry or {@code null} if no entry by that name exists.
     * <p>
     * If multiple entries with the same name exist the first entry in the archive's central directory by that name is returned.
     * </p>
     *
     * @param name name of the entry.
     * @return the ZipArchiveEntry corresponding to the given name - or {@code null} if not present.
     */
    public ZipArchiveEntry getEntry(final String name) {
        final LinkedList<ZipArchiveEntry> entries = nameMap.get(name);
        return entries != null ? entries.getFirst() : null;
    }

    /**
     * Gets the offset of the first local file header in the file.
     *
     * @return the length of the content before the first local file header
     * @since 1.23
     */
    public long getFirstLocalFileHeaderOffset() {
        return firstLocalFileHeaderOffset;
    }

    /**
     * Gets an InputStream for reading the contents of the given entry.
     *
     * @param entry the entry to get the stream for.
     * @return a stream to read the entry from. The returned stream implements {@link InputStreamStatistics}.
     * @throws IOException if unable to create an input stream from the zipEntry.
     */
    public InputStream getInputStream(final ZipArchiveEntry entry) throws IOException {
        if (!(entry instanceof Entry)) {
            return null;
        }
        // cast validity is checked just above
        ZipUtil.checkRequestedFeatures(entry);

        // doesn't get closed if the method is not supported - which
        // should never happen because of the checkRequestedFeatures
        // call above
        final InputStream is = new BufferedInputStream(getRawInputStream(entry)); // NOSONAR
        switch (ZipMethod.getMethodByCode(entry.getMethod())) {
        case STORED:
            return new StoredStatisticsStream(is);
        case UNSHRINKING:
            return new UnshrinkingInputStream(is);
        case IMPLODING:
            try {
                return new ExplodingInputStream(entry.getGeneralPurposeBit().getSlidingDictionarySize(),
                        entry.getGeneralPurposeBit().getNumberOfShannonFanoTrees(), is);
            } catch (final IllegalArgumentException ex) {
                throw new IOException("bad IMPLODE data", ex);
            }
        case DEFLATED:
            final Inflater inflater = new Inflater(true);
            // Inflater with nowrap=true has this odd contract for a zero padding
            // byte following the data stream; this used to be zlib's requirement
            // and has been fixed a long time ago, but the contract persists so
            // we comply.
            // https://docs.oracle.com/javase/8/docs/api/java/util/zip/Inflater.html#Inflater(boolean)
            return new InflaterInputStreamWithStatistics(new SequenceInputStream(is, new ByteArrayInputStream(ONE_ZERO_BYTE)), inflater) {
                @Override
                public void close() throws IOException {
                    try {
                        super.close();
                    } finally {
                        inflater.end();
                    }
                }
            };
        case BZIP2:
            return new BZip2CompressorInputStream(is);
        case ENHANCED_DEFLATED:
            return new Deflate64CompressorInputStream(is);
        case AES_ENCRYPTED:
        case EXPANDING_LEVEL_1:
        case EXPANDING_LEVEL_2:
        case EXPANDING_LEVEL_3:
        case EXPANDING_LEVEL_4:
        case JPEG:
        case LZMA:
        case PKWARE_IMPLODING:
        case PPMD:
        case TOKENIZATION:
        case UNKNOWN:
        case WAVPACK:
        case XZ:
        default:
            throw new UnsupportedZipFeatureException(ZipMethod.getMethodByCode(entry.getMethod()), entry);
        }
    }

    /**
     * Gets the raw stream of the archive entry (compressed form).
     * <p>
     * This method does not relate to how/if we understand the payload in the stream, since we really only intend to move it on to somewhere else.
     * </p>
     * <p>
     * Since version 1.22, this method will make an attempt to read the entry's data stream offset, even if the {@code ignoreLocalFileHeader} parameter was
     * {@code true} in the constructor. An IOException can also be thrown from the body of the method if this lookup fails for some reason.
     * </p>
     *
     * @param entry The entry to get the stream for
     * @return The raw input stream containing (possibly) compressed data.
     * @since 1.11
     * @throws IOException if there is a problem reading data offset (added in version 1.22).
     */
    public InputStream getRawInputStream(final ZipArchiveEntry entry) throws IOException {
        if (!(entry instanceof Entry)) {
            return null;
        }
        final long start = getDataOffset(entry);
        if (start == EntryStreamOffsets.OFFSET_UNKNOWN) {
            return null;
        }
        return createBoundedInputStream(start, entry.getCompressedSize());
    }

    /**
     * Gets the entry's content as a String if isUnixSymlink() returns true for it, otherwise returns null.
     * <p>
     * This method assumes the symbolic link's file name uses the same encoding that as been specified for this ZipFile.
     * </p>
     *
     * @param entry ZipArchiveEntry object that represents the symbolic link
     * @return entry's content as a String
     * @throws IOException problem with content's input stream
     * @since 1.5
     */
    public String getUnixSymlink(final ZipArchiveEntry entry) throws IOException {
        if (entry != null && entry.isUnixSymlink()) {
            try (InputStream in = getInputStream(entry)) {
                return zipEncoding.decode(org.apache.commons.io.IOUtils.toByteArray(in));
            }
        }
        return null;
    }

    /**
     * Reads the central directory of the given archive and populates the internal tables with ZipArchiveEntry instances.
     * <p>
     * The ZipArchiveEntrys will know all data that can be obtained from the central directory alone, but not the data that requires the local file header or
     * additional data to be read.
     * </p>
     *
     * @return a map of zip entries that didn't have the language encoding flag set when read.
     */
    private Map<ZipArchiveEntry, NameAndComment> populateFromCentralDirectory() throws IOException {
        final HashMap<ZipArchiveEntry, NameAndComment> noUTF8Flag = new HashMap<>();

        positionAtCentralDirectory();
        centralDirectoryStartOffset = archive.position();

        wordBbuf.rewind();
        IOUtils.readFully(archive, wordBbuf);
        long sig = ZipLong.getValue(wordBuf);

        if (sig != CFH_SIG && startsWithLocalFileHeader()) {
            throw new IOException("Central directory is empty, can't expand" + " corrupt archive.");
        }

        while (sig == CFH_SIG) {
            readCentralDirectoryEntry(noUTF8Flag);
            wordBbuf.rewind();
            IOUtils.readFully(archive, wordBbuf);
            sig = ZipLong.getValue(wordBuf);
        }
        return noUTF8Flag;
    }

    /**
     * Searches for either the &quot;Zip64 end of central directory locator&quot; or the &quot;End of central dir record&quot;, parses it and positions the
     * stream at the first central directory record.
     */
    private void positionAtCentralDirectory() throws IOException {
        final boolean is64 = positionAtEndOfCentralDirectoryRecord(archive);
        if (!is64) {
            positionAtCentralDirectory32();
        } else {
            positionAtCentralDirectory64();
        }
    }

    /**
     * Parses the &quot;End of central dir record&quot; and positions the stream at the first central directory record.
     *
     * Expects stream to be positioned at the beginning of the &quot;End of central dir record&quot;.
     */
    private void positionAtCentralDirectory32() throws IOException {
        final long endOfCentralDirectoryRecordOffset = archive.position();
        if (isSplitZipArchive) {
            skipBytes(CFD_DISK_OFFSET);
            shortBbuf.rewind();
            IOUtils.readFully(archive, shortBbuf);
            centralDirectoryStartDiskNumber = ZipShort.getValue(shortBuf);

            skipBytes(CFD_LOCATOR_RELATIVE_OFFSET);

            wordBbuf.rewind();
            IOUtils.readFully(archive, wordBbuf);
            centralDirectoryStartRelativeOffset = ZipLong.getValue(wordBuf);
            ((ZipSplitReadOnlySeekableByteChannel) archive).position(centralDirectoryStartDiskNumber, centralDirectoryStartRelativeOffset);
        } else {
            skipBytes(CFD_LENGTH_OFFSET);
            wordBbuf.rewind();
            IOUtils.readFully(archive, wordBbuf);
            final long centralDirectoryLength = ZipLong.getValue(wordBuf);

            wordBbuf.rewind();
            IOUtils.readFully(archive, wordBbuf);
            centralDirectoryStartDiskNumber = 0;
            centralDirectoryStartRelativeOffset = ZipLong.getValue(wordBuf);

            firstLocalFileHeaderOffset = Long.max(endOfCentralDirectoryRecordOffset - centralDirectoryLength - centralDirectoryStartRelativeOffset, 0L);
            archive.position(centralDirectoryStartRelativeOffset + firstLocalFileHeaderOffset);
        }
    }

    /**
     * Parses the &quot;Zip64 end of central directory locator&quot;, finds the &quot;Zip64 end of central directory record&quot; using the parsed information,
     * parses that and positions the stream at the first central directory record.
     *
     * Expects stream to be positioned right behind the &quot;Zip64 end of central directory locator&quot;'s signature.
     */
    private void positionAtCentralDirectory64() throws IOException {
        skipBytes(ZipConstants.WORD);
        if (isSplitZipArchive) {
            wordBbuf.rewind();
            IOUtils.readFully(archive, wordBbuf);
            final long diskNumberOfEOCD = ZipLong.getValue(wordBuf);

            dwordBbuf.rewind();
            IOUtils.readFully(archive, dwordBbuf);
            final long relativeOffsetOfEOCD = ZipEightByteInteger.getLongValue(dwordBuf);
            ((ZipSplitReadOnlySeekableByteChannel) archive).position(diskNumberOfEOCD, relativeOffsetOfEOCD);
        } else {
            skipBytes(ZIP64_EOCDL_LOCATOR_OFFSET - ZipConstants.WORD /* signature has already been read */);
            dwordBbuf.rewind();
            IOUtils.readFully(archive, dwordBbuf);
            archive.position(ZipEightByteInteger.getLongValue(dwordBuf));
        }

        wordBbuf.rewind();
        IOUtils.readFully(archive, wordBbuf);
        if (!Arrays.equals(wordBuf, ZipArchiveOutputStream.ZIP64_EOCD_SIG)) {
            throw new ZipException("Archive's ZIP64 end of central directory locator is corrupt.");
        }

        if (isSplitZipArchive) {
            skipBytes(ZIP64_EOCD_CFD_DISK_OFFSET - ZipConstants.WORD /* signature has already been read */);
            wordBbuf.rewind();
            IOUtils.readFully(archive, wordBbuf);
            centralDirectoryStartDiskNumber = ZipLong.getValue(wordBuf);

            skipBytes(ZIP64_EOCD_CFD_LOCATOR_RELATIVE_OFFSET);

            dwordBbuf.rewind();
            IOUtils.readFully(archive, dwordBbuf);
            centralDirectoryStartRelativeOffset = ZipEightByteInteger.getLongValue(dwordBuf);
            ((ZipSplitReadOnlySeekableByteChannel) archive).position(centralDirectoryStartDiskNumber, centralDirectoryStartRelativeOffset);
        } else {
            skipBytes(ZIP64_EOCD_CFD_LOCATOR_OFFSET - ZipConstants.WORD /* signature has already been read */);
            dwordBbuf.rewind();
            IOUtils.readFully(archive, dwordBbuf);
            centralDirectoryStartDiskNumber = 0;
            centralDirectoryStartRelativeOffset = ZipEightByteInteger.getLongValue(dwordBuf);
            archive.position(centralDirectoryStartRelativeOffset);
        }
    }

    /**
     * Reads an individual entry of the central directory, creates an ZipArchiveEntry from it and adds it to the global maps.
     *
     * @param noUTF8Flag map used to collect entries that don't have their UTF-8 flag set and whose name will be set by data read from the local file header
     *                   later. The current entry may be added to this map.
     */
    private void readCentralDirectoryEntry(final Map<ZipArchiveEntry, NameAndComment> noUTF8Flag) throws IOException {
        cfhBbuf.rewind();
        IOUtils.readFully(archive, cfhBbuf);
        int off = 0;
        final Entry ze = new Entry();

        final int versionMadeBy = ZipShort.getValue(cfhBuf, off);
        off += ZipConstants.SHORT;
        ze.setVersionMadeBy(versionMadeBy);
        ze.setPlatform(versionMadeBy >> BYTE_SHIFT & NIBLET_MASK);

        ze.setVersionRequired(ZipShort.getValue(cfhBuf, off));
        off += ZipConstants.SHORT; // version required

        final GeneralPurposeBit gpFlag = GeneralPurposeBit.parse(cfhBuf, off);
        final boolean hasUTF8Flag = gpFlag.usesUTF8ForNames();
        final ZipEncoding entryEncoding = hasUTF8Flag ? ZipEncodingHelper.ZIP_ENCODING_UTF_8 : zipEncoding;
        if (hasUTF8Flag) {
            ze.setNameSource(ZipArchiveEntry.NameSource.NAME_WITH_EFS_FLAG);
        }
        ze.setGeneralPurposeBit(gpFlag);
        ze.setRawFlag(ZipShort.getValue(cfhBuf, off));

        off += ZipConstants.SHORT;

        // noinspection MagicConstant
        ze.setMethod(ZipShort.getValue(cfhBuf, off));
        off += ZipConstants.SHORT;

        final long time = ZipUtil.dosToJavaTime(ZipLong.getValue(cfhBuf, off));
        ze.setTime(time);
        off += ZipConstants.WORD;

        ze.setCrc(ZipLong.getValue(cfhBuf, off));
        off += ZipConstants.WORD;

        long size = ZipLong.getValue(cfhBuf, off);
        if (size < 0) {
            throw new IOException("broken archive, entry with negative compressed size");
        }
        ze.setCompressedSize(size);
        off += ZipConstants.WORD;

        size = ZipLong.getValue(cfhBuf, off);
        if (size < 0) {
            throw new IOException("broken archive, entry with negative size");
        }
        ze.setSize(size);
        off += ZipConstants.WORD;

        final int fileNameLen = ZipShort.getValue(cfhBuf, off);
        off += ZipConstants.SHORT;
        if (fileNameLen < 0) {
            throw new IOException("broken archive, entry with negative fileNameLen");
        }

        final int extraLen = ZipShort.getValue(cfhBuf, off);
        off += ZipConstants.SHORT;
        if (extraLen < 0) {
            throw new IOException("broken archive, entry with negative extraLen");
        }

        final int commentLen = ZipShort.getValue(cfhBuf, off);
        off += ZipConstants.SHORT;
        if (commentLen < 0) {
            throw new IOException("broken archive, entry with negative commentLen");
        }

        ze.setDiskNumberStart(ZipShort.getValue(cfhBuf, off));
        off += ZipConstants.SHORT;

        ze.setInternalAttributes(ZipShort.getValue(cfhBuf, off));
        off += ZipConstants.SHORT;

        ze.setExternalAttributes(ZipLong.getValue(cfhBuf, off));
        off += ZipConstants.WORD;

        final byte[] fileName = IOUtils.readRange(archive, fileNameLen);
        if (fileName.length < fileNameLen) {
            throw new EOFException();
        }
        ze.setName(entryEncoding.decode(fileName), fileName);

        // LFH offset,
        ze.setLocalHeaderOffset(ZipLong.getValue(cfhBuf, off) + firstLocalFileHeaderOffset);
        // data offset will be filled later
        entries.add(ze);

        final byte[] cdExtraData = IOUtils.readRange(archive, extraLen);
        if (cdExtraData.length < extraLen) {
            throw new EOFException();
        }
        try {
            ze.setCentralDirectoryExtra(cdExtraData);
        } catch (final RuntimeException e) {
            final ZipException z = new ZipException("Invalid extra data in entry " + ze.getName());
            z.initCause(e);
            throw z;
        }

        setSizesAndOffsetFromZip64Extra(ze);
        sanityCheckLFHOffset(ze);

        final byte[] comment = IOUtils.readRange(archive, commentLen);
        if (comment.length < commentLen) {
            throw new EOFException();
        }
        ze.setComment(entryEncoding.decode(comment));

        if (!hasUTF8Flag && useUnicodeExtraFields) {
            noUTF8Flag.put(ze, new NameAndComment(fileName, comment));
        }

        ze.setStreamContiguous(true);
    }

    /**
     * Walks through all recorded entries and adds the data available from the local file header.
     * <p>
     * Also records the offsets for the data to read from the entries.
     * </p>
     */
    private void resolveLocalFileHeaderData(final Map<ZipArchiveEntry, NameAndComment> entriesWithoutUTF8Flag) throws IOException {
        for (final ZipArchiveEntry zipArchiveEntry : entries) {
            // entries are filled in populateFromCentralDirectory and never modified
            final Entry ze = (Entry) zipArchiveEntry;
            final int[] lens = setDataOffset(ze);
            final int fileNameLen = lens[0];
            final int extraFieldLen = lens[1];
            skipBytes(fileNameLen);
            final byte[] localExtraData = IOUtils.readRange(archive, extraFieldLen);
            if (localExtraData.length < extraFieldLen) {
                throw new EOFException();
            }
            try {
                ze.setExtra(localExtraData);
            } catch (final RuntimeException e) {
                final ZipException z = new ZipException("Invalid extra data in entry " + ze.getName());
                z.initCause(e);
                throw z;
            }

            if (entriesWithoutUTF8Flag.containsKey(ze)) {
                final NameAndComment nc = entriesWithoutUTF8Flag.get(ze);
                ZipUtil.setNameAndCommentFromExtraFields(ze, nc.name, nc.comment);
            }
        }
    }

    private void sanityCheckLFHOffset(final ZipArchiveEntry entry) throws IOException {
        if (entry.getDiskNumberStart() < 0) {
            throw new IOException("broken archive, entry with negative disk number");
        }
        if (entry.getLocalHeaderOffset() < 0) {
            throw new IOException("broken archive, entry with negative local file header offset");
        }
        if (isSplitZipArchive) {
            if (entry.getDiskNumberStart() > centralDirectoryStartDiskNumber) {
                throw new IOException("local file header for " + entry.getName() + " starts on a later disk than central directory");
            }
            if (entry.getDiskNumberStart() == centralDirectoryStartDiskNumber && entry.getLocalHeaderOffset() > centralDirectoryStartRelativeOffset) {
                throw new IOException("local file header for " + entry.getName() + " starts after central directory");
            }
        } else if (entry.getLocalHeaderOffset() > centralDirectoryStartOffset) {
            throw new IOException("local file header for " + entry.getName() + " starts after central directory");
        }
    }

    private int[] setDataOffset(final ZipArchiveEntry entry) throws IOException {
        long offset = entry.getLocalHeaderOffset();
        if (isSplitZipArchive) {
            ((ZipSplitReadOnlySeekableByteChannel) archive).position(entry.getDiskNumberStart(), offset + LFH_OFFSET_FOR_FILENAME_LENGTH);
            // the offset should be updated to the global offset
            offset = archive.position() - LFH_OFFSET_FOR_FILENAME_LENGTH;
        } else {
            archive.position(offset + LFH_OFFSET_FOR_FILENAME_LENGTH);
        }
        wordBbuf.rewind();
        IOUtils.readFully(archive, wordBbuf);
        wordBbuf.flip();
        wordBbuf.get(shortBuf);
        final int fileNameLen = ZipShort.getValue(shortBuf);
        wordBbuf.get(shortBuf);
        final int extraFieldLen = ZipShort.getValue(shortBuf);
        entry.setDataOffset(offset + LFH_OFFSET_FOR_FILENAME_LENGTH + ZipConstants.SHORT + ZipConstants.SHORT + fileNameLen + extraFieldLen);
        if (entry.getDataOffset() + entry.getCompressedSize() > centralDirectoryStartOffset) {
            throw new IOException("data for " + entry.getName() + " overlaps with central directory.");
        }
        return new int[] { fileNameLen, extraFieldLen };
    }

    /**
     * If the entry holds a Zip64 extended information extra field, read sizes from there if the entry's sizes are set to 0xFFFFFFFFF, do the same for the
     * offset of the local file header.
     * <p>
     * Ensures the Zip64 extra either knows both compressed and uncompressed size or neither of both as the internal logic in ExtraFieldUtils forces the field
     * to create local header data even if they are never used - and here a field with only one size would be invalid.
     * </p>
     */
    private void setSizesAndOffsetFromZip64Extra(final ZipArchiveEntry entry) throws IOException {
        final ZipExtraField extra = entry.getExtraField(Zip64ExtendedInformationExtraField.HEADER_ID);
        if (extra != null && !(extra instanceof Zip64ExtendedInformationExtraField)) {
            throw new ZipException("archive contains unparseable zip64 extra field");
        }
        final Zip64ExtendedInformationExtraField z64 = (Zip64ExtendedInformationExtraField) extra;
        if (z64 != null) {
            final boolean hasUncompressedSize = entry.getSize() == ZipConstants.ZIP64_MAGIC;
            final boolean hasCompressedSize = entry.getCompressedSize() == ZipConstants.ZIP64_MAGIC;
            final boolean hasRelativeHeaderOffset = entry.getLocalHeaderOffset() == ZipConstants.ZIP64_MAGIC;
            final boolean hasDiskStart = entry.getDiskNumberStart() == ZipConstants.ZIP64_MAGIC_SHORT;
            z64.reparseCentralDirectoryData(hasUncompressedSize, hasCompressedSize, hasRelativeHeaderOffset, hasDiskStart);

            if (hasUncompressedSize) {
                final long size = z64.getSize().getLongValue();
                if (size < 0) {
                    throw new IOException("broken archive, entry with negative size");
                }
                entry.setSize(size);
            } else if (hasCompressedSize) {
                z64.setSize(new ZipEightByteInteger(entry.getSize()));
            }

            if (hasCompressedSize) {
                final long size = z64.getCompressedSize().getLongValue();
                if (size < 0) {
                    throw new IOException("broken archive, entry with negative compressed size");
                }
                entry.setCompressedSize(size);
            } else if (hasUncompressedSize) {
                z64.setCompressedSize(new ZipEightByteInteger(entry.getCompressedSize()));
            }

            if (hasRelativeHeaderOffset) {
                entry.setLocalHeaderOffset(z64.getRelativeHeaderOffset().getLongValue());
            }

            if (hasDiskStart) {
                entry.setDiskNumberStart(z64.getDiskStartNumber().getValue());
            }
        }
    }

    /**
     * Skips the given number of bytes or throws an EOFException if skipping failed.
     */
    private void skipBytes(final int count) throws IOException {
        final long currentPosition = archive.position();
        final long newPosition = currentPosition + count;
        if (newPosition > archive.size()) {
            throw new EOFException();
        }
        archive.position(newPosition);
    }

    /**
     * Sorts entries in place by offset.
     *
     * @param allEntries entries to sort
     * @return the given entries, sorted.
     */
    private ZipArchiveEntry[] sortByOffset(final ZipArchiveEntry[] allEntries) {
        Arrays.sort(allEntries, offsetComparator);
        return allEntries;
    }

    /**
     * Checks whether the archive starts with an LFH. If it doesn't, it may be an empty archive.
     */
    private boolean startsWithLocalFileHeader() throws IOException {
        archive.position(firstLocalFileHeaderOffset);
        wordBbuf.rewind();
        IOUtils.readFully(archive, wordBbuf);
        return Arrays.equals(wordBuf, ZipArchiveOutputStream.LFH_SIG);
    }
}