https://ant.apache.org/: master POM (The Apache Software Foundation) 
/*
 *  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
 *
 *      https://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.
 *
 */

/*
 * This package is based on the work done by Timothy Gerard Endres
 * (time@ice.com) to whom the Ant project is very grateful for his great code.
 */

package org.apache.tools.tar;

import java.io.ByteArrayOutputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;

import org.apache.tools.zip.ZipEncoding;
import org.apache.tools.zip.ZipEncodingHelper;


The TarInputStream reads a UNIX tar archive as an InputStream.
methods are provided to position at each successive entry in
the archive, and the read each entry as a normal input stream
using read().

/**
 * The TarInputStream reads a UNIX tar archive as an InputStream.
 * methods are provided to position at each successive entry in
 * the archive, and the read each entry as a normal input stream
 * using read().
 *
 */
public class TarInputStream extends FilterInputStream {
    private static final int SMALL_BUFFER_SIZE = 256;
    private static final int BUFFER_SIZE = 8 * 1024;
    private static final int LARGE_BUFFER_SIZE = 32 * 1024;
    private static final int BYTE_MASK = 0xFF;

    private final byte[] SKIP_BUF = new byte[BUFFER_SIZE];
    private final byte[] SMALL_BUF = new byte[SMALL_BUFFER_SIZE];

    // CheckStyle:VisibilityModifier OFF - bc
    protected boolean debug;
    protected boolean hasHitEOF;
    protected long entrySize;
    protected long entryOffset;
    protected byte[] readBuf;
    protected TarBuffer buffer;
    protected TarEntry currEntry;

    
This contents of this array is not used at all in this class,
it is only here to avoid repeated object creation during calls
to the no-arg read method.

/**
     * This contents of this array is not used at all in this class,
     * it is only here to avoid repeated object creation during calls
     * to the no-arg read method.
     */
    protected byte[] oneBuf;

    // CheckStyle:VisibilityModifier ON

    private final ZipEncoding encoding;

    
Constructor for TarInputStream.

Params:
  • is – the input stream to use
/**
     * Constructor for TarInputStream.
     * @param is the input stream to use
     */
    public TarInputStream(InputStream is) {
        this(is, TarBuffer.DEFAULT_BLKSIZE, TarBuffer.DEFAULT_RCDSIZE);
    }

    
Constructor for TarInputStream.

Params:
  • is – the input stream to use
  • encoding – name of the encoding to use for file names
/**
     * Constructor for TarInputStream.
     * @param is the input stream to use
     * @param encoding name of the encoding to use for file names
     */
    public TarInputStream(InputStream is, String encoding) {
        this(is, TarBuffer.DEFAULT_BLKSIZE, TarBuffer.DEFAULT_RCDSIZE, encoding);
    }

    
Constructor for TarInputStream.

Params:
  • is – the input stream to use
  • blockSize – the block size to use
/**
     * Constructor for TarInputStream.
     * @param is the input stream to use
     * @param blockSize the block size to use
     */
    public TarInputStream(InputStream is, int blockSize) {
        this(is, blockSize, TarBuffer.DEFAULT_RCDSIZE);
    }

    
Constructor for TarInputStream.

Params:
  • is – the input stream to use
  • blockSize – the block size to use
  • encoding – name of the encoding to use for file names
/**
     * Constructor for TarInputStream.
     * @param is the input stream to use
     * @param blockSize the block size to use
     * @param encoding name of the encoding to use for file names
     */
    public TarInputStream(InputStream is, int blockSize, String encoding) {
        this(is, blockSize, TarBuffer.DEFAULT_RCDSIZE, encoding);
    }

    
Constructor for TarInputStream.

Params:
  • is – the input stream to use
  • blockSize – the block size to use
  • recordSize – the record size to use
/**
     * Constructor for TarInputStream.
     * @param is the input stream to use
     * @param blockSize the block size to use
     * @param recordSize the record size to use
     */
    public TarInputStream(InputStream is, int blockSize, int recordSize) {
        this(is, blockSize, recordSize, null);
    }

    
Constructor for TarInputStream.

Params:
  • is – the input stream to use
  • blockSize – the block size to use
  • recordSize – the record size to use
  • encoding – name of the encoding to use for file names
/**
     * Constructor for TarInputStream.
     * @param is the input stream to use
     * @param blockSize the block size to use
     * @param recordSize the record size to use
     * @param encoding name of the encoding to use for file names
     */
    public TarInputStream(InputStream is, int blockSize, int recordSize,
                          String encoding) {
        super(is);
        this.buffer = new TarBuffer(is, blockSize, recordSize);
        this.readBuf = null;
        this.oneBuf = new byte[1];
        this.debug = false;
        this.hasHitEOF = false;
        this.encoding = ZipEncodingHelper.getZipEncoding(encoding);
    }

    
Sets the debugging flag.

Params:
  • debug – True to turn on debugging.
/**
     * Sets the debugging flag.
     *
     * @param debug True to turn on debugging.
     */
    public void setDebug(boolean debug) {
        this.debug = debug;
        buffer.setDebug(debug);
    }

    
Closes this stream. Calls the TarBuffer's close() method.

Throws:
  • IOException – on error
/**
     * Closes this stream. Calls the TarBuffer's close() method.
     * @throws IOException on error
     */
    @Override
    public void close() throws IOException {
        buffer.close();
    }

    
Get the record size being used by this stream's TarBuffer.

Returns:The TarBuffer record size.
/**
     * Get the record size being used by this stream's TarBuffer.
     *
     * @return The TarBuffer record size.
     */
    public int getRecordSize() {
        return buffer.getRecordSize();
    }

    
Get the available data that can be read from the current
entry in the archive. This does not indicate how much data
is left in the entire archive, only in the current entry.
This value is determined from the entry's size header field
and the amount of data already read from the current entry.
Integer.MAX_VALUE is returned in case more than Integer.MAX_VALUE
bytes are left in the current entry in the archive.

Throws:
Returns:The number of available bytes for the current entry.
/**
     * Get the available data that can be read from the current
     * entry in the archive. This does not indicate how much data
     * is left in the entire archive, only in the current entry.
     * This value is determined from the entry's size header field
     * and the amount of data already read from the current entry.
     * Integer.MAX_VALUE is returned in case more than Integer.MAX_VALUE
     * bytes are left in the current entry in the archive.
     *
     * @return The number of available bytes for the current entry.
     * @throws IOException for signature
     */
    @Override
    public int available() throws IOException {
        if (isDirectory()) {
            return 0;
        }
        if (entrySize - entryOffset > Integer.MAX_VALUE) {
            return Integer.MAX_VALUE;
        }
        return (int) (entrySize - entryOffset);
    }

    
Skip bytes in the input buffer. This skips bytes in the
current entry's data, not the entire archive, and will
stop at the end of the current entry's data if the number
to skip extends beyond that point.

Params:
  • numToSkip – The number of bytes to skip.
Throws:
Returns:the number actually skipped
/**
     * Skip bytes in the input buffer. This skips bytes in the
     * current entry's data, not the entire archive, and will
     * stop at the end of the current entry's data if the number
     * to skip extends beyond that point.
     *
     * @param numToSkip The number of bytes to skip.
     * @return the number actually skipped
     * @throws IOException on error
     */
    @Override
    public long skip(long numToSkip) throws IOException {
        if (numToSkip <= 0 || isDirectory()) {
            return 0;
        }
        // REVIEW
        // This is horribly inefficient, but it ensures that we
        // properly skip over bytes via the TarBuffer...
        //
        long skip = numToSkip;
        while (skip > 0) {
            int realSkip = (int) (skip > SKIP_BUF.length
                                  ? SKIP_BUF.length : skip);
            int numRead = read(SKIP_BUF, 0, realSkip);
            if (numRead == -1) {
                break;
            }
            skip -= numRead;
        }
        return (numToSkip - skip);
    }

    
Since we do not support marking just yet, we return false.

Returns:False.
/**
     * Since we do not support marking just yet, we return false.
     *
     * @return False.
     */
    @Override
    public boolean markSupported() {
        return false;
    }

    
Since we do not support marking just yet, we do nothing.

Params:
  • markLimit – The limit to mark.
/**
     * Since we do not support marking just yet, we do nothing.
     *
     * @param markLimit The limit to mark.
     */
    @Override
    public void mark(int markLimit) {
    }

    
Since we do not support marking just yet, we do nothing.

/**
     * Since we do not support marking just yet, we do nothing.
     */
    @Override
    public void reset() {
    }

    
Get the next entry in this tar archive. This will skip
over any remaining data in the current entry, if there
is one, and place the input stream at the header of the
next entry, and read the header and instantiate a new
TarEntry from the header bytes and return that entry.
If there are no more entries in the archive, null will
be returned to indicate that the end of the archive has
been reached.

Throws:
Returns:The next TarEntry in the archive, or null.
/**
     * Get the next entry in this tar archive. This will skip
     * over any remaining data in the current entry, if there
     * is one, and place the input stream at the header of the
     * next entry, and read the header and instantiate a new
     * TarEntry from the header bytes and return that entry.
     * If there are no more entries in the archive, null will
     * be returned to indicate that the end of the archive has
     * been reached.
     *
     * @return The next TarEntry in the archive, or null.
     * @throws IOException on error
     */
    public TarEntry getNextEntry() throws IOException {
        if (hasHitEOF) {
            return null;
        }

        if (currEntry != null) {
            long numToSkip = entrySize - entryOffset;

            if (debug) {
                System.err.println("TarInputStream: SKIP currENTRY '"
                        + currEntry.getName() + "' SZ "
                        + entrySize + " OFF "
                        + entryOffset + "  skipping "
                        + numToSkip + " bytes");
            }

            while (numToSkip > 0) {
                long skipped = skip(numToSkip);
                if (skipped <= 0) {
                    throw new IOException("failed to skip current tar"
                                               + " entry");
                }
                numToSkip -= skipped;
            }

            readBuf = null;
        }

        byte[] headerBuf = getRecord();

        if (hasHitEOF) {
            currEntry = null;
            return null;
        }

        try {
            currEntry = new TarEntry(headerBuf, encoding);
        } catch (IllegalArgumentException e) {
            throw new IOException("Error detected parsing the header", e);
        }
        if (debug) {
            System.err.println("TarInputStream: SET CURRENTRY '"
                               + currEntry.getName()
                               + "' size = "
                               + currEntry.getSize());
        }

        entryOffset = 0;
        entrySize = currEntry.getSize();

        if (currEntry.isGNULongLinkEntry()) {
            byte[] longLinkData = getLongNameData();
            if (longLinkData == null) {
                // Bugzilla: 40334
                // Malformed tar file - long link entry name not followed by
                // entry
                return null;
            }
            currEntry.setLinkName(encoding.decode(longLinkData));
        }

        if (currEntry.isGNULongNameEntry()) {
            byte[] longNameData = getLongNameData();
            if (longNameData == null) {
                // Bugzilla: 40334
                // Malformed tar file - long entry name not followed by
                // entry
                return null;
            }
            currEntry.setName(encoding.decode(longNameData));
        }

        if (currEntry.isPaxHeader()) { // Process Pax headers
            paxHeaders();
        }

        if (currEntry.isGNUSparse()) { // Process sparse files
            readGNUSparse();
        }

        // If the size of the next element in the archive has changed
        // due to a new size being reported in the posix header
        // information, we update entrySize here so that it contains
        // the correct value.
        entrySize = currEntry.getSize();
        return currEntry;
    }

    
Get the next entry in this tar archive as longname data.

Throws:
Returns:The next entry in the archive as longname data, or null.
/**
     * Get the next entry in this tar archive as longname data.
     *
     * @return The next entry in the archive as longname data, or null.
     * @throws IOException on error
     */
    protected byte[] getLongNameData() throws IOException {
        // read in the name
        ByteArrayOutputStream longName = new ByteArrayOutputStream();
        int length = 0;
        while ((length = read(SMALL_BUF)) >= 0) {
            longName.write(SMALL_BUF, 0, length);
        }
        getNextEntry();
        if (currEntry == null) {
            // Bugzilla: 40334
            // Malformed tar file - long entry name not followed by entry
            return null;
        }
        byte[] longNameData = longName.toByteArray();
        // remove trailing null terminator(s)
        length = longNameData.length;
        while (length > 0 && longNameData[length - 1] == 0) {
            --length;
        }
        if (length != longNameData.length) {
            byte[] l = new byte[length];
            System.arraycopy(longNameData, 0, l, 0, length);
            longNameData = l;
        }
        return longNameData;
    }

    
Get the next record in this tar archive. This will skip
over any remaining data in the current entry, if there
is one, and place the input stream at the header of the
next entry.
If there are no more entries in the archive, null will
be returned to indicate that the end of the archive has
been reached.

Throws:
Returns:The next header in the archive, or null.
/**
     * Get the next record in this tar archive. This will skip
     * over any remaining data in the current entry, if there
     * is one, and place the input stream at the header of the
     * next entry.
     * If there are no more entries in the archive, null will
     * be returned to indicate that the end of the archive has
     * been reached.
     *
     * @return The next header in the archive, or null.
     * @throws IOException on error
     */
    private byte[] getRecord() throws IOException {
        if (hasHitEOF) {
            return null;
        }

        byte[] headerBuf = buffer.readRecord();

        if (headerBuf == null) {
            if (debug) {
                System.err.println("READ NULL RECORD");
            }
            hasHitEOF = true;
        } else if (buffer.isEOFRecord(headerBuf)) {
            if (debug) {
                System.err.println("READ EOF RECORD");
            }
            hasHitEOF = true;
        }

        return hasHitEOF ? null : headerBuf;
    }

    private void paxHeaders() throws IOException {
        Map<String, String> headers = parsePaxHeaders(this);
        getNextEntry(); // Get the actual file entry
        applyPaxHeadersToCurrentEntry(headers);
    }

    Map<String, String> parsePaxHeaders(InputStream i) throws IOException {
        Map<String, String> headers = new HashMap<>();
        // Format is "length keyword=value\n";
        while (true) { // get length
            int ch;
            int len = 0;
            int read = 0;
            while ((ch = i.read()) != -1) {
                read++;
                if (ch == ' ') { // End of length string
                    // Get keyword
                    ByteArrayOutputStream coll = new ByteArrayOutputStream();
                    while ((ch = i.read()) != -1) {
                        read++;
                        if (ch == '=') { // end of keyword
                            String keyword = coll.toString("UTF-8");
                            // Get rest of entry
                            final int restLen = len - read;
                            byte[] rest = new byte[restLen];
                            int got = 0;
                            while (got < restLen && (ch = i.read()) != -1) {
                                rest[got++] = (byte) ch;
                            }
                            if (got != restLen) {
                                throw new IOException("Failed to read "
                                                      + "Paxheader. Expected "
                                                      + restLen
                                                      + " bytes, read "
                                                      + got);
                            }
                            // Drop trailing NL
                            String value = new String(rest, 0,
                                                      restLen - 1, StandardCharsets.UTF_8);
                            headers.put(keyword, value);
                            break;
                        }
                        coll.write((byte) ch);
                    }
                    break; // Processed single header
                }
                len *= 10;
                len += ch - '0';
            }
            if (ch == -1) { // EOF
                break;
            }
        }
        return headers;
    }

    private void applyPaxHeadersToCurrentEntry(Map<String, String> headers) {
        /*
         * The following headers are defined for Pax.
         * atime, ctime, charset: cannot use these without changing TarEntry fields
         * mtime
         * comment
         * gid, gname
         * linkpath
         * size
         * uid,uname
         * SCHILY.devminor, SCHILY.devmajor: don't have setters/getters for those
         */
        headers.forEach((key, val) -> {
            switch (key) {
                case "path":
                    currEntry.setName(val);
                    break;
                case "linkpath":
                    currEntry.setLinkName(val);
                    break;
                case "gid":
                    currEntry.setGroupId(Long.parseLong(val));
                    break;
                case "gname":
                    currEntry.setGroupName(val);
                    break;
                case "uid":
                    currEntry.setUserId(Long.parseLong(val));
                    break;
                case "uname":
                    currEntry.setUserName(val);
                    break;
                case "size":
                    currEntry.setSize(Long.parseLong(val));
                    break;
                case "mtime":
                    currEntry.setModTime((long) (Double.parseDouble(val) * 1000));
                    break;
                case "SCHILY.devminor":
                    currEntry.setDevMinor(Integer.parseInt(val));
                    break;
                case "SCHILY.devmajor":
                    currEntry.setDevMajor(Integer.parseInt(val));
                    break;
            }
        });
    }

    
Adds the sparse chunks from the current entry to the sparse chunks,
including any additional sparse entries following the current entry.

Throws:
  • IOException – on error
@todoSparse files get not yet really processed.
/**
     * Adds the sparse chunks from the current entry to the sparse chunks,
     * including any additional sparse entries following the current entry.
     *
     * @throws IOException on error
     *
     * @todo Sparse files get not yet really processed.
     */
    private void readGNUSparse() throws IOException {
        /* we do not really process sparse files yet
        sparses = new ArrayList();
        sparses.addAll(currEntry.getSparses());
        */
        if (currEntry.isExtended()) {
            TarArchiveSparseEntry entry;
            do {
                byte[] headerBuf = getRecord();
                if (hasHitEOF) {
                    currEntry = null;
                    break;
                }
                entry = new TarArchiveSparseEntry(headerBuf);
                /* we do not really process sparse files yet
                sparses.addAll(entry.getSparses());
                */
            } while (entry.isExtended());
        }
    }

    
Reads a byte from the current tar archive entry.
This method simply calls read(byte[], int, int).

Throws:
Returns:The byte read, or -1 at EOF.
/**
     * Reads a byte from the current tar archive entry.
     *
     * This method simply calls read(byte[], int, int).
     *
     * @return The byte read, or -1 at EOF.
     * @throws IOException on error
     */
    @Override
    public int read() throws IOException {
        int num = read(oneBuf, 0, 1);
        return num == -1 ? -1 : (oneBuf[0]) & BYTE_MASK;
    }

    
Reads bytes from the current tar archive entry.
This method is aware of the boundaries of the current
entry in the archive and will deal with them as if they
were this stream's start and EOF.

Params:
  • buf – The buffer into which to place bytes read.
  • offset – The offset at which to place bytes read.
  • numToRead – The number of bytes to read.
Throws:
Returns:The number of bytes read, or -1 at EOF.
/**
     * Reads bytes from the current tar archive entry.
     *
     * This method is aware of the boundaries of the current
     * entry in the archive and will deal with them as if they
     * were this stream's start and EOF.
     *
     * @param buf The buffer into which to place bytes read.
     * @param offset The offset at which to place bytes read.
     * @param numToRead The number of bytes to read.
     * @return The number of bytes read, or -1 at EOF.
     * @throws IOException on error
     */
    @Override
    public int read(byte[] buf, int offset, int numToRead) throws IOException {
        int totalRead = 0;

        if (entryOffset >= entrySize || isDirectory()) {
            return -1;
        }

        if ((numToRead + entryOffset) > entrySize) {
            numToRead = (int) (entrySize - entryOffset);
        }

        if (readBuf != null) {
            int sz = (numToRead > readBuf.length) ? readBuf.length
                    : numToRead;

            System.arraycopy(readBuf, 0, buf, offset, sz);

            if (sz >= readBuf.length) {
                readBuf = null;
            } else {
                int newLen = readBuf.length - sz;
                byte[] newBuf = new byte[newLen];

                System.arraycopy(readBuf, sz, newBuf, 0, newLen);

                readBuf = newBuf;
            }

            totalRead += sz;
            numToRead -= sz;
            offset += sz;
        }

        while (numToRead > 0) {
            byte[] rec = buffer.readRecord();

            if (rec == null) {
                // Unexpected EOF!
                throw new IOException("unexpected EOF with " + numToRead
                        + " bytes unread");
            }

            int sz = numToRead;
            int recLen = rec.length;

            if (recLen > sz) {
                System.arraycopy(rec, 0, buf, offset, sz);

                readBuf = new byte[recLen - sz];

                System.arraycopy(rec, sz, readBuf, 0, recLen - sz);
            } else {
                sz = recLen;

                System.arraycopy(rec, 0, buf, offset, recLen);
            }

            totalRead += sz;
            numToRead -= sz;
            offset += sz;
        }

        entryOffset += totalRead;

        return totalRead;
    }

    
Copies the contents of the current tar archive entry directly into
an output stream.

Params:
  • out – The OutputStream into which to write the entry's data.
Throws:
/**
     * Copies the contents of the current tar archive entry directly into
     * an output stream.
     *
     * @param out The OutputStream into which to write the entry's data.
     * @throws IOException on error
     */
    public void copyEntryContents(OutputStream out) throws IOException {
        byte[] buf = new byte[LARGE_BUFFER_SIZE];

        while (true) {
            int numRead = read(buf, 0, buf.length);

            if (numRead == -1) {
                break;
            }

            out.write(buf, 0, numRead);
        }
    }

    
Whether this class is able to read the given entry.

May return false if the current entry is a sparse file.


Params:
  • te – TarEntry
Returns:boolean
/**
     * Whether this class is able to read the given entry.
     *
     * <p>May return false if the current entry is a sparse file.</p>
     *
     * @param te TarEntry
     * @return boolean
     */
    public boolean canReadEntryData(TarEntry te) {
        return !te.isGNUSparse();
    }

    private boolean isDirectory() {
        return currEntry != null && currEntry.isDirectory();
    }
}