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| <document> |
| <properties> |
| <title>Overview</title> |
| <author email="dev@commons.apache.org">Commons Documentation Team</author> |
| </properties> |
| <body> |
| <section name="Apache Commons Compress™"> |
| <p> |
| The Apache Commons Compress library defines an API for |
| working with ar, cpio, Unix dump, tar, zip, gzip, XZ, |
| Pack200, bzip2, 7z, arj, lzma, snappy, DEFLATE, lz4, |
| Brotli, Zstandard, DEFLATE64 and Z files. |
| </p> |
| <p> |
| The code in this component has many origins: |
| </p> |
| <ul> |
| <li>The bzip2, tar and zip support came from Avalon's |
| Excalibur, but originally from Ant, as far as life in |
| Apache goes. The tar package is originally Tim Endres' |
| public domain package. The bzip2 package is based on |
| the work done by Keiron Liddle as well as Julian Seward's |
| <a href="http://www.bzip.org/index.html">libbzip2</a>. |
| It has migrated |
| via:<br/> Ant -> Avalon-Excalibur -> Commons-IO |
| -> Commons-Compress.</li> |
| <li>The cpio package has been contributed by Michael Kuss |
| and |
| the <a href="http://jrpm.sourceforge.net/">jRPM</a> |
| project.</li> |
| </ul> |
| |
| </section> |
| |
| <section name="Status"> |
| <p>The current release is 1.20 and requires Java 7.</p> |
| |
| <p>Below we highlight some new features, for a full list |
| of changes see the <a href="changes-report.html">Changes |
| Report</a>.</p> |
| |
| <subsection name="What's new in 1.20?"> |
| <ul> |
| <li><code>SevenZFile</code> now supports random |
| access.</li> |
| <li>The zip package now supports split archives.</li> |
| <li>The tar package now supports reading sparse entries.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.19?"> |
| <ul> |
| <li><code>ParallelScatterZipCreator</code> now writes |
| entries in the same order they have been added to the |
| archive.</li> |
| <li><code>ZipArchiveInputStream</code> and |
| <code>ZipFile</code> are more forgiving when parsing |
| extra fields by default now.</li> |
| <li><code>TarArchiveInputStream</code> has a new lenient |
| mode that may allow it to read certain broken |
| archives.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.18?"> |
| <ul> |
| <li>The CPIO package now properly handles file names |
| using a mult-byte encoding.</li> |
| <li>ZipArchiveInputStream can now deal with APK files |
| containing an APK signing block.</li> |
| <li>It is no possible to specifiy various parameters |
| for Zstd output.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.17?"> |
| <ul> |
| <li>A new <code>InputStreamStatistics</code> interface |
| is implemented by many streams and may be used to |
| provide feedback or detect abnormally high compression |
| ratios that may indicate a ZIP bomb during |
| decompression.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.16.1?"> |
| <ul> |
| <li>Fixed the OSGi manifest that was broken in Compress 1.16.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.16?"> |
| <ul> |
| <li>Support for Zstandard compression.</li> |
| <li>Read-only support for DEFLATE64 compression as |
| stand-alone CompressorInputStream and as method used in |
| ZIP and 7z archives.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.15?"> |
| <ul> |
| <li>Added <code>Automatic-Module-Name</code> so the module |
| name will be org.apache.commons.compress when the jar is used |
| as an automatic module in Java9+.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.14?"> |
| <ul> |
| <li>Added support for writing the Snappy format</li> |
| <li>Added support for the LZ4 compression format</li> |
| <li>Added read-only support for Brotli decompression by |
| using the <a |
| href="https://github.com/google/brotli">Google Brotli |
| decoder</a>.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.13?"> |
| <ul> |
| <li>The 7z package as well as |
| <code>ZipArchiveOutputStream</code> and |
| <code>ZipFile</code> can now use |
| <code>SeekableByteChannel</code> when random acces is |
| needed. This allows archives to be read from inputs and |
| written to outputs that are seekable but are not |
| represented by <code>File</code>s.</li> |
| <li>It is now possible to add Compressor- and |
| ArchiverStream implementations using the JDK's |
| ServiceLoader mechanism. Please see |
| <a href="examples.html#Extending_Commons_Compress">Extending Commons Compress</a>.</li> |
| <li>Added support for writing the legacy LZMA format as |
| compressor stream and inside 7z archives - this requires |
| XZ for Java 1.6.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.12?"> |
| <ul> |
| <li>Added support for the Snappy dialect used in iWork archives.</li> |
| <li><code>SevenZFile</code> throws an |
| IllegalStateException for empty entries.</li> |
| <li>BZip2CompressorOutputStream no longer tries to |
| finish the output stream in finalize. This is a breaking |
| change for code that relied on the finalizer.</li> |
| <li>Various fixes and improvements for tar, cpio |
| and zip.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.11?"> |
| <ul> |
| <li>Added read-only support for BZIP2 compression used |
| inside of ZIP archives.</li> |
| <li>Speed improvements in <code>SevenZFile</code></li> |
| <li>Various fixes and improvements for tar, ar, snappy |
| and zip.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.10?"> |
| <ul> |
| <li>The old |
| <code>org.apache.commons.compress.compressors.z._internal_</code> |
| now is |
| <code>org.apache.commons.compress.compressors.lzw</code> |
| and the code is now an official part of Commons |
| Compress' API.</li> |
| <li>Added support for parallel ZIP compression.</li> |
| <li>Added support for raw transfer of entries from one ZIP file to another without uncompress/compress.</li> |
| <li>Performance improvements for creating ZIP files with lots of small entries.</li> |
| <li>Added auto-detection for LZMA.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.9?"> |
| <ul> |
| <li>support for raw DEFLATE streams</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.8.1?"> |
| <p>Compress 1.8.1 is a bug fix release with fixes for the |
| tar, ar and snappy formats as well as the |
| <code>IOUtils</code> class. In addition |
| <code>CompressorStreamFactory</code> can now autodetect |
| the .Z compress format.</p> |
| </subsection> |
| <subsection name="What's new in 1.8?"> |
| <ul> |
| <li>Bug fixes to the tar, zip and 7z packages</li> |
| <li>Access to metadata when reading gzip streams</li> |
| <li>Finer grained control over the methods used when |
| creating 7z archives and support for some the most |
| important filter methods used in 7z archives.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.7?"> |
| <ul> |
| <li>Read-only support for the Snappy compression.</li> |
| <li>Read-only support for the traditional Unix compress |
| format used for <code>.Z</code> files.</li> |
| </ul> |
| </subsection> |
| <subsection name="What's new in 1.6?"> |
| <ul> |
| <li>Support for the 7z format.</li> |
| <li>Read-only support for uncompressed ARJ |
| archives.</li> |
| <li>Read-only support for the "stand-alone" LZMA |
| format.</li> |
| </ul> |
| </subsection> |
| </section> |
| |
| <section name="Documentation"> |
| <p>The compress component is split into <em>compressors</em> and |
| <em>archivers</em>. While <em>compressors</em> |
| (un)compress streams that usually store a single |
| entry, <em>archivers</em> deal with archives that contain |
| structured content represented |
| by <code>ArchiveEntry</code> instances which in turn |
| usually correspond to single files or directories.</p> |
| |
| <p>Currently the bzip2, Pack200, XZ, gzip, lzma, brotli, |
| Zstandard and Z formats are |
| supported as compressors where gzip support is mostly provided by |
| the <code>java.util.zip</code> package and Pack200 support |
| by the <code>java.util.jar</code> package of the Java |
| class library. XZ and lzma support is provided by the public |
| domain <a href="https://tukaani.org/xz/java.html">XZ for |
| Java</a> library. Brotli support is provided by the MIT |
| licensed <a href="https://github.com/google/brotli">Google |
| Brotli decoder</a>. Zstandard support is provided by the BSD |
| licensed <a href="https://github.com/luben/zstd-jni">Zstd-jni</a>. |
| As of Commons Compress 1.20 support for the DEFLATE64, Z and Brotli |
| formats is read-only.</p> |
| |
| <p>The ar, arj, cpio, dump, tar, 7z and zip formats are supported as |
| archivers where the <a href="zip.html">zip</a> |
| implementation provides capabilities that go beyond the |
| features found in java.util.zip. As of Commons Compress |
| 1.20 support for the dump and arj formats is |
| read-only - 7z can read most compressed and encrypted |
| archives but only write unencrypted ones. LZMA(2) support |
| in 7z requires <a href="https://tukaani.org/xz/java.html">XZ for |
| Java</a> as well.</p> |
| |
| <p>The compress component provides abstract base classes for |
| compressors and archivers together with factories that can |
| be used to choose implementations by algorithm name. In |
| the case of input streams the factories can also be used |
| to guess the format and provide the matching |
| implementation.</p> |
| |
| <ul> |
| <li>The <a href="examples.html">user guide</a> contains |
| more detailed information and some examples.</li> |
| <li>The <a href="limitations.html">known limitations and |
| problems</a> page lists the currently known problems |
| grouped by the format they apply to.</li> |
| <li>The <a href="apidocs/index.html">Javadoc</a> of the latest GIT</li> |
| <li>The <a href="https://gitbox.apache.org/repos/asf?p=commons-compress.git;a=tree">GIT |
| repository</a> can be browsed.</li> |
| </ul> |
| </section> |
| <section name="Releases"> |
| <p> |
| <a href="https://commons.apache.org/compress/download_compress.cgi">Download now!</a> |
| </p> |
| </section> |
| </body> |
| </document> |
