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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">lzma</span></code> — Compression using the LZMA algorithm</a><ul>
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<li><a class="reference internal" href="#reading-and-writing-compressed-files">Reading and writing compressed files</a></li>
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<section id="module-lzma">
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<span id="lzma-compression-using-the-lzma-algorithm"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">lzma</span></code> — Compression using the LZMA algorithm<a class="headerlink" href="#module-lzma" title="Link to this heading">¶</a></h1>
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<div class="versionadded">
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<p><span class="versionmodified added">Added in version 3.3.</span></p>
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<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Lib/lzma.py">Lib/lzma.py</a></p>
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<hr class="docutils" />
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<p>This module provides classes and convenience functions for compressing and
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decompressing data using the LZMA compression algorithm. Also included is a file
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||
interface supporting the <code class="docutils literal notranslate"><span class="pre">.xz</span></code> and legacy <code class="docutils literal notranslate"><span class="pre">.lzma</span></code> file formats used by the
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<strong class="program">xz</strong> utility, as well as raw compressed streams.</p>
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<p>The interface provided by this module is very similar to that of the <a class="reference internal" href="bz2.html#module-bz2" title="bz2: Interfaces for bzip2 compression and decompression."><code class="xref py py-mod docutils literal notranslate"><span class="pre">bz2</span></code></a>
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module. Note that <a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a> and <a class="reference internal" href="bz2.html#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">bz2.BZ2File</span></code></a> are <em>not</em>
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||
thread-safe, so if you need to use a single <a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a> instance
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||
from multiple threads, it is necessary to protect it with a lock.</p>
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<dl class="py exception">
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<dt class="sig sig-object py" id="lzma.LZMAError">
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||
<em class="property"><span class="k"><span class="pre">exception</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">lzma.</span></span><span class="sig-name descname"><span class="pre">LZMAError</span></span><a class="headerlink" href="#lzma.LZMAError" title="Link to this definition">¶</a></dt>
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<dd><p>This exception is raised when an error occurs during compression or
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||
decompression, or while initializing the compressor/decompressor state.</p>
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</dd></dl>
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<section id="reading-and-writing-compressed-files">
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<h2>Reading and writing compressed files<a class="headerlink" href="#reading-and-writing-compressed-files" title="Link to this heading">¶</a></h2>
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<dl class="py function">
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<dt class="sig sig-object py" id="lzma.open">
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<span class="sig-prename descclassname"><span class="pre">lzma.</span></span><span class="sig-name descname"><span class="pre">open</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'rb'</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">format</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">check</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">-1</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">preset</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">filters</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">encoding</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">errors</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">newline</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.open" title="Link to this definition">¶</a></dt>
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<dd><p>Open an LZMA-compressed file in binary or text mode, returning a <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file
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object</span></a>.</p>
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<p>The <em>filename</em> argument can be either an actual file name (given as a
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<a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-class docutils literal notranslate"><span class="pre">str</span></code></a>, <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> or <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like</span></a> object), in
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which case the named file is opened, or it can be an existing file object
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to read from or write to.</p>
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<p>The <em>mode</em> argument can be any of <code class="docutils literal notranslate"><span class="pre">"r"</span></code>, <code class="docutils literal notranslate"><span class="pre">"rb"</span></code>, <code class="docutils literal notranslate"><span class="pre">"w"</span></code>, <code class="docutils literal notranslate"><span class="pre">"wb"</span></code>,
|
||
<code class="docutils literal notranslate"><span class="pre">"x"</span></code>, <code class="docutils literal notranslate"><span class="pre">"xb"</span></code>, <code class="docutils literal notranslate"><span class="pre">"a"</span></code> or <code class="docutils literal notranslate"><span class="pre">"ab"</span></code> for binary mode, or <code class="docutils literal notranslate"><span class="pre">"rt"</span></code>,
|
||
<code class="docutils literal notranslate"><span class="pre">"wt"</span></code>, <code class="docutils literal notranslate"><span class="pre">"xt"</span></code>, or <code class="docutils literal notranslate"><span class="pre">"at"</span></code> for text mode. The default is <code class="docutils literal notranslate"><span class="pre">"rb"</span></code>.</p>
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<p>When opening a file for reading, the <em>format</em> and <em>filters</em> arguments have
|
||
the same meanings as for <a class="reference internal" href="#lzma.LZMADecompressor" title="lzma.LZMADecompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMADecompressor</span></code></a>. In this case, the <em>check</em>
|
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and <em>preset</em> arguments should not be used.</p>
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<p>When opening a file for writing, the <em>format</em>, <em>check</em>, <em>preset</em> and
|
||
<em>filters</em> arguments have the same meanings as for <a class="reference internal" href="#lzma.LZMACompressor" title="lzma.LZMACompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMACompressor</span></code></a>.</p>
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||
<p>For binary mode, this function is equivalent to the <a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a>
|
||
constructor: <code class="docutils literal notranslate"><span class="pre">LZMAFile(filename,</span> <span class="pre">mode,</span> <span class="pre">...)</span></code>. In this case, the <em>encoding</em>,
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||
<em>errors</em> and <em>newline</em> arguments must not be provided.</p>
|
||
<p>For text mode, a <a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a> object is created, and wrapped in an
|
||
<a class="reference internal" href="io.html#io.TextIOWrapper" title="io.TextIOWrapper"><code class="xref py py-class docutils literal notranslate"><span class="pre">io.TextIOWrapper</span></code></a> instance with the specified encoding, error
|
||
handling behavior, and line ending(s).</p>
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||
<div class="versionchanged">
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||
<p><span class="versionmodified changed">Changed in version 3.4: </span>Added support for the <code class="docutils literal notranslate"><span class="pre">"x"</span></code>, <code class="docutils literal notranslate"><span class="pre">"xb"</span></code> and <code class="docutils literal notranslate"><span class="pre">"xt"</span></code> modes.</p>
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</div>
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<div class="versionchanged">
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||
<p><span class="versionmodified changed">Changed in version 3.6: </span>Accepts a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p>
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</div>
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</dd></dl>
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<dl class="py class">
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<dt class="sig sig-object py" id="lzma.LZMAFile">
|
||
<em class="property"><span class="k"><span class="pre">class</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">lzma.</span></span><span class="sig-name descname"><span class="pre">LZMAFile</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'r'</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">format</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">check</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">-1</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">preset</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">filters</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.LZMAFile" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Open an LZMA-compressed file in binary mode.</p>
|
||
<p>An <a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a> can wrap an already-open <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file object</span></a>, or operate
|
||
directly on a named file. The <em>filename</em> argument specifies either the file
|
||
object to wrap, or the name of the file to open (as a <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-class docutils literal notranslate"><span class="pre">str</span></code></a>,
|
||
<a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> or <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like</span></a> object). When wrapping an
|
||
existing file object, the wrapped file will not be closed when the
|
||
<a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a> is closed.</p>
|
||
<p>The <em>mode</em> argument can be either <code class="docutils literal notranslate"><span class="pre">"r"</span></code> for reading (default), <code class="docutils literal notranslate"><span class="pre">"w"</span></code> for
|
||
overwriting, <code class="docutils literal notranslate"><span class="pre">"x"</span></code> for exclusive creation, or <code class="docutils literal notranslate"><span class="pre">"a"</span></code> for appending. These
|
||
can equivalently be given as <code class="docutils literal notranslate"><span class="pre">"rb"</span></code>, <code class="docutils literal notranslate"><span class="pre">"wb"</span></code>, <code class="docutils literal notranslate"><span class="pre">"xb"</span></code> and <code class="docutils literal notranslate"><span class="pre">"ab"</span></code>
|
||
respectively.</p>
|
||
<p>If <em>filename</em> is a file object (rather than an actual file name), a mode of
|
||
<code class="docutils literal notranslate"><span class="pre">"w"</span></code> does not truncate the file, and is instead equivalent to <code class="docutils literal notranslate"><span class="pre">"a"</span></code>.</p>
|
||
<p>When opening a file for reading, the input file may be the concatenation of
|
||
multiple separate compressed streams. These are transparently decoded as a
|
||
single logical stream.</p>
|
||
<p>When opening a file for reading, the <em>format</em> and <em>filters</em> arguments have
|
||
the same meanings as for <a class="reference internal" href="#lzma.LZMADecompressor" title="lzma.LZMADecompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMADecompressor</span></code></a>. In this case, the <em>check</em>
|
||
and <em>preset</em> arguments should not be used.</p>
|
||
<p>When opening a file for writing, the <em>format</em>, <em>check</em>, <em>preset</em> and
|
||
<em>filters</em> arguments have the same meanings as for <a class="reference internal" href="#lzma.LZMACompressor" title="lzma.LZMACompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMACompressor</span></code></a>.</p>
|
||
<p><a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a> supports all the members specified by
|
||
<a class="reference internal" href="io.html#io.BufferedIOBase" title="io.BufferedIOBase"><code class="xref py py-class docutils literal notranslate"><span class="pre">io.BufferedIOBase</span></code></a>, except for <a class="reference internal" href="io.html#io.BufferedIOBase.detach" title="io.BufferedIOBase.detach"><code class="xref py py-meth docutils literal notranslate"><span class="pre">detach()</span></code></a>
|
||
and <a class="reference internal" href="io.html#io.IOBase.truncate" title="io.IOBase.truncate"><code class="xref py py-meth docutils literal notranslate"><span class="pre">truncate()</span></code></a>.
|
||
Iteration and the <a class="reference internal" href="../reference/compound_stmts.html#with"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">with</span></code></a> statement are supported.</p>
|
||
<p>The following method and attributes are also provided:</p>
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="lzma.LZMAFile.peek">
|
||
<span class="sig-name descname"><span class="pre">peek</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">size</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">-1</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.LZMAFile.peek" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Return buffered data without advancing the file position. At least one
|
||
byte of data will be returned, unless EOF has been reached. The exact
|
||
number of bytes returned is unspecified (the <em>size</em> argument is ignored).</p>
|
||
<div class="admonition note">
|
||
<p class="admonition-title">Note</p>
|
||
<p>While calling <a class="reference internal" href="#lzma.LZMAFile.peek" title="lzma.LZMAFile.peek"><code class="xref py py-meth docutils literal notranslate"><span class="pre">peek()</span></code></a> does not change the file position of
|
||
the <a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a>, it may change the position of the underlying
|
||
file object (e.g. if the <a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a> was constructed by passing a
|
||
file object for <em>filename</em>).</p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<dl class="py attribute">
|
||
<dt class="sig sig-object py" id="lzma.LZMAFile.mode">
|
||
<span class="sig-name descname"><span class="pre">mode</span></span><a class="headerlink" href="#lzma.LZMAFile.mode" title="Link to this definition">¶</a></dt>
|
||
<dd><p><code class="docutils literal notranslate"><span class="pre">'rb'</span></code> for reading and <code class="docutils literal notranslate"><span class="pre">'wb'</span></code> for writing.</p>
|
||
<div class="versionadded">
|
||
<p><span class="versionmodified added">Added in version 3.13.</span></p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<dl class="py attribute">
|
||
<dt class="sig sig-object py" id="lzma.LZMAFile.name">
|
||
<span class="sig-name descname"><span class="pre">name</span></span><a class="headerlink" href="#lzma.LZMAFile.name" title="Link to this definition">¶</a></dt>
|
||
<dd><p>The lzma file name. Equivalent to the <a class="reference internal" href="io.html#io.FileIO.name" title="io.FileIO.name"><code class="xref py py-attr docutils literal notranslate"><span class="pre">name</span></code></a>
|
||
attribute of the underlying <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file object</span></a>.</p>
|
||
<div class="versionadded">
|
||
<p><span class="versionmodified added">Added in version 3.13.</span></p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.4: </span>Added support for the <code class="docutils literal notranslate"><span class="pre">"x"</span></code> and <code class="docutils literal notranslate"><span class="pre">"xb"</span></code> modes.</p>
|
||
</div>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.5: </span>The <a class="reference internal" href="io.html#io.BufferedIOBase.read" title="io.BufferedIOBase.read"><code class="xref py py-meth docutils literal notranslate"><span class="pre">read()</span></code></a> method now accepts an argument of
|
||
<code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>
|
||
</div>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.6: </span>Accepts a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
</section>
|
||
<section id="compressing-and-decompressing-data-in-memory">
|
||
<h2>Compressing and decompressing data in memory<a class="headerlink" href="#compressing-and-decompressing-data-in-memory" title="Link to this heading">¶</a></h2>
|
||
<dl class="py class">
|
||
<dt class="sig sig-object py" id="lzma.LZMACompressor">
|
||
<em class="property"><span class="k"><span class="pre">class</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">lzma.</span></span><span class="sig-name descname"><span class="pre">LZMACompressor</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">format</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">FORMAT_XZ</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">check</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">-1</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">preset</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">filters</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.LZMACompressor" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Create a compressor object, which can be used to compress data incrementally.</p>
|
||
<p>For a more convenient way of compressing a single chunk of data, see
|
||
<a class="reference internal" href="#lzma.compress" title="lzma.compress"><code class="xref py py-func docutils literal notranslate"><span class="pre">compress()</span></code></a>.</p>
|
||
<p>The <em>format</em> argument specifies what container format should be used.
|
||
Possible values are:</p>
|
||
<ul class="simple">
|
||
<li><dl class="simple">
|
||
<dt><code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_XZ</span></code>: The <code class="docutils literal notranslate"><span class="pre">.xz</span></code> container format.</dt><dd><p>This is the default format.</p>
|
||
</dd>
|
||
</dl>
|
||
</li>
|
||
<li><dl class="simple">
|
||
<dt><code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_ALONE</span></code>: The legacy <code class="docutils literal notranslate"><span class="pre">.lzma</span></code> container format.</dt><dd><p>This format is more limited than <code class="docutils literal notranslate"><span class="pre">.xz</span></code> – it does not support integrity
|
||
checks or multiple filters.</p>
|
||
</dd>
|
||
</dl>
|
||
</li>
|
||
<li><dl class="simple">
|
||
<dt><code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_RAW</span></code>: A raw data stream, not using any container format.</dt><dd><p>This format specifier does not support integrity checks, and requires that
|
||
you always specify a custom filter chain (for both compression and
|
||
decompression). Additionally, data compressed in this manner cannot be
|
||
decompressed using <code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_AUTO</span></code> (see <a class="reference internal" href="#lzma.LZMADecompressor" title="lzma.LZMADecompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMADecompressor</span></code></a>).</p>
|
||
</dd>
|
||
</dl>
|
||
</li>
|
||
</ul>
|
||
<p>The <em>check</em> argument specifies the type of integrity check to include in the
|
||
compressed data. This check is used when decompressing, to ensure that the
|
||
data has not been corrupted. Possible values are:</p>
|
||
<ul class="simple">
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">CHECK_NONE</span></code>: No integrity check.
|
||
This is the default (and the only acceptable value) for
|
||
<code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_ALONE</span></code> and <code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_RAW</span></code>.</p></li>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">CHECK_CRC32</span></code>: 32-bit Cyclic Redundancy Check.</p></li>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">CHECK_CRC64</span></code>: 64-bit Cyclic Redundancy Check.
|
||
This is the default for <code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_XZ</span></code>.</p></li>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">CHECK_SHA256</span></code>: 256-bit Secure Hash Algorithm.</p></li>
|
||
</ul>
|
||
<p>If the specified check is not supported, an <a class="reference internal" href="#lzma.LZMAError" title="lzma.LZMAError"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAError</span></code></a> is raised.</p>
|
||
<p>The compression settings can be specified either as a preset compression
|
||
level (with the <em>preset</em> argument), or in detail as a custom filter chain
|
||
(with the <em>filters</em> argument).</p>
|
||
<p>The <em>preset</em> argument (if provided) should be an integer between <code class="docutils literal notranslate"><span class="pre">0</span></code> and
|
||
<code class="docutils literal notranslate"><span class="pre">9</span></code> (inclusive), optionally OR-ed with the constant
|
||
<code class="xref py py-const docutils literal notranslate"><span class="pre">PRESET_EXTREME</span></code>. If neither <em>preset</em> nor <em>filters</em> are given, the
|
||
default behavior is to use <code class="xref py py-const docutils literal notranslate"><span class="pre">PRESET_DEFAULT</span></code> (preset level <code class="docutils literal notranslate"><span class="pre">6</span></code>).
|
||
Higher presets produce smaller output, but make the compression process
|
||
slower.</p>
|
||
<div class="admonition note">
|
||
<p class="admonition-title">Note</p>
|
||
<p>In addition to being more CPU-intensive, compression with higher presets
|
||
also requires much more memory (and produces output that needs more memory
|
||
to decompress). With preset <code class="docutils literal notranslate"><span class="pre">9</span></code> for example, the overhead for an
|
||
<a class="reference internal" href="#lzma.LZMACompressor" title="lzma.LZMACompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMACompressor</span></code></a> object can be as high as 800 MiB. For this reason,
|
||
it is generally best to stick with the default preset.</p>
|
||
</div>
|
||
<p>The <em>filters</em> argument (if provided) should be a filter chain specifier.
|
||
See <a class="reference internal" href="#filter-chain-specs"><span class="std std-ref">Specifying custom filter chains</span></a> for details.</p>
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="lzma.LZMACompressor.compress">
|
||
<span class="sig-name descname"><span class="pre">compress</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.LZMACompressor.compress" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Compress <em>data</em> (a <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object), returning a <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>
|
||
object containing compressed data for at least part of the input. Some of
|
||
<em>data</em> may be buffered internally, for use in later calls to
|
||
<a class="reference internal" href="#lzma.compress" title="lzma.compress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">compress()</span></code></a> and <a class="reference internal" href="#lzma.LZMACompressor.flush" title="lzma.LZMACompressor.flush"><code class="xref py py-meth docutils literal notranslate"><span class="pre">flush()</span></code></a>. The returned data should be
|
||
concatenated with the output of any previous calls to <a class="reference internal" href="#lzma.compress" title="lzma.compress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">compress()</span></code></a>.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="lzma.LZMACompressor.flush">
|
||
<span class="sig-name descname"><span class="pre">flush</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#lzma.LZMACompressor.flush" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Finish the compression process, returning a <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object
|
||
containing any data stored in the compressor’s internal buffers.</p>
|
||
<p>The compressor cannot be used after this method has been called.</p>
|
||
</dd></dl>
|
||
|
||
</dd></dl>
|
||
|
||
<dl class="py class">
|
||
<dt class="sig sig-object py" id="lzma.LZMADecompressor">
|
||
<em class="property"><span class="k"><span class="pre">class</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">lzma.</span></span><span class="sig-name descname"><span class="pre">LZMADecompressor</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">format</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">FORMAT_AUTO</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">memlimit</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">filters</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.LZMADecompressor" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Create a decompressor object, which can be used to decompress data
|
||
incrementally.</p>
|
||
<p>For a more convenient way of decompressing an entire compressed stream at
|
||
once, see <a class="reference internal" href="#lzma.decompress" title="lzma.decompress"><code class="xref py py-func docutils literal notranslate"><span class="pre">decompress()</span></code></a>.</p>
|
||
<p>The <em>format</em> argument specifies the container format that should be used. The
|
||
default is <code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_AUTO</span></code>, which can decompress both <code class="docutils literal notranslate"><span class="pre">.xz</span></code> and
|
||
<code class="docutils literal notranslate"><span class="pre">.lzma</span></code> files. Other possible values are <code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_XZ</span></code>,
|
||
<code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_ALONE</span></code>, and <code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_RAW</span></code>.</p>
|
||
<p>The <em>memlimit</em> argument specifies a limit (in bytes) on the amount of memory
|
||
that the decompressor can use. When this argument is used, decompression will
|
||
fail with an <a class="reference internal" href="#lzma.LZMAError" title="lzma.LZMAError"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAError</span></code></a> if it is not possible to decompress the input
|
||
within the given memory limit.</p>
|
||
<p>The <em>filters</em> argument specifies the filter chain that was used to create
|
||
the stream being decompressed. This argument is required if <em>format</em> is
|
||
<code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_RAW</span></code>, but should not be used for other formats.
|
||
See <a class="reference internal" href="#filter-chain-specs"><span class="std std-ref">Specifying custom filter chains</span></a> for more information about filter chains.</p>
|
||
<div class="admonition note">
|
||
<p class="admonition-title">Note</p>
|
||
<p>This class does not transparently handle inputs containing multiple
|
||
compressed streams, unlike <a class="reference internal" href="#lzma.decompress" title="lzma.decompress"><code class="xref py py-func docutils literal notranslate"><span class="pre">decompress()</span></code></a> and <a class="reference internal" href="#lzma.LZMAFile" title="lzma.LZMAFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMAFile</span></code></a>. To
|
||
decompress a multi-stream input with <a class="reference internal" href="#lzma.LZMADecompressor" title="lzma.LZMADecompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMADecompressor</span></code></a>, you must
|
||
create a new decompressor for each stream.</p>
|
||
</div>
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="lzma.LZMADecompressor.decompress">
|
||
<span class="sig-name descname"><span class="pre">decompress</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">max_length</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">-1</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.LZMADecompressor.decompress" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Decompress <em>data</em> (a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a>), returning
|
||
uncompressed data as bytes. Some of <em>data</em> may be buffered
|
||
internally, for use in later calls to <a class="reference internal" href="#lzma.decompress" title="lzma.decompress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">decompress()</span></code></a>. The
|
||
returned data should be concatenated with the output of any
|
||
previous calls to <a class="reference internal" href="#lzma.decompress" title="lzma.decompress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">decompress()</span></code></a>.</p>
|
||
<p>If <em>max_length</em> is nonnegative, returns at most <em>max_length</em>
|
||
bytes of decompressed data. If this limit is reached and further
|
||
output can be produced, the <a class="reference internal" href="#lzma.LZMADecompressor.needs_input" title="lzma.LZMADecompressor.needs_input"><code class="xref py py-attr docutils literal notranslate"><span class="pre">needs_input</span></code></a> attribute will
|
||
be set to <code class="docutils literal notranslate"><span class="pre">False</span></code>. In this case, the next call to
|
||
<a class="reference internal" href="#lzma.LZMADecompressor.decompress" title="lzma.LZMADecompressor.decompress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">decompress()</span></code></a> may provide <em>data</em> as <code class="docutils literal notranslate"><span class="pre">b''</span></code> to obtain
|
||
more of the output.</p>
|
||
<p>If all of the input data was decompressed and returned (either
|
||
because this was less than <em>max_length</em> bytes, or because
|
||
<em>max_length</em> was negative), the <a class="reference internal" href="#lzma.LZMADecompressor.needs_input" title="lzma.LZMADecompressor.needs_input"><code class="xref py py-attr docutils literal notranslate"><span class="pre">needs_input</span></code></a> attribute
|
||
will be set to <code class="docutils literal notranslate"><span class="pre">True</span></code>.</p>
|
||
<p>Attempting to decompress data after the end of stream is reached
|
||
raises an <a class="reference internal" href="exceptions.html#EOFError" title="EOFError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">EOFError</span></code></a>. Any data found after the end of the
|
||
stream is ignored and saved in the <a class="reference internal" href="#lzma.LZMADecompressor.unused_data" title="lzma.LZMADecompressor.unused_data"><code class="xref py py-attr docutils literal notranslate"><span class="pre">unused_data</span></code></a> attribute.</p>
|
||
<div class="versionchanged">
|
||
<p><span class="versionmodified changed">Changed in version 3.5: </span>Added the <em>max_length</em> parameter.</p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<dl class="py attribute">
|
||
<dt class="sig sig-object py" id="lzma.LZMADecompressor.check">
|
||
<span class="sig-name descname"><span class="pre">check</span></span><a class="headerlink" href="#lzma.LZMADecompressor.check" title="Link to this definition">¶</a></dt>
|
||
<dd><p>The ID of the integrity check used by the input stream. This may be
|
||
<code class="xref py py-const docutils literal notranslate"><span class="pre">CHECK_UNKNOWN</span></code> until enough of the input has been decoded to
|
||
determine what integrity check it uses.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py attribute">
|
||
<dt class="sig sig-object py" id="lzma.LZMADecompressor.eof">
|
||
<span class="sig-name descname"><span class="pre">eof</span></span><a class="headerlink" href="#lzma.LZMADecompressor.eof" title="Link to this definition">¶</a></dt>
|
||
<dd><p><code class="docutils literal notranslate"><span class="pre">True</span></code> if the end-of-stream marker has been reached.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py attribute">
|
||
<dt class="sig sig-object py" id="lzma.LZMADecompressor.unused_data">
|
||
<span class="sig-name descname"><span class="pre">unused_data</span></span><a class="headerlink" href="#lzma.LZMADecompressor.unused_data" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Data found after the end of the compressed stream.</p>
|
||
<p>Before the end of the stream is reached, this will be <code class="docutils literal notranslate"><span class="pre">b""</span></code>.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py attribute">
|
||
<dt class="sig sig-object py" id="lzma.LZMADecompressor.needs_input">
|
||
<span class="sig-name descname"><span class="pre">needs_input</span></span><a class="headerlink" href="#lzma.LZMADecompressor.needs_input" title="Link to this definition">¶</a></dt>
|
||
<dd><p><code class="docutils literal notranslate"><span class="pre">False</span></code> if the <a class="reference internal" href="#lzma.LZMADecompressor.decompress" title="lzma.LZMADecompressor.decompress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">decompress()</span></code></a> method can provide more
|
||
decompressed data before requiring new uncompressed input.</p>
|
||
<div class="versionadded">
|
||
<p><span class="versionmodified added">Added in version 3.5.</span></p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
</dd></dl>
|
||
|
||
<dl class="py function">
|
||
<dt class="sig sig-object py" id="lzma.compress">
|
||
<span class="sig-prename descclassname"><span class="pre">lzma.</span></span><span class="sig-name descname"><span class="pre">compress</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">format</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">FORMAT_XZ</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">check</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">-1</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">preset</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">filters</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.compress" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Compress <em>data</em> (a <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object), returning the compressed data as a
|
||
<a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object.</p>
|
||
<p>See <a class="reference internal" href="#lzma.LZMACompressor" title="lzma.LZMACompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMACompressor</span></code></a> above for a description of the <em>format</em>, <em>check</em>,
|
||
<em>preset</em> and <em>filters</em> arguments.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py function">
|
||
<dt class="sig sig-object py" id="lzma.decompress">
|
||
<span class="sig-prename descclassname"><span class="pre">lzma.</span></span><span class="sig-name descname"><span class="pre">decompress</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">format</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">FORMAT_AUTO</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">memlimit</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">filters</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.decompress" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Decompress <em>data</em> (a <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object), returning the uncompressed data
|
||
as a <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object.</p>
|
||
<p>If <em>data</em> is the concatenation of multiple distinct compressed streams,
|
||
decompress all of these streams, and return the concatenation of the results.</p>
|
||
<p>See <a class="reference internal" href="#lzma.LZMADecompressor" title="lzma.LZMADecompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">LZMADecompressor</span></code></a> above for a description of the <em>format</em>,
|
||
<em>memlimit</em> and <em>filters</em> arguments.</p>
|
||
</dd></dl>
|
||
|
||
</section>
|
||
<section id="miscellaneous">
|
||
<h2>Miscellaneous<a class="headerlink" href="#miscellaneous" title="Link to this heading">¶</a></h2>
|
||
<dl class="py function">
|
||
<dt class="sig sig-object py" id="lzma.is_check_supported">
|
||
<span class="sig-prename descclassname"><span class="pre">lzma.</span></span><span class="sig-name descname"><span class="pre">is_check_supported</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">check</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#lzma.is_check_supported" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if the given integrity check is supported on this system.</p>
|
||
<p><code class="xref py py-const docutils literal notranslate"><span class="pre">CHECK_NONE</span></code> and <code class="xref py py-const docutils literal notranslate"><span class="pre">CHECK_CRC32</span></code> are always supported.
|
||
<code class="xref py py-const docutils literal notranslate"><span class="pre">CHECK_CRC64</span></code> and <code class="xref py py-const docutils literal notranslate"><span class="pre">CHECK_SHA256</span></code> may be unavailable if you are
|
||
using a version of <strong class="program">liblzma</strong> that was compiled with a limited
|
||
feature set.</p>
|
||
</dd></dl>
|
||
|
||
</section>
|
||
<section id="specifying-custom-filter-chains">
|
||
<span id="filter-chain-specs"></span><h2>Specifying custom filter chains<a class="headerlink" href="#specifying-custom-filter-chains" title="Link to this heading">¶</a></h2>
|
||
<p>A filter chain specifier is a sequence of dictionaries, where each dictionary
|
||
contains the ID and options for a single filter. Each dictionary must contain
|
||
the key <code class="docutils literal notranslate"><span class="pre">"id"</span></code>, and may contain additional keys to specify filter-dependent
|
||
options. Valid filter IDs are as follows:</p>
|
||
<ul class="simple">
|
||
<li><p>Compression filters:</p>
|
||
<ul>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">FILTER_LZMA1</span></code> (for use with <code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_ALONE</span></code>)</p></li>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">FILTER_LZMA2</span></code> (for use with <code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_XZ</span></code> and <code class="xref py py-const docutils literal notranslate"><span class="pre">FORMAT_RAW</span></code>)</p></li>
|
||
</ul>
|
||
</li>
|
||
<li><p>Delta filter:</p>
|
||
<ul>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">FILTER_DELTA</span></code></p></li>
|
||
</ul>
|
||
</li>
|
||
<li><p>Branch-Call-Jump (BCJ) filters:</p>
|
||
<ul>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">FILTER_X86</span></code></p></li>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">FILTER_IA64</span></code></p></li>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">FILTER_ARM</span></code></p></li>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">FILTER_ARMTHUMB</span></code></p></li>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">FILTER_POWERPC</span></code></p></li>
|
||
<li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">FILTER_SPARC</span></code></p></li>
|
||
</ul>
|
||
</li>
|
||
</ul>
|
||
<p>A filter chain can consist of up to 4 filters, and cannot be empty. The last
|
||
filter in the chain must be a compression filter, and any other filters must be
|
||
delta or BCJ filters.</p>
|
||
<p>Compression filters support the following options (specified as additional
|
||
entries in the dictionary representing the filter):</p>
|
||
<ul class="simple">
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">preset</span></code>: A compression preset to use as a source of default values for
|
||
options that are not specified explicitly.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">dict_size</span></code>: Dictionary size in bytes. This should be between 4 KiB and
|
||
1.5 GiB (inclusive).</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">lc</span></code>: Number of literal context bits.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">lp</span></code>: Number of literal position bits. The sum <code class="docutils literal notranslate"><span class="pre">lc</span> <span class="pre">+</span> <span class="pre">lp</span></code> must be at
|
||
most 4.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">pb</span></code>: Number of position bits; must be at most 4.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">mode</span></code>: <code class="xref py py-const docutils literal notranslate"><span class="pre">MODE_FAST</span></code> or <code class="xref py py-const docutils literal notranslate"><span class="pre">MODE_NORMAL</span></code>.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">nice_len</span></code>: What should be considered a “nice length” for a match.
|
||
This should be 273 or less.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">mf</span></code>: What match finder to use – <code class="xref py py-const docutils literal notranslate"><span class="pre">MF_HC3</span></code>, <code class="xref py py-const docutils literal notranslate"><span class="pre">MF_HC4</span></code>,
|
||
<code class="xref py py-const docutils literal notranslate"><span class="pre">MF_BT2</span></code>, <code class="xref py py-const docutils literal notranslate"><span class="pre">MF_BT3</span></code>, or <code class="xref py py-const docutils literal notranslate"><span class="pre">MF_BT4</span></code>.</p></li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">depth</span></code>: Maximum search depth used by match finder. 0 (default) means to
|
||
select automatically based on other filter options.</p></li>
|
||
</ul>
|
||
<p>The delta filter stores the differences between bytes, producing more repetitive
|
||
input for the compressor in certain circumstances. It supports one option,
|
||
<code class="docutils literal notranslate"><span class="pre">dist</span></code>. This indicates the distance between bytes to be subtracted. The
|
||
default is 1, i.e. take the differences between adjacent bytes.</p>
|
||
<p>The BCJ filters are intended to be applied to machine code. They convert
|
||
relative branches, calls and jumps in the code to use absolute addressing, with
|
||
the aim of increasing the redundancy that can be exploited by the compressor.
|
||
These filters support one option, <code class="docutils literal notranslate"><span class="pre">start_offset</span></code>. This specifies the address
|
||
that should be mapped to the beginning of the input data. The default is 0.</p>
|
||
</section>
|
||
<section id="examples">
|
||
<h2>Examples<a class="headerlink" href="#examples" title="Link to this heading">¶</a></h2>
|
||
<p>Reading in a compressed file:</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">lzma</span>
|
||
<span class="k">with</span> <span class="n">lzma</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s2">"file.xz"</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
|
||
<span class="n">file_content</span> <span class="o">=</span> <span class="n">f</span><span class="o">.</span><span class="n">read</span><span class="p">()</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>Creating a compressed file:</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">lzma</span>
|
||
<span class="n">data</span> <span class="o">=</span> <span class="sa">b</span><span class="s2">"Insert Data Here"</span>
|
||
<span class="k">with</span> <span class="n">lzma</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s2">"file.xz"</span><span class="p">,</span> <span class="s2">"w"</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
|
||
<span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>Compressing data in memory:</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">lzma</span>
|
||
<span class="n">data_in</span> <span class="o">=</span> <span class="sa">b</span><span class="s2">"Insert Data Here"</span>
|
||
<span class="n">data_out</span> <span class="o">=</span> <span class="n">lzma</span><span class="o">.</span><span class="n">compress</span><span class="p">(</span><span class="n">data_in</span><span class="p">)</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>Incremental compression:</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">lzma</span>
|
||
<span class="n">lzc</span> <span class="o">=</span> <span class="n">lzma</span><span class="o">.</span><span class="n">LZMACompressor</span><span class="p">()</span>
|
||
<span class="n">out1</span> <span class="o">=</span> <span class="n">lzc</span><span class="o">.</span><span class="n">compress</span><span class="p">(</span><span class="sa">b</span><span class="s2">"Some data</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
|
||
<span class="n">out2</span> <span class="o">=</span> <span class="n">lzc</span><span class="o">.</span><span class="n">compress</span><span class="p">(</span><span class="sa">b</span><span class="s2">"Another piece of data</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
|
||
<span class="n">out3</span> <span class="o">=</span> <span class="n">lzc</span><span class="o">.</span><span class="n">compress</span><span class="p">(</span><span class="sa">b</span><span class="s2">"Even more data</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
|
||
<span class="n">out4</span> <span class="o">=</span> <span class="n">lzc</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
|
||
<span class="c1"># Concatenate all the partial results:</span>
|
||
<span class="n">result</span> <span class="o">=</span> <span class="sa">b</span><span class="s2">""</span><span class="o">.</span><span class="n">join</span><span class="p">([</span><span class="n">out1</span><span class="p">,</span> <span class="n">out2</span><span class="p">,</span> <span class="n">out3</span><span class="p">,</span> <span class="n">out4</span><span class="p">])</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>Writing compressed data to an already-open file:</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">lzma</span>
|
||
<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="s2">"file.xz"</span><span class="p">,</span> <span class="s2">"wb"</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
|
||
<span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">b</span><span class="s2">"This data will not be compressed</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
|
||
<span class="k">with</span> <span class="n">lzma</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="n">f</span><span class="p">,</span> <span class="s2">"w"</span><span class="p">)</span> <span class="k">as</span> <span class="n">lzf</span><span class="p">:</span>
|
||
<span class="n">lzf</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">b</span><span class="s2">"This *will* be compressed</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
|
||
<span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">b</span><span class="s2">"Not compressed</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>Creating a compressed file using a custom filter chain:</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">lzma</span>
|
||
<span class="n">my_filters</span> <span class="o">=</span> <span class="p">[</span>
|
||
<span class="p">{</span><span class="s2">"id"</span><span class="p">:</span> <span class="n">lzma</span><span class="o">.</span><span class="n">FILTER_DELTA</span><span class="p">,</span> <span class="s2">"dist"</span><span class="p">:</span> <span class="mi">5</span><span class="p">},</span>
|
||
<span class="p">{</span><span class="s2">"id"</span><span class="p">:</span> <span class="n">lzma</span><span class="o">.</span><span class="n">FILTER_LZMA2</span><span class="p">,</span> <span class="s2">"preset"</span><span class="p">:</span> <span class="mi">7</span> <span class="o">|</span> <span class="n">lzma</span><span class="o">.</span><span class="n">PRESET_EXTREME</span><span class="p">},</span>
|
||
<span class="p">]</span>
|
||
<span class="k">with</span> <span class="n">lzma</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s2">"file.xz"</span><span class="p">,</span> <span class="s2">"w"</span><span class="p">,</span> <span class="n">filters</span><span class="o">=</span><span class="n">my_filters</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
|
||
<span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="sa">b</span><span class="s2">"blah blah blah"</span><span class="p">)</span>
|
||
</pre></div>
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</div>
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<ul>
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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">lzma</span></code> — Compression using the LZMA algorithm</a><ul>
|
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<li><a class="reference internal" href="#reading-and-writing-compressed-files">Reading and writing compressed files</a></li>
|
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<li><a class="reference internal" href="#compressing-and-decompressing-data-in-memory">Compressing and decompressing data in memory</a></li>
|
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<li><a class="reference internal" href="#miscellaneous">Miscellaneous</a></li>
|
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<li><a class="reference internal" href="#specifying-custom-filter-chains">Specifying custom filter chains</a></li>
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<li><a class="reference internal" href="#examples">Examples</a></li>
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