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<p class='location'>Struct CompressionOptions</p><div class="block items"><ul><li><a href="#fields">Fields</a></li><li><a href="#methods">Methods</a></li><li><a href="#implementations">Trait Implementations</a></li></ul></div><p class='location'><a href='index.html'>deflate</a></p><script>window.sidebarCurrent = {name: 'CompressionOptions', ty: 'struct', relpath: ''};</script><script defer src="sidebar-items.js"></script>
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<h1 class='fqn'><span class='in-band'>Struct <a href='index.html'>deflate</a>::<wbr><a class="struct" href=''>CompressionOptions</a></span><span class='out-of-band'><span id='render-detail'>
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[<span class='inner'>&#x2212;</span>]
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</span><a class='srclink' href='../src/deflate/compression_options.rs.html#78-120' title='goto source code'>[src]</a></span></h1>
<pre class='rust struct'>pub struct CompressionOptions {
pub max_hash_checks: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u16.html">u16</a>,
pub lazy_if_less_than: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u16.html">u16</a>,
pub matching_type: <a class="enum" href="../deflate/enum.MatchingType.html" title="enum deflate::MatchingType">MatchingType</a>,
pub special: <a class="enum" href="../deflate/enum.SpecialOptions.html" title="enum deflate::SpecialOptions">SpecialOptions</a>,
}</pre><div class='docblock'><p>A struct describing the options for a compressor or compression function.</p>
<p>These values are not stable and still subject to change!</p>
</div><h2 id='fields' class='fields'>Fields</h2><span id='structfield.max_hash_checks' class="structfield">
<span id='max_hash_checks.v' class='invisible'>
<code>max_hash_checks: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u16.html">u16</a></code>
</span></span><div class='docblock'><p>The maximum number of checks to make in the hash table for matches.</p>
<p>Higher numbers mean slower, but better compression. Very high (say <code>&gt;1024</code>) values
will impact compression speed a lot. The maximum match length is 2<sup>15,</sup> so values higher than
this won&#39;t make any difference, and will be truncated to 2<sup>15</sup> by the compression
function/writer.</p>
<p>Default value: <code>128</code></p>
</div><span id='structfield.lazy_if_less_than' class="structfield">
<span id='lazy_if_less_than.v' class='invisible'>
<code>lazy_if_less_than: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u16.html">u16</a></code>
</span></span><div class='docblock'><p>Only lazy match if we have a length less than this value.</p>
<p>Higher values degrade compression slightly, but improve compression speed.</p>
<ul>
<li><code>0</code>: Never lazy match. (Same effect as setting MatchingType to greedy, but may be slower).</li>
<li><code>1...257</code>: Only check for a better match if the first match was shorter than this value.</li>
<li><code>258</code>: Always lazy match.</li>
</ul>
<p>As the maximum length of a match is <code>258</code>, values higher than this will have
no further effect.</p>
<ul>
<li>Default value: <code>32</code></li>
</ul>
</div><span id='structfield.matching_type' class="structfield">
<span id='matching_type.v' class='invisible'>
<code>matching_type: <a class="enum" href="../deflate/enum.MatchingType.html" title="enum deflate::MatchingType">MatchingType</a></code>
</span></span><div class='docblock'><p>Whether to use lazy or greedy matching.</p>
<p>Lazy matching will provide better compression, at the expense of compression speed.</p>
<p>As a special case, if max_hash_checks is set to 0, and matching_type is set to lazy,
compression using only run-length encoding (i.e maximum match distance of 1) is performed.
(This may be changed in the future but is defined like this at the moment to avoid API
breakage.</p>
<p><a href="./enum.MatchingType.html">See <code>MatchingType</code></a></p>
<ul>
<li>Default value: <code>MatchingType::Lazy</code></li>
</ul>
</div><span id='structfield.special' class="structfield">
<span id='special.v' class='invisible'>
<code>special: <a class="enum" href="../deflate/enum.SpecialOptions.html" title="enum deflate::SpecialOptions">SpecialOptions</a></code>
</span></span><div class='docblock'><p>Force fixed/stored blocks (Not implemented yet).
* Default value: <code>SpecialOptions::Normal</code></p>
</div><h2 id='methods'>Methods</h2><h3 class='impl'><span class='in-band'><code>impl <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/deflate/compression_options.rs.html#124-179' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.high' class="method"><span id='high.v' class='invisible'><code>fn <a href='#method.high' class='fnname'>high</a>() -&gt; <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span></h4>
<div class='docblock'><p>Returns compression settings rouhgly corresponding to the <code>HIGH(9)</code> setting in miniz.</p>
</div><h4 id='method.fast' class="method"><span id='fast.v' class='invisible'><code>fn <a href='#method.fast' class='fnname'>fast</a>() -&gt; <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span></h4>
<div class='docblock'><p>Returns a fast set of compression settings</p>
<p>Ideally this should roughly correspond to the <code>FAST(1)</code> setting in miniz.
However, that setting makes miniz use a somewhat different algorhithm,
so currently hte fast level in this library is slower and better compressing
than the corresponding level in miniz.</p>
</div><h4 id='method.huffman_only' class="method"><span id='huffman_only.v' class='invisible'><code>fn <a href='#method.huffman_only' class='fnname'>huffman_only</a>() -&gt; <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span></h4>
<div class='docblock'><p>Returns a set of compression settings that makes the compressor only compress using
huffman coding. (Ignoring any length/distance matching)</p>
<p>This will normally have the worst compression ratio (besides only using uncompressed data),
but may be the fastest method in some cases.</p>
</div><h4 id='method.rle' class="method"><span id='rle.v' class='invisible'><code>fn <a href='#method.rle' class='fnname'>rle</a>() -&gt; <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span></h4>
<div class='docblock'><p>Returns a set of compression settings that makes the compressor compress only using
run-length encoding (i.e only looking for matches one byte back).</p>
<p>This is very fast, but tends to compress worse than looking for more matches using hash
chains that the slower settings do.
Works best on data that has runs of equivialent bytes, like binary or simple images,
less good for text.</p>
</div></div><h2 id='implementations'>Trait Implementations</h2><h3 class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Copy.html" title="trait core::marker::Copy">Copy</a> for <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/deflate/compression_options.rs.html#77' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'></div><h3 class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a> for <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/deflate/compression_options.rs.html#77' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.clone' class="method"><span id='clone.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone' class='fnname'>clone</a>(&amp;self) -&gt; <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span></h4>
<div class='docblock'><p>Returns a copy of the value. <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone">Read more</a></p>
</div><h4 id='method.clone_from' class="method"><span id='clone_from.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from' class='fnname'>clone_from</a>(&amp;mut self, source: &amp;Self)</code><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div></span></h4>
<div class='docblock'><p>Performs copy-assignment from <code>source</code>. <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from">Read more</a></p>
</div></div><h3 class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/deflate/compression_options.rs.html#77' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.fmt' class="method"><span id='fmt.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt' class='fnname'>fmt</a>(&amp;self, __arg_0: &amp;mut <a class="struct" href="https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a>) -&gt; <a class="type" href="https://doc.rust-lang.org/nightly/core/fmt/type.Result.html" title="type core::fmt::Result">Result</a></code></span></h4>
<div class='docblock'><p>Formats the value using the given formatter.</p>
</div></div><h3 class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> for <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/deflate/compression_options.rs.html#77' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'></div><h3 class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html" title="trait core::cmp::PartialEq">PartialEq</a> for <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/deflate/compression_options.rs.html#77' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.eq' class="method"><span id='eq.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#tymethod.eq' class='fnname'>eq</a>(&amp;self, __arg_0: &amp;<a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a>) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span></h4>
<div class='docblock'><p>This method tests for <code>self</code> and <code>other</code> values to be equal, and is used by <code>==</code>. <a href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#tymethod.eq">Read more</a></p>
</div><h4 id='method.ne' class="method"><span id='ne.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#method.ne' class='fnname'>ne</a>(&amp;self, __arg_0: &amp;<a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a>) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span></h4>
<div class='docblock'><p>This method tests for <code>!=</code>.</p>
</div></div><h3 class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a> for <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/deflate/compression_options.rs.html#77' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.hash' class="method"><span id='hash.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html#tymethod.hash' class='fnname'>hash</a>&lt;__H:&nbsp;<a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hasher.html" title="trait core::hash::Hasher">Hasher</a>&gt;(&amp;self, __arg_0: &amp;mut __H)</code></span></h4>
<div class='docblock'><p>Feeds this value into the given [<code>Hasher</code>]. <a href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html#tymethod.hash">Read more</a></p>
</div><h4 id='method.hash_slice' class="method"><span id='hash_slice.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html#method.hash_slice' class='fnname'>hash_slice</a>&lt;H&gt;(data: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.slice.html">&amp;[Self]</a>, state: &amp;mut H) <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;H: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hasher.html" title="trait core::hash::Hasher">Hasher</a>,&nbsp;</span></code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h4>
<div class='docblock'><p>Feeds a slice of this type into the given [<code>Hasher</code>]. <a href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html#method.hash_slice">Read more</a></p>
</div></div><h3 class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/default/trait.Default.html" title="trait core::default::Default">Default</a> for <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/deflate/compression_options.rs.html#181-186' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.default' class="method"><span id='default.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/default/trait.Default.html#tymethod.default' class='fnname'>default</a>() -&gt; <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span></h4>
<div class='docblock'><p>Returns the options describing the default compression level.</p>
</div></div><h3 class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.From.html" title="trait core::convert::From">From</a>&lt;<a class="enum" href="../deflate/enum.Compression.html" title="enum deflate::Compression">Compression</a>&gt; for <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/deflate/compression_options.rs.html#188-196' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.from' class="method"><span id='from.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/convert/trait.From.html#tymethod.from' class='fnname'>from</a>(compression: <a class="enum" href="../deflate/enum.Compression.html" title="enum deflate::Compression">Compression</a>) -&gt; <a class="struct" href="../deflate/struct.CompressionOptions.html" title="struct deflate::CompressionOptions">CompressionOptions</a></code></span></h4>
<div class='docblock'><p>Performs the conversion.</p>
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