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<p class='location'>Crate bytes</p><div class="sidebar-elems"><div class="block items"><ul><li><a href="#modules">Modules</a></li><li><a href="#structs">Structs</a></li><li><a href="#enums">Enums</a></li><li><a href="#traits">Traits</a></li></ul></div><p class='location'></p><script>window.sidebarCurrent = {name: 'bytes', ty: 'mod', relpath: '../'};</script></div>
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<h1 class='fqn'><span class='in-band'>Crate <a class="mod" href=''>bytes</a></span><span class='out-of-band'><span id='render-detail'>
<a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">
[<span class='inner'>&#x2212;</span>]
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</span><a class='srclink' href='../src/bytes/lib.rs.html#1-101' title='goto source code'>[src]</a></span></h1>
<div class='docblock'><p>Provides abstractions for working with bytes.</p>
<p>The <code>bytes</code> crate provides an efficient byte buffer structure
(<a href="struct.Bytes.html"><code>Bytes</code></a>) and traits for working with buffer
implementations (<a href="trait.Buf.html"><code>Buf</code></a>, <a href="trait.BufMut.html"><code>BufMut</code></a>).</p>
<h1 id="bytes" class="section-header"><a href="#bytes"><code>Bytes</code></a></h1>
<p><code>Bytes</code> is an efficient container for storing and operating on continguous
slices of memory. It is intended for use primarily in networking code, but
could have applications elsewhere as well.</p>
<p><code>Bytes</code> values facilitate zero-copy network programming by allowing multiple
<code>Bytes</code> objects to point to the same underlying memory. This is managed by
using a reference count to track when the memory is no longer needed and can
be freed.</p>
<p>A <code>Bytes</code> handle can be created directly from an existing byte store (such as <code>&amp;[u8]</code>
or <code>Vec&lt;u8&gt;</code>), but usually a <code>BytesMut</code> is used first and written to. For
example:</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">bytes</span>::{<span class="ident">BytesMut</span>, <span class="ident">BufMut</span>, <span class="ident">BigEndian</span>};
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> <span class="ident">BytesMut</span>::<span class="ident">with_capacity</span>(<span class="number">1024</span>);
<span class="ident">buf</span>.<span class="ident">put</span>(<span class="kw-2">&amp;</span><span class="string">b&quot;hello world&quot;</span>[..]);
<span class="ident">buf</span>.<span class="ident">put_u16</span>::<span class="op">&lt;</span><span class="ident">BigEndian</span><span class="op">&gt;</span>(<span class="number">1234</span>);
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="ident">buf</span>.<span class="ident">take</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">a</span>, <span class="string">b&quot;hello world\x04\xD2&quot;</span>[..]);
<span class="ident">buf</span>.<span class="ident">put</span>(<span class="kw-2">&amp;</span><span class="string">b&quot;goodbye world&quot;</span>[..]);
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="ident">buf</span>.<span class="ident">take</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">b</span>, <span class="string">b&quot;goodbye world&quot;</span>[..]);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">buf</span>.<span class="ident">capacity</span>(), <span class="number">998</span>);</pre>
<p>In the above example, only a single buffer of 1024 is allocated. The handles
<code>a</code> and <code>b</code> will share the underlying buffer and maintain indices tracking
the view into the buffer represented by the handle.</p>
<p>See the <a href="struct.Bytes.html">struct docs</a> for more details.</p>
<h1 id="buf-bufmut" class="section-header"><a href="#buf-bufmut"><code>Buf</code>, <code>BufMut</code></a></h1>
<p>These two traits provide read and write access to buffers. The underlying
storage may or may not be in contiguous memory. For example, <code>Bytes</code> is a
buffer that guarantees contiguous memory, but a <a href="https://en.wikipedia.org/wiki/Rope_(data_structure)">rope</a> stores the bytes in
disjoint chunks. <code>Buf</code> and <code>BufMut</code> maintain cursors tracking the current
position in the underlying byte storage. When bytes are read or written, the
cursor is advanced.</p>
<h2 id="relation-with-read-and-write" class="section-header"><a href="#relation-with-read-and-write">Relation with <code>Read</code> and <code>Write</code></a></h2>
<p>At first glance, it may seem that <code>Buf</code> and <code>BufMut</code> overlap in
functionality with <code>std::io::Read</code> and <code>std::io::Write</code>. However, they
serve different purposes. A buffer is the value that is provided as an
argument to <code>Read::read</code> and <code>Write::write</code>. <code>Read</code> and <code>Write</code> may then
perform a syscall, which has the potential of failing. Operations on <code>Buf</code>
and <code>BufMut</code> are infallible.</p>
</div><h2 id='modules' class='section-header'><a href="#modules">Modules</a></h2>
<table>
<tr class=' module-item'>
<td><a class="mod" href="buf/index.html"
title='mod bytes::buf'>buf</a></td>
<td class='docblock-short'>
<p>Utilities for working with buffers.</p>
</td>
</tr></table><h2 id='structs' class='section-header'><a href="#structs">Structs</a></h2>
<table>
<tr class=' module-item'>
<td><a class="struct" href="struct.Bytes.html"
title='struct bytes::Bytes'>Bytes</a></td>
<td class='docblock-short'>
<p>A reference counted contiguous slice of memory.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="struct" href="struct.BytesMut.html"
title='struct bytes::BytesMut'>BytesMut</a></td>
<td class='docblock-short'>
<p>A unique reference to a contiguous slice of memory.</p>
</td>
</tr></table><h2 id='enums' class='section-header'><a href="#enums">Enums</a></h2>
<table>
<tr class=' module-item'>
<td><a class="enum" href="enum.BigEndian.html"
title='enum bytes::BigEndian'>BigEndian</a></td>
<td class='docblock-short'>
<p>Defines big-endian serialization.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="enum" href="enum.LittleEndian.html"
title='enum bytes::LittleEndian'>LittleEndian</a></td>
<td class='docblock-short'>
<p>Defines little-endian serialization.</p>
</td>
</tr></table><h2 id='traits' class='section-header'><a href="#traits">Traits</a></h2>
<table>
<tr class=' module-item'>
<td><a class="trait" href="trait.Buf.html"
title='trait bytes::Buf'>Buf</a></td>
<td class='docblock-short'>
<p>Read bytes from a buffer.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.BufMut.html"
title='trait bytes::BufMut'>BufMut</a></td>
<td class='docblock-short'>
<p>A trait for values that provide sequential write access to bytes.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.ByteOrder.html"
title='trait bytes::ByteOrder'>ByteOrder</a></td>
<td class='docblock-short'>
<p><code>ByteOrder</code> describes types that can serialize integers as bytes.</p>
</td>
</tr>
<tr class=' module-item'>
<td><a class="trait" href="trait.IntoBuf.html"
title='trait bytes::IntoBuf'>IntoBuf</a></td>
<td class='docblock-short'>
<p>Conversion into a <code>Buf</code></p>
</td>
</tr></table></section>
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