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<p class='location'>Trait Hasher</p><div class="block items"><ul><li><a href="#required-methods">Required Methods</a></li><li><a href="#provided-methods">Provided Methods</a></li><li><a href="#implementors">Implementors</a></li></ul></div><p class='location'><a href='../index.html'>core</a>::<wbr><a href='index.html'>hash</a></p><script>window.sidebarCurrent = {name: 'Hasher', ty: 'trait', relpath: ''};</script><script defer src="sidebar-items.js"></script>
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<h1 class='fqn'><span class='in-band'>Trait <a href='../index.html'>core</a>::<wbr><a href='index.html'>hash</a>::<wbr><a class="trait" href=''>Hasher</a></span><span class='out-of-band'><span class='since' title='Stable since Rust version 1.0.0'>1.0.0</span><span id='render-detail'>
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</span><a class='srclink' href='../../src/core/hash/mod.rs.html#242-353' title='goto source code'>[src]</a></span></h1>
<pre class='rust trait'>pub trait Hasher {
fn <a href='#tymethod.finish' class='fnname'>finish</a>(&self) -> u64;
fn <a href='#tymethod.write' class='fnname'>write</a>(&mut self, bytes: &[u8]);
fn <a href='#method.write_u8' class='fnname'>write_u8</a>(&mut self, i: u8) { ... }
fn <a href='#method.write_u16' class='fnname'>write_u16</a>(&mut self, i: u16) { ... }
fn <a href='#method.write_u32' class='fnname'>write_u32</a>(&mut self, i: u32) { ... }
fn <a href='#method.write_u64' class='fnname'>write_u64</a>(&mut self, i: u64) { ... }
fn <a href='#method.write_u128' class='fnname'>write_u128</a>(&mut self, i: u128) { ... }
fn <a href='#method.write_usize' class='fnname'>write_usize</a>(&mut self, i: usize) { ... }
fn <a href='#method.write_i8' class='fnname'>write_i8</a>(&mut self, i: i8) { ... }
fn <a href='#method.write_i16' class='fnname'>write_i16</a>(&mut self, i: i16) { ... }
fn <a href='#method.write_i32' class='fnname'>write_i32</a>(&mut self, i: i32) { ... }
fn <a href='#method.write_i64' class='fnname'>write_i64</a>(&mut self, i: i64) { ... }
fn <a href='#method.write_i128' class='fnname'>write_i128</a>(&mut self, i: i128) { ... }
fn <a href='#method.write_isize' class='fnname'>write_isize</a>(&mut self, i: isize) { ... }
}</pre><div class='docblock'><p>A trait for hashing an arbitrary stream of bytes.</p>
<p>Instances of <code>Hasher</code> usually represent state that is changed while hashing
data.</p>
<p><code>Hasher</code> provides a fairly basic interface for retrieving the generated hash
(with <a href="#tymethod.finish"><code>finish</code></a>), and writing integers as well as slices of bytes into an
instance (with <a href="#tymethod.write"><code>write</code></a> and <a href="#method.write_u8"><code>write_u8</code></a> etc.). Most of the time, <code>Hasher</code>
instances are used in conjunction with the <a href="trait.Hash.html"><code>Hash</code></a> trait.</p>
<h1 id='examples' class='section-header'><a href='#examples'>Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">hash_map</span>::<span class="ident">DefaultHasher</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">hash</span>::<span class="ident">Hasher</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">hasher</span> <span class="op">=</span> <span class="ident">DefaultHasher</span>::<span class="ident">new</span>();
<span class="ident">hasher</span>.<span class="ident">write_u32</span>(<span class="number">1989</span>);
<span class="ident">hasher</span>.<span class="ident">write_u8</span>(<span class="number">11</span>);
<span class="ident">hasher</span>.<span class="ident">write_u8</span>(<span class="number">9</span>);
<span class="ident">hasher</span>.<span class="ident">write</span>(<span class="string">b"Huh?"</span>);
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"Hash is {:x}!"</span>, <span class="ident">hasher</span>.<span class="ident">finish</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=fn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3Ahash_map%3A%3ADefaultHasher%3B%0Ause%20std%3A%3Ahash%3A%3AHasher%3B%0A%0Alet%20mut%20hasher%20%3D%20DefaultHasher%3A%3Anew()%3B%0A%0Ahasher.write_u32(1989)%3B%0Ahasher.write_u8(11)%3B%0Ahasher.write_u8(9)%3B%0Ahasher.write(b%22Huh%3F%22)%3B%0A%0Aprintln!(%22Hash%20is%20%7B%3Ax%7D!%22%2C%20hasher.finish())%3B%0A%7D">Run</a></pre>
</div>
<h2 id='required-methods'>Required Methods</h2>
<div class='methods'>
<h3 id='tymethod.finish' class='method'><span id='finish.v' class='invisible'><code>fn <a href='#tymethod.finish' class='fnname'>finish</a>(&self) -> u64</code></span></h3><div class='docblock'><p>Completes a round of hashing, producing the output hash generated.</p>
<h1 id='examples-1' class='section-header'><a href='#examples-1'>Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">hash_map</span>::<span class="ident">DefaultHasher</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">hash</span>::<span class="ident">Hasher</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">hasher</span> <span class="op">=</span> <span class="ident">DefaultHasher</span>::<span class="ident">new</span>();
<span class="ident">hasher</span>.<span class="ident">write</span>(<span class="string">b"Cool!"</span>);
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"Hash is {:x}!"</span>, <span class="ident">hasher</span>.<span class="ident">finish</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=fn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3Ahash_map%3A%3ADefaultHasher%3B%0Ause%20std%3A%3Ahash%3A%3AHasher%3B%0A%0Alet%20mut%20hasher%20%3D%20DefaultHasher%3A%3Anew()%3B%0Ahasher.write(b%22Cool!%22)%3B%0A%0Aprintln!(%22Hash%20is%20%7B%3Ax%7D!%22%2C%20hasher.finish())%3B%0A%7D">Run</a></pre>
</div><h3 id='tymethod.write' class='method'><span id='write.v' class='invisible'><code>fn <a href='#tymethod.write' class='fnname'>write</a>(&mut self, bytes: &[u8])</code></span></h3><div class='docblock'><p>Writes some data into this <code>Hasher</code>.</p>
<h1 id='examples-2' class='section-header'><a href='#examples-2'>Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">hash_map</span>::<span class="ident">DefaultHasher</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">hash</span>::<span class="ident">Hasher</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">hasher</span> <span class="op">=</span> <span class="ident">DefaultHasher</span>::<span class="ident">new</span>();
<span class="kw">let</span> <span class="ident">data</span> <span class="op">=</span> [<span class="number">0x01</span>, <span class="number">0x23</span>, <span class="number">0x45</span>, <span class="number">0x67</span>, <span class="number">0x89</span>, <span class="number">0xab</span>, <span class="number">0xcd</span>, <span class="number">0xef</span>];
<span class="ident">hasher</span>.<span class="ident">write</span>(<span class="kw-2">&</span><span class="ident">data</span>);
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"Hash is {:x}!"</span>, <span class="ident">hasher</span>.<span class="ident">finish</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=fn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3Ahash_map%3A%3ADefaultHasher%3B%0Ause%20std%3A%3Ahash%3A%3AHasher%3B%0A%0Alet%20mut%20hasher%20%3D%20DefaultHasher%3A%3Anew()%3B%0Alet%20data%20%3D%20%5B0x01%2C%200x23%2C%200x45%2C%200x67%2C%200x89%2C%200xab%2C%200xcd%2C%200xef%5D%3B%0A%0Ahasher.write(%26data)%3B%0A%0Aprintln!(%22Hash%20is%20%7B%3Ax%7D!%22%2C%20hasher.finish())%3B%0A%7D">Run</a></pre>
</div></div>
<h2 id='provided-methods'>Provided Methods</h2>
<div class='methods'>
<h3 id='method.write_u8' class='method'><span id='write_u8.v' class='invisible'><code>fn <a href='#method.write_u8' class='fnname'>write_u8</a>(&mut self, i: u8)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>u8</code> into this hasher.</p>
</div><h3 id='method.write_u16' class='method'><span id='write_u16.v' class='invisible'><code>fn <a href='#method.write_u16' class='fnname'>write_u16</a>(&mut self, i: u16)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>u16</code> into this hasher.</p>
</div><h3 id='method.write_u32' class='method'><span id='write_u32.v' class='invisible'><code>fn <a href='#method.write_u32' class='fnname'>write_u32</a>(&mut self, i: u32)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>u32</code> into this hasher.</p>
</div><h3 id='method.write_u64' class='method'><span id='write_u64.v' class='invisible'><code>fn <a href='#method.write_u64' class='fnname'>write_u64</a>(&mut self, i: u64)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>u64</code> into this hasher.</p>
</div><h3 id='method.write_u128' class='method'><span id='write_u128.v' class='invisible'><code>fn <a href='#method.write_u128' class='fnname'>write_u128</a>(&mut self, i: u128)</code></span></h3><div class='stability'><div class='stab unstable'><span class=microscope>🔬</span> This is a nightly-only experimental API. (<code>i128 </code><a href="https://github.com/rust-lang/rust/issues/35118">#35118</a>)</div></div><div class='docblock'><p>Writes a single <code>u128</code> into this hasher.</p>
</div><h3 id='method.write_usize' class='method'><span id='write_usize.v' class='invisible'><code>fn <a href='#method.write_usize' class='fnname'>write_usize</a>(&mut self, i: usize)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>usize</code> into this hasher.</p>
</div><h3 id='method.write_i8' class='method'><span id='write_i8.v' class='invisible'><code>fn <a href='#method.write_i8' class='fnname'>write_i8</a>(&mut self, i: i8)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>i8</code> into this hasher.</p>
</div><h3 id='method.write_i16' class='method'><span id='write_i16.v' class='invisible'><code>fn <a href='#method.write_i16' class='fnname'>write_i16</a>(&mut self, i: i16)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>i16</code> into this hasher.</p>
</div><h3 id='method.write_i32' class='method'><span id='write_i32.v' class='invisible'><code>fn <a href='#method.write_i32' class='fnname'>write_i32</a>(&mut self, i: i32)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>i32</code> into this hasher.</p>
</div><h3 id='method.write_i64' class='method'><span id='write_i64.v' class='invisible'><code>fn <a href='#method.write_i64' class='fnname'>write_i64</a>(&mut self, i: i64)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>i64</code> into this hasher.</p>
</div><h3 id='method.write_i128' class='method'><span id='write_i128.v' class='invisible'><code>fn <a href='#method.write_i128' class='fnname'>write_i128</a>(&mut self, i: i128)</code></span></h3><div class='stability'><div class='stab unstable'><span class=microscope>🔬</span> This is a nightly-only experimental API. (<code>i128 </code><a href="https://github.com/rust-lang/rust/issues/35118">#35118</a>)</div></div><div class='docblock'><p>Writes a single <code>i128</code> into this hasher.</p>
</div><h3 id='method.write_isize' class='method'><span id='write_isize.v' class='invisible'><code>fn <a href='#method.write_isize' class='fnname'>write_isize</a>(&mut self, i: isize)</code><div class='since' title='Stable since Rust version 1.3.0'>1.3.0</div></span></h3><div class='docblock'><p>Writes a single <code>isize</code> into this hasher.</p>
</div></div>
<h2 id='implementors'>Implementors</h2>
<ul class='item-list' id='implementors-list'>
<li><code>impl Hasher for <a class="struct" href="../../core/hash/struct.SipHasher.html" title="struct core::hash::SipHasher">SipHasher</a></code></li>
<li><code>impl Hasher for <a class="struct" href="../../core/hash/struct.SipHasher13.html" title="struct core::hash::SipHasher13">SipHasher13</a></code></li>
<li><code>impl Hasher for <a class="struct" href="../../core/hash/struct.SipHasher24.html" title="struct core::hash::SipHasher24">SipHasher24</a></code></li>
</ul><script type="text/javascript" async
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