27 lines
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27 lines
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<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Derives an optimized `Hash` implementation."><title>ByteHash in zerocopy - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2"href="../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../static.files/rustdoc-ca0dd0c4.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="zerocopy" data-themes="" data-resource-suffix="" data-rustdoc-version="1.93.1 (01f6ddf75 2026-02-11) (Arch Linux rust 1:1.93.1-1)" data-channel="1.93.1" data-search-js="search-9e2438ea.js" data-stringdex-js="stringdex-a3946164.js" data-settings-js="settings-c38705f0.js" ><script src="../static.files/storage-e2aeef58.js"></script><script defer src="sidebar-items.js"></script><script defer src="../static.files/main-a410ff4d.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-263c88ec.css"></noscript><link rel="alternate icon" type="image/png" href="../static.files/favicon-32x32-eab170b8.png"><link rel="icon" type="image/svg+xml" href="../static.files/favicon-044be391.svg"></head><body class="rustdoc derive"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><rustdoc-topbar><h2><a href="#">ByteHash</a></h2></rustdoc-topbar><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../zerocopy/index.html">zerocopy</a><span class="version">0.8.39</span></h2></div><div class="sidebar-elems"><div id="rustdoc-modnav"></div></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><div class="width-limiter"><section id="main-content" class="content"><div class="main-heading"><div class="rustdoc-breadcrumbs"><a href="index.html">zerocopy</a></div><h1>Derive Macro <span class="derive">Byte<wbr>Hash</span> <button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="../src/zerocopy_derive/lib.rs.html#82">Source</a> </span></div><pre class="rust item-decl"><code>#[derive(ByteHash)]
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{
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<span class="comment">// Attributes available to this derive:</span>
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#[zerocopy]
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}
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</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Derives an optimized <a href="https://doc.rust-lang.org/1.93.1/core/hash/trait.Hash.html" title="trait core::hash::Hash"><code>Hash</code></a> implementation.</p>
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<p>This derive can be applied to structs and enums implementing both
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<a href="trait.Immutable.html" title="trait zerocopy::Immutable"><code>Immutable</code></a> and <a href="trait.IntoBytes.html" title="trait zerocopy::IntoBytes"><code>IntoBytes</code></a>; e.g.:</p>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="attr">#[derive(ByteHash, Immutable, IntoBytes)]
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#[repr(C)]
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</span><span class="kw">struct </span>MyStruct {
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...
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}
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<span class="attr">#[derive(ByteHash, Immutable, IntoBytes)]
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#[repr(u8)]
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</span><span class="kw">enum </span>MyEnum {
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...
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}</code></pre></div>
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<p>The standard library’s <a href="https://doc.rust-lang.org/1.93.1/core/hash/macros/derive.Hash.html" title="derive core::hash::macros::Hash"><code>derive(Hash)</code></a> produces hashes by
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individually hashing each field and combining the results. Instead, the
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implementations of <a href="https://doc.rust-lang.org/1.93.1/core/hash/trait.Hash.html#tymethod.hash" title="method core::hash::Hash::hash"><code>Hash::hash()</code></a> and <a href="https://doc.rust-lang.org/1.93.1/core/hash/trait.Hash.html#method.hash_slice" title="associated function core::hash::Hash::hash_slice"><code>Hash::hash_slice()</code></a> generated by
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<code>derive(ByteHash)</code> convert the entirety of <code>self</code> to a byte slice and hashes
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it in a single call to <a href="https://doc.rust-lang.org/1.93.1/core/hash/trait.Hasher.html#tymethod.write" title="method core::hash::Hasher::write"><code>Hasher::write()</code></a>. This may have performance
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advantages.</p>
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</div></details></section></div></main></body></html> |