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deploy: b3bd34a9bbae9c73eb2d66a212d6921bd7499b69
2024-07-26 09:42:18 +00:00
<!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="Compare `n` bytes at the given pointers for equality."><title>is_equal_raw in memchr::arch::all - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-46f98efaafac5295.ttf.woff2,FiraSans-Regular-018c141bf0843ffd.woff2,FiraSans-Medium-8f9a781e4970d388.woff2,SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2,SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../../../static.files/rustdoc-dd39b87e5fcfba68.css"><meta name="rustdoc-vars" data-root-path="../../../" data-static-root-path="../../../static.files/" data-current-crate="memchr" data-themes="" data-resource-suffix="" data-rustdoc-version="1.80.0 (051478957 2024-07-21)" data-channel="1.80.0" data-search-js="search-d52510db62a78183.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../../../static.files/storage-118b08c4c78b968e.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../../static.files/main-20a3ad099b048cf2.js"></script><noscript><link rel="stylesheet" href="../../../static.files/noscript-df360f571f6edeae.css"></noscript><link rel="alternate icon" type="image/png" href="../../../static.files/favicon-32x32-422f7d1d52889060.png"><link rel="icon" type="image/svg+xml" href="../../../static.files/favicon-2c020d218678b618.svg"></head><body class="rustdoc fn"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle" title="show sidebar"></button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../../../memchr/index.html">memchr</a><span class="version">2.7.4</span></h2></div><div class="sidebar-elems"><h2><a href="index.html">In memchr::arch::all</a></h2></div></nav><div class="sidebar-resizer"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><h1>Function <a href="../../index.html">memchr</a>::<wbr><a href="../index.html">arch</a>::<wbr><a href="index.html">all</a>::<wbr><a class="fn" href="#">is_equal_raw</a><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><span class="out-of-band"><a class="src" href="../../../src/memchr/arch/all/mod.rs.html#108-158">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>&#x2212;</span>]</button></span></div><pre class="rust item-decl"><code>pub unsafe fn is_equal_raw(x: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.pointer.html">*const </a><a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.u8.html">u8</a>, y: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.pointer.html">*const </a><a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.u8.html">u8</a>, n: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.bool.html">bool</a></code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Compare <code>n</code> bytes at the given pointers for equality.</p>
deploy: 4a83cfd6f9c58b14a87234162281aad1aef83c3e
2024-02-13 06:38:44 +00:00
<p>This returns true if and only if <code>*x.add(i) == *y.add(i)</code> for all
<code>0 &lt;= i &lt; n</code>.</p>
deploy: 39fc7f2b9fd58ce67982b1c71c788f3b031ae3df
2024-03-27 11:12:16 +00:00
<h2 id="inlining"><a class="doc-anchor" href="#inlining">§</a>Inlining</h2>
deploy: 4a83cfd6f9c58b14a87234162281aad1aef83c3e
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<p>This routine is marked <code>inline(always)</code>. If you want to call this function
in a way that is not always inlined, you’ll need to wrap a call to it in
another function that is marked as <code>inline(never)</code> or just <code>inline</code>.</p>
deploy: 39fc7f2b9fd58ce67982b1c71c788f3b031ae3df
2024-03-27 11:12:16 +00:00
<h2 id="motivation"><a class="doc-anchor" href="#motivation">§</a>Motivation</h2>
deploy: 4a83cfd6f9c58b14a87234162281aad1aef83c3e
2024-02-13 06:38:44 +00:00
<p>Why not use slice equality instead? Well, slice equality usually results in
a call out to the current platform’s <code>libc</code> which might not be inlineable
or have other overhead. This routine isn’t guaranteed to be a win, but it
might be in some cases.</p>
deploy: 39fc7f2b9fd58ce67982b1c71c788f3b031ae3df
2024-03-27 11:12:16 +00:00
<h2 id="safety"><a class="doc-anchor" href="#safety">§</a>Safety</h2>
deploy: 4a83cfd6f9c58b14a87234162281aad1aef83c3e
2024-02-13 06:38:44 +00:00
<ul>
<li>Both <code>x</code> and <code>y</code> must be valid for reads of up to <code>n</code> bytes.</li>
<li>Both <code>x</code> and <code>y</code> must point to an initialized value.</li>
<li>Both <code>x</code> and <code>y</code> must each point to an allocated object and
must either be in bounds or at most one byte past the end of the
allocated object. <code>x</code> and <code>y</code> do not need to point to the same allocated
object, but they may.</li>
<li>Both <code>x</code> and <code>y</code> must be <em>derived from</em> a pointer to their respective
allocated objects.</li>
<li>The distance between <code>x</code> and <code>x+n</code> must not overflow <code>isize</code>. Similarly
for <code>y</code> and <code>y+n</code>.</li>
<li>The distance being in bounds must not rely on “wrapping around” the
address space.</li>
</ul>
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