| <!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="Like `memrchr`, but searches for either of two bytes instead of just one."><meta name="keywords" content="rust, rustlang, rust-lang, memrchr2"><title>memrchr2 in memchr - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../normalize.css"><link rel="stylesheet" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../ayu.css" disabled><link rel="stylesheet" href="../dark.css" disabled><link rel="stylesheet" href="../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../storage.js"></script><script defer src="sidebar-items.js"></script><script defer src="../main.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../favicon.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">☰</button><a class="sidebar-logo" href="../memchr/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../memchr/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><div class="sidebar-elems"><h2><a href="index.html">In memchr</a></h2></div></nav><main><div class="width-limiter"><nav class="sub"><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1 class="fqn">Function <a href="index.html">memchr</a>::<wbr><a class="fn" href="#">memrchr2</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../src/memchr/memchr/mod.rs.html#325-352">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><pre class="rust fn"><code>pub fn memrchr2(needle1: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>, needle2: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>, haystack: &[<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>]) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>></code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Like <code>memrchr</code>, but searches for either of two bytes instead of just one.</p> |
| <p>This returns the index corresponding to the last occurrence of <code>needle1</code> or |
| the last occurrence of <code>needle2</code> in <code>haystack</code> (whichever occurs later), or |
| <code>None</code> if neither one is found. If an index is returned, it is guaranteed |
| to be less than <code>usize::MAX</code>.</p> |
| <p>While this is operationally the same as something like |
| <code>haystack.iter().rposition(|&b| b == needle1 || b == needle2)</code>, <code>memrchr2</code> |
| will use a highly optimized routine that can be up to an order of magnitude |
| faster in some cases.</p> |
| <h2 id="example"><a href="#example">Example</a></h2> |
| <p>This shows how to find the last position of either of two bytes in a byte |
| string.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>memchr::memrchr2; |
| |
| <span class="kw">let </span>haystack = <span class="string">b"the quick brown fox"</span>; |
| <span class="macro">assert_eq!</span>(memrchr2(<span class="string">b'k'</span>, <span class="string">b'q'</span>, haystack), <span class="prelude-val">Some</span>(<span class="number">8</span>));</code></pre></div> |
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