| <!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="Returns the index of the last occurrence of the given needle."><meta name="keywords" content="rust, rustlang, rust-lang, rfind"><title>rfind in memchr::memmem - 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::memmem</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 href="index.html">memmem</a>::<wbr><a class="fn" href="#">rfind</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/memmem/mod.rs.html#296-302">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 rfind(haystack: &[u8], needle: &[u8]) -> Option<usize></code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Returns the index of the last occurrence of the given needle.</p> |
| <p>Note that if you’re are searching for the same needle in many different |
| small haystacks, it may be faster to initialize a <a href="struct.FinderRev.html" title="FinderRev"><code>FinderRev</code></a> once, |
| and reuse it for each search.</p> |
| <h2 id="complexity"><a href="#complexity">Complexity</a></h2> |
| <p>This routine is guaranteed to have worst case linear time complexity |
| with respect to both the needle and the haystack. That is, this runs |
| in <code>O(needle.len() + haystack.len())</code> time.</p> |
| <p>This routine is also guaranteed to have worst case constant space |
| complexity.</p> |
| <h2 id="examples"><a href="#examples">Examples</a></h2> |
| <p>Basic usage:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>memchr::memmem; |
| |
| <span class="kw">let </span>haystack = <span class="string">b"foo bar baz"</span>; |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">0</span>), memmem::rfind(haystack, <span class="string">b"foo"</span>)); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), memmem::rfind(haystack, <span class="string">b"bar"</span>)); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">8</span>), memmem::rfind(haystack, <span class="string">b"ba"</span>)); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">None</span>, memmem::rfind(haystack, <span class="string">b"quux"</span>));</code></pre></div> |
| </div></details></section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="memchr" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
