| <!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="This module provides forward and reverse substring search routines."><meta name="keywords" content="rust, rustlang, rust-lang, memmem"><title>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="../../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 mod"><!--[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><h2 class="location"><a href="#">Module memmem</a></h2><div class="sidebar-elems"><section><ul class="block"><li><a href="#structs">Structs</a></li><li><a href="#enums">Enums</a></li><li><a href="#functions">Functions</a></li></ul></section></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">Module <a href="../index.html">memchr</a>::<wbr><a class="mod" href="#">memmem</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#1-1321">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>This module provides forward and reverse substring search routines.</p> |
| <p>Unlike the standard library’s substring search routines, these work on |
| arbitrary bytes. For all non-empty needles, these routines will report exactly |
| the same values as the corresponding routines in the standard library. For |
| the empty needle, the standard library reports matches only at valid UTF-8 |
| boundaries, where as these routines will report matches at every position.</p> |
| <p>Other than being able to work on arbitrary bytes, the primary reason to prefer |
| these routines over the standard library routines is that these will generally |
| be faster. In some cases, significantly so.</p> |
| <h2 id="example-iterating-over-substring-matches"><a href="#example-iterating-over-substring-matches">Example: iterating over substring matches</a></h2> |
| <p>This example shows how to use <a href="fn.find_iter.html" title="find_iter"><code>find_iter</code></a> to find occurrences of a substring |
| in a haystack.</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 foo baz foo"</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>it = memmem::find_iter(haystack, <span class="string">"foo"</span>); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">0</span>), it.next()); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">8</span>), it.next()); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">16</span>), it.next()); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">None</span>, it.next());</code></pre></div> |
| <h2 id="example-iterating-over-substring-matches-in-reverse"><a href="#example-iterating-over-substring-matches-in-reverse">Example: iterating over substring matches in reverse</a></h2> |
| <p>This example shows how to use <a href="fn.rfind_iter.html" title="rfind_iter"><code>rfind_iter</code></a> to find occurrences of a substring |
| in a haystack starting from the end of the haystack.</p> |
| <p><strong>NOTE:</strong> This module does not implement double ended iterators, so reverse |
| searches aren’t done by calling <code>rev</code> on a forward iterator.</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 foo baz foo"</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>it = memmem::rfind_iter(haystack, <span class="string">"foo"</span>); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">16</span>), it.next()); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">8</span>), it.next()); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">0</span>), it.next()); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">None</span>, it.next());</code></pre></div> |
| <h2 id="example-repeating-a-search-for-the-same-needle"><a href="#example-repeating-a-search-for-the-same-needle">Example: repeating a search for the same needle</a></h2> |
| <p>It may be possible for the overhead of constructing a substring searcher to be |
| measurable in some workloads. In cases where the same needle is used to search |
| many haystacks, it is possible to do construction once and thus to avoid it for |
| subsequent searches. This can be done with a <a href="struct.Finder.html" title="Finder"><code>Finder</code></a> (or a <a href="struct.FinderRev.html" title="FinderRev"><code>FinderRev</code></a> for |
| reverse searches).</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>memchr::memmem; |
| |
| <span class="kw">let </span>finder = memmem::Finder::new(<span class="string">"foo"</span>); |
| |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), finder.find(<span class="string">b"baz foo quux"</span>)); |
| <span class="macro">assert_eq!</span>(<span class="prelude-val">None</span>, finder.find(<span class="string">b"quux baz bar"</span>));</code></pre></div> |
| </div></details><h2 id="structs" class="small-section-header"><a href="#structs">Structs</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.FindIter.html" title="memchr::memmem::FindIter struct">FindIter</a></div><div class="item-right docblock-short">An iterator over non-overlapping substring matches.</div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.FindRevIter.html" title="memchr::memmem::FindRevIter struct">FindRevIter</a></div><div class="item-right docblock-short">An iterator over non-overlapping substring matches in reverse.</div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.Finder.html" title="memchr::memmem::Finder struct">Finder</a></div><div class="item-right docblock-short">A single substring searcher fixed to a particular needle.</div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.FinderBuilder.html" title="memchr::memmem::FinderBuilder struct">FinderBuilder</a></div><div class="item-right docblock-short">A builder for constructing non-default forward or reverse memmem finders.</div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.FinderRev.html" title="memchr::memmem::FinderRev struct">FinderRev</a></div><div class="item-right docblock-short">A single substring reverse searcher fixed to a particular needle.</div></div></div><h2 id="enums" class="small-section-header"><a href="#enums">Enums</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="enum" href="enum.Prefilter.html" title="memchr::memmem::Prefilter enum">Prefilter</a></div><div class="item-right docblock-short">Prefilter controls whether heuristics are used to accelerate searching.</div></div></div><h2 id="functions" class="small-section-header"><a href="#functions">Functions</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="fn" href="fn.find.html" title="memchr::memmem::find fn">find</a></div><div class="item-right docblock-short">Returns the index of the first occurrence of the given needle.</div></div><div class="item-row"><div class="item-left module-item"><a class="fn" href="fn.find_iter.html" title="memchr::memmem::find_iter fn">find_iter</a></div><div class="item-right docblock-short">Returns an iterator over all non-overlapping occurrences of a substring in |
| a haystack.</div></div><div class="item-row"><div class="item-left module-item"><a class="fn" href="fn.rfind.html" title="memchr::memmem::rfind fn">rfind</a></div><div class="item-right docblock-short">Returns the index of the last occurrence of the given needle.</div></div><div class="item-row"><div class="item-left module-item"><a class="fn" href="fn.rfind_iter.html" title="memchr::memmem::rfind_iter fn">rfind_iter</a></div><div class="item-right docblock-short">Returns a reverse iterator over all non-overlapping occurrences of a |
| substring in a haystack.</div></div></div></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> |
