<!DOCTYPE html><htmllang="en"><head><metacharset="utf-8"><metaname="viewport"content="width=device-width, initial-scale=1.0"><metaname="generator"content="rustdoc"><metaname="description"content="A single substring reverse searcher fixed to a particular needle."><title>FinderRev in memchr::memmem - Rust</title><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/SourceSerif4-Regular-46f98efaafac5295.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><linkrel="preload"as="font"type="font/woff2"crossoriginhref="../../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2"><linkrel="stylesheet"href="../../static.files/normalize-76eba96aa4d2e634.css"><linkrel="stylesheet"href="../../static.files/rustdoc-ac92e1bbe349e143.css"><metaname="rustdoc-vars"data-root-path="../../"data-static-root-path="../../static.files/"data-current-crate="memchr"data-themes=""data-resource-suffix=""data-rustdoc-version="1.76.0 (07dca489a 2024-02-04)"data-channel="1.76.0"data-search-js="search-2b6ce74ff89ae146.js"data-settings-js="settings-4313503d2e1961c2.js"><scriptsrc="../../static.files/storage-f2adc0d6ca4d09fb.js"></script><scriptdefersrc="sidebar-items.js"></script><scriptdefersrc="../../static.files/main-305769736d49e732.js"></script><noscript><linkrel="stylesheet"href="../../static.files/noscript-feafe1bb7466e4bd.css"></noscript><linkrel="alternate icon"type="image/png"href="../../static.files/favicon-16x16-8b506e7a72182f1c.png"><linkrel="alternate icon"type="image/png"href="../../static.files/favicon-32x32-422f7d1d52889060.png"><linkrel="icon"type="image/svg+xml"href="../../static.files/favicon-2c020d218678b618.svg"></head><bodyclass="rustdoc struct"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><navclass="mobile-topbar"><buttonclass="sidebar-menu-toggle">☰</button></nav><navclass="sidebar"><divclass="sidebar-crate"><h2><ahref="../../memchr/index.html">memchr</a><spanclass="version">2.7.1</span></h2></div><h2class="location"><ahref="#">FinderRev</a></h2><divclass="sidebar-elems"><section><h3><ahref="#implementations">Methods</a></h3><ulclass="block method"><li><ahref="#method.as_ref">as_ref</a></li><li><ahref="#method.into_owned">into_owned</a></li><li><ahref="#method.needle">needle</a></li><li><ahref="#method.new">new</a></li><li><ahref="#method.rfind">rfind</a></li><li><ahref="#method.rfind_iter">rfind_iter</a></li></ul><h3><ahref="#trait-implementations">Trait Implementations</a></h3><ulclass="block trait-implementation"><li><ahref="#impl-Clone-for-FinderRev%3C'n%3E">Clone</a></li><li><ahref="#impl-Debug-for-FinderRev%3C'n%3E">Debug</a></li></ul><h3><ahref="#synthetic-implementations">Auto Trait Implementations</a></h3><ulclass="block synthetic-implementation"><li><ahref="#impl-RefUnwindSafe-for-FinderRev%3C'n%3E">RefUnwindSafe</a></li><li><ahref="#impl-Send-for-FinderRev%3C'n%3E">Send</a></li><li><ahref="#impl-Sync-for-FinderRev%3C'n%3E">Sync</a></li><li><ahref="#impl-Unpin-for-FinderRev%3C'n%3E">Unpin</a></li><li><ahref="#impl-UnwindSafe-for-FinderRev%3C'n%3E">UnwindSafe</a></li></ul><h3><ahref="#blanket-implementations">Blanket Implementations</a></h3><ulclass="block blanket-implementation"><li><ahref="#impl-Any-for-T">Any</a></li><li><ahref="#impl-Borrow%3CT%3E-for-T">Borrow<T></a></li><li><ahref="#impl-BorrowMut%3CT%3E-for-T">BorrowMut<T></a></li><li><ahref="#impl-From%3CT%3E-for-T">From<T></a></li><li><ahref="#impl-Into%3CU%3E-for-T">Into<U></a></li><li><ahref="#impl-ToOwned-for-T">ToOwned</a></li><li><ahref="#impl-TryFrom%3CU%3E-for-T">TryFrom<U></a>
<main><divclass="width-limiter"><navclass="sub"><formclass="search-form"><span></span><divid="sidebar-button"tabindex="-1"><ahref="../../memchr/all.html"title="show sidebar"></a></div><inputclass="search-input"name="search"aria-label="Run search in the documentation"autocomplete="off"spellcheck="false"placeholder="Click or press ‘S’ to search, ‘?’ for more options…"type="search"><divid="help-button"tabindex="-1"><ahref="../../help.html"title="help">?</a></div><divid="settings-menu"tabindex="-1"><ahref="../../settings.html"title="settings"><imgwidth="22"height="22"alt="Change settings"src="../../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><sectionid="main-content"class="content"><divclass="main-heading"><h1>Struct <ahref="../index.html">memchr</a>::<wbr><ahref="index.html">memmem</a>::<wbr><aclass="struct"href="#">FinderRev</a><buttonid="copy-path"title="Copy item path to clipboard"><imgsrc="../../static.files/clipboard-7571035ce49a181d.svg"width="19"height="18"alt="Copy item path"></button></h1><spanclass="out-of-band"><aclass="src"href="../../src/memchr/memmem/mod.rs.html#524-527">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><code>pub struct FinderRev<'n> { <spanclass="comment">/* private fields */</span> }</code></pre><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>A single substring reverse searcher fixed to a particular needle.</p>
<p>The purpose of this type is to permit callers to construct a substring
searcher that can be used to search haystacks without the overhead of
constructing the searcher in the first place. This is a somewhat niche
concern when it’s necessary to re-use the same needle to search multiple
different haystacks with as little overhead as possible. In general,
using <ahref="fn.rfind.html"title="fn memchr::memmem::rfind"><code>rfind</code></a> is good enough, but <code>FinderRev</code> is useful when you can
meaningfully observe searcher construction time in a profile.</p>
<p>When the <code>std</code> feature is enabled, then this type has an <code>into_owned</code>
version which permits building a <code>FinderRev</code> that is not connected to
</div></details><h2id="implementations"class="section-header">Implementations<ahref="#implementations"class="anchor">§</a></h2><divid="implementations-list"><detailsclass="toggle implementors-toggle"open><summary><sectionid="impl-FinderRev%3C'n%3E"class="impl"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#529-646">source</a><ahref="#impl-FinderRev%3C'n%3E"class="anchor">§</a><h3class="code-header">impl<'n><aclass="struct"href="struct.FinderRev.html"title="struct memchr::memmem::FinderRev">FinderRev</a><'n></h3></section></summary><divclass="impl-items"><detailsclass="toggle method-toggle"open><summary><sectionid="method.new"class="method"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#532-534">source</a><h4class="code-header">pub fn <ahref="#method.new"class="fn">new</a><B: ?<aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/marker/trait.Sized.html"title="trait core::marker::Sized">Sized</a> + <aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/convert/trait.AsRef.html"title="trait core::convert::AsRef">AsRef</a><[<aclass="primitive"href="https://doc.rust-lang.org/1.76.0/std/primitive.u8.html">u8</a>]>>(needle: <aclass="primitive"href="https://doc.rust-lang.org/1.76.0/std/primitive.reference.html">&'n B</a>) -><aclass="struct"href="struct.FinderRev.html"title="struct memchr::memmem::FinderRev">FinderRev</a><'n></h4></section></summary><divclass="docblock"><p>Create a new reverse finder for the given needle.</p>
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.rfind"class="method"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#563-565">source</a><h4class="code-header">pub fn <ahref="#method.rfind"class="fn">rfind</a><B: <aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/convert/trait.AsRef.html"title="trait core::convert::AsRef">AsRef</a><[<aclass="primitive"href="https://doc.rust-lang.org/1.76.0/std/primitive.u8.html">u8</a>]>>(&self, haystack: B) -><aclass="enum"href="https://doc.rust-lang.org/1.76.0/core/option/enum.Option.html"title="enum core::option::Option">Option</a><<aclass="primitive"href="https://doc.rust-lang.org/1.76.0/std/primitive.usize.html">usize</a>></h4></section></summary><divclass="docblock"><p>Returns the index of the last occurrence of this needle in the given
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.rfind_iter"class="method"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#595-600">source</a><h4class="code-header">pub fn <ahref="#method.rfind_iter"class="fn">rfind_iter</a><'a, 'h>(&'a self, haystack: &'h [<aclass="primitive"href="https://doc.rust-lang.org/1.76.0/std/primitive.u8.html">u8</a>]) -><aclass="struct"href="struct.FindRevIter.html"title="struct memchr::memmem::FindRevIter">FindRevIter</a><'h, 'a><ahref="#"class="tooltip"data-notable-ty="FindRevIter<'h, 'a>">ⓘ</a></h4></section></summary><divclass="docblock"><p>Returns a reverse iterator over all occurrences of a substring in a
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.into_owned"class="method"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#611-616">source</a><h4class="code-header">pub fn <ahref="#method.into_owned"class="fn">into_owned</a>(self) -><aclass="struct"href="struct.FinderRev.html"title="struct memchr::memmem::FinderRev">FinderRev</a><'static></h4></section></summary><divclass="docblock"><p>Convert this finder into its owned variant, such that it no longer
borrows the needle.</p>
<p>If this is already an owned finder, then this is a no-op. Otherwise,
this copies the needle.</p>
<p>This is only available when the <code>std</code> feature is enabled.</p>
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.as_ref"class="method"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#629-634">source</a><h4class="code-header">pub fn <ahref="#method.as_ref"class="fn">as_ref</a>(&self) -><aclass="struct"href="struct.FinderRev.html"title="struct memchr::memmem::FinderRev">FinderRev</a><'_></h4></section></summary><divclass="docblock"><p>Convert this finder into its borrowed variant.</p>
<p>This is primarily useful if your finder is owned and you’d like to
store its borrowed variant in some intermediate data structure.</p>
<p>Note that the lifetime parameter of the returned finder is tied to the
lifetime of <code>self</code>, and may be shorter than the <code>'n</code> lifetime of the
needle itself. Namely, a finder’s needle can be either borrowed or
owned, so the lifetime of the needle returned must necessarily be the
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.needle"class="method"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#643-645">source</a><h4class="code-header">pub fn <ahref="#method.needle"class="fn">needle</a>(&self) ->&[<aclass="primitive"href="https://doc.rust-lang.org/1.76.0/std/primitive.u8.html">u8</a>] <ahref="#"class="tooltip"data-notable-ty="&[u8]">ⓘ</a></h4></section></summary><divclass="docblock"><p>Returns the needle that this finder searches for.</p>
</div></details></div></details></div><h2id="trait-implementations"class="section-header">Trait Implementations<ahref="#trait-implementations"class="anchor">§</a></h2><divid="trait-implementations-list"><detailsclass="toggle implementors-toggle"open><summary><sectionid="impl-Clone-for-FinderRev%3C'n%3E"class="impl"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#523">source</a><ahref="#impl-Clone-for-FinderRev%3C'n%3E"class="anchor">§</a><h3class="code-header">impl<'n><aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/clone/trait.Clone.html"title="trait core::clone::Clone">Clone</a> for <aclass="struct"href="struct.FinderRev.html"title="struct memchr::memmem::FinderRev">FinderRev</a><'n></h3></section></summary><divclass="impl-items"><detailsclass="toggle method-toggle"open><summary><sectionid="method.clone"class="method trait-impl"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#523">source</a><ahref="#method.clone"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.76.0/core/clone/trait.Clone.html#tymethod.clone"class="fn">clone</a>(&self) -><aclass="struct"href="struct.FinderRev.html"title="struct memchr::memmem::FinderRev">FinderRev</a><'n></h4></section></summary><divclass='docblock'>Returns a copy of the value. <ahref="https://doc.rust-lang.org/1.76.0/core/clone/trait.Clone.html#tymethod.clone">Read more</a></div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.clone_from"class="method trait-impl"><spanclass="rightside"><spanclass="since"title="Stable since Rust version 1.0.0">1.0.0</span> · <aclass="src"href="https://doc.rust-lang.org/1.76.0/src/core/clone.rs.html#169">source</a></span><ahref="#method.clone_from"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.76.0/core/clone/trait.Clone.html#method.clone_from"class="fn">clone_from</a>(&mut self, source: <aclass="primitive"href="https://doc.rust-lang.org/1.76.0/std/primitive.reference.html">&Self</a>)</h4></section></summary><divclass='docblock'>Performs copy-assignment from <code>source</code>. <ahref="https://doc.rust-lang.org/1.76.0/core/clone/trait.Clone.html#method.clone_from">Read more</a></div></details></div></details><detailsclass="toggle implementors-toggle"open><summary><sectionid="impl-Debug-for-FinderRev%3C'n%3E"class="impl"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#523">source</a><ahref="#impl-Debug-for-FinderRev%3C'n%3E"class="anchor">§</a><h3class="code-header">impl<'n><aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/fmt/trait.Debug.html"title="trait core::fmt::Debug">Debug</a> for <aclass="struct"href="struct.FinderRev.html"title="struct memchr::memmem::FinderRev">FinderRev</a><'n></h3></section></summary><divclass="impl-items"><detailsclass="toggle method-toggle"open><summary><sectionid="method.fmt"class="method trait-impl"><aclass="src rightside"href="../../src/memchr/memmem/mod.rs.html#523">source</a><ahref="#method.fmt"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.76.0/core/fmt/trait.Debug.html#tymethod.fmt"class="fn">fmt</a>(&self, f: &mut <aclass="struct"href="https://doc.rust-lang.org/1.76.0/core/fmt/struct.Formatter.html"title="struct core::fmt::Formatter">Formatter</a><'_>) -><aclass="type"href="https://doc.rust-lang.org/1.76.0/core/fmt/type.Result.html"title="type core::fmt::Result">Result</a></h4></section></summary><divclass='docblock'>Formats the value using the given formatter. <ahref="https://doc.rust-lang.org/1.76.0/core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></div></details></div></details></div><h2id="synthetic-implementations"class="section-header">Auto Trait Implementations<ahref="#synthetic-implementations"class="anchor">§</a></h2><divid="synthetic-implementations-list"><sectionid="impl-RefUnwindSafe-for-FinderRev%3C'n%3E"class="impl"><ahref="#impl
<p>That is, this conversion is whatever the implementation of
<code><ahref="https://doc.rust-lang.org/1.76.0/core/convert/trait.From.html"title="trait core::convert::From">From</a><T> for U</code> chooses to do.</p>
</div></details></div></details><detailsclass="toggle implementors-toggle"><summary><sectionid="impl-ToOwned-for-T"class="impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.76.0/src/alloc/borrow.rs.html#83-85">source</a><ahref="#impl-ToOwned-for-T"class="anchor">§</a><h3class="code-header">impl<T><aclass="trait"href="https://doc.rust-lang.org/1.76.0/alloc/borrow/trait.ToOwned.html"title="trait alloc::borrow::ToOwned">ToOwned</a> for T<divclass="where">where
T: <aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/clone/trait.Clone.html"title="trait core::clone::Clone">Clone</a>,</div></h3></section></summary><divclass="impl-items"><detailsclass="toggle"open><summary><sectionid="associatedtype.Owned"class="associatedtype trait-impl"><ahref="#associatedtype.Owned"class="anchor">§</a><h4class="code-header">type <ahref="https://doc.rust-lang.org/1.76.0/alloc/borrow/trait.ToOwned.html#associatedtype.Owned"class="associatedtype">Owned</a> = T</h4></section></summary><divclass='docblock'>The resulting type after obtaining ownership.</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.to_owned"class="method trait-impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.76.0/src/alloc/borrow.rs.html#88">source</a><ahref="#method.to_owned"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.76.0/alloc/borrow/trait.ToOwned.html#tymethod.to_owned"class="fn">to_owned</a>(&self) -> T</h4></section></summary><divclass='docblock'>Creates owned data from borrowed data, usually by cloning. <ahref="https://doc.rust-lang.org/1.76.0/alloc/borrow/trait.ToOwned.html#tymethod.to_owned">Read more</a></div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.clone_into"class="method trait-impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.76.0/src/alloc/borrow.rs.html#92">source</a><ahref="#method.clone_into"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.76.0/alloc/borrow/trait.ToOwned.html#method.clone_into"class="fn">clone_into</a>(&self, target: <aclass="primitive"href="https://doc.rust-lang.org/1.76.0/std/primitive.reference.html">&mut T</a>)</h4></section></summary><divclass='docblock'>Uses borrowed data to replace owned data, usually by cloning. <ahref="https://doc.rust-lang.org/1.76.0/alloc/borrow/trait.ToOwned.html#method.clone_into">Read more</a></div></details></div></details><detailsclass="toggle implementors-toggle"><summary><sectionid="impl-TryFrom%3CU%3E-for-T"class="impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.76.0/src/core/convert/mod.rs.html#803-805">source</a><ahref="#impl-TryFrom%3CU%3E-for-T"class="anchor">§</a><h3class="code-header">impl<T, U><aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><U> for T<divclass="where">where
U: <aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/convert/trait.Into.html"title="trait core::convert::Into">Into</a><T>,</div></h3></section></summary><divclass="impl-items"><detailsclass="toggle"open><summary><sectionid="associatedtype.Error"class="associatedtype trait-impl"><ahref="#associatedtype.Error"class="anchor">§</a><h4class="code-header">type <ahref="https://doc.rust-lang.org/1.76.0/core/convert/trait.TryFrom.html#associatedtype.Error"class="associatedtype">Error</a> = <aclass="enum"href="https://doc.rust-lang.org/1.76.0/core/convert/enum.Infallible.html"title="enum core::convert::Infallible">Infallible</a></h4></section></summary><divclass='docblock'>The type returned in the event of a conversion error.</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.try_from"class="method trait-impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.76.0/src/core/convert/mod.rs.html#810">source</a><ahref="#method.try_from"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.76.0/core/convert/trait.TryFrom.html#tymethod.try_from"class="fn">try_from</a>(value: U) -><aclass="enum"href="https://doc.rust-lang.org/1.76.0/core/result/enum.Result.html"title="enum core::result::Result">Result</a><T, <T as <aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><U>>::<aclass="associatedtype"href="https://doc.rust-lang.org/1.76.0/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a>></h4></section></summary><divclass='docblock'>Performs the conversion.</div></details></div></details><detailsclass="toggle implementors-toggle"><summary><sectionid="impl-TryInto%3CU%3E-for-T"class="impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.76.0/src/core/convert/mod.rs.html#788-790">source</a><ahref="#impl-TryInto%3CU%3E-for-T"class="anchor">§</a><h3class="code-header">impl<T, U><aclass="trait"href="https://doc.rust-lang.org/1.76.0/core/convert/trait.TryInto.html"title="trait core::convert::TryInto">TryInto</a><U> for T<divclass="where">where
