<!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="Rust-PHF is a library to generate efficient lookup tables at compile time using perfect hash functions."><title>phf - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceSerif4-Regular-46f98efaafac5295.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceSerif4-Bold-a2c9cd1067f8b328.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2"><link rel="stylesheet" href="../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../static.files/rustdoc-c4dbdcde0fbd8430.css" id="mainThemeStyle"><link rel="stylesheet" id="themeStyle" href="../static.files/light-db279b6232be9c13.css"><link rel="stylesheet" disabled href="../static.files/dark-cf923f49f397b216.css"><link rel="stylesheet" disabled href="../static.files/ayu-be46fdc453a55015.css"><script src="../static.files/storage-3891ce972e3a2bf8.js"></script><script defer src="../crates.js"></script><script defer src="../static.files/main-98a684e84ae5b08b.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-13285aec31fa243e.css"></noscript><link rel="alternate icon" type="image/png" href="../static.files/favicon-16x16-8b506e7a72182f1c.png"><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 mod crate"><!--[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="logo-container" href="../phf/index.html"><img class="rust-logo" src="../static.files/rust-logo-151179464ae7ed46.svg" alt="logo"></a><h2></h2></nav><nav class="sidebar"><a class="logo-container" href="../phf/index.html"><img class="rust-logo" src="../static.files/rust-logo-151179464ae7ed46.svg" alt="logo"></a><h2 class="location"><a href="#">Crate phf</a></h2><div class="sidebar-elems"><ul class="block"><li class="version">Version 0.11.2</li><li><a id="all-types" href="all.html">All Items</a></li></ul><section><ul class="block"><li><a href="#modules">Modules</a></li><li><a href="#structs">Structs</a></li><li><a href="#traits">Traits</a></li></ul></section></div></nav><main><div class="width-limiter"><nav class="sub"><form class="search-form"><span></span><input class="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"><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="../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1>Crate <a class="mod" href="#">phf</a><button id="copy-path" title="Copy item path to clipboard"><img src="../static.files/clipboard-7571035ce49a181d.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../src/phf/lib.rs.html#1-152">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>−</span>]</button></span></div><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Rust-PHF is a library to generate efficient lookup tables at compile time using
<a href="http://en.wikipedia.org/wiki/Perfect_hash_function">perfect hash functions</a>.</p>
<p>It currently uses the
<a href="http://cmph.sourceforge.net/papers/esa09.pdf">CHD algorithm</a> and can generate
a 100,000 entry map in roughly .4 seconds.</p>
<p>MSRV (minimum supported rust version) is Rust 1.60.</p>
<h3 id="usage"><a href="#usage">Usage</a></h3>
<p>PHF data structures can be constructed via either the procedural
macros in the <code>phf_macros</code> crate or code generation supported by the
<code>phf_codegen</code> crate. If you prefer macros, you can easily use them by
enabling the <code>macros</code> feature of the <code>phf</code> crate, like:</p>
<div class="example-wrap"><pre class="language-toml"><code> [dependencies]
phf = { version = "0.11", features = ["macros"] }
</code></pre></div>
<p>To compile the <code>phf</code> crate with a dependency on
libcore instead of libstd, enabling use in environments where libstd
will not work, set <code>default-features = false</code> for the dependency:</p>
<div class="example-wrap"><pre class="language-toml"><code>[dependencies]
# to use `phf` in `no_std` environments
phf = { version = "0.11", default-features = false }
</code></pre></div><h3 id="example-with-the-macros-feature-enabled"><a href="#example-with-the-macros-feature-enabled">Example (with the <code>macros</code> feature enabled)</a></h3>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>phf::phf_map;
<span class="attr">#[derive(Clone)]
</span><span class="kw">pub enum </span>Keyword {
Loop,
Continue,
Break,
Fn,
Extern,
}
<span class="kw">static </span>KEYWORDS: phf::Map<<span class="kw-2">&</span><span class="lifetime">'static </span>str, Keyword> = <span class="macro">phf_map! </span>{
<span class="string">"loop" </span>=> Keyword::Loop,
<span class="string">"continue" </span>=> Keyword::Continue,
<span class="string">"break" </span>=> Keyword::Break,
<span class="string">"fn" </span>=> Keyword::Fn,
<span class="string">"extern" </span>=> Keyword::Extern,
};
<span class="kw">pub fn </span>parse_keyword(keyword: <span class="kw-2">&</span>str) -> <span class="prelude-ty">Option</span><Keyword> {
KEYWORDS.get(keyword).cloned()
}</code></pre></div>
<p>Alternatively, you can use the <a href="https://docs.rs/phf_codegen"><code>phf_codegen</code></a> crate to generate PHF datatypes
in a build script.</p>
<h3 id="note"><a href="#note">Note</a></h3>
<p>Currently, the macro syntax has some limitations and may not
work as you want. See <a href="https://github.com/rust-phf/rust-phf/issues/183">#183</a> or <a href="https://github.com/rust-phf/rust-phf/issues/196">#196</a> for example.</p>
</div></details><h2 id="modules" class="small-section-header"><a href="#modules">Modules</a></h2><ul class="item-table"><li><div class="item-name"><a class="mod" href="map/index.html" title="mod phf::map">map</a></div><div class="desc docblock-short">An immutable map constructed at compile time.</div></li><li><div class="item-name"><a class="mod" href="ordered_map/index.html" title="mod phf::ordered_map">ordered_map</a></div><div class="desc docblock-short">An order-preserving immutable map constructed at compile time.</div></li><li><div class="item-name"><a class="mod" href="ordered_set/index.html" title="mod phf::ordered_set">ordered_set</a></div><div class="desc docblock-short">An order-preserving immutable set constructed at compile time.</div></li><li><div class="item-name"><a class="mod" href="set/index.html" title="mod phf::set">set</a></div><div class="desc docblock-short">An immutable set constructed at compile time.</div></li></ul><h2 id="structs" class="small-section-header"><a href="#structs">Structs</a></h2><ul class="item-table"><li><div class="item-name"><a class="struct" href="struct.Map.html" title="struct phf::Map">Map</a></div><div class="desc docblock-short">An immutable map constructed at compile time.</div></li><li><div class="item-name"><a class="struct" href="struct.OrderedMap.html" title="struct phf::OrderedMap">OrderedMap</a></div><div class="desc docblock-short">An order-preserving immutable map constructed at compile time.</div></li><li><div class="item-name"><a class="struct" href="struct.OrderedSet.html" title="struct phf::OrderedSet">OrderedSet</a></div><div class="desc docblock-short">An order-preserving immutable set constructed at compile time.</div></li><li><div class="item-name"><a class="struct" href="struct.Set.html" title="struct phf::Set">Set</a></div><div class="desc docblock-short">An immutable set constructed at compile time.</div></li></ul><h2 id="traits" class="small-section-header"><a href="#traits">Traits</a></h2><ul class="item-table"><li><div class="item-name"><a class="trait" href="trait.PhfHash.html" title="trait phf::PhfHash">PhfHash</a></div><div class="desc docblock-short">A trait implemented by types which can be used in PHF data structures.</div></li></ul></section></div></main><div id="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="phf" data-themes="" data-resource-suffix="" data-rustdoc-version="1.69.0 (84c898d65 2023-04-16) (built from a source tarball)" data-search-js="search-8a59a8356673ec1f.js" data-settings-js="settings-f0c5c39777a9a2f6.js" data-settings-css="settings-0bcba95ff279c1db.css" ></div></body></html>