<!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="Source to the Rust file `libstd/memchr.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>memchr.rs.html -- source</title><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../dark.css"><link rel="stylesheet" type="text/css" href="../../light.css" id="themeStyle"><script src="../../storage.js"></script><link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"></head><body class="rustdoc source"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../std/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../../settings.html"><img src="../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span> <span id="2"> 2</span> <span id="3"> 3</span> <span id="4"> 4</span> <span id="5"> 5</span> <span id="6"> 6</span> <span id="7"> 7</span> <span id="8"> 8</span> <span id="9"> 9</span> <span id="10"> 10</span> <span id="11"> 11</span> <span id="12"> 12</span> <span id="13"> 13</span> <span id="14"> 14</span> <span id="15"> 15</span> <span id="16"> 16</span> <span id="17"> 17</span> <span id="18"> 18</span> <span id="19"> 19</span> <span id="20"> 20</span> <span id="21"> 21</span> <span id="22"> 22</span> <span id="23"> 23</span> <span id="24"> 24</span> <span id="25"> 25</span> <span id="26"> 26</span> <span id="27"> 27</span> <span id="28"> 28</span> <span id="29"> 29</span> <span id="30"> 30</span> <span id="31"> 31</span> <span id="32"> 32</span> <span id="33"> 33</span> <span id="34"> 34</span> <span id="35"> 35</span> <span id="36"> 36</span> <span id="37"> 37</span> <span id="38"> 38</span> <span id="39"> 39</span> <span id="40"> 40</span> <span id="41"> 41</span> <span id="42"> 42</span> <span id="43"> 43</span> <span id="44"> 44</span> <span id="45"> 45</span> <span id="46"> 46</span> <span id="47"> 47</span> <span id="48"> 48</span> <span id="49"> 49</span> <span id="50"> 50</span> <span id="51"> 51</span> <span id="52"> 52</span> <span id="53"> 53</span> <span id="54"> 54</span> <span id="55"> 55</span> <span id="56"> 56</span> <span id="57"> 57</span> <span id="58"> 58</span> <span id="59"> 59</span> <span id="60"> 60</span> <span id="61"> 61</span> <span id="62"> 62</span> <span id="63"> 63</span> <span id="64"> 64</span> <span id="65"> 65</span> <span id="66"> 66</span> <span id="67"> 67</span> <span id="68"> 68</span> <span id="69"> 69</span> <span id="70"> 70</span> <span id="71"> 71</span> <span id="72"> 72</span> <span id="73"> 73</span> <span id="74"> 74</span> <span id="75"> 75</span> <span id="76"> 76</span> <span id="77"> 77</span> <span id="78"> 78</span> <span id="79"> 79</span> <span id="80"> 80</span> <span id="81"> 81</span> <span id="82"> 82</span> <span id="83"> 83</span> <span id="84"> 84</span> <span id="85"> 85</span> <span id="86"> 86</span> <span id="87"> 87</span> <span id="88"> 88</span> <span id="89"> 89</span> <span id="90"> 90</span> <span id="91"> 91</span> <span id="92"> 92</span> <span id="93"> 93</span> <span id="94"> 94</span> <span id="95"> 95</span> <span id="96"> 96</span> <span id="97"> 97</span> <span id="98"> 98</span> <span id="99"> 99</span> <span id="100">100</span> <span id="101">101</span> <span id="102">102</span> <span id="103">103</span> <span id="104">104</span> <span id="105">105</span> <span id="106">106</span> <span id="107">107</span> <span id="108">108</span> <span id="109">109</span> <span id="110">110</span> <span id="111">111</span> <span id="112">112</span> <span id="113">113</span> <span id="114">114</span> <span id="115">115</span> <span id="116">116</span> <span id="117">117</span> <span id="118">118</span> <span id="119">119</span> <span id="120">120</span> <span id="121">121</span> <span id="122">122</span> <span id="123">123</span> <span id="124">124</span> <span id="125">125</span> <span id="126">126</span> <span id="127">127</span> <span id="128">128</span> <span id="129">129</span> <span id="130">130</span> <span id="131">131</span> <span id="132">132</span> <span id="133">133</span> <span id="134">134</span> <span id="135">135</span> <span id="136">136</span> <span id="137">137</span> <span id="138">138</span> <span id="139">139</span> <span id="140">140</span> <span id="141">141</span> <span id="142">142</span> <span id="143">143</span> </pre><pre class="rust "> <span class="comment">// Copyright 2015 The Rust Project Developers. See the COPYRIGHT</span> <span class="comment">// file at the top-level directory of this distribution and at</span> <span class="comment">// http://rust-lang.org/COPYRIGHT.</span> <span class="comment">//</span> <span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span> <span class="comment">// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span> <span class="comment">// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your</span> <span class="comment">// option. This file may not be copied, modified, or distributed</span> <span class="comment">// except according to those terms.</span> <span class="comment">//</span> <span class="comment">// Original implementation taken from rust-memchr</span> <span class="comment">// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch</span> <span class="doccomment">/// A safe interface to `memchr`.</span> <span class="doccomment">///</span> <span class="doccomment">/// Returns the index corresponding to the first occurrence of `needle` in</span> <span class="doccomment">/// `haystack`, or `None` if one is not found.</span> <span class="doccomment">///</span> <span class="doccomment">/// memchr reduces to super-optimized machine code at around an order of</span> <span class="doccomment">/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.</span> <span class="doccomment">/// (See benchmarks.)</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// This shows how to find the first position of a byte in a byte string.</span> <span class="doccomment">///</span> <span class="doccomment">/// ```ignore (cannot-doctest-private-modules)</span> <span class="doccomment">/// use memchr::memchr;</span> <span class="doccomment">///</span> <span class="doccomment">/// let haystack = b"the quick brown fox";</span> <span class="doccomment">/// assert_eq!(memchr(b'k', haystack), Some(8));</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">memchr</span>(<span class="ident">needle</span>: <span class="ident">u8</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { ::<span class="ident">sys</span>::<span class="ident">memchr</span>::<span class="ident">memchr</span>(<span class="ident">needle</span>, <span class="ident">haystack</span>) } <span class="doccomment">/// A safe interface to `memrchr`.</span> <span class="doccomment">///</span> <span class="doccomment">/// Returns the index corresponding to the last occurrence of `needle` in</span> <span class="doccomment">/// `haystack`, or `None` if one is not found.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// This shows how to find the last position of a byte in a byte string.</span> <span class="doccomment">///</span> <span class="doccomment">/// ```ignore (cannot-doctest-private-modules)</span> <span class="doccomment">/// use memchr::memrchr;</span> <span class="doccomment">///</span> <span class="doccomment">/// let haystack = b"the quick brown fox";</span> <span class="doccomment">/// assert_eq!(memrchr(b'o', haystack), Some(17));</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">memrchr</span>(<span class="ident">needle</span>: <span class="ident">u8</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { ::<span class="ident">sys</span>::<span class="ident">memchr</span>::<span class="ident">memrchr</span>(<span class="ident">needle</span>, <span class="ident">haystack</span>) } <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span> <span class="kw">mod</span> <span class="ident">tests</span> { <span class="comment">// test the implementations for the current plattform</span> <span class="kw">use</span> <span class="kw">super</span>::{<span class="ident">memchr</span>, <span class="ident">memrchr</span>}; <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_one</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="ident">memchr</span>(<span class="string">b'a'</span>, <span class="string">b"a"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_begin</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="ident">memchr</span>(<span class="string">b'a'</span>, <span class="string">b"aaaa"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_end</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">memchr</span>(<span class="string">b'z'</span>, <span class="string">b"aaaaz"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_nul</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">memchr</span>(<span class="string">b'\x00'</span>, <span class="string">b"aaaa\x00"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_past_nul</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">5</span>), <span class="ident">memchr</span>(<span class="string">b'z'</span>, <span class="string">b"aaaa\x00z"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">no_match_empty</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">None</span>, <span class="ident">memchr</span>(<span class="string">b'a'</span>, <span class="string">b""</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">no_match</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">None</span>, <span class="ident">memchr</span>(<span class="string">b'a'</span>, <span class="string">b"xyz"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_one_reversed</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="ident">memrchr</span>(<span class="string">b'a'</span>, <span class="string">b"a"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_begin_reversed</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">3</span>), <span class="ident">memrchr</span>(<span class="string">b'a'</span>, <span class="string">b"aaaa"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_end_reversed</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="ident">memrchr</span>(<span class="string">b'z'</span>, <span class="string">b"zaaaa"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_nul_reversed</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">memrchr</span>(<span class="string">b'\x00'</span>, <span class="string">b"aaaa\x00"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">matches_past_nul_reversed</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="ident">memrchr</span>(<span class="string">b'z'</span>, <span class="string">b"z\x00aaaa"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">no_match_empty_reversed</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">None</span>, <span class="ident">memrchr</span>(<span class="string">b'a'</span>, <span class="string">b""</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">no_match_reversed</span>() { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">None</span>, <span class="ident">memrchr</span>(<span class="string">b'a'</span>, <span class="string">b"xyz"</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">each_alignment</span>() { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">data</span> <span class="op">=</span> [<span class="number">1u8</span>; <span class="number">64</span>]; <span class="kw">let</span> <span class="ident">needle</span> <span class="op">=</span> <span class="number">2</span>; <span class="kw">let</span> <span class="ident">pos</span> <span class="op">=</span> <span class="number">40</span>; <span class="ident">data</span>[<span class="ident">pos</span>] <span class="op">=</span> <span class="ident">needle</span>; <span class="kw">for</span> <span class="ident">start</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">16</span> { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="ident">pos</span> <span class="op">-</span> <span class="ident">start</span>), <span class="ident">memchr</span>(<span class="ident">needle</span>, <span class="kw-2">&</span><span class="ident">data</span>[<span class="ident">start</span>..])); } } } </pre> </section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../../";window.currentCrate = "std";</script><script src="../../aliases.js"></script><script src="../../main.js"></script><script defer src="../../search-index.js"></script></body></html>