| <!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 of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/utf8-ranges-1.0.5/src/char_utf8.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>char_utf8.rs - source</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="../../source-script.js"></script><script defer src="../../source-files.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 source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../utf8_ranges/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../utf8_ranges/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><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="example-wrap"><pre class="src-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> |
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| <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> |
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| <span id="36">36</span> |
| </pre><pre class="rust"><code><span class="comment">// Pulled from std::char until encode_utf8 stabilizes. ---AG |
| |
| // UTF-8 ranges and tags for encoding characters |
| </span><span class="kw">const </span>TAG_CONT: u8 = <span class="number">0b1000_0000</span>; |
| <span class="kw">const </span>TAG_TWO_B: u8 = <span class="number">0b1100_0000</span>; |
| <span class="kw">const </span>TAG_THREE_B: u8 = <span class="number">0b1110_0000</span>; |
| <span class="kw">const </span>TAG_FOUR_B: u8 = <span class="number">0b1111_0000</span>; |
| <span class="kw">const </span>MAX_ONE_B: u32 = <span class="number">0x80</span>; |
| <span class="kw">const </span>MAX_TWO_B: u32 = <span class="number">0x800</span>; |
| <span class="kw">const </span>MAX_THREE_B: u32 = <span class="number">0x10000</span>; |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>encode_utf8(character: char, dst: <span class="kw-2">&mut </span>[u8]) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">let </span>code = character <span class="kw">as </span>u32; |
| <span class="kw">if </span>code < MAX_ONE_B && !dst.is_empty() { |
| dst[<span class="number">0</span>] = code <span class="kw">as </span>u8; |
| <span class="prelude-val">Some</span>(<span class="number">1</span>) |
| } <span class="kw">else if </span>code < MAX_TWO_B && dst.len() >= <span class="number">2 </span>{ |
| dst[<span class="number">0</span>] = (code >> <span class="number">6 </span>& <span class="number">0x1F</span>) <span class="kw">as </span>u8 | TAG_TWO_B; |
| dst[<span class="number">1</span>] = (code & <span class="number">0x3F</span>) <span class="kw">as </span>u8 | TAG_CONT; |
| <span class="prelude-val">Some</span>(<span class="number">2</span>) |
| } <span class="kw">else if </span>code < MAX_THREE_B && dst.len() >= <span class="number">3 </span>{ |
| dst[<span class="number">0</span>] = (code >> <span class="number">12 </span>& <span class="number">0x0F</span>) <span class="kw">as </span>u8 | TAG_THREE_B; |
| dst[<span class="number">1</span>] = (code >> <span class="number">6 </span>& <span class="number">0x3F</span>) <span class="kw">as </span>u8 | TAG_CONT; |
| dst[<span class="number">2</span>] = (code & <span class="number">0x3F</span>) <span class="kw">as </span>u8 | TAG_CONT; |
| <span class="prelude-val">Some</span>(<span class="number">3</span>) |
| } <span class="kw">else if </span>dst.len() >= <span class="number">4 </span>{ |
| dst[<span class="number">0</span>] = (code >> <span class="number">18 </span>& <span class="number">0x07</span>) <span class="kw">as </span>u8 | TAG_FOUR_B; |
| dst[<span class="number">1</span>] = (code >> <span class="number">12 </span>& <span class="number">0x3F</span>) <span class="kw">as </span>u8 | TAG_CONT; |
| dst[<span class="number">2</span>] = (code >> <span class="number">6 </span>& <span class="number">0x3F</span>) <span class="kw">as </span>u8 | TAG_CONT; |
| dst[<span class="number">3</span>] = (code & <span class="number">0x3F</span>) <span class="kw">as </span>u8 | TAG_CONT; |
| <span class="prelude-val">Some</span>(<span class="number">4</span>) |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">None |
| </span>} |
| } |
| </code></pre></div> |
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