<!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 `liballoc/str.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>str.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='../../alloc/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"> 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id="510">510</span> <span id="511">511</span> <span id="512">512</span> <span id="513">513</span> <span id="514">514</span> <span id="515">515</span> <span id="516">516</span> <span id="517">517</span> <span id="518">518</span> <span id="519">519</span> <span id="520">520</span> <span id="521">521</span> <span id="522">522</span> </pre><pre class="rust "> <span class="comment">// Copyright 2012-2017 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="doccomment">//! Unicode string slices.</span> <span class="doccomment">//!</span> <span class="doccomment">//! The `&str` type is one of the two main string types, the other being `String`.</span> <span class="doccomment">//! Unlike its `String` counterpart, its contents are borrowed.</span> <span class="doccomment">//!</span> <span class="doccomment">//! # Basic Usage</span> <span class="doccomment">//!</span> <span class="doccomment">//! A basic string declaration of `&str` type:</span> <span class="doccomment">//!</span> <span class="doccomment">//! ```</span> <span class="doccomment">//! let hello_world = "Hello, World!";</span> <span class="doccomment">//! ```</span> <span class="doccomment">//!</span> <span class="doccomment">//! Here we have declared a string literal, also known as a string slice.</span> <span class="doccomment">//! String literals have a static lifetime, which means the string `hello_world`</span> <span class="doccomment">//! is guaranteed to be valid for the duration of the entire program.</span> <span class="doccomment">//! We can explicitly specify `hello_world`'s lifetime as well:</span> <span class="doccomment">//!</span> <span class="doccomment">//! ```</span> <span class="doccomment">//! let hello_world: &'static str = "Hello, world!";</span> <span class="doccomment">//! ```</span> <span class="doccomment">//!</span> <span class="doccomment">//! *[See also the `str` primitive type](../../std/primitive.str.html).*</span> <span class="attribute">#![<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="comment">// Many of the usings in this module are only used in the test configuration.</span> <span class="comment">// It's cleaner to just turn off the unused_imports warning than to fix them.</span> <span class="attribute">#![<span class="ident">allow</span>(<span class="ident">unused_imports</span>)]</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">fmt</span>; <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span> <span class="kw">as</span> <span class="ident">core_str</span>; <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">stage0</span>)]</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::<span class="ident">StrExt</span>; <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::<span class="ident">pattern</span>::<span class="ident">Pattern</span>; <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::<span class="ident">pattern</span>::{<span class="ident">Searcher</span>, <span class="ident">ReverseSearcher</span>, <span class="ident">DoubleEndedSearcher</span>}; <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">mem</span>; <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">ptr</span>; <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">iter</span>::<span class="ident">FusedIterator</span>; <span class="kw">use</span> <span class="ident">borrow</span>::{<span class="ident">Borrow</span>, <span class="ident">ToOwned</span>}; <span class="kw">use</span> <span class="ident">boxed</span>::<span class="ident">Box</span>; <span class="kw">use</span> <span class="ident">slice</span>::{<span class="ident">SliceConcatExt</span>, <span class="ident">SliceIndex</span>}; <span class="kw">use</span> <span class="ident">string</span>::<span class="ident">String</span>; <span class="kw">use</span> <span class="ident">vec</span>::<span class="ident">Vec</span>; <span class="kw">use</span> <span class="ident">vec_deque</span>::<span class="ident">VecDeque</span>; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::{<span class="ident">FromStr</span>, <span class="ident">Utf8Error</span>}; <span class="attribute">#[<span class="ident">allow</span>(<span class="ident">deprecated</span>)]</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::{<span class="ident">Lines</span>, <span class="ident">LinesAny</span>}; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::{<span class="ident">Split</span>, <span class="ident">RSplit</span>}; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::{<span class="ident">SplitN</span>, <span class="ident">RSplitN</span>}; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::{<span class="ident">SplitTerminator</span>, <span class="ident">RSplitTerminator</span>}; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::{<span class="ident">Matches</span>, <span class="ident">RMatches</span>}; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::{<span class="ident">MatchIndices</span>, <span class="ident">RMatchIndices</span>}; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::{<span class="ident">from_utf8</span>, <span class="ident">from_utf8_mut</span>, <span class="ident">Chars</span>, <span class="ident">CharIndices</span>, <span class="ident">Bytes</span>}; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::{<span class="ident">from_utf8_unchecked</span>, <span class="ident">from_utf8_unchecked_mut</span>, <span class="ident">ParseBoolError</span>}; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::<span class="ident">SplitWhitespace</span>; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::<span class="ident">pattern</span>; <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"encode_utf16"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.8.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">str</span>::<span class="ident">EncodeUtf16</span>; <span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"slice_concat_ext"</span>, <span class="ident">reason</span> <span class="op">=</span> <span class="string">"trait should not have to exist"</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">"27747"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">S</span>: <span class="ident">Borrow</span><span class="op"><</span><span class="ident">str</span><span class="op">>></span> <span class="ident">SliceConcatExt</span><span class="op"><</span><span class="ident">str</span><span class="op">></span> <span class="kw">for</span> [<span class="ident">S</span>] { <span class="kw">type</span> <span class="ident">Output</span> <span class="op">=</span> <span class="ident">String</span>; <span class="kw">fn</span> <span class="ident">concat</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">if</span> <span class="self">self</span>.<span class="ident">is_empty</span>() { <span class="kw">return</span> <span class="ident">String</span>::<span class="ident">new</span>(); } <span class="comment">// `len` calculation may overflow but push_str will check boundaries</span> <span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">iter</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>.<span class="ident">borrow</span>().<span class="ident">len</span>()).<span class="ident">sum</span>(); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">with_capacity</span>(<span class="ident">len</span>); <span class="kw">for</span> <span class="ident">s</span> <span class="kw">in</span> <span class="self">self</span> { <span class="ident">result</span>.<span class="ident">push_str</span>(<span class="ident">s</span>.<span class="ident">borrow</span>()) } <span class="ident">result</span> } <span class="kw">fn</span> <span class="ident">join</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">sep</span>: <span class="kw-2">&</span><span class="ident">str</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">if</span> <span class="self">self</span>.<span class="ident">is_empty</span>() { <span class="kw">return</span> <span class="ident">String</span>::<span class="ident">new</span>(); } <span class="comment">// concat is faster</span> <span class="kw">if</span> <span class="ident">sep</span>.<span class="ident">is_empty</span>() { <span class="kw">return</span> <span class="self">self</span>.<span class="ident">concat</span>(); } <span class="comment">// this is wrong without the guarantee that `self` is non-empty</span> <span class="comment">// `len` calculation may overflow but push_str but will check boundaries</span> <span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">sep</span>.<span class="ident">len</span>() <span class="op">*</span> (<span class="self">self</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="number">1</span>) <span class="op">+</span> <span class="self">self</span>.<span class="ident">iter</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>.<span class="ident">borrow</span>().<span class="ident">len</span>()).<span class="ident">sum</span>::<span class="op"><</span><span class="ident">usize</span><span class="op">></span>(); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">with_capacity</span>(<span class="ident">len</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">first</span> <span class="op">=</span> <span class="bool-val">true</span>; <span class="kw">for</span> <span class="ident">s</span> <span class="kw">in</span> <span class="self">self</span> { <span class="kw">if</span> <span class="ident">first</span> { <span class="ident">first</span> <span class="op">=</span> <span class="bool-val">false</span>; } <span class="kw">else</span> { <span class="ident">result</span>.<span class="ident">push_str</span>(<span class="ident">sep</span>); } <span class="ident">result</span>.<span class="ident">push_str</span>(<span class="ident">s</span>.<span class="ident">borrow</span>()); } <span class="ident">result</span> } <span class="kw">fn</span> <span class="ident">connect</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">sep</span>: <span class="kw-2">&</span><span class="ident">str</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="self">self</span>.<span class="ident">join</span>(<span class="ident">sep</span>) } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span> <span class="ident">Borrow</span><span class="op"><</span><span class="ident">str</span><span class="op">></span> <span class="kw">for</span> <span class="ident">String</span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">borrow</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="ident">str</span> { <span class="kw-2">&</span><span class="self">self</span>[..] } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span> <span class="ident">ToOwned</span> <span class="kw">for</span> <span class="ident">str</span> { <span class="kw">type</span> <span class="ident">Owned</span> <span class="op">=</span> <span class="ident">String</span>; <span class="kw">fn</span> <span class="ident">to_owned</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">unsafe</span> { <span class="ident">String</span>::<span class="ident">from_utf8_unchecked</span>(<span class="self">self</span>.<span class="ident">as_bytes</span>().<span class="ident">to_owned</span>()) } } <span class="kw">fn</span> <span class="ident">clone_into</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">target</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">String</span>) { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">b</span> <span class="op">=</span> <span class="ident">mem</span>::<span class="ident">replace</span>(<span class="ident">target</span>, <span class="ident">String</span>::<span class="ident">new</span>()).<span class="ident">into_bytes</span>(); <span class="self">self</span>.<span class="ident">as_bytes</span>().<span class="ident">clone_into</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">b</span>); <span class="kw-2">*</span><span class="ident">target</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">String</span>::<span class="ident">from_utf8_unchecked</span>(<span class="ident">b</span>) } } } <span class="doccomment">/// Methods for string slices.</span> <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">stage0</span>, <span class="ident">lang</span> <span class="op">=</span> <span class="string">"str"</span>)]</span> <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">not</span>(<span class="ident">stage0</span>), <span class="ident">lang</span> <span class="op">=</span> <span class="string">"str_alloc"</span>)]</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">test</span>))]</span> <span class="kw">impl</span> <span class="ident">str</span> { <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">stage0</span>)]</span> <span class="macro">str_core_methods</span><span class="macro">!</span>(); <span class="doccomment">/// Converts a `Box<str>` into a `Box<[u8]>` without copying or allocating.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Basic usage:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let s = "this is a string";</span> <span class="doccomment">/// let boxed_str = s.to_owned().into_boxed_str();</span> <span class="doccomment">/// let boxed_bytes = boxed_str.into_boxed_bytes();</span> <span class="doccomment">/// assert_eq!(*boxed_bytes, *s.as_bytes());</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"str_box_extras"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.20.0"</span>)]</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_boxed_bytes</span>(<span class="self">self</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">str</span><span class="op">></span>) <span class="op">-></span> <span class="ident">Box</span><span class="op"><</span>[<span class="ident">u8</span>]<span class="op">></span> { <span class="self">self</span>.<span class="ident">into</span>() } <span class="doccomment">/// Replaces all matches of a pattern with another string.</span> <span class="doccomment">///</span> <span class="doccomment">/// `replace` creates a new [`String`], and copies the data from this string slice into it.</span> <span class="doccomment">/// While doing so, it attempts to find matches of a pattern. If it finds any, it</span> <span class="doccomment">/// replaces them with the replacement string slice.</span> <span class="doccomment">///</span> <span class="doccomment">/// [`String`]: string/struct.String.html</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Basic usage:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let s = "this is old";</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!("this is new", s.replace("old", "new"));</span> <span class="doccomment">/// ```</span> <span class="doccomment">///</span> <span class="doccomment">/// When the pattern doesn't match:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let s = "this is old";</span> <span class="doccomment">/// assert_eq!(s, s.replace("cookie monster", "little lamb"));</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">must_use</span>]</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">replace</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">P</span>: <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">>></span>(<span class="kw-2">&</span><span class="lifetime">'a</span> <span class="self">self</span>, <span class="ident">from</span>: <span class="ident">P</span>, <span class="ident">to</span>: <span class="kw-2">&</span><span class="ident">str</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">new</span>(); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">last_end</span> <span class="op">=</span> <span class="number">0</span>; <span class="kw">for</span> (<span class="ident">start</span>, <span class="ident">part</span>) <span class="kw">in</span> <span class="self">self</span>.<span class="ident">match_indices</span>(<span class="ident">from</span>) { <span class="ident">result</span>.<span class="ident">push_str</span>(<span class="kw">unsafe</span> { <span class="self">self</span>.<span class="ident">slice_unchecked</span>(<span class="ident">last_end</span>, <span class="ident">start</span>) }); <span class="ident">result</span>.<span class="ident">push_str</span>(<span class="ident">to</span>); <span class="ident">last_end</span> <span class="op">=</span> <span class="ident">start</span> <span class="op">+</span> <span class="ident">part</span>.<span class="ident">len</span>(); } <span class="ident">result</span>.<span class="ident">push_str</span>(<span class="kw">unsafe</span> { <span class="self">self</span>.<span class="ident">slice_unchecked</span>(<span class="ident">last_end</span>, <span class="self">self</span>.<span class="ident">len</span>()) }); <span class="ident">result</span> } <span class="doccomment">/// Replaces first N matches of a pattern with another string.</span> <span class="doccomment">///</span> <span class="doccomment">/// `replacen` creates a new [`String`], and copies the data from this string slice into it.</span> <span class="doccomment">/// While doing so, it attempts to find matches of a pattern. If it finds any, it</span> <span class="doccomment">/// replaces them with the replacement string slice at most `count` times.</span> <span class="doccomment">///</span> <span class="doccomment">/// [`String`]: string/struct.String.html</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Basic usage:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let s = "foo foo 123 foo";</span> <span class="doccomment">/// assert_eq!("new new 123 foo", s.replacen("foo", "new", 2));</span> <span class="doccomment">/// assert_eq!("faa fao 123 foo", s.replacen('o', "a", 3));</span> <span class="doccomment">/// assert_eq!("foo foo new23 foo", s.replacen(char::is_numeric, "new", 1));</span> <span class="doccomment">/// ```</span> <span class="doccomment">///</span> <span class="doccomment">/// When the pattern doesn't match:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let s = "this is old";</span> <span class="doccomment">/// assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">must_use</span>]</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"str_replacen"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.16.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">replacen</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">P</span>: <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">>></span>(<span class="kw-2">&</span><span class="lifetime">'a</span> <span class="self">self</span>, <span class="ident">pat</span>: <span class="ident">P</span>, <span class="ident">to</span>: <span class="kw-2">&</span><span class="ident">str</span>, <span class="ident">count</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="comment">// Hope to reduce the times of re-allocation</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">with_capacity</span>(<span class="number">32</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">last_end</span> <span class="op">=</span> <span class="number">0</span>; <span class="kw">for</span> (<span class="ident">start</span>, <span class="ident">part</span>) <span class="kw">in</span> <span class="self">self</span>.<span class="ident">match_indices</span>(<span class="ident">pat</span>).<span class="ident">take</span>(<span class="ident">count</span>) { <span class="ident">result</span>.<span class="ident">push_str</span>(<span class="kw">unsafe</span> { <span class="self">self</span>.<span class="ident">slice_unchecked</span>(<span class="ident">last_end</span>, <span class="ident">start</span>) }); <span class="ident">result</span>.<span class="ident">push_str</span>(<span class="ident">to</span>); <span class="ident">last_end</span> <span class="op">=</span> <span class="ident">start</span> <span class="op">+</span> <span class="ident">part</span>.<span class="ident">len</span>(); } <span class="ident">result</span>.<span class="ident">push_str</span>(<span class="kw">unsafe</span> { <span class="self">self</span>.<span class="ident">slice_unchecked</span>(<span class="ident">last_end</span>, <span class="self">self</span>.<span class="ident">len</span>()) }); <span class="ident">result</span> } <span class="doccomment">/// Returns the lowercase equivalent of this string slice, as a new [`String`].</span> <span class="doccomment">///</span> <span class="doccomment">/// 'Lowercase' is defined according to the terms of the Unicode Derived Core Property</span> <span class="doccomment">/// `Lowercase`.</span> <span class="doccomment">///</span> <span class="doccomment">/// Since some characters can expand into multiple characters when changing</span> <span class="doccomment">/// the case, this function returns a [`String`] instead of modifying the</span> <span class="doccomment">/// parameter in-place.</span> <span class="doccomment">///</span> <span class="doccomment">/// [`String`]: string/struct.String.html</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Basic usage:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let s = "HELLO";</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!("hello", s.to_lowercase());</span> <span class="doccomment">/// ```</span> <span class="doccomment">///</span> <span class="doccomment">/// A tricky example, with sigma:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let sigma = "Σ";</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!("σ", sigma.to_lowercase());</span> <span class="doccomment">///</span> <span class="doccomment">/// // but at the end of a word, it's ς, not σ:</span> <span class="doccomment">/// let odysseus = "ὈΔΥΣΣΕΎΣ";</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!("ὀδυσσεύς", odysseus.to_lowercase());</span> <span class="doccomment">/// ```</span> <span class="doccomment">///</span> <span class="doccomment">/// Languages without case are not changed:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let new_year = "农历新年";</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!(new_year, new_year.to_lowercase());</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"unicode_case_mapping"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.2.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">to_lowercase</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">s</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">with_capacity</span>(<span class="self">self</span>.<span class="ident">len</span>()); <span class="kw">for</span> (<span class="ident">i</span>, <span class="ident">c</span>) <span class="kw">in</span> <span class="self">self</span>[..].<span class="ident">char_indices</span>() { <span class="kw">if</span> <span class="ident">c</span> <span class="op">==</span> <span class="string">'Σ'</span> { <span class="comment">// Σ maps to σ, except at the end of a word where it maps to ς.</span> <span class="comment">// This is the only conditional (contextual) but language-independent mapping</span> <span class="comment">// in `SpecialCasing.txt`,</span> <span class="comment">// so hard-code it rather than have a generic "condition" mechanism.</span> <span class="comment">// See https://github.com/rust-lang/rust/issues/26035</span> <span class="ident">map_uppercase_sigma</span>(<span class="self">self</span>, <span class="ident">i</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">s</span>) } <span class="kw">else</span> { <span class="ident">s</span>.<span class="ident">extend</span>(<span class="ident">c</span>.<span class="ident">to_lowercase</span>()); } } <span class="kw">return</span> <span class="ident">s</span>; <span class="kw">fn</span> <span class="ident">map_uppercase_sigma</span>(<span class="ident">from</span>: <span class="kw-2">&</span><span class="ident">str</span>, <span class="ident">i</span>: <span class="ident">usize</span>, <span class="ident">to</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">String</span>) { <span class="comment">// See http://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G33992</span> <span class="comment">// for the definition of `Final_Sigma`.</span> <span class="macro">debug_assert</span><span class="macro">!</span>(<span class="string">'Σ'</span>.<span class="ident">len_utf8</span>() <span class="op">==</span> <span class="number">2</span>); <span class="kw">let</span> <span class="ident">is_word_final</span> <span class="op">=</span> <span class="ident">case_ignoreable_then_cased</span>(<span class="ident">from</span>[..<span class="ident">i</span>].<span class="ident">chars</span>().<span class="ident">rev</span>()) <span class="op">&&</span> <span class="op">!</span><span class="ident">case_ignoreable_then_cased</span>(<span class="ident">from</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">2</span>..].<span class="ident">chars</span>()); <span class="ident">to</span>.<span class="ident">push_str</span>(<span class="kw">if</span> <span class="ident">is_word_final</span> { <span class="string">"ς"</span> } <span class="kw">else</span> { <span class="string">"σ"</span> }); } <span class="kw">fn</span> <span class="ident">case_ignoreable_then_cased</span><span class="op"><</span><span class="ident">I</span>: <span class="ident">Iterator</span><span class="op"><</span><span class="ident">Item</span> <span class="op">=</span> <span class="ident">char</span><span class="op">>></span>(<span class="ident">iter</span>: <span class="ident">I</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="kw">use</span> <span class="ident">core</span>::<span class="ident">unicode</span>::<span class="ident">derived_property</span>::{<span class="ident">Cased</span>, <span class="ident">Case_Ignorable</span>}; <span class="kw">match</span> <span class="ident">iter</span>.<span class="ident">skip_while</span>(<span class="op">|</span><span class="kw-2">&</span><span class="ident">c</span><span class="op">|</span> <span class="ident">Case_Ignorable</span>(<span class="ident">c</span>)).<span class="ident">next</span>() { <span class="prelude-val">Some</span>(<span class="ident">c</span>) <span class="op">=></span> <span class="ident">Cased</span>(<span class="ident">c</span>), <span class="prelude-val">None</span> <span class="op">=></span> <span class="bool-val">false</span>, } } } <span class="doccomment">/// Returns the uppercase equivalent of this string slice, as a new [`String`].</span> <span class="doccomment">///</span> <span class="doccomment">/// 'Uppercase' is defined according to the terms of the Unicode Derived Core Property</span> <span class="doccomment">/// `Uppercase`.</span> <span class="doccomment">///</span> <span class="doccomment">/// Since some characters can expand into multiple characters when changing</span> <span class="doccomment">/// the case, this function returns a [`String`] instead of modifying the</span> <span class="doccomment">/// parameter in-place.</span> <span class="doccomment">///</span> <span class="doccomment">/// [`String`]: string/struct.String.html</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Basic usage:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let s = "hello";</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!("HELLO", s.to_uppercase());</span> <span class="doccomment">/// ```</span> <span class="doccomment">///</span> <span class="doccomment">/// Scripts without case are not changed:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let new_year = "农历新年";</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!(new_year, new_year.to_uppercase());</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"unicode_case_mapping"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.2.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">to_uppercase</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">s</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">with_capacity</span>(<span class="self">self</span>.<span class="ident">len</span>()); <span class="ident">s</span>.<span class="ident">extend</span>(<span class="self">self</span>.<span class="ident">chars</span>().<span class="ident">flat_map</span>(<span class="op">|</span><span class="ident">c</span><span class="op">|</span> <span class="ident">c</span>.<span class="ident">to_uppercase</span>())); <span class="kw">return</span> <span class="ident">s</span>; } <span class="doccomment">/// Escapes each char in `s` with [`char::escape_debug`].</span> <span class="doccomment">///</span> <span class="doccomment">/// [`char::escape_debug`]: primitive.char.html#method.escape_debug</span> <span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"str_escape"</span>, <span class="ident">reason</span> <span class="op">=</span> <span class="string">"return type may change to be an iterator"</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">"27791"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">escape_debug</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="self">self</span>.<span class="ident">chars</span>().<span class="ident">flat_map</span>(<span class="op">|</span><span class="ident">c</span><span class="op">|</span> <span class="ident">c</span>.<span class="ident">escape_debug</span>()).<span class="ident">collect</span>() } <span class="doccomment">/// Escapes each char in `s` with [`char::escape_default`].</span> <span class="doccomment">///</span> <span class="doccomment">/// [`char::escape_default`]: primitive.char.html#method.escape_default</span> <span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"str_escape"</span>, <span class="ident">reason</span> <span class="op">=</span> <span class="string">"return type may change to be an iterator"</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">"27791"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">escape_default</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="self">self</span>.<span class="ident">chars</span>().<span class="ident">flat_map</span>(<span class="op">|</span><span class="ident">c</span><span class="op">|</span> <span class="ident">c</span>.<span class="ident">escape_default</span>()).<span class="ident">collect</span>() } <span class="doccomment">/// Escapes each char in `s` with [`char::escape_unicode`].</span> <span class="doccomment">///</span> <span class="doccomment">/// [`char::escape_unicode`]: primitive.char.html#method.escape_unicode</span> <span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"str_escape"</span>, <span class="ident">reason</span> <span class="op">=</span> <span class="string">"return type may change to be an iterator"</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">"27791"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">escape_unicode</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="self">self</span>.<span class="ident">chars</span>().<span class="ident">flat_map</span>(<span class="op">|</span><span class="ident">c</span><span class="op">|</span> <span class="ident">c</span>.<span class="ident">escape_unicode</span>()).<span class="ident">collect</span>() } <span class="doccomment">/// Converts a [`Box<str>`] into a [`String`] without copying or allocating.</span> <span class="doccomment">///</span> <span class="doccomment">/// [`String`]: string/struct.String.html</span> <span class="doccomment">/// [`Box<str>`]: boxed/struct.Box.html</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Basic usage:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let string = String::from("birthday gift");</span> <span class="doccomment">/// let boxed_str = string.clone().into_boxed_str();</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!(boxed_str.into_string(), string);</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"box_str"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.4.0"</span>)]</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_string</span>(<span class="self">self</span>: <span class="ident">Box</span><span class="op"><</span><span class="ident">str</span><span class="op">></span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">let</span> <span class="ident">slice</span> <span class="op">=</span> <span class="ident">Box</span>::<span class="op"><</span>[<span class="ident">u8</span>]<span class="op">></span>::<span class="ident">from</span>(<span class="self">self</span>); <span class="kw">unsafe</span> { <span class="ident">String</span>::<span class="ident">from_utf8_unchecked</span>(<span class="ident">slice</span>.<span class="ident">into_vec</span>()) } } <span class="doccomment">/// Create a [`String`] by repeating a string `n` times.</span> <span class="doccomment">///</span> <span class="doccomment">/// [`String`]: string/struct.String.html</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Basic usage:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// assert_eq!("abc".repeat(4), String::from("abcabcabcabc"));</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"repeat_str"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.16.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">repeat</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">n</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">unsafe</span> { <span class="ident">String</span>::<span class="ident">from_utf8_unchecked</span>(<span class="self">self</span>.<span class="ident">as_bytes</span>().<span class="ident">repeat</span>(<span class="ident">n</span>)) } } <span class="doccomment">/// Returns a copy of this string where each character is mapped to its</span> <span class="doccomment">/// ASCII upper case equivalent.</span> <span class="doccomment">///</span> <span class="doccomment">/// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',</span> <span class="doccomment">/// but non-ASCII letters are unchanged.</span> <span class="doccomment">///</span> <span class="doccomment">/// To uppercase the value in-place, use [`make_ascii_uppercase`].</span> <span class="doccomment">///</span> <span class="doccomment">/// To uppercase ASCII characters in addition to non-ASCII characters, use</span> <span class="doccomment">/// [`to_uppercase`].</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let s = "Grüße, Jürgen ❤";</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());</span> <span class="doccomment">/// ```</span> <span class="doccomment">///</span> <span class="doccomment">/// [`make_ascii_uppercase`]: #method.make_ascii_uppercase</span> <span class="doccomment">/// [`to_uppercase`]: #method.to_uppercase</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"ascii_methods_on_intrinsics"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.23.0"</span>)]</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">to_ascii_uppercase</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">bytes</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">as_bytes</span>().<span class="ident">to_vec</span>(); <span class="ident">bytes</span>.<span class="ident">make_ascii_uppercase</span>(); <span class="comment">// make_ascii_uppercase() preserves the UTF-8 invariant.</span> <span class="kw">unsafe</span> { <span class="ident">String</span>::<span class="ident">from_utf8_unchecked</span>(<span class="ident">bytes</span>) } } <span class="doccomment">/// Returns a copy of this string where each character is mapped to its</span> <span class="doccomment">/// ASCII lower case equivalent.</span> <span class="doccomment">///</span> <span class="doccomment">/// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',</span> <span class="doccomment">/// but non-ASCII letters are unchanged.</span> <span class="doccomment">///</span> <span class="doccomment">/// To lowercase the value in-place, use [`make_ascii_lowercase`].</span> <span class="doccomment">///</span> <span class="doccomment">/// To lowercase ASCII characters in addition to non-ASCII characters, use</span> <span class="doccomment">/// [`to_lowercase`].</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let s = "Grüße, Jürgen ❤";</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());</span> <span class="doccomment">/// ```</span> <span class="doccomment">///</span> <span class="doccomment">/// [`make_ascii_lowercase`]: #method.make_ascii_lowercase</span> <span class="doccomment">/// [`to_lowercase`]: #method.to_lowercase</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"ascii_methods_on_intrinsics"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.23.0"</span>)]</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">to_ascii_lowercase</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">String</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">bytes</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">as_bytes</span>().<span class="ident">to_vec</span>(); <span class="ident">bytes</span>.<span class="ident">make_ascii_lowercase</span>(); <span class="comment">// make_ascii_lowercase() preserves the UTF-8 invariant.</span> <span class="kw">unsafe</span> { <span class="ident">String</span>::<span class="ident">from_utf8_unchecked</span>(<span class="ident">bytes</span>) } } } <span class="doccomment">/// Converts a boxed slice of bytes to a boxed string slice without checking</span> <span class="doccomment">/// that the string contains valid UTF-8.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Basic usage:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// let smile_utf8 = Box::new([226, 152, 186]);</span> <span class="doccomment">/// let smile = unsafe { std::str::from_boxed_utf8_unchecked(smile_utf8) };</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!("☺", &*smile);</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"str_box_extras"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.20.0"</span>)]</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">pub</span> <span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">from_boxed_utf8_unchecked</span>(<span class="ident">v</span>: <span class="ident">Box</span><span class="op"><</span>[<span class="ident">u8</span>]<span class="op">></span>) <span class="op">-></span> <span class="ident">Box</span><span class="op"><</span><span class="ident">str</span><span class="op">></span> { <span class="ident">Box</span>::<span class="ident">from_raw</span>(<span class="ident">Box</span>::<span class="ident">into_raw</span>(<span class="ident">v</span>) <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">str</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 = "alloc";</script><script src="../../aliases.js"></script><script src="../../main.js"></script><script defer src="../../search-index.js"></script></body></html>