| <!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/itertools-0.10.5/src/put_back_n_impl.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>put_back_n_impl.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="../../itertools/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="../../itertools/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> |
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| </pre><pre class="rust"><code><span class="kw">use </span>alloc::vec::Vec; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::size_hint; |
| |
| <span class="doccomment">/// An iterator adaptor that allows putting multiple |
| /// items in front of the iterator. |
| /// |
| /// Iterator element type is `I::Item`. |
| </span><span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">pub struct </span>PutBackN<I: Iterator> { |
| top: Vec<I::Item>, |
| iter: I, |
| } |
| |
| <span class="doccomment">/// Create an iterator where you can put back multiple values to the front |
| /// of the iteration. |
| /// |
| /// Iterator element type is `I::Item`. |
| </span><span class="kw">pub fn </span>put_back_n<I>(iterable: I) -> PutBackN<I::IntoIter> |
| <span class="kw">where </span>I: IntoIterator |
| { |
| PutBackN { |
| top: Vec::new(), |
| iter: iterable.into_iter(), |
| } |
| } |
| |
| <span class="kw">impl</span><I: Iterator> PutBackN<I> { |
| <span class="doccomment">/// Puts x in front of the iterator. |
| /// The values are yielded in order of the most recently put back |
| /// values first. |
| /// |
| /// ```rust |
| /// use itertools::put_back_n; |
| /// |
| /// let mut it = put_back_n(1..5); |
| /// it.next(); |
| /// it.put_back(1); |
| /// it.put_back(0); |
| /// |
| /// assert!(itertools::equal(it, 0..5)); |
| /// ``` |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>put_back(<span class="kw-2">&mut </span><span class="self">self</span>, x: I::Item) { |
| <span class="self">self</span>.top.push(x); |
| } |
| } |
| |
| <span class="kw">impl</span><I: Iterator> Iterator <span class="kw">for </span>PutBackN<I> { |
| <span class="kw">type </span>Item = I::Item; |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>next(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>::Item> { |
| <span class="self">self</span>.top.pop().or_else(|| <span class="self">self</span>.iter.next()) |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>size_hint(<span class="kw-2">&</span><span class="self">self</span>) -> (usize, <span class="prelude-ty">Option</span><usize>) { |
| size_hint::add_scalar(<span class="self">self</span>.iter.size_hint(), <span class="self">self</span>.top.len()) |
| } |
| } |
| |
| </code></pre></div> |
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