<!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 `src/libcore/iter/adapters/zip.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>zip.rs.html -- source</title><link rel="stylesheet" type="text/css" href="../../../../normalize1.35.0.css"><link rel="stylesheet" type="text/css" href="../../../../rustdoc1.35.0.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../../dark1.35.0.css"><link rel="stylesheet" type="text/css" href="../../../../light1.35.0.css" id="themeStyle"><script src="../../../../storage1.35.0.js"></script><noscript><link rel="stylesheet" href="../../../../noscript1.35.0.css"></noscript><link rel="shortcut icon" href="../../../../favicon1.35.0.ico"><style type="text/css">#crate-search{background-image:url("../../../../down-arrow1.35.0.svg");}</style></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='../../../../core/index.html'><img src='../../../../rust-logo1.35.0.png' alt='logo' width='100'></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../../brush1.35.0.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../../theme1.35.0.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../../../../settings.html"><img src="../../../../wheel1.35.0.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span>
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</pre><div class="example-wrap"><pre class="rust ">
<span class="kw">use</span> <span class="ident">cmp</span>;
<span class="kw">use</span> <span class="kw">super</span>::<span class="kw">super</span>::{<span class="ident">Iterator</span>, <span class="ident">DoubleEndedIterator</span>, <span class="ident">ExactSizeIterator</span>, <span class="ident">FusedIterator</span>, <span class="ident">TrustedLen</span>};
<span class="doccomment">/// An iterator that iterates two other iterators simultaneously.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This `struct` is created by the [`zip`] method on [`Iterator`]. See its</span>
<span class="doccomment">/// documentation for more.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// [`zip`]: trait.Iterator.html#method.zip</span>
<span class="doccomment">/// [`Iterator`]: trait.Iterator.html</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span>
<span class="attribute">#[<span class="ident">must_use</span> <span class="op">=</span> <span class="string">"iterators are lazy and do nothing unless consumed"</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">struct</span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> {
<span class="ident">a</span>: <span class="ident">A</span>,
<span class="ident">b</span>: <span class="ident">B</span>,
<span class="comment">// index and len are only used by the specialized version of zip</span>
<span class="ident">index</span>: <span class="ident">usize</span>,
<span class="ident">len</span>: <span class="ident">usize</span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">A</span>: <span class="ident">Iterator</span>, <span class="ident">B</span>: <span class="ident">Iterator</span><span class="op">></span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> {
<span class="kw">pub</span>(<span class="kw">in</span> <span class="kw">super</span>::<span class="kw">super</span>) <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">a</span>: <span class="ident">A</span>, <span class="ident">b</span>: <span class="ident">B</span>) <span class="op">-></span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> {
<span class="ident">ZipImpl</span>::<span class="ident">new</span>(<span class="ident">a</span>, <span class="ident">b</span>)
}
<span class="kw">fn</span> <span class="ident">super_nth</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="kw-2">mut</span> <span class="ident">n</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">A</span>::<span class="ident">Item</span>, <span class="ident">B</span>::<span class="ident">Item</span>)<span class="op">></span> {
<span class="kw">while</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">x</span>) <span class="op">=</span> <span class="ident">Iterator</span>::<span class="ident">next</span>(<span class="self">self</span>) {
<span class="kw">if</span> <span class="ident">n</span> <span class="op">==</span> <span class="number">0</span> { <span class="kw">return</span> <span class="prelude-val">Some</span>(<span class="ident">x</span>) }
<span class="ident">n</span> <span class="op">-=</span> <span class="number">1</span>;
}
<span class="prelude-val">None</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="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="kw">where</span> <span class="ident">A</span>: <span class="ident">Iterator</span>, <span class="ident">B</span>: <span class="ident">Iterator</span>
{
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> (<span class="ident">A</span>::<span class="ident">Item</span>, <span class="ident">B</span>::<span class="ident">Item</span>);
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span> {
<span class="ident">ZipImpl</span>::<span class="ident">next</span>(<span class="self">self</span>)
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>) {
<span class="ident">ZipImpl</span>::<span class="ident">size_hint</span>(<span class="self">self</span>)
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">nth</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">n</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span> {
<span class="ident">ZipImpl</span>::<span class="ident">nth</span>(<span class="self">self</span>, <span class="ident">n</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="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="ident">DoubleEndedIterator</span> <span class="kw">for</span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="kw">where</span>
<span class="ident">A</span>: <span class="ident">DoubleEndedIterator</span> <span class="op">+</span> <span class="ident">ExactSizeIterator</span>,
<span class="ident">B</span>: <span class="ident">DoubleEndedIterator</span> <span class="op">+</span> <span class="ident">ExactSizeIterator</span>,
{
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">A</span>::<span class="ident">Item</span>, <span class="ident">B</span>::<span class="ident">Item</span>)<span class="op">></span> {
<span class="ident">ZipImpl</span>::<span class="ident">next_back</span>(<span class="self">self</span>)
}
}
<span class="comment">// Zip specialization trait</span>
<span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span>
<span class="kw">trait</span> <span class="ident">ZipImpl</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> {
<span class="kw">type</span> <span class="ident">Item</span>;
<span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">a</span>: <span class="ident">A</span>, <span class="ident">b</span>: <span class="ident">B</span>) <span class="op">-></span> <span class="self">Self</span>;
<span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span>;
<span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>);
<span class="kw">fn</span> <span class="ident">nth</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">n</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span>;
<span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">DoubleEndedIterator</span> <span class="op">+</span> <span class="ident">ExactSizeIterator</span>,
<span class="ident">B</span>: <span class="ident">DoubleEndedIterator</span> <span class="op">+</span> <span class="ident">ExactSizeIterator</span>;
}
<span class="comment">// General Zip impl</span>
<span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span>
<span class="kw">impl</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="ident">ZipImpl</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">Iterator</span>, <span class="ident">B</span>: <span class="ident">Iterator</span>
{
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> (<span class="ident">A</span>::<span class="ident">Item</span>, <span class="ident">B</span>::<span class="ident">Item</span>);
<span class="ident">default</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">a</span>: <span class="ident">A</span>, <span class="ident">b</span>: <span class="ident">B</span>) <span class="op">-></span> <span class="self">Self</span> {
<span class="ident">Zip</span> {
<span class="ident">a</span>,
<span class="ident">b</span>,
<span class="ident">index</span>: <span class="number">0</span>, <span class="comment">// unused</span>
<span class="ident">len</span>: <span class="number">0</span>, <span class="comment">// unused</span>
}
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="ident">default</span> <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">A</span>::<span class="ident">Item</span>, <span class="ident">B</span>::<span class="ident">Item</span>)<span class="op">></span> {
<span class="self">self</span>.<span class="ident">a</span>.<span class="ident">next</span>().<span class="ident">and_then</span>(<span class="op">|</span><span class="ident">x</span><span class="op">|</span> {
<span class="self">self</span>.<span class="ident">b</span>.<span class="ident">next</span>().<span class="ident">and_then</span>(<span class="op">|</span><span class="ident">y</span><span class="op">|</span> {
<span class="prelude-val">Some</span>((<span class="ident">x</span>, <span class="ident">y</span>))
})
})
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="ident">default</span> <span class="kw">fn</span> <span class="ident">nth</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">n</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span> {
<span class="self">self</span>.<span class="ident">super_nth</span>(<span class="ident">n</span>)
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="ident">default</span> <span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">A</span>::<span class="ident">Item</span>, <span class="ident">B</span>::<span class="ident">Item</span>)<span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">DoubleEndedIterator</span> <span class="op">+</span> <span class="ident">ExactSizeIterator</span>,
<span class="ident">B</span>: <span class="ident">DoubleEndedIterator</span> <span class="op">+</span> <span class="ident">ExactSizeIterator</span>
{
<span class="kw">let</span> <span class="ident">a_sz</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">a</span>.<span class="ident">len</span>();
<span class="kw">let</span> <span class="ident">b_sz</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">b</span>.<span class="ident">len</span>();
<span class="kw">if</span> <span class="ident">a_sz</span> <span class="op">!=</span> <span class="ident">b_sz</span> {
<span class="comment">// Adjust a, b to equal length</span>
<span class="kw">if</span> <span class="ident">a_sz</span> <span class="op">></span> <span class="ident">b_sz</span> {
<span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">a_sz</span> <span class="op">-</span> <span class="ident">b_sz</span> { <span class="self">self</span>.<span class="ident">a</span>.<span class="ident">next_back</span>(); }
} <span class="kw">else</span> {
<span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">b_sz</span> <span class="op">-</span> <span class="ident">a_sz</span> { <span class="self">self</span>.<span class="ident">b</span>.<span class="ident">next_back</span>(); }
}
}
<span class="kw">match</span> (<span class="self">self</span>.<span class="ident">a</span>.<span class="ident">next_back</span>(), <span class="self">self</span>.<span class="ident">b</span>.<span class="ident">next_back</span>()) {
(<span class="prelude-val">Some</span>(<span class="ident">x</span>), <span class="prelude-val">Some</span>(<span class="ident">y</span>)) <span class="op">=></span> <span class="prelude-val">Some</span>((<span class="ident">x</span>, <span class="ident">y</span>)),
(<span class="prelude-val">None</span>, <span class="prelude-val">None</span>) <span class="op">=></span> <span class="prelude-val">None</span>,
<span class="kw">_</span> <span class="op">=></span> <span class="macro">unreachable</span><span class="macro">!</span>(),
}
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="ident">default</span> <span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>) {
<span class="kw">let</span> (<span class="ident">a_lower</span>, <span class="ident">a_upper</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">a</span>.<span class="ident">size_hint</span>();
<span class="kw">let</span> (<span class="ident">b_lower</span>, <span class="ident">b_upper</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">b</span>.<span class="ident">size_hint</span>();
<span class="kw">let</span> <span class="ident">lower</span> <span class="op">=</span> <span class="ident">cmp</span>::<span class="ident">min</span>(<span class="ident">a_lower</span>, <span class="ident">b_lower</span>);
<span class="kw">let</span> <span class="ident">upper</span> <span class="op">=</span> <span class="kw">match</span> (<span class="ident">a_upper</span>, <span class="ident">b_upper</span>) {
(<span class="prelude-val">Some</span>(<span class="ident">x</span>), <span class="prelude-val">Some</span>(<span class="ident">y</span>)) <span class="op">=></span> <span class="prelude-val">Some</span>(<span class="ident">cmp</span>::<span class="ident">min</span>(<span class="ident">x</span>,<span class="ident">y</span>)),
(<span class="prelude-val">Some</span>(<span class="ident">x</span>), <span class="prelude-val">None</span>) <span class="op">=></span> <span class="prelude-val">Some</span>(<span class="ident">x</span>),
(<span class="prelude-val">None</span>, <span class="prelude-val">Some</span>(<span class="ident">y</span>)) <span class="op">=></span> <span class="prelude-val">Some</span>(<span class="ident">y</span>),
(<span class="prelude-val">None</span>, <span class="prelude-val">None</span>) <span class="op">=></span> <span class="prelude-val">None</span>
};
(<span class="ident">lower</span>, <span class="ident">upper</span>)
}
}
<span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span>
<span class="kw">impl</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="ident">ZipImpl</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">TrustedRandomAccess</span>, <span class="ident">B</span>: <span class="ident">TrustedRandomAccess</span>
{
<span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">a</span>: <span class="ident">A</span>, <span class="ident">b</span>: <span class="ident">B</span>) <span class="op">-></span> <span class="self">Self</span> {
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">cmp</span>::<span class="ident">min</span>(<span class="ident">a</span>.<span class="ident">len</span>(), <span class="ident">b</span>.<span class="ident">len</span>());
<span class="ident">Zip</span> {
<span class="ident">a</span>,
<span class="ident">b</span>,
<span class="ident">index</span>: <span class="number">0</span>,
<span class="ident">len</span>,
}
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">A</span>::<span class="ident">Item</span>, <span class="ident">B</span>::<span class="ident">Item</span>)<span class="op">></span> {
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">index</span> <span class="op"><</span> <span class="self">self</span>.<span class="ident">len</span> {
<span class="kw">let</span> <span class="ident">i</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">index</span>;
<span class="self">self</span>.<span class="ident">index</span> <span class="op">+=</span> <span class="number">1</span>;
<span class="kw">unsafe</span> {
<span class="prelude-val">Some</span>((<span class="self">self</span>.<span class="ident">a</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>), <span class="self">self</span>.<span class="ident">b</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>)))
}
} <span class="kw">else</span> <span class="kw">if</span> <span class="ident">A</span>::<span class="ident">may_have_side_effect</span>() <span class="op">&&</span> <span class="self">self</span>.<span class="ident">index</span> <span class="op"><</span> <span class="self">self</span>.<span class="ident">a</span>.<span class="ident">len</span>() {
<span class="comment">// match the base implementation's potential side effects</span>
<span class="kw">unsafe</span> {
<span class="self">self</span>.<span class="ident">a</span>.<span class="ident">get_unchecked</span>(<span class="self">self</span>.<span class="ident">index</span>);
}
<span class="self">self</span>.<span class="ident">index</span> <span class="op">+=</span> <span class="number">1</span>;
<span class="prelude-val">None</span>
} <span class="kw">else</span> {
<span class="prelude-val">None</span>
}
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>) {
<span class="kw">let</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="self">self</span>.<span class="ident">index</span>;
(<span class="ident">len</span>, <span class="prelude-val">Some</span>(<span class="ident">len</span>))
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">nth</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">n</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span> {
<span class="kw">let</span> <span class="ident">delta</span> <span class="op">=</span> <span class="ident">cmp</span>::<span class="ident">min</span>(<span class="ident">n</span>, <span class="self">self</span>.<span class="ident">len</span> <span class="op">-</span> <span class="self">self</span>.<span class="ident">index</span>);
<span class="kw">let</span> <span class="ident">end</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">index</span> <span class="op">+</span> <span class="ident">delta</span>;
<span class="kw">while</span> <span class="self">self</span>.<span class="ident">index</span> <span class="op"><</span> <span class="ident">end</span> {
<span class="kw">let</span> <span class="ident">i</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">index</span>;
<span class="self">self</span>.<span class="ident">index</span> <span class="op">+=</span> <span class="number">1</span>;
<span class="kw">if</span> <span class="ident">A</span>::<span class="ident">may_have_side_effect</span>() {
<span class="kw">unsafe</span> { <span class="self">self</span>.<span class="ident">a</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>); }
}
<span class="kw">if</span> <span class="ident">B</span>::<span class="ident">may_have_side_effect</span>() {
<span class="kw">unsafe</span> { <span class="self">self</span>.<span class="ident">b</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>); }
}
}
<span class="self">self</span>.<span class="ident">super_nth</span>(<span class="ident">n</span> <span class="op">-</span> <span class="ident">delta</span>)
}
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">A</span>::<span class="ident">Item</span>, <span class="ident">B</span>::<span class="ident">Item</span>)<span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">DoubleEndedIterator</span> <span class="op">+</span> <span class="ident">ExactSizeIterator</span>,
<span class="ident">B</span>: <span class="ident">DoubleEndedIterator</span> <span class="op">+</span> <span class="ident">ExactSizeIterator</span>
{
<span class="comment">// Adjust a, b to equal length</span>
<span class="kw">if</span> <span class="ident">A</span>::<span class="ident">may_have_side_effect</span>() {
<span class="kw">let</span> <span class="ident">sz</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">a</span>.<span class="ident">len</span>();
<span class="kw">if</span> <span class="ident">sz</span> <span class="op">></span> <span class="self">self</span>.<span class="ident">len</span> {
<span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">sz</span> <span class="op">-</span> <span class="ident">cmp</span>::<span class="ident">max</span>(<span class="self">self</span>.<span class="ident">len</span>, <span class="self">self</span>.<span class="ident">index</span>) {
<span class="self">self</span>.<span class="ident">a</span>.<span class="ident">next_back</span>();
}
}
}
<span class="kw">if</span> <span class="ident">B</span>::<span class="ident">may_have_side_effect</span>() {
<span class="kw">let</span> <span class="ident">sz</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">b</span>.<span class="ident">len</span>();
<span class="kw">if</span> <span class="ident">sz</span> <span class="op">></span> <span class="self">self</span>.<span class="ident">len</span> {
<span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">sz</span> <span class="op">-</span> <span class="self">self</span>.<span class="ident">len</span> {
<span class="self">self</span>.<span class="ident">b</span>.<span class="ident">next_back</span>();
}
}
}
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">index</span> <span class="op"><</span> <span class="self">self</span>.<span class="ident">len</span> {
<span class="self">self</span>.<span class="ident">len</span> <span class="op">-=</span> <span class="number">1</span>;
<span class="kw">let</span> <span class="ident">i</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">len</span>;
<span class="kw">unsafe</span> {
<span class="prelude-val">Some</span>((<span class="self">self</span>.<span class="ident">a</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>), <span class="self">self</span>.<span class="ident">b</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>)))
}
} <span class="kw">else</span> {
<span class="prelude-val">None</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="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="ident">ExactSizeIterator</span> <span class="kw">for</span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">ExactSizeIterator</span>, <span class="ident">B</span>: <span class="ident">ExactSizeIterator</span> {}
<span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span>
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="ident">TrustedRandomAccess</span> <span class="kw">for</span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">TrustedRandomAccess</span>,
<span class="ident">B</span>: <span class="ident">TrustedRandomAccess</span>,
{
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">get_unchecked</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">i</span>: <span class="ident">usize</span>) <span class="op">-></span> (<span class="ident">A</span>::<span class="ident">Item</span>, <span class="ident">B</span>::<span class="ident">Item</span>) {
(<span class="self">self</span>.<span class="ident">a</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>), <span class="self">self</span>.<span class="ident">b</span>.<span class="ident">get_unchecked</span>(<span class="ident">i</span>))
}
<span class="kw">fn</span> <span class="ident">may_have_side_effect</span>() <span class="op">-></span> <span class="ident">bool</span> {
<span class="ident">A</span>::<span class="ident">may_have_side_effect</span>() <span class="op">||</span> <span class="ident">B</span>::<span class="ident">may_have_side_effect</span>()
}
}
<span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"fused"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.26.0"</span>)]</span>
<span class="kw">impl</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="ident">FusedIterator</span> <span class="kw">for</span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">FusedIterator</span>, <span class="ident">B</span>: <span class="ident">FusedIterator</span>, {}
<span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"trusted_len"</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">"37572"</span>)]</span>
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span> <span class="ident">TrustedLen</span> <span class="kw">for</span> <span class="ident">Zip</span><span class="op"><</span><span class="ident">A</span>, <span class="ident">B</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">TrustedLen</span>, <span class="ident">B</span>: <span class="ident">TrustedLen</span>,
{}
<span class="doccomment">/// An iterator whose items are random-accessible efficiently</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Safety</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The iterator's .len() and size_hint() must be exact.</span>
<span class="doccomment">/// `.len()` must be cheap to call.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// .get_unchecked() must return distinct mutable references for distinct</span>
<span class="doccomment">/// indices (if applicable), and must return a valid reference if index is in</span>
<span class="doccomment">/// 0..self.len().</span>
<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">unsafe</span> <span class="kw">trait</span> <span class="ident">TrustedRandomAccess</span> : <span class="ident">ExactSizeIterator</span> {
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">get_unchecked</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">i</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="self">Self</span>::<span class="ident">Item</span>;
<span class="doccomment">/// Returns `true` if getting an iterator element may have</span>
<span class="doccomment">/// side effects. Remember to take inner iterators into account.</span>
<span class="kw">fn</span> <span class="ident">may_have_side_effect</span>() <span class="op">-></span> <span class="ident">bool</span>;
}
</pre></div>
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distrib
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Mageia
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armv7hl
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0c2243f8a1696816431e7210e991fa52
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