| <!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/tuple_impl.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>tuple_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="doccomment">//! Some iterator that produces tuples |
| |
| </span><span class="kw">use </span>std::iter::Fuse; |
| <span class="kw">use </span>std::iter::FusedIterator; |
| <span class="kw">use </span>std::iter::Take; |
| <span class="kw">use </span>std::iter::Cycle; |
| <span class="kw">use </span>std::marker::PhantomData; |
| |
| <span class="comment">// `HomogeneousTuple` is a public facade for `TupleCollect`, allowing |
| // tuple-related methods to be used by clients in generic contexts, while |
| // hiding the implementation details of `TupleCollect`. |
| // See https://github.com/rust-itertools/itertools/issues/387 |
| |
| </span><span class="doccomment">/// Implemented for homogeneous tuples of size up to 12. |
| </span><span class="kw">pub trait </span>HomogeneousTuple |
| : TupleCollect |
| {} |
| |
| <span class="kw">impl</span><T: TupleCollect> HomogeneousTuple <span class="kw">for </span>T {} |
| |
| <span class="doccomment">/// An iterator over a incomplete tuple. |
| /// |
| /// See [`.tuples()`](crate::Itertools::tuples) and |
| /// [`Tuples::into_buffer()`]. |
| </span><span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">pub struct </span>TupleBuffer<T> |
| <span class="kw">where </span>T: HomogeneousTuple |
| { |
| cur: usize, |
| buf: T::Buffer, |
| } |
| |
| <span class="kw">impl</span><T> TupleBuffer<T> |
| <span class="kw">where </span>T: HomogeneousTuple |
| { |
| <span class="kw">fn </span>new(buf: T::Buffer) -> <span class="self">Self </span>{ |
| TupleBuffer { |
| cur: <span class="number">0</span>, |
| buf, |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><T> Iterator <span class="kw">for </span>TupleBuffer<T> |
| <span class="kw">where </span>T: HomogeneousTuple |
| { |
| <span class="kw">type </span>Item = T::Item; |
| |
| <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="kw">let </span>s = <span class="self">self</span>.buf.as_mut(); |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref mut </span>item) = s.get_mut(<span class="self">self</span>.cur) { |
| <span class="self">self</span>.cur += <span class="number">1</span>; |
| item.take() |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">None |
| </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>) { |
| <span class="kw">let </span>buffer = <span class="kw-2">&</span><span class="self">self</span>.buf.as_ref()[<span class="self">self</span>.cur..]; |
| <span class="kw">let </span>len = <span class="kw">if </span>buffer.is_empty() { |
| <span class="number">0 |
| </span>} <span class="kw">else </span>{ |
| buffer.iter() |
| .position(|x| x.is_none()) |
| .unwrap_or_else(|| buffer.len()) |
| }; |
| (len, <span class="prelude-val">Some</span>(len)) |
| } |
| } |
| |
| <span class="kw">impl</span><T> ExactSizeIterator <span class="kw">for </span>TupleBuffer<T> |
| <span class="kw">where </span>T: HomogeneousTuple |
| { |
| } |
| |
| <span class="doccomment">/// An iterator that groups the items in tuples of a specific size. |
| /// |
| /// See [`.tuples()`](crate::Itertools::tuples) for more information. |
| </span><span class="attribute">#[derive(Clone, Debug)] |
| #[must_use = <span class="string">"iterator adaptors are lazy and do nothing unless consumed"</span>] |
| </span><span class="kw">pub struct </span>Tuples<I, T> |
| <span class="kw">where </span>I: Iterator<Item = T::Item>, |
| T: HomogeneousTuple |
| { |
| iter: Fuse<I>, |
| buf: T::Buffer, |
| } |
| |
| <span class="doccomment">/// Create a new tuples iterator. |
| </span><span class="kw">pub fn </span>tuples<I, T>(iter: I) -> Tuples<I, T> |
| <span class="kw">where </span>I: Iterator<Item = T::Item>, |
| T: HomogeneousTuple |
| { |
| Tuples { |
| iter: iter.fuse(), |
| buf: Default::default(), |
| } |
| } |
| |
| <span class="kw">impl</span><I, T> Iterator <span class="kw">for </span>Tuples<I, T> |
| <span class="kw">where </span>I: Iterator<Item = T::Item>, |
| T: HomogeneousTuple |
| { |
| <span class="kw">type </span>Item = T; |
| |
| <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> { |
| T::collect_from_iter(<span class="kw-2">&mut </span><span class="self">self</span>.iter, <span class="kw-2">&mut </span><span class="self">self</span>.buf) |
| } |
| } |
| |
| <span class="kw">impl</span><I, T> Tuples<I, T> |
| <span class="kw">where </span>I: Iterator<Item = T::Item>, |
| T: HomogeneousTuple |
| { |
| <span class="doccomment">/// Return a buffer with the produced items that was not enough to be grouped in a tuple. |
| /// |
| /// ``` |
| /// use itertools::Itertools; |
| /// |
| /// let mut iter = (0..5).tuples(); |
| /// assert_eq!(Some((0, 1, 2)), iter.next()); |
| /// assert_eq!(None, iter.next()); |
| /// itertools::assert_equal(vec![3, 4], iter.into_buffer()); |
| /// ``` |
| </span><span class="kw">pub fn </span>into_buffer(<span class="self">self</span>) -> TupleBuffer<T> { |
| TupleBuffer::new(<span class="self">self</span>.buf) |
| } |
| } |
| |
| |
| <span class="doccomment">/// An iterator over all contiguous windows that produces tuples of a specific size. |
| /// |
| /// See [`.tuple_windows()`](crate::Itertools::tuple_windows) for more |
| /// information. |
| </span><span class="attribute">#[must_use = <span class="string">"iterator adaptors are lazy and do nothing unless consumed"</span>] |
| #[derive(Clone, Debug)] |
| </span><span class="kw">pub struct </span>TupleWindows<I, T> |
| <span class="kw">where </span>I: Iterator<Item = T::Item>, |
| T: HomogeneousTuple |
| { |
| iter: I, |
| last: <span class="prelude-ty">Option</span><T>, |
| } |
| |
| <span class="doccomment">/// Create a new tuple windows iterator. |
| </span><span class="kw">pub fn </span>tuple_windows<I, T>(<span class="kw-2">mut </span>iter: I) -> TupleWindows<I, T> |
| <span class="kw">where </span>I: Iterator<Item = T::Item>, |
| T: HomogeneousTuple, |
| T::Item: Clone |
| { |
| <span class="kw">use </span>std::iter::once; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>last = <span class="prelude-val">None</span>; |
| <span class="kw">if </span>T::num_items() != <span class="number">1 </span>{ |
| <span class="comment">// put in a duplicate item in front of the tuple; this simplifies |
| // .next() function. |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(item) = iter.next() { |
| <span class="kw">let </span>iter = once(item.clone()).chain(once(item)).chain(<span class="kw-2">&mut </span>iter); |
| last = T::collect_from_iter_no_buf(iter); |
| } |
| } |
| |
| TupleWindows { |
| iter, |
| last, |
| } |
| } |
| |
| <span class="kw">impl</span><I, T> Iterator <span class="kw">for </span>TupleWindows<I, T> |
| <span class="kw">where </span>I: Iterator<Item = T::Item>, |
| T: HomogeneousTuple + Clone, |
| T::Item: Clone |
| { |
| <span class="kw">type </span>Item = T; |
| |
| <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="kw">if </span>T::num_items() == <span class="number">1 </span>{ |
| <span class="kw">return </span>T::collect_from_iter_no_buf(<span class="kw-2">&mut </span><span class="self">self</span>.iter) |
| } |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref mut </span>last) = <span class="self">self</span>.last { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(new) = <span class="self">self</span>.iter.next() { |
| last.left_shift_push(new); |
| <span class="kw">return </span><span class="prelude-val">Some</span>(last.clone()); |
| } |
| } |
| <span class="prelude-val">None |
| </span>} |
| } |
| |
| <span class="kw">impl</span><I, T> FusedIterator <span class="kw">for </span>TupleWindows<I, T> |
| <span class="kw">where </span>I: FusedIterator<Item = T::Item>, |
| T: HomogeneousTuple + Clone, |
| T::Item: Clone |
| {} |
| |
| <span class="doccomment">/// An iterator over all windows,wrapping back to the first elements when the |
| /// window would otherwise exceed the length of the iterator, producing tuples |
| /// of a specific size. |
| /// |
| /// See [`.circular_tuple_windows()`](crate::Itertools::circular_tuple_windows) for more |
| /// information. |
| </span><span class="attribute">#[must_use = <span class="string">"iterator adaptors are lazy and do nothing unless consumed"</span>] |
| #[derive(Debug)] |
| </span><span class="kw">pub struct </span>CircularTupleWindows<I, T: Clone> |
| <span class="kw">where </span>I: Iterator<Item = T::Item> + Clone, |
| T: TupleCollect + Clone |
| { |
| iter: Take<TupleWindows<Cycle<I>, T>>, |
| phantom_data: PhantomData<T> |
| } |
| |
| <span class="kw">pub fn </span>circular_tuple_windows<I, T>(iter: I) -> CircularTupleWindows<I, T> |
| <span class="kw">where </span>I: Iterator<Item = T::Item> + Clone + ExactSizeIterator, |
| T: TupleCollect + Clone, |
| T::Item: Clone |
| { |
| <span class="kw">let </span>len = iter.len(); |
| <span class="kw">let </span>iter = tuple_windows(iter.cycle()).take(len); |
| |
| CircularTupleWindows { |
| iter, |
| phantom_data: PhantomData{} |
| } |
| } |
| |
| <span class="kw">impl</span><I, T> Iterator <span class="kw">for </span>CircularTupleWindows<I, T> |
| <span class="kw">where </span>I: Iterator<Item = T::Item> + Clone, |
| T: TupleCollect + Clone, |
| T::Item: Clone |
| { |
| <span class="kw">type </span>Item = T; |
| |
| <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>.iter.next() |
| } |
| } |
| |
| <span class="kw">pub trait </span>TupleCollect: Sized { |
| <span class="kw">type </span>Item; |
| <span class="kw">type </span>Buffer: Default + AsRef<[<span class="prelude-ty">Option</span><<span class="self">Self</span>::Item>]> + AsMut<[<span class="prelude-ty">Option</span><<span class="self">Self</span>::Item>]>; |
| |
| <span class="kw">fn </span>collect_from_iter<I>(iter: I, buf: <span class="kw-2">&mut </span><span class="self">Self</span>::Buffer) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>> |
| <span class="kw">where </span>I: IntoIterator<Item = <span class="self">Self</span>::Item>; |
| |
| <span class="kw">fn </span>collect_from_iter_no_buf<I>(iter: I) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>> |
| <span class="kw">where </span>I: IntoIterator<Item = <span class="self">Self</span>::Item>; |
| |
| <span class="kw">fn </span>num_items() -> usize; |
| |
| <span class="kw">fn </span>left_shift_push(<span class="kw-2">&mut </span><span class="self">self</span>, item: <span class="self">Self</span>::Item); |
| } |
| |
| <span class="macro">macro_rules! </span>count_ident{ |
| () => {<span class="number">0</span>}; |
| (<span class="macro-nonterminal">$i0</span>:ident, $(<span class="macro-nonterminal">$i</span>:ident,)<span class="kw-2">*</span>) => {<span class="number">1 </span>+ <span class="macro">count_ident!</span>($(<span class="macro-nonterminal">$i</span>,)<span class="kw-2">*</span>)}; |
| } |
| <span class="macro">macro_rules! </span>rev_for_each_ident{ |
| (<span class="macro-nonterminal">$m</span>:ident, ) => {}; |
| (<span class="macro-nonterminal">$m</span>:ident, <span class="macro-nonterminal">$i0</span>:ident, $(<span class="macro-nonterminal">$i</span>:ident,)<span class="kw-2">*</span>) => { |
| <span class="macro">rev_for_each_ident!</span>(<span class="macro-nonterminal">$m</span>, $(<span class="macro-nonterminal">$i</span>,)<span class="kw-2">*</span>); |
| <span class="macro-nonterminal">$</span><span class="macro">m!</span>(<span class="macro-nonterminal">$i0</span>); |
| }; |
| } |
| |
| <span class="macro">macro_rules! </span>impl_tuple_collect { |
| (<span class="macro-nonterminal">$dummy</span>:ident,) => {}; <span class="comment">// stop |
| </span>(<span class="macro-nonterminal">$dummy</span>:ident, $(<span class="macro-nonterminal">$Y</span>:ident,)<span class="kw-2">*</span>) => ( |
| <span class="macro">impl_tuple_collect!</span>($(<span class="macro-nonterminal">$Y</span>,)<span class="kw-2">*</span>); |
| <span class="kw">impl</span><A> TupleCollect <span class="kw">for </span>($(<span class="macro">ignore_ident!</span>(<span class="macro-nonterminal">$Y</span>, A),)<span class="kw-2">*</span>) { |
| <span class="kw">type </span>Item = A; |
| <span class="kw">type </span>Buffer = [<span class="prelude-ty">Option</span><A>; <span class="macro">count_ident!</span>($(<span class="macro-nonterminal">$Y</span>,)<span class="kw-2">*</span>) - <span class="number">1</span>]; |
| |
| <span class="attribute">#[allow(unused_assignments, unused_mut)] |
| </span><span class="kw">fn </span>collect_from_iter<I>(iter: I, buf: <span class="kw-2">&mut </span><span class="self">Self</span>::Buffer) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>> |
| <span class="kw">where </span>I: IntoIterator<Item = A> |
| { |
| <span class="kw">let </span><span class="kw-2">mut </span>iter = iter.into_iter(); |
| $( |
| <span class="kw">let </span><span class="kw-2">mut </span><span class="macro-nonterminal">$Y </span>= <span class="prelude-val">None</span>; |
| )* |
| |
| <span class="kw">loop </span>{ |
| $( |
| <span class="macro-nonterminal">$Y </span>= iter.next(); |
| <span class="kw">if </span><span class="macro-nonterminal">$Y</span>.is_none() { |
| <span class="kw">break |
| </span>} |
| )* |
| <span class="kw">return </span><span class="prelude-val">Some</span>(($(<span class="macro-nonterminal">$Y</span>.unwrap()),<span class="kw-2">*</span>,)) |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>i = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>s = buf.as_mut(); |
| $( |
| <span class="kw">if </span>i < s.len() { |
| s[i] = <span class="macro-nonterminal">$Y</span>; |
| i += <span class="number">1</span>; |
| } |
| )* |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| |
| <span class="kw">fn </span>collect_from_iter_no_buf<I>(iter: I) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>> |
| <span class="kw">where </span>I: IntoIterator<Item = A> |
| { |
| <span class="kw">let </span><span class="kw-2">mut </span>iter = iter.into_iter(); |
| |
| <span class="prelude-val">Some</span>(($( |
| { <span class="kw">let </span><span class="macro-nonterminal">$Y </span>= iter.next()<span class="question-mark">?</span>; <span class="macro-nonterminal">$Y </span>}, |
| )<span class="kw-2">*</span>)) |
| } |
| |
| <span class="kw">fn </span>num_items() -> usize { |
| <span class="macro">count_ident!</span>($(<span class="macro-nonterminal">$Y</span>,)<span class="kw-2">*</span>) |
| } |
| |
| <span class="kw">fn </span>left_shift_push(<span class="kw-2">&mut </span><span class="self">self</span>, <span class="kw-2">mut </span>item: A) { |
| <span class="kw">use </span>std::mem::replace; |
| |
| <span class="kw">let </span><span class="kw-2">&mut </span>($(<span class="kw-2">ref mut </span><span class="macro-nonterminal">$Y</span>),<span class="kw-2">*</span>,) = <span class="self">self</span>; |
| <span class="macro">macro_rules! </span>replace_item{(<span class="macro-nonterminal">$i</span>:ident) => { |
| item = replace(<span class="macro-nonterminal">$i</span>, item); |
| }} |
| <span class="macro">rev_for_each_ident!</span>(replace_item, $(<span class="macro-nonterminal">$Y</span>,)<span class="kw-2">*</span>); |
| drop(item); |
| } |
| } |
| ) |
| } |
| <span class="macro">impl_tuple_collect!</span>(dummy, a, b, c, d, e, f, g, h, i, j, k, l,); |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="itertools" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |