| <!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/num-bigint-0.3.3/src/biguint/shift.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>shift.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="../../../num_bigint/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="../../../num_bigint/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 super</span>::{biguint_from_vec, BigUint}; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::big_digit; |
| <span class="kw">use </span><span class="kw">crate</span>::std_alloc::{Cow, Vec}; |
| |
| <span class="kw">use </span>core::mem; |
| <span class="kw">use </span>core::ops::{Shl, ShlAssign, Shr, ShrAssign}; |
| <span class="kw">use </span>num_traits::{PrimInt, Zero}; |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>biguint_shl<T: PrimInt>(n: Cow<<span class="lifetime">'_</span>, BigUint>, shift: T) -> BigUint { |
| <span class="kw">if </span>shift < T::zero() { |
| <span class="macro">panic!</span>(<span class="string">"attempt to shift left with negative"</span>); |
| } |
| <span class="kw">if </span>n.is_zero() { |
| <span class="kw">return </span>n.into_owned(); |
| } |
| <span class="kw">let </span>bits = T::from(big_digit::BITS).unwrap(); |
| <span class="kw">let </span>digits = (shift / bits).to_usize().expect(<span class="string">"capacity overflow"</span>); |
| <span class="kw">let </span>shift = (shift % bits).to_u8().unwrap(); |
| biguint_shl2(n, digits, shift) |
| } |
| |
| <span class="kw">fn </span>biguint_shl2(n: Cow<<span class="lifetime">'_</span>, BigUint>, digits: usize, shift: u8) -> BigUint { |
| <span class="kw">let </span><span class="kw-2">mut </span>data = <span class="kw">match </span>digits { |
| <span class="number">0 </span>=> n.into_owned().data, |
| <span class="kw">_ </span>=> { |
| <span class="kw">let </span>len = digits.saturating_add(n.data.len() + <span class="number">1</span>); |
| <span class="kw">let </span><span class="kw-2">mut </span>data = Vec::with_capacity(len); |
| data.resize(digits, <span class="number">0</span>); |
| data.extend(n.data.iter()); |
| data |
| } |
| }; |
| |
| <span class="kw">if </span>shift > <span class="number">0 </span>{ |
| <span class="kw">let </span><span class="kw-2">mut </span>carry = <span class="number">0</span>; |
| <span class="kw">let </span>carry_shift = big_digit::BITS <span class="kw">as </span>u8 - shift; |
| <span class="kw">for </span>elem <span class="kw">in </span>data[digits..].iter_mut() { |
| <span class="kw">let </span>new_carry = <span class="kw-2">*</span>elem >> carry_shift; |
| <span class="kw-2">*</span>elem = (<span class="kw-2">*</span>elem << shift) | carry; |
| carry = new_carry; |
| } |
| <span class="kw">if </span>carry != <span class="number">0 </span>{ |
| data.push(carry); |
| } |
| } |
| |
| biguint_from_vec(data) |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>biguint_shr<T: PrimInt>(n: Cow<<span class="lifetime">'_</span>, BigUint>, shift: T) -> BigUint { |
| <span class="kw">if </span>shift < T::zero() { |
| <span class="macro">panic!</span>(<span class="string">"attempt to shift right with negative"</span>); |
| } |
| <span class="kw">if </span>n.is_zero() { |
| <span class="kw">return </span>n.into_owned(); |
| } |
| <span class="kw">let </span>bits = T::from(big_digit::BITS).unwrap(); |
| <span class="kw">let </span>digits = (shift / bits).to_usize().unwrap_or(core::usize::MAX); |
| <span class="kw">let </span>shift = (shift % bits).to_u8().unwrap(); |
| biguint_shr2(n, digits, shift) |
| } |
| |
| <span class="kw">fn </span>biguint_shr2(n: Cow<<span class="lifetime">'_</span>, BigUint>, digits: usize, shift: u8) -> BigUint { |
| <span class="kw">if </span>digits >= n.data.len() { |
| <span class="kw">let </span><span class="kw-2">mut </span>n = n.into_owned(); |
| n.set_zero(); |
| <span class="kw">return </span>n; |
| } |
| <span class="kw">let </span><span class="kw-2">mut </span>data = <span class="kw">match </span>n { |
| Cow::Borrowed(n) => n.data[digits..].to_vec(), |
| Cow::Owned(<span class="kw-2">mut </span>n) => { |
| n.data.drain(..digits); |
| n.data |
| } |
| }; |
| |
| <span class="kw">if </span>shift > <span class="number">0 </span>{ |
| <span class="kw">let </span><span class="kw-2">mut </span>borrow = <span class="number">0</span>; |
| <span class="kw">let </span>borrow_shift = big_digit::BITS <span class="kw">as </span>u8 - shift; |
| <span class="kw">for </span>elem <span class="kw">in </span>data.iter_mut().rev() { |
| <span class="kw">let </span>new_borrow = <span class="kw-2">*</span>elem << borrow_shift; |
| <span class="kw-2">*</span>elem = (<span class="kw-2">*</span>elem >> shift) | borrow; |
| borrow = new_borrow; |
| } |
| } |
| |
| biguint_from_vec(data) |
| } |
| |
| <span class="macro">macro_rules! </span>impl_shift { |
| (@<span class="kw-2">ref </span><span class="macro-nonterminal">$Shx</span>:ident :: <span class="macro-nonterminal">$shx</span>:ident, <span class="macro-nonterminal">$ShxAssign</span>:ident :: <span class="macro-nonterminal">$shx_assign</span>:ident, <span class="macro-nonterminal">$rhs</span>:ty) => { |
| <span class="kw">impl</span><<span class="lifetime">'b</span>> <span class="macro-nonterminal">$Shx</span><<span class="kw-2">&</span><span class="lifetime">'b </span><span class="macro-nonterminal">$rhs</span>> <span class="kw">for </span>BigUint { |
| <span class="kw">type </span>Output = BigUint; |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span><span class="macro-nonterminal">$shx</span>(<span class="self">self</span>, rhs: <span class="kw-2">&</span><span class="lifetime">'b </span><span class="macro-nonterminal">$rhs</span>) -> BigUint { |
| <span class="macro-nonterminal">$Shx</span>::<span class="macro-nonterminal">$shx</span>(<span class="self">self</span>, <span class="kw-2">*</span>rhs) |
| } |
| } |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, <span class="lifetime">'b</span>> <span class="macro-nonterminal">$Shx</span><<span class="kw-2">&</span><span class="lifetime">'b </span><span class="macro-nonterminal">$rhs</span>> <span class="kw">for </span><span class="kw-2">&</span><span class="lifetime">'a </span>BigUint { |
| <span class="kw">type </span>Output = BigUint; |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span><span class="macro-nonterminal">$shx</span>(<span class="self">self</span>, rhs: <span class="kw-2">&</span><span class="lifetime">'b </span><span class="macro-nonterminal">$rhs</span>) -> BigUint { |
| <span class="macro-nonterminal">$Shx</span>::<span class="macro-nonterminal">$shx</span>(<span class="self">self</span>, <span class="kw-2">*</span>rhs) |
| } |
| } |
| <span class="kw">impl</span><<span class="lifetime">'b</span>> <span class="macro-nonterminal">$ShxAssign</span><<span class="kw-2">&</span><span class="lifetime">'b </span><span class="macro-nonterminal">$rhs</span>> <span class="kw">for </span>BigUint { |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span><span class="macro-nonterminal">$shx_assign</span>(<span class="kw-2">&mut </span><span class="self">self</span>, rhs: <span class="kw-2">&</span><span class="lifetime">'b </span><span class="macro-nonterminal">$rhs</span>) { |
| <span class="macro-nonterminal">$ShxAssign</span>::<span class="macro-nonterminal">$shx_assign</span>(<span class="self">self</span>, <span class="kw-2">*</span>rhs); |
| } |
| } |
| }; |
| ($(<span class="macro-nonterminal">$rhs</span>:ty),+) => {$( |
| <span class="kw">impl </span>Shl<<span class="macro-nonterminal">$rhs</span>> <span class="kw">for </span>BigUint { |
| <span class="kw">type </span>Output = BigUint; |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>shl(<span class="self">self</span>, rhs: <span class="macro-nonterminal">$rhs</span>) -> BigUint { |
| biguint_shl(Cow::Owned(<span class="self">self</span>), rhs) |
| } |
| } |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> Shl<<span class="macro-nonterminal">$rhs</span>> <span class="kw">for </span><span class="kw-2">&</span><span class="lifetime">'a </span>BigUint { |
| <span class="kw">type </span>Output = BigUint; |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>shl(<span class="self">self</span>, rhs: <span class="macro-nonterminal">$rhs</span>) -> BigUint { |
| biguint_shl(Cow::Borrowed(<span class="self">self</span>), rhs) |
| } |
| } |
| <span class="kw">impl </span>ShlAssign<<span class="macro-nonterminal">$rhs</span>> <span class="kw">for </span>BigUint { |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>shl_assign(<span class="kw-2">&mut </span><span class="self">self</span>, rhs: <span class="macro-nonterminal">$rhs</span>) { |
| <span class="kw">let </span>n = mem::replace(<span class="self">self</span>, BigUint::zero()); |
| <span class="kw-2">*</span><span class="self">self </span>= n << rhs; |
| } |
| } |
| <span class="macro">impl_shift! </span>{ @<span class="kw-2">ref </span>Shl::shl, ShlAssign::shl_assign, <span class="macro-nonterminal">$rhs </span>} |
| |
| <span class="kw">impl </span>Shr<<span class="macro-nonterminal">$rhs</span>> <span class="kw">for </span>BigUint { |
| <span class="kw">type </span>Output = BigUint; |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>shr(<span class="self">self</span>, rhs: <span class="macro-nonterminal">$rhs</span>) -> BigUint { |
| biguint_shr(Cow::Owned(<span class="self">self</span>), rhs) |
| } |
| } |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> Shr<<span class="macro-nonterminal">$rhs</span>> <span class="kw">for </span><span class="kw-2">&</span><span class="lifetime">'a </span>BigUint { |
| <span class="kw">type </span>Output = BigUint; |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>shr(<span class="self">self</span>, rhs: <span class="macro-nonterminal">$rhs</span>) -> BigUint { |
| biguint_shr(Cow::Borrowed(<span class="self">self</span>), rhs) |
| } |
| } |
| <span class="kw">impl </span>ShrAssign<<span class="macro-nonterminal">$rhs</span>> <span class="kw">for </span>BigUint { |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>shr_assign(<span class="kw-2">&mut </span><span class="self">self</span>, rhs: <span class="macro-nonterminal">$rhs</span>) { |
| <span class="kw">let </span>n = mem::replace(<span class="self">self</span>, BigUint::zero()); |
| <span class="kw-2">*</span><span class="self">self </span>= n >> rhs; |
| } |
| } |
| <span class="macro">impl_shift! </span>{ @<span class="kw-2">ref </span>Shr::shr, ShrAssign::shr_assign, <span class="macro-nonterminal">$rhs </span>} |
| )<span class="kw-2">*</span>}; |
| } |
| |
| <span class="macro">impl_shift! </span>{ u8, u16, u32, u64, u128, usize } |
| <span class="macro">impl_shift! </span>{ i8, i16, i32, i64, i128, isize } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="num_bigint" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |