| <!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-traits-0.2.15/src/sign.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>sign.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_traits/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_traits/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>core::num::Wrapping; |
| <span class="kw">use </span>core::ops::Neg; |
| |
| <span class="kw">use </span>float::FloatCore; |
| <span class="kw">use </span>Num; |
| |
| <span class="doccomment">/// Useful functions for signed numbers (i.e. numbers that can be negative). |
| </span><span class="kw">pub trait </span>Signed: Sized + Num + Neg<Output = <span class="self">Self</span>> { |
| <span class="doccomment">/// Computes the absolute value. |
| /// |
| /// For `f32` and `f64`, `NaN` will be returned if the number is `NaN`. |
| /// |
| /// For signed integers, `::MIN` will be returned if the number is `::MIN`. |
| </span><span class="kw">fn </span>abs(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>; |
| |
| <span class="doccomment">/// The positive difference of two numbers. |
| /// |
| /// Returns `zero` if the number is less than or equal to `other`, otherwise the difference |
| /// between `self` and `other` is returned. |
| </span><span class="kw">fn </span>abs_sub(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="self">Self</span>) -> <span class="self">Self</span>; |
| |
| <span class="doccomment">/// Returns the sign of the number. |
| /// |
| /// For `f32` and `f64`: |
| /// |
| /// * `1.0` if the number is positive, `+0.0` or `INFINITY` |
| /// * `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY` |
| /// * `NaN` if the number is `NaN` |
| /// |
| /// For signed integers: |
| /// |
| /// * `0` if the number is zero |
| /// * `1` if the number is positive |
| /// * `-1` if the number is negative |
| </span><span class="kw">fn </span>signum(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>; |
| |
| <span class="doccomment">/// Returns true if the number is positive and false if the number is zero or negative. |
| </span><span class="kw">fn </span>is_positive(<span class="kw-2">&</span><span class="self">self</span>) -> bool; |
| |
| <span class="doccomment">/// Returns true if the number is negative and false if the number is zero or positive. |
| </span><span class="kw">fn </span>is_negative(<span class="kw-2">&</span><span class="self">self</span>) -> bool; |
| } |
| |
| <span class="macro">macro_rules! </span>signed_impl { |
| ($(<span class="macro-nonterminal">$t</span>:ty)<span class="kw-2">*</span>) => ($( |
| <span class="kw">impl </span>Signed <span class="kw">for </span><span class="macro-nonterminal">$t </span>{ |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>abs(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="macro-nonterminal">$t </span>{ |
| <span class="kw">if </span><span class="self">self</span>.is_negative() { -<span class="kw-2">*</span><span class="self">self </span>} <span class="kw">else </span>{ <span class="kw-2">*</span><span class="self">self </span>} |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>abs_sub(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="macro-nonterminal">$t</span>) -> <span class="macro-nonterminal">$t </span>{ |
| <span class="kw">if </span><span class="kw-2">*</span><span class="self">self </span><= <span class="kw-2">*</span>other { <span class="number">0 </span>} <span class="kw">else </span>{ <span class="kw-2">*</span><span class="self">self </span>- <span class="kw-2">*</span>other } |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>signum(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="macro-nonterminal">$t </span>{ |
| <span class="kw">match </span><span class="kw-2">*</span><span class="self">self </span>{ |
| n <span class="kw">if </span>n > <span class="number">0 </span>=> <span class="number">1</span>, |
| <span class="number">0 </span>=> <span class="number">0</span>, |
| <span class="kw">_ </span>=> -<span class="number">1</span>, |
| } |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>is_positive(<span class="kw-2">&</span><span class="self">self</span>) -> bool { <span class="kw-2">*</span><span class="self">self </span>> <span class="number">0 </span>} |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>is_negative(<span class="kw-2">&</span><span class="self">self</span>) -> bool { <span class="kw-2">*</span><span class="self">self </span>< <span class="number">0 </span>} |
| } |
| )<span class="kw-2">*</span>) |
| } |
| |
| <span class="macro">signed_impl!</span>(isize i8 i16 i32 i64); |
| |
| <span class="attribute">#[cfg(has_i128)] |
| </span><span class="macro">signed_impl!</span>(i128); |
| |
| <span class="kw">impl</span><T: Signed> Signed <span class="kw">for </span>Wrapping<T> |
| <span class="kw">where |
| </span>Wrapping<T>: Num + Neg<Output = Wrapping<T>>, |
| { |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>abs(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self </span>{ |
| Wrapping(<span class="self">self</span>.<span class="number">0</span>.abs()) |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>abs_sub(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="self">Self</span>) -> <span class="self">Self </span>{ |
| Wrapping(<span class="self">self</span>.<span class="number">0</span>.abs_sub(<span class="kw-2">&</span>other.<span class="number">0</span>)) |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>signum(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self </span>{ |
| Wrapping(<span class="self">self</span>.<span class="number">0</span>.signum()) |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>is_positive(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.<span class="number">0</span>.is_positive() |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>is_negative(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.<span class="number">0</span>.is_negative() |
| } |
| } |
| |
| <span class="macro">macro_rules! </span>signed_float_impl { |
| (<span class="macro-nonterminal">$t</span>:ty) => { |
| <span class="kw">impl </span>Signed <span class="kw">for </span><span class="macro-nonterminal">$t </span>{ |
| <span class="doccomment">/// Computes the absolute value. Returns `NAN` if the number is `NAN`. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">fn </span>abs(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="macro-nonterminal">$t </span>{ |
| FloatCore::abs(<span class="kw-2">*</span><span class="self">self</span>) |
| } |
| |
| <span class="doccomment">/// The positive difference of two numbers. Returns `0.0` if the number is |
| /// less than or equal to `other`, otherwise the difference between`self` |
| /// and `other` is returned. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">fn </span>abs_sub(<span class="kw-2">&</span><span class="self">self</span>, other: <span class="kw-2">&</span><span class="macro-nonterminal">$t</span>) -> <span class="macro-nonterminal">$t </span>{ |
| <span class="kw">if </span><span class="kw-2">*</span><span class="self">self </span><= <span class="kw-2">*</span>other { |
| <span class="number">0. |
| </span>} <span class="kw">else </span>{ |
| <span class="kw-2">*</span><span class="self">self </span>- <span class="kw-2">*</span>other |
| } |
| } |
| |
| <span class="doccomment">/// # Returns |
| /// |
| /// - `1.0` if the number is positive, `+0.0` or `INFINITY` |
| /// - `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY` |
| /// - `NAN` if the number is NaN |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">fn </span>signum(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="macro-nonterminal">$t </span>{ |
| FloatCore::signum(<span class="kw-2">*</span><span class="self">self</span>) |
| } |
| |
| <span class="doccomment">/// Returns `true` if the number is positive, including `+0.0` and `INFINITY` |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">fn </span>is_positive(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| FloatCore::is_sign_positive(<span class="kw-2">*</span><span class="self">self</span>) |
| } |
| |
| <span class="doccomment">/// Returns `true` if the number is negative, including `-0.0` and `NEG_INFINITY` |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">fn </span>is_negative(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| FloatCore::is_sign_negative(<span class="kw-2">*</span><span class="self">self</span>) |
| } |
| } |
| }; |
| } |
| |
| <span class="macro">signed_float_impl!</span>(f32); |
| <span class="macro">signed_float_impl!</span>(f64); |
| |
| <span class="doccomment">/// Computes the absolute value. |
| /// |
| /// For `f32` and `f64`, `NaN` will be returned if the number is `NaN` |
| /// |
| /// For signed integers, `::MIN` will be returned if the number is `::MIN`. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">pub fn </span>abs<T: Signed>(value: T) -> T { |
| value.abs() |
| } |
| |
| <span class="doccomment">/// The positive difference of two numbers. |
| /// |
| /// Returns zero if `x` is less than or equal to `y`, otherwise the difference |
| /// between `x` and `y` is returned. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">pub fn </span>abs_sub<T: Signed>(x: T, y: T) -> T { |
| x.abs_sub(<span class="kw-2">&</span>y) |
| } |
| |
| <span class="doccomment">/// Returns the sign of the number. |
| /// |
| /// For `f32` and `f64`: |
| /// |
| /// * `1.0` if the number is positive, `+0.0` or `INFINITY` |
| /// * `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY` |
| /// * `NaN` if the number is `NaN` |
| /// |
| /// For signed integers: |
| /// |
| /// * `0` if the number is zero |
| /// * `1` if the number is positive |
| /// * `-1` if the number is negative |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">pub fn </span>signum<T: Signed>(value: T) -> T { |
| value.signum() |
| } |
| |
| <span class="doccomment">/// A trait for values which cannot be negative |
| </span><span class="kw">pub trait </span>Unsigned: Num {} |
| |
| <span class="macro">macro_rules! </span>empty_trait_impl { |
| (<span class="macro-nonterminal">$name</span>:ident <span class="kw">for </span>$(<span class="macro-nonterminal">$t</span>:ty)<span class="kw-2">*</span>) => ($( |
| <span class="kw">impl </span><span class="macro-nonterminal">$name </span><span class="kw">for </span><span class="macro-nonterminal">$t </span>{} |
| )<span class="kw-2">*</span>) |
| } |
| |
| <span class="macro">empty_trait_impl!</span>(Unsigned <span class="kw">for </span>usize u8 u16 u32 u64); |
| <span class="attribute">#[cfg(has_i128)] |
| </span><span class="macro">empty_trait_impl!</span>(Unsigned <span class="kw">for </span>u128); |
| |
| <span class="kw">impl</span><T: Unsigned> Unsigned <span class="kw">for </span>Wrapping<T> <span class="kw">where </span>Wrapping<T>: Num {} |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>unsigned_wrapping_is_unsigned() { |
| <span class="kw">fn </span>require_unsigned<T: Unsigned>(<span class="kw">_</span>: <span class="kw-2">&</span>T) {} |
| require_unsigned(<span class="kw-2">&</span>Wrapping(<span class="number">42_u32</span>)); |
| } |
| |
| <span class="comment">// Commenting this out since it doesn't compile on Rust 1.8, |
| // because on this version Wrapping doesn't implement Neg and therefore can't |
| // implement Signed. |
| // #[test] |
| // fn signed_wrapping_is_signed() { |
| // fn require_signed<T: Signed>(_: &T) {} |
| // require_signed(&Wrapping(-42)); |
| // } |
| </span></code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="num_traits" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
