| <!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/time-0.3.21/src/util.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>util.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="icon" href="https://avatars0.githubusercontent.com/u/55999857"></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="../../time/index.html"><div class="logo-container"> |
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| </pre><pre class="rust"><code><span class="doccomment">//! Utility functions. |
| |
| </span><span class="kw">pub use </span>time_core::util::{days_in_year, is_leap_year, weeks_in_year}; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::Month; |
| |
| <span class="doccomment">/// Whether to adjust the date, and in which direction. Useful when implementing arithmetic. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">enum </span>DateAdjustment { |
| <span class="doccomment">/// The previous day should be used. |
| </span>Previous, |
| <span class="doccomment">/// The next day should be used. |
| </span>Next, |
| <span class="doccomment">/// The date should be used as-is. |
| </span><span class="prelude-val">None</span>, |
| } |
| |
| <span class="doccomment">/// Get the number of days in the month of a given year. |
| /// |
| /// ```rust |
| /// # use time::{Month, util}; |
| /// assert_eq!(util::days_in_year_month(2020, Month::February), 29); |
| /// ``` |
| </span><span class="kw">pub const fn </span>days_in_year_month(year: i32, month: Month) -> u8 { |
| <span class="kw">use </span>Month::<span class="kw-2">*</span>; |
| <span class="kw">match </span>month { |
| January | March | May | July | August | October | December => <span class="number">31</span>, |
| April | June | September | November => <span class="number">30</span>, |
| February <span class="kw">if </span>is_leap_year(year) => <span class="number">29</span>, |
| February => <span class="number">28</span>, |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"local-offset"</span>)] |
| </span><span class="doccomment">/// Utility functions relating to the local UTC offset. |
| </span><span class="kw">pub mod </span>local_offset { |
| <span class="kw">use </span>core::sync::atomic::{AtomicBool, Ordering}; |
| |
| <span class="doccomment">/// Whether obtaining the local UTC offset is required to be sound. |
| </span><span class="kw">static </span>LOCAL_OFFSET_IS_SOUND: AtomicBool = AtomicBool::new(<span class="bool-val">true</span>); |
| |
| <span class="doccomment">/// The soundness of obtaining the local UTC offset. |
| </span><span class="attribute">#[derive(Debug, Clone, Copy, PartialEq, Eq)] |
| </span><span class="kw">pub enum </span>Soundness { |
| <span class="doccomment">/// Obtaining the local UTC offset is required to be sound. Undefined behavior will never |
| /// occur. This is the default. |
| </span>Sound, |
| <span class="doccomment">/// Obtaining the local UTC offset is allowed to invoke undefined behavior. **Setting this |
| /// value is strongly discouraged.** To do so, you must comply with the safety requirements |
| /// of [`time::local_offset::set_soundness`](set_soundness). |
| </span>Unsound, |
| } |
| |
| <span class="doccomment">/// Set whether obtaining the local UTC offset is allowed to invoke undefined behavior. **Use of |
| /// this function is heavily discouraged.** |
| /// |
| /// # Safety |
| /// |
| /// If this method is called with [`Soundness::Sound`], the call is always sound. If this method |
| /// is called with [`Soundness::Unsound`], the following conditions apply. |
| /// |
| /// - If the operating system provides a thread-safe environment, the call is sound. |
| /// - If the process is single-threaded, the call is sound. |
| /// - If the process is multi-threaded, no other thread may mutate the environment in any way at |
| /// the same time a call to a method that obtains the local UTC offset. This includes adding, |
| /// removing, or modifying an environment variable. |
| /// |
| /// The first two conditions are automatically checked by `time`, such that you do not need to |
| /// declare your code unsound. Currently, the only known operating systems that does _not_ |
| /// provide a thread-safe environment are some Unix-like OS's. All other operating systems |
| /// should succeed when attempting to obtain the local UTC offset. |
| /// |
| /// Note that you must not only verify this safety condition for your code, but for **all** code |
| /// that will be included in the final binary. Notably, it applies to both direct and transitive |
| /// dependencies and to both Rust and non-Rust code. **For this reason it is not possible to |
| /// soundly pass [`Soundness::Unsound`] to this method if you are writing a library that may |
| /// used by others.** |
| /// |
| /// If using this method is absolutely necessary, it is recommended to keep the time between |
| /// setting the soundness to [`Soundness::Unsound`] and setting it back to [`Soundness::Sound`] |
| /// as short as possible. |
| /// |
| /// The following methods currently obtain the local UTC offset: |
| /// |
| /// - [`OffsetDateTime::now_local`](crate::OffsetDateTime::now_local) |
| /// - [`UtcOffset::local_offset_at`](crate::UtcOffset::local_offset_at) |
| /// - [`UtcOffset::current_local_offset`](crate::UtcOffset::current_local_offset) |
| </span><span class="kw">pub unsafe fn </span>set_soundness(soundness: Soundness) { |
| LOCAL_OFFSET_IS_SOUND.store(soundness == Soundness::Sound, Ordering::SeqCst); |
| } |
| |
| <span class="doccomment">/// Obtains the soundness of obtaining the local UTC offset. If it is [`Soundness::Unsound`], |
| /// it is allowed to invoke undefined behavior when obtaining the local UTC offset. |
| </span><span class="kw">pub fn </span>get_soundness() -> Soundness { |
| <span class="kw">match </span>LOCAL_OFFSET_IS_SOUND.load(Ordering::SeqCst) { |
| <span class="bool-val">false </span>=> Soundness::Unsound, |
| <span class="bool-val">true </span>=> Soundness::Sound, |
| } |
| } |
| } |
| </code></pre></div> |
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