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#[cfg(feature = "std")] use crate::OffsetDateTime; use crate::{ error, format::{parse, ParsedItems}, DeferredFormat, Duration, ParseResult, }; #[cfg(not(feature = "std"))] use alloc::{ borrow::ToOwned, string::{String, ToString}, }; use core::fmt::{self, Display}; /// An offset from UTC. /// /// Guaranteed to store values up to ±23:59:59. Any values outside this range /// may have incidental support that can change at any time without notice. If /// you need support outside this range, please file an issue with your use /// case. #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))] #[cfg_attr( feature = "serde", serde(from = "crate::serde::UtcOffset", into = "crate::serde::UtcOffset") )] #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)] pub struct UtcOffset { /// The number of seconds offset from UTC. Positive is east, negative is /// west. pub(crate) seconds: i32, } impl UtcOffset { /// A `UtcOffset` that is UTC. /// /// ```rust /// # use time::{UtcOffset, offset}; /// assert_eq!(UtcOffset::UTC, offset!(UTC)); /// ``` pub const UTC: Self = Self::seconds(0); /// Create a `UtcOffset` representing an easterly offset by the number of /// hours provided. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::east_hours(1).as_hours(), 1); /// assert_eq!(UtcOffset::east_hours(2).as_minutes(), 120); /// ``` pub const fn east_hours(hours: u8) -> Self { Self::hours(hours as i8) } /// Create a `UtcOffset` representing a westerly offset by the number of /// hours provided. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::west_hours(1).as_hours(), -1); /// assert_eq!(UtcOffset::west_hours(2).as_minutes(), -120); /// ``` pub const fn west_hours(hours: u8) -> Self { Self::hours(-(hours as i8)) } /// Create a `UtcOffset` representing an offset by the number of hours /// provided. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::hours(2).as_minutes(), 120); /// assert_eq!(UtcOffset::hours(-2).as_minutes(), -120); /// ``` pub const fn hours(hours: i8) -> Self { Self::seconds(hours as i32 * 3_600) } /// Create a `UtcOffset` representing an easterly offset by the number of /// minutes provided. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::east_minutes(60).as_hours(), 1); /// ``` pub const fn east_minutes(minutes: u16) -> Self { Self::minutes(minutes as i16) } /// Create a `UtcOffset` representing a westerly offset by the number of /// minutes provided. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::west_minutes(60).as_hours(), -1); /// ``` pub const fn west_minutes(minutes: u16) -> Self { Self::minutes(-(minutes as i16)) } /// Create a `UtcOffset` representing a offset by the number of minutes /// provided. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::minutes(60).as_hours(), 1); /// assert_eq!(UtcOffset::minutes(-60).as_hours(), -1); /// ``` pub const fn minutes(minutes: i16) -> Self { Self::seconds(minutes as i32 * 60) } /// Create a `UtcOffset` representing an easterly offset by the number of /// seconds provided. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::east_seconds(3_600).as_hours(), 1); /// assert_eq!(UtcOffset::east_seconds(1_800).as_minutes(), 30); /// ``` pub const fn east_seconds(seconds: u32) -> Self { Self::seconds(seconds as i32) } /// Create a `UtcOffset` representing a westerly offset by the number of /// seconds provided. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::west_seconds(3_600).as_hours(), -1); /// assert_eq!(UtcOffset::west_seconds(1_800).as_minutes(), -30); /// ``` pub const fn west_seconds(seconds: u32) -> Self { Self::seconds(-(seconds as i32)) } /// Create a `UtcOffset` representing an offset by the number of seconds /// provided. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::seconds(3_600).as_hours(), 1); /// assert_eq!(UtcOffset::seconds(-3_600).as_hours(), -1); /// ``` pub const fn seconds(seconds: i32) -> Self { Self { seconds } } /// Get the number of seconds from UTC the value is. Positive is east, /// negative is west. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::UTC.as_seconds(), 0); /// assert_eq!(UtcOffset::hours(12).as_seconds(), 43_200); /// assert_eq!(UtcOffset::hours(-12).as_seconds(), -43_200); /// ``` pub const fn as_seconds(self) -> i32 { self.seconds } /// Get the number of minutes from UTC the value is. Positive is east, /// negative is west. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::UTC.as_minutes(), 0); /// assert_eq!(UtcOffset::hours(12).as_minutes(), 720); /// assert_eq!(UtcOffset::hours(-12).as_minutes(), -720); /// ``` pub const fn as_minutes(self) -> i16 { (self.as_seconds() / 60) as i16 } /// Get the number of hours from UTC the value is. Positive is east, /// negative is west. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::UTC.as_hours(), 0); /// assert_eq!(UtcOffset::hours(12).as_hours(), 12); /// assert_eq!(UtcOffset::hours(-12).as_hours(), -12); /// ``` pub const fn as_hours(self) -> i8 { (self.as_seconds() / 3_600) as i8 } /// Convert a `UtcOffset` to ` Duration`. Useful for implementing operators. pub(crate) const fn as_duration(self) -> Duration { Duration::seconds(self.seconds as i64) } /// Obtain the system's UTC offset at a known moment in time. If the offset /// cannot be determined, UTC is returned. /// /// ```rust /// # #![allow(deprecated)] /// # use time::{UtcOffset, OffsetDateTime}; /// let unix_epoch = OffsetDateTime::unix_epoch(); /// let local_offset = UtcOffset::local_offset_at(unix_epoch); /// println!("{}", local_offset.format("%z")); /// ``` #[cfg(feature = "std")] #[cfg_attr(__time_02_docs, doc(cfg(feature = "std")))] #[deprecated( since = "0.2.23", note = "UTC is returned if the local offset cannot be determined" )] pub fn local_offset_at(datetime: OffsetDateTime) -> Self { try_local_offset_at(datetime).unwrap_or(Self::UTC) } /// Attempt to obtain the system's UTC offset at a known moment in time. If /// the offset cannot be determined, an error is returned. /// /// ```rust /// # use time::{UtcOffset, OffsetDateTime}; /// let unix_epoch = OffsetDateTime::unix_epoch(); /// let local_offset = UtcOffset::try_local_offset_at(unix_epoch); /// # if false { /// assert!(local_offset.is_ok()); /// # } /// ``` #[cfg(feature = "std")] #[cfg_attr(__time_02_docs, doc(cfg(feature = "std")))] pub fn try_local_offset_at( datetime: OffsetDateTime, ) -> Result<Self, error::IndeterminateOffset> { try_local_offset_at(datetime).ok_or(error::IndeterminateOffset) } /// Obtain the system's current UTC offset. If the offset cannot be /// determined, UTC is returned. /// /// ```rust /// # #![allow(deprecated)] /// # use time::UtcOffset; /// let local_offset = UtcOffset::current_local_offset(); /// println!("{}", local_offset.format("%z")); /// ``` #[cfg(feature = "std")] #[cfg_attr(__time_02_docs, doc(cfg(feature = "std")))] #[deprecated( since = "0.2.23", note = "UTC is returned if the local offset cannot be determined" )] pub fn current_local_offset() -> Self { let now = OffsetDateTime::now_utc(); try_local_offset_at(now).unwrap_or(Self::UTC) } /// Attempt to obtain the system's current UTC offset. If the offset cannot /// be determined, an error is returned. /// /// ```rust /// # use time::UtcOffset; /// let local_offset = UtcOffset::try_current_local_offset(); /// # if false { /// assert!(local_offset.is_ok()); /// # } /// ``` #[cfg(feature = "std")] #[cfg_attr(__time_02_docs, doc(cfg(feature = "std")))] pub fn try_current_local_offset() -> Result<Self, error::IndeterminateOffset> { let now = OffsetDateTime::now_utc(); try_local_offset_at(now).ok_or(error::IndeterminateOffset) } } /// Methods that allow parsing and formatting the `UtcOffset`. impl UtcOffset { /// Format the `UtcOffset` using the provided string. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::hours(2).format("%z"), "+0200"); /// assert_eq!(UtcOffset::hours(-2).format("%z"), "-0200"); /// ``` pub fn format(self, format: impl AsRef<str>) -> String { self.lazy_format(format).to_string() } /// Format the `UtcOffset` using the provided string. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::hours(2).lazy_format("%z").to_string(), "+0200"); /// assert_eq!(UtcOffset::hours(-2).lazy_format("%z").to_string(), "-0200"); /// ``` pub fn lazy_format(self, format: impl AsRef<str>) -> impl Display { DeferredFormat::new(format.as_ref()) .with_offset(self) .to_owned() } /// Attempt to parse the `UtcOffset` using the provided string. /// /// ```rust /// # use time::UtcOffset; /// assert_eq!(UtcOffset::parse("+0200", "%z"), Ok(UtcOffset::hours(2))); /// assert_eq!(UtcOffset::parse("-0200", "%z"), Ok(UtcOffset::hours(-2))); /// ``` pub fn parse(s: impl AsRef<str>, format: impl AsRef<str>) -> ParseResult<Self> { Self::try_from_parsed_items(parse(s.as_ref(), &format.into())?) } /// Given the items already parsed, attempt to create a `UtcOffset`. pub(crate) fn try_from_parsed_items(items: ParsedItems) -> ParseResult<Self> { items.offset.ok_or(error::Parse::InsufficientInformation) } } impl Display for UtcOffset { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { let sign = if self.seconds < 0 { '-' } else { '+' }; let hours = self.as_hours().abs(); let minutes = self.as_minutes().abs() - hours as i16 * 60; let seconds = self.as_seconds().abs() - hours as i32 * 3_600 - minutes as i32 * 60; write!(f, "{}{}", sign, hours)?; if minutes != 0 || seconds != 0 { write!(f, ":{:02}", minutes)?; } if seconds != 0 { write!(f, ":{:02}", seconds)?; } Ok(()) } } /// Attempt to obtain the system's UTC offset. If the offset cannot be /// determined, `None` is returned. #[cfg(feature = "std")] #[allow(clippy::too_many_lines, clippy::missing_const_for_fn)] fn try_local_offset_at(datetime: OffsetDateTime) -> Option<UtcOffset> { #[cfg(target_family = "unix")] { // See #293 for details. let _ = datetime; None // use standback::{convert::TryInto, mem::MaybeUninit}; // // /// Convert the given Unix timestamp to a `libc::tm`. Returns `None` on // /// any error. // fn timestamp_to_tm(timestamp: i64) -> Option<libc::tm> { // extern "C" { // #[cfg_attr(target_os = "netbsd", link_name = "__tzset50")] // fn tzset(); // } // // // The exact type of `timestamp` beforehand can vary, so this // // conversion is necessary. // #[allow(clippy::useless_conversion)] // let timestamp = timestamp.try_into().ok()?; // // let mut tm = MaybeUninit::uninit(); // // // Update timezone information from system. `localtime_r` does not // // do this for us. // // // // Safety: tzset is thread-safe. // #[allow(unsafe_code)] // unsafe { // tzset(); // } // // // Safety: We are calling a system API, which mutates the `tm` // // variable. If a null pointer is returned, an error occurred. // #[allow(unsafe_code)] // let tm_ptr = unsafe { libc::localtime_r(×tamp, tm.as_mut_ptr()) }; // // if tm_ptr.is_null() { // None // } else { // // Safety: The value was initialized, as we no longer have a // // null pointer. // #[allow(unsafe_code)] // { // Some(unsafe { tm.assume_init() }) // } // } // } // // let tm = timestamp_to_tm(datetime.unix_timestamp())?; // // // `tm_gmtoff` extension // #[cfg(not(any(target_os = "solaris", target_os = "illumos")))] // { // tm.tm_gmtoff.try_into().ok().map(UtcOffset::seconds) // } // // // No `tm_gmtoff` extension // #[cfg(any(target_os = "solaris", target_os = "illumos"))] // { // use crate::Date; // use standback::convert::TryFrom; // // let mut tm = tm; // if tm.tm_sec == 60 { // // Leap seconds are not currently supported. // tm.tm_sec = 59; // } // // let local_timestamp = // Date::try_from_yo(1900 + tm.tm_year, u16::try_from(tm.tm_yday).ok()? + 1) // .ok()? // .try_with_hms( // tm.tm_hour.try_into().ok()?, // tm.tm_min.try_into().ok()?, // tm.tm_sec.try_into().ok()?, // ) // .ok()? // .assume_utc() // .unix_timestamp(); // // (local_timestamp - datetime.unix_timestamp()) // .try_into() // .ok() // .map(UtcOffset::seconds) // } } #[cfg(target_family = "windows")] { use standback::{convert::TryInto, mem::MaybeUninit}; use winapi::{ shared::minwindef::FILETIME, um::{ minwinbase::SYSTEMTIME, timezoneapi::{SystemTimeToFileTime, SystemTimeToTzSpecificLocalTime}, }, }; /// Convert a `SYSTEMTIME` to a `FILETIME`. Returns `None` if any error /// occurred. fn systemtime_to_filetime(systime: &SYSTEMTIME) -> Option<FILETIME> { let mut ft = MaybeUninit::uninit(); // Safety: `SystemTimeToFileTime` is thread-safe. We are only // assuming initialization if the call succeeded. #[allow(unsafe_code)] { if 0 == unsafe { SystemTimeToFileTime(systime, ft.as_mut_ptr()) } { // failed None } else { Some(unsafe { ft.assume_init() }) } } } /// Convert a `FILETIME` to an `i64`, representing a number of seconds. fn filetime_to_secs(filetime: &FILETIME) -> i64 { /// FILETIME represents 100-nanosecond intervals const FT_TO_SECS: i64 = 10_000_000; ((filetime.dwHighDateTime as i64) << 32 | filetime.dwLowDateTime as i64) / FT_TO_SECS } /// Convert an `OffsetDateTime` to a `SYSTEMTIME`. fn offset_to_systemtime(datetime: OffsetDateTime) -> SYSTEMTIME { let (month, day_of_month) = datetime.to_offset(UtcOffset::UTC).month_day(); SYSTEMTIME { wYear: datetime.year() as u16, wMonth: month as u16, wDay: day_of_month as u16, wDayOfWeek: 0, // ignored wHour: datetime.hour() as u16, wMinute: datetime.minute() as u16, wSecond: datetime.second() as u16, wMilliseconds: datetime.millisecond(), } } // This function falls back to UTC if any system call fails. let systime_utc = offset_to_systemtime(datetime.to_offset(UtcOffset::UTC)); // Safety: `local_time` is only read if it is properly initialized, and // `SystemTimeToTzSpecificLocalTime` is thread-safe. #[allow(unsafe_code)] let systime_local = unsafe { let mut local_time = MaybeUninit::uninit(); if 0 == SystemTimeToTzSpecificLocalTime( core::ptr::null(), // use system's current timezone &systime_utc, local_time.as_mut_ptr(), ) { // call failed return None; } else { local_time.assume_init() } }; // Convert SYSTEMTIMEs to FILETIMEs so we can perform arithmetic on // them. let ft_system = systemtime_to_filetime(&systime_utc)?; let ft_local = systemtime_to_filetime(&systime_local)?; let diff_secs = filetime_to_secs(&ft_local) - filetime_to_secs(&ft_system); diff_secs.try_into().ok().map(UtcOffset::seconds) } #[cfg(__time_02_cargo_web)] { use stdweb::{js, unstable::TryInto}; let timestamp_utc = datetime.unix_timestamp(); let low_bits = (timestamp_utc & 0xFF_FF_FF_FF) as i32; let high_bits = (timestamp_utc >> 32) as i32; let timezone_offset = js! { return new Date(((@{high_bits} << 32) + @{low_bits}) * 1000) .getTimezoneOffset() * -60; }; timezone_offset.try_into().ok().map(UtcOffset::seconds) } #[cfg(not(any(target_family = "unix", target_family = "windows", __time_02_cargo_web)))] { // Silence the unused variable warning when appropriate. let _ = datetime; None } } #[cfg(test)] mod test { use super::*; use crate::ext::NumericalDuration; #[test] fn as_duration() { assert_eq!(UtcOffset::hours(1).as_duration(), 1.hours()); assert_eq!(UtcOffset::hours(-1).as_duration(), (-1).hours()); } }