Struct utc2k::LocalOffset

pub struct LocalOffset { /* private fields */ }

Available on crate feature local only.

Local Offset.

This struct attempts to determine the appropriate UTC offset for the local timezone in a thread-safe manner, but only for unix systems.

Instantiation will never fail, though.

If the platform isn’t supported or no offset can be determined, the “offset” will simply be zero (i.e. as if it were UTC).

Examples

To obtain the current local offset, use LocalOffset::now.

To obtain the local offset for a specific unix timestamp, use its From<u32> implementation instead.

use utc2k::LocalOffset;

// The current offset.
let now = LocalOffset::now();

// The offset for a specific time.
let then = LocalOffset::from(946_684_800_u32);

If all you want is the offset, you can grab that by calling LocalOffset::offset afterward.

This struct can, however, also be used to trick FmtUtc2k and Utc2k into representing local rather than UTC datetimes by using their From<LocalOffset> implementations, or the FmtUtc2k::now_local/Utc2k::now_local shorthands.

If you do this, however, it is worth noting that comparing tricked and untricked objects makes no logical sense, so you shouldn’t mix-and-match if you need to test for equality or ordering.

Additionally, you should avoid localizing a datetime if you plan on using the to_rfc2822 or to_rfc3339 formatting helpers. They always assume they’re representing a UTC timestamp, so will add the wrong suffix to their output if your local offset is non-zero.

Other than that, the trick works perfectly well. ;)

use utc2k::{LocalOffset, Utc2k};

let now_utc = Utc2k::now();

// These two are equivalent.
let now_local = Utc2k::from(LocalOffset::now());
let now_local = Utc2k::now_local();

If you need to convert from a local timestamp into a UTC one, you can leverage std::ops::Neg to invert the offset, like:

use utc2k::{LocalOffset, Utc2k};

let offset = LocalOffset::from(946_684_800_u32);
let utc = Utc2k::from(-offset);

Implementations

impl LocalOffset

pub fn now() -> Self

Now.

Return the current, local offset. If no offset can be determined, UTC will be assumed.

Examples

let now = utc2k::LocalOffset::now();

pub const fn localtime(self) -> u32

Local Timestamp.

Return the sum of the unix timestamp and the offset.

pub const fn offset(self) -> i32

Offset.

Return the local offset (in seconds). Zero is returned if there is no offset, or no offset could be determined.

pub const fn unixtime(self) -> u32

Unixtime.

Return the unix timestamp this instance applies to (i.e. the value it was seeded with).

Examples

use utc2k::LocalOffset;

let offset = LocalOffset::from(946_684_800_u32);
assert_eq!(offset.unixtime(), 946_684_800_u32);

Trait Implementations

impl Clone for LocalOffset

fn clone(&self) -> LocalOffset

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LocalOffset

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for LocalOffset

fn default() -> LocalOffset

Returns the “default value” for a type.

impl From<LocalOffset> for FmtUtc2k

fn from(src: LocalOffset) -> Self

Converts to this type from the input type.

impl From<LocalOffset> for Utc2k

fn from(src: LocalOffset) -> Self

Converts to this type from the input type.

impl From<LocalOffset> for i32

fn from(src: LocalOffset) -> Self

Converts to this type from the input type.

impl From<Utc2k> for LocalOffset

fn from(src: Utc2k) -> Self

From Utc2k

Warning: this should only be used for Utc2k instances holding honest UTC datetimes. If you call this on a tricked/local instance, the offset will get applied twice!

impl From<u32> for LocalOffset

fn from(unixtime: u32) -> Self

Converts to this type from the input type.

impl Hash for LocalOffset

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Neg for LocalOffset

type Output = LocalOffset

The resulting type after applying the - operator.

fn neg(self) -> Self::Output

Performs the unary - operation.

impl PartialEq for LocalOffset

fn eq(&self, other: &LocalOffset) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for LocalOffset

impl Eq for LocalOffset

impl StructuralPartialEq for LocalOffset