Merge pull request #235 from cakebaker/bump_version_to_0_13_0

chore: bump version to `0.13.0`

Cargo.lock

@@ -158,7 +158,7 @@ dependencies = [
 
 [[package]]
 name = "parse_datetime"
-version = "0.12.0"
+version = "0.13.0"
 dependencies = [
  "jiff",
  "num-traits",
@@ -223,9 +223,9 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.11.2"
+version = "1.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "23d7fd106d8c02486a8d64e778353d1cffe08ce79ac2e82f540c86d0facf6912"
+checksum = "8b5288124840bee7b386bc413c487869b360b2b4ec421ea56425128692f2a82c"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -235,9 +235,9 @@ dependencies = [
 
 [[package]]
 name = "regex-automata"
-version = "0.4.10"
+version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6b9458fa0bfeeac22b5ca447c63aaf45f28439a709ccd244698632f9aa6394d6"
+checksum = "833eb9ce86d40ef33cb1306d8accf7bc8ec2bfea4355cbdebb3df68b40925cad"
 dependencies = [
  "aho-corasick",
  "memchr",

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "parse_datetime"
 description = "parsing human-readable time strings and converting them to a DateTime"
-version = "0.12.0"
+version = "0.13.0"
 edition = "2021"
 license = "MIT"
 repository = "https://github.com/uutils/parse_datetime"

src/items/builder.rs

@@ -3,7 +3,7 @@
 
 use jiff::{civil, Span, Zoned};
 
-use super::{date, epoch, error, relative, time, timezone, weekday, year, Item};
+use super::{date, epoch, error, offset, relative, time, weekday, year, Item};
 
 /// The builder is used to construct a DateTime object from various components.
 /// The parser creates a `DateTimeBuilder` object with the parsed components,
@@ -17,7 +17,8 @@ pub(crate) struct DateTimeBuilder {
     date: Option<date::Date>,
     time: Option<time::Time>,
     weekday: Option<weekday::Weekday>,
-    timezone: Option<timezone::Offset>,
+    offset: Option<offset::Offset>,
+    timezone: Option<jiff::tz::TimeZone>,
     relative: Vec<relative::Relative>,
 }
 
@@ -33,6 +34,20 @@ impl DateTimeBuilder {
         self
     }
 
+    /// Sets the timezone rule for the builder.
+    ///
+    /// By default, the builder uses the time zone rules indicated by the `TZ`
+    /// environment variable, or the system default rules if `TZ` is not set.
+    /// This method allows overriding the time zone rules.
+    fn set_timezone(mut self, tz: jiff::tz::TimeZone) -> Result<Self, &'static str> {
+        if self.timezone.is_some() {
+            return Err("timezone rule cannot appear more than once");
+        }
+
+        self.timezone = Some(tz);
+        Ok(self)
+    }
+
     /// Sets a timestamp value. Timestamp values are exclusive to other date/time
     /// items (date, time, weekday, timezone, relative adjustments).
     pub(super) fn set_timestamp(mut self, ts: epoch::Timestamp) -> Result<Self, &'static str> {
@@ -41,7 +56,7 @@ impl DateTimeBuilder {
         } else if self.date.is_some()
             || self.time.is_some()
             || self.weekday.is_some()
-            || self.timezone.is_some()
+            || self.offset.is_some()
             || !self.relative.is_empty()
         {
             return Err("timestamp cannot be combined with other date/time items");
@@ -51,7 +66,7 @@ impl DateTimeBuilder {
         Ok(self)
     }
 
-    pub(super) fn set_date(mut self, date: date::Date) -> Result<Self, &'static str> {
+    fn set_date(mut self, date: date::Date) -> Result<Self, &'static str> {
         if self.timestamp.is_some() {
             return Err("timestamp cannot be combined with other date/time items");
         } else if self.date.is_some() {
@@ -62,12 +77,12 @@ impl DateTimeBuilder {
         Ok(self)
     }
 
-    pub(super) fn set_time(mut self, time: time::Time) -> Result<Self, &'static str> {
+    fn set_time(mut self, time: time::Time) -> Result<Self, &'static str> {
         if self.timestamp.is_some() {
             return Err("timestamp cannot be combined with other date/time items");
         } else if self.time.is_some() {
             return Err("time cannot appear more than once");
-        } else if self.timezone.is_some() && time.offset.is_some() {
+        } else if self.offset.is_some() && time.offset.is_some() {
             return Err("time offset and timezone are mutually exclusive");
         }
 
@@ -75,7 +90,7 @@ impl DateTimeBuilder {
         Ok(self)
     }
 
-    pub(super) fn set_weekday(mut self, weekday: weekday::Weekday) -> Result<Self, &'static str> {
+    fn set_weekday(mut self, weekday: weekday::Weekday) -> Result<Self, &'static str> {
         if self.timestamp.is_some() {
             return Err("timestamp cannot be combined with other date/time items");
         } else if self.weekday.is_some() {
@@ -86,23 +101,20 @@ impl DateTimeBuilder {
         Ok(self)
     }
 
-    pub(super) fn set_timezone(mut self, timezone: timezone::Offset) -> Result<Self, &'static str> {
+    fn set_offset(mut self, timezone: offset::Offset) -> Result<Self, &'static str> {
         if self.timestamp.is_some() {
             return Err("timestamp cannot be combined with other date/time items");
-        } else if self.timezone.is_some() {
-            return Err("timezone cannot appear more than once");
-        } else if self.time.as_ref().and_then(|t| t.offset.as_ref()).is_some() {
-            return Err("time offset and timezone are mutually exclusive");
+        } else if self.offset.is_some()
+            || self.time.as_ref().and_then(|t| t.offset.as_ref()).is_some()
+        {
+            return Err("time offset cannot appear more than once");
         }
 
-        self.timezone = Some(timezone);
+        self.offset = Some(timezone);
         Ok(self)
     }
 
-    pub(super) fn push_relative(
-        mut self,
-        relative: relative::Relative,
-    ) -> Result<Self, &'static str> {
+    fn push_relative(mut self, relative: relative::Relative) -> Result<Self, &'static str> {
         if self.timestamp.is_some() {
             return Err("timestamp cannot be combined with other date/time items");
         }
@@ -117,7 +129,7 @@ impl DateTimeBuilder {
     /// If a date is already set but lacks a year, the number is interpreted as
     /// a year. Otherwise, it's interpreted as a time in HHMM, HMM, HH, or H
     /// format.
-    pub(super) fn set_pure(mut self, pure: String) -> Result<Self, &'static str> {
+    fn set_pure(mut self, pure: String) -> Result<Self, &'static str> {
         if self.timestamp.is_some() {
             return Err("timestamp cannot be combined with other date/time items");
         }
@@ -149,7 +161,11 @@ impl DateTimeBuilder {
     }
 
     pub(super) fn build(self) -> Result<Zoned, error::Error> {
-        let base = self.base.unwrap_or(Zoned::now());
+        let base = self.base.unwrap_or(if let Some(tz) = &self.timezone {
+            jiff::Timestamp::now().to_zoned(tz.clone())
+        } else {
+            Zoned::now()
+        });
 
         // If a timestamp is set, we use it to build the `Zoned` object.
         if let Some(ts) = self.timestamp {
@@ -158,10 +174,10 @@ impl DateTimeBuilder {
 
         // If any of the following items are set, we truncate the time portion
         // of the base date to zero; otherwise, we use the base date as is.
-        let mut dt = if self.timestamp.is_none()
-            && self.date.is_none()
+        let mut dt = if self.date.is_none()
             && self.time.is_none()
             && self.weekday.is_none()
+            && self.offset.is_none()
             && self.timezone.is_none()
         {
             base
@@ -239,7 +255,7 @@ impl DateTimeBuilder {
             })?;
         }
 
-        if let Some(offset) = self.timezone {
+        if let Some(offset) = self.offset {
             let (offset, hour_adjustment) = offset.normalize();
             dt = dt.checked_add(Span::new().hours(hour_adjustment))?;
             dt = dt.datetime().to_zoned((&offset).try_into()?)?;
@@ -262,8 +278,9 @@ impl TryFrom<Vec<Item>> for DateTimeBuilder {
                 Item::Date(d) => builder.set_date(d)?,
                 Item::Time(t) => builder.set_time(t)?,
                 Item::Weekday(weekday) => builder.set_weekday(weekday)?,
-                Item::TimeZone(tz) => builder.set_timezone(tz)?,
+                Item::Offset(offset) => builder.set_offset(offset)?,
                 Item::Relative(rel) => builder.push_relative(rel)?,
+                Item::TimeZone(tz) => builder.set_timezone(tz)?,
                 Item::Pure(pure) => builder.set_pure(pure)?,
             }
         }

src/items/mod.rs

@@ -21,6 +21,7 @@
 //!  - [`combined`]
 //!  - [`date`]
 //!  - [`epoch`]
+//!  - [`offset`]
 //!  - [`pure`]
 //!  - [`relative`]
 //!  - [`time`]
@@ -32,6 +33,7 @@
 mod combined;
 mod date;
 mod epoch;
+mod offset;
 mod pure;
 mod relative;
 mod time;
@@ -66,15 +68,15 @@ enum Item {
     Time(time::Time),
     Weekday(weekday::Weekday),
     Relative(relative::Relative),
-    TimeZone(timezone::Offset),
+    Offset(offset::Offset),
+    TimeZone(jiff::tz::TimeZone),
     Pure(String),
 }
 
 /// Parse a date and time string and build a `Zoned` object. The parsed result
 /// is resolved against the given base date and time.
 pub(crate) fn parse_at_date<S: AsRef<str> + Clone>(base: Zoned, input: S) -> Result<Zoned, Error> {
-    let input = input.as_ref().to_ascii_lowercase();
-    match parse(&mut input.as_str()) {
+    match parse(&mut input.as_ref()) {
         Ok(builder) => builder.set_base(base).build(),
         Err(e) => Err(e.into()),
     }
@@ -83,8 +85,7 @@ pub(crate) fn parse_at_date<S: AsRef<str> + Clone>(base: Zoned, input: S) -> Res
 /// Parse a date and time string and build a `Zoned` object. The parsed result
 /// is resolved against the current local date and time.
 pub(crate) fn parse_at_local<S: AsRef<str> + Clone>(input: S) -> Result<Zoned, Error> {
-    let input = input.as_ref().to_ascii_lowercase();
-    match parse(&mut input.as_str()) {
+    match parse(&mut input.as_ref()) {
         Ok(builder) => builder.build(), // the builder uses current local date and time if no base is given.
         Err(e) => Err(e.into()),
     }
@@ -95,12 +96,14 @@ pub(crate) fn parse_at_local<S: AsRef<str> + Clone>(input: S) -> Result<Zoned, E
 /// Grammar:
 ///
 /// ```ebnf
-/// spec                = timestamp | items ;
+/// spec                = [ tz_rule ] ( timestamp | items ) ;
+///
+/// tz_rule            = "TZ=" , "\"" , ( posix_tz | iana_tz ) , "\"" ;
 ///
 /// timestamp           = "@" , float ;
 ///
 /// items               = item , { item } ;
-/// item                = datetime | date | time | relative | weekday | timezone | pure ;
+/// item                = datetime | date | time | relative | weekday | offset | pure ;
 ///
 /// datetime            = date , [ "t" | whitespace ] , iso_time ;
 ///
@@ -179,7 +182,7 @@ pub(crate) fn parse_at_local<S: AsRef<str> + Clone>(input: S) -> Result<Zoned, E
 ///                     | "saturday" | "sat" | "sat."
 ///                     | "sunday" | "sun" | "sun." ;
 ///
-/// timezone            = named_zone , [ time_offset ] ;
+/// offset             = named_zone , [ time_offset ] ;
 ///
 /// pure               = { digit }
 ///
@@ -189,35 +192,60 @@ fn parse(input: &mut &str) -> ModalResult<DateTimeBuilder> {
     trace("parse", alt((parse_timestamp, parse_items))).parse_next(input)
 }
 
-/// Parse a timestamp.
+/// Parse a standalone epoch timestamp (e.g., `@1758724019`).
 ///
-/// From the GNU docs:
+/// GNU `date` specifies that a timestamp item is *complete* and *must not* be
+/// combined with any other date/time item.
 ///
-/// > (Timestamp) Such a number cannot be combined with any other date item, as
-/// > it specifies a complete timestamp.
+/// Notes:
+///
+/// - If a timezone rule (`TZ="..."`) appears at the beginning of the input, it
+///   has no effect on the epoch value. We intentionally parse and ignore it.
+/// - Trailing input (aside from optional whitespaces) is rejected.
 fn parse_timestamp(input: &mut &str) -> ModalResult<DateTimeBuilder> {
+    // Parse and ignore an optional leading timezone rule.
+    let _ = timezone::parse(input);
+
     trace(
         "parse_timestamp",
+        // Expect exactly one timestamp and then EOF (allowing trailing spaces).
         terminated(epoch::parse.map(Item::Timestamp), preceded(space, eof)),
     )
-    .verify_map(|ts: Item| {
-        if let Item::Timestamp(ts) = ts {
-            DateTimeBuilder::new().set_timestamp(ts).ok()
-        } else {
-            None
-        }
+    .verify_map(|item: Item| match item {
+        Item::Timestamp(ts) => DateTimeBuilder::new().set_timestamp(ts).ok(),
+        _ => None,
     })
     .parse_next(input)
 }
 
-/// Parse a sequence of items.
+/// Parse a sequence of date/time items, honoring an optional leading TZ rule.
+///
+/// Notes:
+///
+/// - If a timezone rule (`TZ="..."`) appears at the beginning of the input,
+///   parse it first. The timezone rule is case-sensitive.
+/// - After the optional timezone rule is parsed, we convert the input to
+///   lowercase to allow case-insensitive parsing of the remaining items.
+/// - Trailing input (aside from optional whitespaces) is rejected.
 fn parse_items(input: &mut &str) -> ModalResult<DateTimeBuilder> {
-    let (items, _): (Vec<Item>, _) = trace(
+    // Parse and consume an optional leading timezone rule.
+    let tz = timezone::parse(input).map(Item::TimeZone);
+
+    // Convert input to lowercase for case-insensitive parsing.
+    let lower = input.to_ascii_lowercase();
+    let input = &mut lower.as_str();
+
+    let (mut items, _): (Vec<Item>, _) = trace(
         "parse_items",
+        // Parse zero or more items until EOF (allowing trailing spaces).
         repeat_till(0.., parse_item, preceded(space, eof)),
     )
     .parse_next(input)?;
 
+    if let Ok(tz) = tz {
+        items.push(tz);
+    }
+
     items.try_into().map_err(|e| expect_error(input, e))
 }
 
@@ -231,7 +259,7 @@ fn parse_item(input: &mut &str) -> ModalResult<Item> {
             time::parse.map(Item::Time),
             relative::parse.map(Item::Relative),
             weekday::parse.map(Item::Weekday),
-            timezone::parse.map(Item::TimeZone),
+            offset::parse.map(Item::Offset),
             pure::parse.map(Item::Pure),
         )),
     )
@@ -251,7 +279,7 @@ fn expect_error(input: &mut &str, reason: &'static str) -> ErrMode<ContextError>
 mod tests {
     use jiff::{civil::DateTime, tz::TimeZone, ToSpan, Zoned};
 
-    use super::{parse, DateTimeBuilder};
+    use super::*;
 
     fn at_date(builder: DateTimeBuilder, base: Zoned) -> Zoned {
         builder.set_base(base).build().unwrap()
@@ -369,7 +397,7 @@ mod tests {
         assert!(result
             .unwrap_err()
             .to_string()
-            .contains("timezone cannot appear more than once"));
+            .contains("time offset cannot appear more than once"));
 
         let result = parse(&mut "2025-05-19 abcdef");
         assert!(result.is_err());
@@ -527,4 +555,22 @@ mod tests {
         assert_eq!(result.hour(), 1);
         assert_eq!(result.minute(), 0);
     }
+
+    #[test]
+    fn timezone_rule() {
+        let parse_build = |mut s| parse(&mut s).unwrap().build().unwrap();
+
+        for (input, expected) in [
+            (
+                r#"TZ="Europe/Paris" 2025-01-02"#,
+                "2025-01-02 00:00:00[Europe/Paris]".parse().unwrap(),
+            ),
+            (
+                r#"TZ="Europe/Paris" 2025-01-02 03:04:05"#,
+                "2025-01-02 03:04:05[Europe/Paris]".parse().unwrap(),
+            ),
+        ] {
+            assert_eq!(parse_build(input), expected, "{input}");
+        }
+    }
 }

src/items/offset.rs

@@ -0,0 +1,468 @@
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+//! Parse an offset item.
+//!
+//! From the GNU docs:
+//!
+//! > A “time zone item” specifies an international time zone, indicated by a
+//! > small set of letters, e.g., ‘UTC’ or ‘Z’ for Coordinated Universal Time.
+//! > Any included periods are ignored.  By following a non-daylight-saving
+//! > time zone by the string ‘DST’ in a separate word (that is, separated by
+//! > some white space), the corresponding daylight saving time zone may be
+//! > specified.  Alternatively, a non-daylight-saving time zone can be
+//! > followed by a time zone correction, to add the two values.  This is
+//! > normally done only for ‘UTC’; for example, ‘UTC+05:30’ is equivalent to
+//! > ‘+05:30’.
+//! >
+//! >    Time zone items other than ‘UTC’ and ‘Z’ are obsolescent and are not
+//! > recommended, because they are ambiguous; for example, ‘EST’ has a
+//! > different meaning in Australia than in the United States, and ‘A’ has
+//! > different meaning as a military time zone than as an obsolete RFC 822
+//! > time zone.  Instead, it's better to use unambiguous numeric time zone
+//! > corrections like ‘-0500’, as described in the previous section.
+//! >
+//! >    If neither a time zone item nor a time zone correction is supplied,
+//! > timestamps are interpreted using the rules of the default time zone.
+
+use std::fmt::Display;
+
+use winnow::{
+    combinator::{alt, peek},
+    error::{ContextError, ErrMode},
+    stream::{AsChar, Stream},
+    token::take_while,
+    ModalResult, Parser,
+};
+
+use super::{
+    primitive::{colon, ctx_err, dec_uint, dec_uint_str, plus_or_minus, s},
+    relative,
+};
+
+/// Represents a time zone offset from UTC.
+///
+/// This struct is used to represent a time zone offset in hours and minutes,
+/// with a boolean indicating whether the offset is negative (i.e., west of
+/// UTC).
+#[derive(PartialEq, Debug, Clone, Default)]
+pub(super) struct Offset {
+    negative: bool,
+    hours: u8,
+    minutes: u8,
+}
+
+impl Offset {
+    /// Merge two timezone offsets.
+    ///
+    /// Note: when parsing an offset from a string (e.g., "+08:00"), the hours
+    /// and minutes are validated to ensure they fall within valid bounds. In
+    /// contrast, merging two offsets does not perform such validation. This
+    /// behavior is intentional to match GNU date.
+    fn merge(self, offset: Offset) -> Offset {
+        fn combine(a: u16, neg_a: bool, b: u16, neg_b: bool) -> (u16, bool) {
+            if neg_a == neg_b {
+                (a + b, neg_a)
+            } else if a > b {
+                (a - b, neg_a)
+            } else {
+                (b - a, neg_b)
+            }
+        }
+        let (total_minutes, negative) = combine(
+            (self.hours as u16) * 60 + (self.minutes as u16),
+            self.negative,
+            (offset.hours as u16) * 60 + (offset.minutes as u16),
+            offset.negative,
+        );
+        let hours = (total_minutes / 60) as u8;
+        let minutes = (total_minutes % 60) as u8;
+
+        Offset {
+            negative,
+            hours,
+            minutes,
+        }
+    }
+
+    /// Normalize the offset so that the hour field is within the accepted range.
+    ///
+    /// - If the hour field is less than 24, or exactly 24 with a zero minute,
+    ///   the offset is already normalized, and the function returns the offset
+    ///   itself along with a zero hour adjustment.
+    /// - Otherwise, the hour field is reduced to 23 while preserving the minute
+    ///   field, and the function returns the normalized offset along with the
+    ///   hour adjustment needed to reach the original offset.
+    pub(super) fn normalize(self) -> (Offset, i8) {
+        if self.hours < 24 || (self.hours == 24 && self.minutes == 0) {
+            return (self, 0);
+        }
+
+        let hour_adjustment = (self.hours as i8 - 23) * if self.negative { 1 } else { -1 };
+        (
+            Offset {
+                negative: self.negative,
+                hours: 23,
+                minutes: self.minutes,
+            },
+            hour_adjustment,
+        )
+    }
+}
+
+impl TryFrom<(bool, u8, u8)> for Offset {
+    type Error = &'static str;
+
+    fn try_from((negative, hours, minutes): (bool, u8, u8)) -> Result<Self, Self::Error> {
+        if hours > 24 {
+            return Err("timezone hour must be between 0 and 24");
+        }
+        if minutes > 60 || (hours == 24 && minutes != 0) {
+            return Err("timezone minute must be between 0 and 60");
+        }
+
+        Ok(Offset {
+            negative,
+            hours,
+            minutes,
+        })
+    }
+}
+
+impl TryFrom<&Offset> for jiff::tz::TimeZone {
+    type Error = &'static str;
+
+    fn try_from(
+        Offset {
+            negative,
+            hours,
+            minutes,
+        }: &Offset,
+    ) -> Result<Self, Self::Error> {
+        let secs = (*hours as i32) * 3600 + (*minutes as i32) * 60;
+        let secs = if *negative { -secs } else { secs };
+
+        let offset = jiff::tz::Offset::from_seconds(secs).map_err(|_| "offset is invalid")?;
+        Ok(jiff::tz::TimeZone::fixed(offset))
+    }
+}
+
+impl Display for Offset {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+        write!(
+            fmt,
+            "{}{:02}:{:02}",
+            if self.negative { "-" } else { "+" },
+            self.hours,
+            self.minutes
+        )
+    }
+}
+
+pub(super) fn parse(input: &mut &str) -> ModalResult<Offset> {
+    timezone_name_offset.parse_next(input)
+}
+
+/// Parse a timezone starting with `+` or `-`.
+pub(super) fn timezone_offset(input: &mut &str) -> ModalResult<Offset> {
+    // Strings like "+8 years" are ambiguous, they can either be parsed as a
+    // timezone offset "+8" and a relative time "years", or just a relative time
+    // "+8 years". GNU date parses them the second way, so we do the same here.
+    //
+    // Return early if the input can be parsed as a relative time.
+    if peek(relative::parse).parse_next(input).is_ok() {
+        return Err(ErrMode::Backtrack(ContextError::new()));
+    }
+
+    alt((timezone_offset_colon, timezone_offset_colonless)).parse_next(input)
+}
+
+/// Parse a timezone by name, with an optional numeric offset appended.
+fn timezone_name_offset(input: &mut &str) -> ModalResult<Offset> {
+    /// I'm assuming there are no timezone abbreviations with more
+    /// than 6 charactres
+    const MAX_TZ_SIZE: usize = 6;
+    let nextword = s(take_while(1..=MAX_TZ_SIZE, AsChar::is_alpha)).parse_next(input)?;
+    let tz = timezone_name_to_offset(nextword)?;
+
+    // Strings like "UTC +8 years" are ambiguous, they can either be parsed as
+    // "UTC+8" and "years", or "UTC" and "+8 years". GNU date parses them the
+    // second way, so we do the same here.
+    //
+    // Only process if the input cannot be parsed as a relative time.
+    if peek(relative::parse).parse_next(input).is_err() {
+        let start = input.checkpoint();
+        if let Ok(other_tz) = timezone_offset.parse_next(input) {
+            let new_tz = tz.merge(other_tz);
+
+            return Ok(new_tz);
+        };
+        input.reset(&start);
+    }
+
+    Ok(tz)
+}
+
+/// Parse a timezone offset with a colon separating hours and minutes, e.g.,
+/// `+08:00`, `+8:00`, `+8:0`.
+fn timezone_offset_colon(input: &mut &str) -> ModalResult<Offset> {
+    (plus_or_minus, s(dec_uint), s(colon), s(dec_uint))
+        .parse_next(input)
+        .and_then(|(sign, hours, _, minutes)| {
+            (sign == '-', hours, minutes)
+                .try_into()
+                .map_err(|e| ErrMode::Cut(ctx_err(e)))
+        })
+}
+
+/// Parse a timezone offset without colon, e.g., `+0800`, `+800`, `+08`, `+8`.
+fn timezone_offset_colonless(input: &mut &str) -> ModalResult<Offset> {
+    (plus_or_minus, s(dec_uint_str))
+        .verify_map(|(sign, s)| {
+            // GNU date accepts numeric offset strings with leading zeroes. For
+            // example, `+000000110` is valid. In such cases, the string is
+            // truncated to the last four characters. Thus, `+000000110` becomes
+            // `+0110` (note that one leading zero is kept).
+            let s = if s.len() > 4 && s.trim_start_matches('0').len() <= 4 {
+                &s[s.len() - 4..]
+            } else {
+                s
+            };
+
+            // Hour and minute values are dependent on the length of the string.
+            // For example:
+            //
+            // - "5"   -> 05:00
+            // - "05"  -> 05:00
+            // - "530" -> 05:30 (the minute is the last two characters here)
+            // - "0530"-> 05:30
+            // - "0000530" -> 05:30
+            let (h_str, m_str) = match s.len() {
+                1 | 2 => (s, "0"),
+                3 => s.split_at(1),
+                4 => s.split_at(2),
+                _ => return None,
+            };
+
+            let hours = h_str.parse::<u8>().ok()?;
+            let minutes = m_str.parse::<u8>().ok()?;
+            Some((sign, hours, minutes))
+        })
+        .parse_next(input)
+        .and_then(|(sign, hours, minutes)| {
+            (sign == '-', hours, minutes)
+                .try_into()
+                .map_err(|e| ErrMode::Cut(ctx_err(e)))
+        })
+}
+
+/// Named timezone list.
+///
+/// The full list of timezones can be extracted from
+/// https://www.timeanddate.com/time/zones/. GNU date only supports a subset of
+/// these. We support the same subset as GNU date.
+fn timezone_name_to_offset(input: &str) -> ModalResult<Offset> {
+    let mut offset_str = match input {
+        "z" => Ok("+0"),
+        "y" => Ok("-12"),
+        "x" => Ok("-11"),
+        "wet" => Ok("+0"),
+        "west" => Ok("+1"),
+        "wat" => Ok("+1"),
+        "w" => Ok("-10"),
+        "v" => Ok("-9"),
+        "utc" => Ok("+0"),
+        "u" => Ok("-8"),
+        "t" => Ok("-7"),
+        "sst" => Ok("-11"),
+        "sgt" => Ok("+8"),
+        "sast" => Ok("+2"),
+        "s" => Ok("-6"),
+        "r" => Ok("-5"),
+        "q" => Ok("-4"),
+        "pst" => Ok("-8"),
+        "pdt" => Ok("-7"),
+        "p" => Ok("-3"),
+        "o" => Ok("-2"),
+        "nzst" => Ok("+12"),
+        "nzdt" => Ok("+13"),
+        "nst" => Ok("-3:30"),
+        "ndt" => Ok("-2:30"),
+        "n" => Ok("-1"),
+        "mst" => Ok("-7"),
+        "msk" => Ok("+3"),
+        "msd" => Ok("+4"),
+        "mdt" => Ok("-6"),
+        "m" => Ok("+12"),
+        "l" => Ok("+11"),
+        "k" => Ok("+10"),
+        "jst" => Ok("+9"),
+        "ist" => Ok("+5:30"),
+        "i" => Ok("+9"),
+        "hst" => Ok("-10"),
+        "h" => Ok("+8"),
+        "gst" => Ok("+4"),
+        "gmt" => Ok("+0"),
+        "g" => Ok("+7"),
+        "f" => Ok("+6"),
+        "est" => Ok("-5"),
+        "eet" => Ok("+2"),
+        "eest" => Ok("+3"),
+        "edt" => Ok("-4"),
+        "eat" => Ok("+3"),
+        "e" => Ok("+5"),
+        "d" => Ok("+4"),
+        "cst" => Ok("-6"),
+        "clt" => Ok("-4"),
+        "clst" => Ok("-3"),
+        "cet" => Ok("+1"),
+        "cest" => Ok("+2"),
+        "cdt" => Ok("-5"),
+        "cat" => Ok("+2"),
+        "c" => Ok("+3"),
+        "bst" => Ok("+6"),
+        "brt" => Ok("-3"),
+        "brst" => Ok("-2"),
+        "b" => Ok("+2"),
+        "ast" => Ok("-3"),
+        "art" => Ok("-3"),
+        "akst" => Ok("-9"),
+        "akdt" => Ok("-8"),
+        "adt" => Ok("+4"),
+        "a" => Ok("+1"),
+        _ => Err(ErrMode::Backtrack(ContextError::new())),
+    }?;
+
+    timezone_offset(&mut offset_str)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn off(negative: bool, hours: u8, minutes: u8) -> Offset {
+        Offset {
+            negative,
+            hours,
+            minutes,
+        }
+    }
+
+    #[test]
+    fn timezone_offset_with_colon() {
+        for (input, expected) in [
+            ("+00:00", off(false, 0, 0)),        // UTC
+            ("-00:00", off(true, 0, 0)),         // UTC
+            ("+01:00", off(false, 1, 0)),        // positive offset
+            ("-06:00", off(true, 6, 0)),         // negative offset
+            ("+05:30", off(false, 5, 30)),       // positive offset with non-zero minutes
+            ("-03:30", off(true, 3, 30)),        // negative offset with non-zero minutes
+            ("- 06:00", off(true, 6, 0)),        // space after sign
+            ("- 06 : 00", off(true, 6, 0)),      // space around colon
+            ("+5:3", off(false, 5, 3)),          // single-digit hours and single-digit minutes
+            ("+5:03", off(false, 5, 3)),         // single-digit hours
+            ("+05:3", off(false, 5, 3)),         // single-digit minutes
+            ("+00005:00030", off(false, 5, 30)), // leading zeroes in hours and minutes
+            ("+00:00abc", off(false, 0, 0)), // space separator can be ignored if immediately followed by alphas (GNU date behavior)
+        ] {
+            let mut s = input;
+            assert_eq!(timezone_offset(&mut s).unwrap(), expected, "{input}");
+        }
+
+        for input in [
+            "+25:00", // invalid: hours > 24
+            "-23:61", // invalid: minutes > 60
+            "+24:01", // invalid: minutes > 0 when hours == 24
+        ] {
+            let mut s = input;
+            assert!(timezone_offset(&mut s).is_err(), "{input}");
+        }
+    }
+
+    #[test]
+    fn timezone_offset_without_colon() {
+        for (input, expected) in [
+            ("+0000", off(false, 0, 0)),      // UTC
+            ("-0000", off(true, 0, 0)),       // UTC
+            ("+0100", off(false, 1, 0)),      // positive offset
+            ("-0600", off(true, 6, 0)),       // negative offset
+            ("+0530", off(false, 5, 30)),     // positive offset with non-zero minutes
+            ("-0330", off(true, 3, 30)),      // negative offset with non-zero minutes
+            ("- 0330", off(true, 3, 30)),     // space after sign
+            ("+530", off(false, 5, 30)),      // single-digit hours
+            ("+05", off(false, 5, 0)),        // double-digit hours and no minutes
+            ("+5", off(false, 5, 0)),         // single-digit hours and no minutes
+            ("+00000530", off(false, 5, 30)), // leading zeroes
+            ("+0000abc", off(false, 0, 0)), // space separator can be ignored if immediately followed by alphas (GNU date behavior)
+        ] {
+            let mut s = input;
+            assert_eq!(timezone_offset(&mut s).unwrap(), expected, "{input}");
+        }
+
+        for input in [
+            "+2500",    // invalid: hours > 24
+            "-2361",    // invalid: minutes > 60
+            "+2401",    // invalid: minutes > 0 when hours == 24
+            "+23 days", // invalid: ambiguous with relative time parsing
+        ] {
+            let mut s = input;
+            assert!(timezone_offset(&mut s).is_err(), "{input}");
+        }
+    }
+
+    #[test]
+    fn timezone_name_without_offset() {
+        for (input, expected) in [
+            ("utc", off(false, 0, 0)),  // UTC
+            ("gmt", off(false, 0, 0)),  // UTC
+            ("z", off(false, 0, 0)),    // UTC
+            ("west", off(false, 1, 0)), // positive offset
+            ("cst", off(true, 6, 0)),   // negative offset
+            ("ist", off(false, 5, 30)), // positive offset with non-zero minutes
+            ("nst", off(true, 3, 30)),  // negative offset with non-zero minutes
+            ("z123", off(false, 0, 0)), // space separator can be ignored if immediately followed by digits (GNU date behavior)
+        ] {
+            let mut s = input;
+            assert_eq!(timezone_name_offset(&mut s).unwrap(), expected, "{input}");
+        }
+
+        for input in [
+            "abc",    // invalid: non-existent timezone
+            "utcabc", // invalid: non-existent timezone
+        ] {
+            let mut s = input;
+            assert!(timezone_name_offset(&mut s).is_err(), "{input}");
+        }
+    }
+
+    #[test]
+    fn timezone_name_with_offset() {
+        for (input, expected) in [
+            ("utc+5:30", off(false, 5, 30)),     // UTC with possitive offset
+            ("utc-5:30", off(true, 5, 30)),      // UTC with negative offset
+            ("utc +5:30", off(false, 5, 30)),    // space after timezone name
+            ("utc + 5 : 30", off(false, 5, 30)), // spaces
+            ("a+5:30", off(false, 6, 30)),       // merge two positive offsets (a=+1)
+            ("a-5:30", off(true, 4, 30)),        // merge positive and negative offsets (a=+1)
+            ("n-5:30", off(true, 6, 30)),        // merge two negative offsets (n=-1)
+            ("n+5:30", off(false, 4, 30)),       // merge negative and positive offsets (n=-1)
+            ("m+24", off(false, 36, 0)),         // maximum possible positive offset (m=+12)
+            ("y-24", off(true, 36, 0)),          // maximum possible negative offset (y=-12)
+        ] {
+            let mut s = input;
+            assert_eq!(timezone_name_offset(&mut s).unwrap(), expected, "{input}");
+        }
+
+        for input in [
+            "abc+08:00",   // invalid: non-existent timezone
+            "utc+25",      // invalid: invalid offset
+            "utc+23 days", // invalid: ambiguous with relative time parsing
+        ] {
+            let mut s = input;
+            assert!(
+                timezone_name_offset(&mut s).is_err() || !s.is_empty(),
+                "{input}"
+            );
+        }
+    }
+}

src/items/time.rs

@@ -45,8 +45,8 @@ use winnow::{
 
 use super::{
     epoch::sec_and_nsec,
+    offset::{timezone_offset, Offset},
     primitive::{colon, ctx_err, dec_uint, s},
-    timezone::{timezone_offset, Offset},
 };
 
 #[derive(PartialEq, Clone, Debug, Default)]