Major refactoring of the time API

CHANGELOG.md

@@ -8,9 +8,41 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 # [unreleased]
 
+Major API changes for the time API. If you are using the time API, it is strongly recommended
+to check all the API changes in the **Changed** chapter.
+
+## Fixed
+
+- CUC timestamp was fixed to include leap second corrections because it is based on the TAI
+  time reference. The default CUC time object do not implement `CcsdsTimeProvider` anymore
+  because the trait methods require cached leap second information. This task is now performed
+  by the `cuc::CucTimeWithLeapSecs` which implements the trait.
+
 ## Added
 
 - `From<$EcssEnum$TY> from $TY` for the ECSS enum type definitions.
+- Added basic support conversions to the `time` library. Introduce new `chrono` and `timelib`
+  feature gate.
+- Added `CcsdsTimeProvider::timelib_date_time`.
+
+## Changed
+
+- Renamed `CcsdsTimeProvider::date_time` to `CcsdsTimeProvider::chrono_date_time`
+- Renamed `CcsdsTimeCodes` to `CcsdsTimeCode`
+- Renamed `cds::TimeProvider` to `cds::CdsTime`
+- Renamed `cuc::TimeProviderCcsdsEpoch` to `cuc::CucTime`
+- `UnixTimestamp` renamed to `UnixTime`
+- `UnixTime` seconds are now private and can be retrieved using the `secs` member method.
+- `UnixTime::new` renamed to `UnixTime::new_checked`.
+- `UnixTime` now has a nanosecond subsecond precision. The `new` constructor now expects
+   nanoseconds as the second argument.
+- Added new `UnixTime::new_subsec_millis` and `UnixTime::new_subsec_millis_checked` API
+  to still allow creating a timestamp with only millisecond subsecond resolution.
+- `CcsdsTimeProvider` now has a new `subsec_nanos` method in addition to a default
+  implementation for the `subsec_millis` method.
+- `CcsdsTimeProvider::date_time` renamed to `CcsdsTimeProvider::chrono_date_time`.
+- Added `UnixTime::MIN`, `UnixTime::MAX` and `UnixTime::EPOCH`.
+- Added `UnixTime::timelib_date_time`.
 
 # [v0.11.0-rc.0] 2024-03-04
 

Cargo.toml

@@ -34,22 +34,31 @@ optional = true
 default-features = false
 features = ["derive"]
 
+[dependencies.time]
+version = "0.3"
+default-features = false
+optional = true
+
 [dependencies.chrono]
 version = "0.4"
 default-features = false
+optional = true
 
 [dependencies.num-traits]
 version = "0.2"
 default-features = false
 
-[dev-dependencies.postcard]
+[dev-dependencies]
-version = "1"
+postcard = "1"
+chrono = "0.4"
 
 [features]
 default = ["std"]
 std = ["chrono/std", "chrono/clock", "alloc", "thiserror"]
 serde = ["dep:serde", "chrono/serde"]
 alloc = ["postcard/alloc", "chrono/alloc"]
+chrono = ["dep:chrono"]
+timelib = ["dep:time"]
 
 [package.metadata.docs.rs]
 all-features = true

README.md

@@ -43,6 +43,8 @@ deserializing them with an appropriate `serde` provider like
 ## Optional Features
 
  - [`serde`](https://serde.rs/): Adds `serde` support for most types by adding `Serialize` and `Deserialize` `derive`s
+ - [`chrono`](https://crates.io/crates/chrono): Add basic support for the `chrono` time library.
+ - [`timelib`](https://crates.io/crates/time): Add basic support for the `time` time library.
 
 # Examples
 

src/ecss/tm.rs

@@ -1097,7 +1097,7 @@ mod tests {
 
     use super::*;
     use crate::ecss::PusVersion::PusC;
-    use crate::time::cds::TimeProvider;
+    use crate::time::cds::CdsTime;
     #[cfg(feature = "serde")]
     use crate::time::CcsdsTimeProvider;
     use crate::SpHeader;
@@ -1136,7 +1136,7 @@ mod tests {
     #[test]
     fn test_basic_simple_api() {
         let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
-        let time_provider = TimeProvider::new_with_u16_days(0, 0);
+        let time_provider = CdsTime::new_with_u16_days(0, 0);
         let mut stamp_buf: [u8; 8] = [0; 8];
         let pus_tm =
             PusTmCreator::new_simple(&mut sph, 17, 2, &time_provider, &mut stamp_buf, None, true)
@@ -1534,7 +1534,7 @@ mod tests {
     #[cfg(feature = "serde")]
     fn test_serialization_creator_serde() {
         let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
-        let time_provider = TimeProvider::new_with_u16_days(0, 0);
+        let time_provider = CdsTime::new_with_u16_days(0, 0);
         let mut stamp_buf: [u8; 8] = [0; 8];
         let pus_tm =
             PusTmCreator::new_simple(&mut sph, 17, 2, &time_provider, &mut stamp_buf, None, true)
@@ -1549,7 +1549,7 @@ mod tests {
     #[cfg(feature = "serde")]
     fn test_serialization_reader_serde() {
         let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
-        let time_provider = TimeProvider::new_with_u16_days(0, 0);
+        let time_provider = CdsTime::new_with_u16_days(0, 0);
         let mut stamp_buf: [u8; 8] = [0; 8];
         let pus_tm =
             PusTmCreator::new_simple(&mut sph, 17, 2, &time_provider, &mut stamp_buf, None, true)

src/time/ascii.rs

@@ -2,11 +2,8 @@
 //! [CCSDS 301.0-B-4](https://public.ccsds.org/Pubs/301x0b4e1.pdf) section 3.5 .
 //! See [chrono::DateTime::format] for a usage example of the generated
 //! [chrono::format::DelayedFormat] structs.
-#[cfg(feature = "alloc")]
+#[cfg(all(feature = "alloc", feature = "chrono"))]
-use chrono::{
+pub use alloc_mod_chrono::*;
-    format::{DelayedFormat, StrftimeItems},
-    DateTime, Utc,
-};
 
 /// Tuple of format string and formatted size for time code A.
 ///
@@ -34,36 +31,41 @@ pub const FMT_STR_CODE_B_WITH_SIZE: (&str, usize) = ("%Y-%jT%T%.3f", 21);
 /// Three digits are used for the decimal fraction and a terminator is added at the end.
 pub const FMT_STR_CODE_B_TERMINATED_WITH_SIZE: (&str, usize) = ("%Y-%jT%T%.3fZ", 22);
 
-/// Generates a time code formatter using the [FMT_STR_CODE_A_WITH_SIZE] format.
+#[cfg(all(feature = "alloc", feature = "chrono"))]
-#[cfg(feature = "alloc")]
+pub mod alloc_mod_chrono {
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
+    use super::*;
-pub fn generate_time_code_a(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
+    use chrono::{
+        format::{DelayedFormat, StrftimeItems},
+        DateTime, Utc,
+    };
+
+    /// Generates a time code formatter using the [FMT_STR_CODE_A_WITH_SIZE] format.
+    #[cfg_attr(doc_cfg, doc(cfg(all(feature = "alloc", feature = "chrono"))))]
+    pub fn generate_time_code_a(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
         date.format(FMT_STR_CODE_A_WITH_SIZE.0)
-}
+    }
 
-/// Generates a time code formatter using the [FMT_STR_CODE_A_TERMINATED_WITH_SIZE] format.
+    /// Generates a time code formatter using the [FMT_STR_CODE_A_TERMINATED_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
+    #[cfg_attr(doc_cfg, doc(cfg(all(feature = "alloc", feature = "chrono"))))]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
+    pub fn generate_time_code_a_terminated(
-pub fn generate_time_code_a_terminated(
         date: &DateTime<Utc>,
-) -> DelayedFormat<StrftimeItems<'static>> {
+    ) -> DelayedFormat<StrftimeItems<'static>> {
         date.format(FMT_STR_CODE_A_TERMINATED_WITH_SIZE.0)
-}
+    }
 
-/// Generates a time code formatter using the [FMT_STR_CODE_B_WITH_SIZE] format.
+    /// Generates a time code formatter using the [FMT_STR_CODE_B_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
+    #[cfg_attr(doc_cfg, doc(cfg(all(feature = "alloc", feature = "chrono"))))]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
+    pub fn generate_time_code_b(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
-pub fn generate_time_code_b(date: &DateTime<Utc>) -> DelayedFormat<StrftimeItems<'static>> {
         date.format(FMT_STR_CODE_B_WITH_SIZE.0)
-}
+    }
 
-/// Generates a time code formatter using the [FMT_STR_CODE_B_TERMINATED_WITH_SIZE] format.
+    /// Generates a time code formatter using the [FMT_STR_CODE_B_TERMINATED_WITH_SIZE] format.
-#[cfg(feature = "alloc")]
+    #[cfg_attr(doc_cfg, doc(cfg(all(feature = "alloc", feature = "chrono"))))]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "alloc")))]
+    pub fn generate_time_code_b_terminated(
-pub fn generate_time_code_b_terminated(
         date: &DateTime<Utc>,
-) -> DelayedFormat<StrftimeItems<'static>> {
+    ) -> DelayedFormat<StrftimeItems<'static>> {
         date.format(FMT_STR_CODE_B_TERMINATED_WITH_SIZE.0)
+    }
 }
 
 #[cfg(test)]
@@ -77,7 +79,7 @@ mod tests {
         let date = Utc::now();
         let stamp_formatter = generate_time_code_a(&date);
         let stamp = format!("{}", stamp_formatter);
-        let t_sep = stamp.find("T");
+        let t_sep = stamp.find('T');
         assert!(t_sep.is_some());
         assert_eq!(t_sep.unwrap(), 10);
         assert_eq!(stamp.len(), FMT_STR_CODE_A_WITH_SIZE.1);
@@ -88,10 +90,10 @@ mod tests {
         let date = Utc::now();
         let stamp_formatter = generate_time_code_a_terminated(&date);
         let stamp = format!("{}", stamp_formatter);
-        let t_sep = stamp.find("T");
+        let t_sep = stamp.find('T');
         assert!(t_sep.is_some());
         assert_eq!(t_sep.unwrap(), 10);
-        let z_terminator = stamp.find("Z");
+        let z_terminator = stamp.find('Z');
         assert!(z_terminator.is_some());
         assert_eq!(
             z_terminator.unwrap(),
@@ -105,7 +107,7 @@ mod tests {
         let date = Utc::now();
         let stamp_formatter = generate_time_code_b(&date);
         let stamp = format!("{}", stamp_formatter);
-        let t_sep = stamp.find("T");
+        let t_sep = stamp.find('T');
         assert!(t_sep.is_some());
         assert_eq!(t_sep.unwrap(), 8);
         assert_eq!(stamp.len(), FMT_STR_CODE_B_WITH_SIZE.1);
@@ -116,10 +118,10 @@ mod tests {
         let date = Utc::now();
         let stamp_formatter = generate_time_code_b_terminated(&date);
         let stamp = format!("{}", stamp_formatter);
-        let t_sep = stamp.find("T");
+        let t_sep = stamp.find('T');
         assert!(t_sep.is_some());
         assert_eq!(t_sep.unwrap(), 8);
-        let z_terminator = stamp.find("Z");
+        let z_terminator = stamp.find('Z');
         assert!(z_terminator.is_some());
         assert_eq!(
             z_terminator.unwrap(),

src/time/mod.rs

@@ -1,6 +1,7 @@
 //! CCSDS Time Code Formats according to [CCSDS 301.0-B-4](https://public.ccsds.org/Pubs/301x0b4e1.pdf)
 use crate::ByteConversionError;
-use chrono::{DateTime, LocalResult, TimeZone, Utc};
+#[cfg(feature = "chrono")]
+use chrono::{TimeZone, Utc};
 use core::cmp::Ordering;
 use core::fmt::{Display, Formatter};
 use core::ops::{Add, AddAssign, Sub};
@@ -13,6 +14,7 @@ use num_traits::float::FloatCore;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
+
 #[cfg(feature = "std")]
 use std::error::Error;
 #[cfg(feature = "std")]
@@ -27,10 +29,11 @@ pub mod cuc;
 pub const DAYS_CCSDS_TO_UNIX: i32 = -4383;
 pub const SECONDS_PER_DAY: u32 = 86400;
 pub const MS_PER_DAY: u32 = SECONDS_PER_DAY * 1000;
+pub const NANOS_PER_SECOND: u32 = 1_000_000_000;
 
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub enum CcsdsTimeCodes {
+pub enum CcsdsTimeCode {
     CucCcsdsEpoch = 0b001,
     CucAgencyEpoch = 0b010,
     Cds = 0b100,
@@ -38,16 +41,16 @@ pub enum CcsdsTimeCodes {
     AgencyDefined = 0b110,
 }
 
-impl TryFrom<u8> for CcsdsTimeCodes {
+impl TryFrom<u8> for CcsdsTimeCode {
     type Error = ();
 
     fn try_from(value: u8) -> Result<Self, Self::Error> {
         match value {
-            x if x == CcsdsTimeCodes::CucCcsdsEpoch as u8 => Ok(CcsdsTimeCodes::CucCcsdsEpoch),
+            x if x == CcsdsTimeCode::CucCcsdsEpoch as u8 => Ok(CcsdsTimeCode::CucCcsdsEpoch),
-            x if x == CcsdsTimeCodes::CucAgencyEpoch as u8 => Ok(CcsdsTimeCodes::CucAgencyEpoch),
+            x if x == CcsdsTimeCode::CucAgencyEpoch as u8 => Ok(CcsdsTimeCode::CucAgencyEpoch),
-            x if x == CcsdsTimeCodes::Cds as u8 => Ok(CcsdsTimeCodes::Cds),
+            x if x == CcsdsTimeCode::Cds as u8 => Ok(CcsdsTimeCode::Cds),
-            x if x == CcsdsTimeCodes::Ccs as u8 => Ok(CcsdsTimeCodes::Ccs),
+            x if x == CcsdsTimeCode::Ccs as u8 => Ok(CcsdsTimeCode::Ccs),
-            x if x == CcsdsTimeCodes::AgencyDefined as u8 => Ok(CcsdsTimeCodes::AgencyDefined),
+            x if x == CcsdsTimeCode::AgencyDefined as u8 => Ok(CcsdsTimeCode::AgencyDefined),
             _ => Err(()),
         }
     }
@@ -55,20 +58,20 @@ impl TryFrom<u8> for CcsdsTimeCodes {
 
 /// Retrieve the CCSDS time code from the p-field. If no valid time code identifier is found, the
 /// value of the raw time code identification field is returned.
-pub fn ccsds_time_code_from_p_field(pfield: u8) -> Result<CcsdsTimeCodes, u8> {
+pub fn ccsds_time_code_from_p_field(pfield: u8) -> Result<CcsdsTimeCode, u8> {
     let raw_bits = (pfield >> 4) & 0b111;
-    CcsdsTimeCodes::try_from(raw_bits).map_err(|_| raw_bits)
+    CcsdsTimeCode::try_from(raw_bits).map_err(|_| raw_bits)
 }
 
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[non_exhaustive]
 pub enum TimestampError {
-    InvalidTimeCode { expected: CcsdsTimeCodes, found: u8 },
+    InvalidTimeCode { expected: CcsdsTimeCode, found: u8 },
     ByteConversion(ByteConversionError),
     Cds(cds::CdsError),
     Cuc(cuc::CucError),
-    DateBeforeCcsdsEpoch(DateTime<Utc>),
+    DateBeforeCcsdsEpoch(UnixTime),
     CustomEpochNotSupported,
 }
 
@@ -91,7 +94,7 @@ impl Display for TimestampError {
                 write!(f, "time stamp: {e}")
             }
             TimestampError::DateBeforeCcsdsEpoch(e) => {
-                write!(f, "datetime with date before ccsds epoch: {e}")
+                write!(f, "datetime with date before ccsds epoch: {e:?}")
             }
             TimestampError::CustomEpochNotSupported => {
                 write!(f, "custom epochs are not supported")
@@ -204,16 +207,15 @@ pub trait TimeWriter {
     }
 }
 
-pub trait TimeReader {
+pub trait TimeReader: Sized {
-    fn from_bytes(buf: &[u8]) -> Result<Self, TimestampError>
+    fn from_bytes(buf: &[u8]) -> Result<Self, TimestampError>;
-    where
-        Self: Sized;
 }
 
 /// Trait for generic CCSDS time providers.
 ///
-/// The UNIX helper methods and the [Self::date_time] method are not strictly necessary but extremely
+/// The UNIX helper methods and the helper method are not strictly necessary but extremely
 /// practical because they are a very common and simple exchange format for time information.
+/// Therefore, it was decided to keep them in this trait as well.
 pub trait CcsdsTimeProvider {
     fn len_as_bytes(&self) -> usize;
 
@@ -222,56 +224,120 @@ pub trait CcsdsTimeProvider {
     /// entry denotes the length of the pfield and the second entry is the value of the pfield
     /// in big endian format.
     fn p_field(&self) -> (usize, [u8; 2]);
-    fn ccdsd_time_code(&self) -> CcsdsTimeCodes;
+    fn ccdsd_time_code(&self) -> CcsdsTimeCode;
 
-    fn unix_seconds(&self) -> i64;
+    fn unix_secs(&self) -> i64;
-    fn subsecond_millis(&self) -> u16;
+    fn subsec_nanos(&self) -> u32;
-    fn unix_stamp(&self) -> UnixTimestamp {
+
-        UnixTimestamp::const_new(self.unix_seconds(), self.subsecond_millis())
+    fn subsec_millis(&self) -> u16 {
+        (self.subsec_nanos() / 1_000_000) as u16
     }
 
-    fn date_time(&self) -> Option<DateTime<Utc>>;
+    fn unix_time(&self) -> UnixTime {
+        UnixTime::new(self.unix_secs(), self.subsec_nanos())
+    }
+
+    #[cfg(feature = "chrono")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "chrono")))]
+    fn chrono_date_time(&self) -> chrono::LocalResult<chrono::DateTime<chrono::Utc>> {
+        chrono::Utc.timestamp_opt(self.unix_secs(), self.subsec_nanos())
+    }
+
+    #[cfg(feature = "timelib")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "timelib")))]
+    fn timelib_date_time(&self) -> Result<time::OffsetDateTime, time::error::ComponentRange> {
+        Ok(time::OffsetDateTime::from_unix_timestamp(self.unix_secs())?
+            + time::Duration::nanoseconds(self.subsec_nanos().into()))
+    }
 }
 
-/// UNIX timestamp: Elapsed seconds since 1970-01-01T00:00:00+00:00.
+/// UNIX time: Elapsed non-leap seconds since 1970-01-01T00:00:00+00:00 UTC.
 ///
-/// Also can optionally include subsecond millisecond for greater accuracy.
+/// This is a commonly used time format and can therefore also be used as a generic format to
+/// convert other CCSDS time formats to and from. The subsecond precision is in nanoseconds
+/// similarly to other common time formats and libraries.
 #[derive(Default, Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub struct UnixTimestamp {
+pub struct UnixTime {
-    pub unix_seconds: i64,
+    secs: i64,
-    subsecond_millis: u16,
+    subsec_nanos: u32,
 }
 
-impl UnixTimestamp {
+impl UnixTime {
-    /// Returns [None] if the subsecond millisecond value is larger than 999.
+    /// The UNIX epoch time: 1970-01-01T00:00:00+00:00 UTC.
-    pub fn new(unix_seconds: i64, subsec_millis: u16) -> Option<Self> {
+    pub const EPOCH: Self = Self {
-        if subsec_millis > 999 {
+        secs: 0,
+        subsec_nanos: 0,
+    };
+
+    /// The minimum possible `UnixTime`.
+    pub const MIN: Self = Self {
+        secs: i64::MIN,
+        subsec_nanos: 0,
+    };
+
+    /// The maximum possible `UnixTime`.
+    pub const MAX: Self = Self {
+        secs: i64::MAX,
+        subsec_nanos: NANOS_PER_SECOND - 1,
+    };
+
+    /// Returns [None] if the subsecond nanosecond value is invalid (larger than fraction of a
+    /// second)
+    pub fn new_checked(unix_seconds: i64, subsec_nanos: u32) -> Option<Self> {
+        if subsec_nanos >= NANOS_PER_SECOND {
             return None;
         }
-        Some(Self::const_new(unix_seconds, subsec_millis))
+        Some(Self::new(unix_seconds, subsec_nanos))
     }
 
-    /// Like [Self::new] but const. Panics if the subsecond value is larger than 999.
+    /// Returns [None] if the subsecond millisecond value is invalid (larger than fraction of a
-    pub const fn const_new(unix_seconds: i64, subsecond_millis: u16) -> Self {
+    /// second)
-        if subsecond_millis > 999 {
+    pub fn new_subsec_millis_checked(unix_seconds: i64, subsec_millis: u16) -> Option<Self> {
-            panic!("subsec milliseconds exceeds 999");
+        if subsec_millis >= 1000 {
+            return None;
+        }
+        Self::new_checked(unix_seconds, subsec_millis as u32 * 1_000_000)
+    }
+
+    /// This function will panic if the subsecond value is larger than the fraction of a second.
+    /// Use [Self::new_checked] if you want to handle this case without a panic.
+    pub const fn new(unix_seconds: i64, subsecond_nanos: u32) -> Self {
+        if subsecond_nanos >= NANOS_PER_SECOND {
+            panic!("invalid subsecond nanos value");
         }
         Self {
-            unix_seconds,
+            secs: unix_seconds,
-            subsecond_millis,
+            subsec_nanos: subsecond_nanos,
         }
     }
 
-    pub fn new_only_seconds(unix_seconds: i64) -> Self {
+    /// This function will panic if the subsecond value is larger than the fraction of a second.
+    /// Use [Self::new_subsec_millis_checked] if you want to handle this case without a panic.
+    pub const fn new_subsec_millis(unix_seconds: i64, subsecond_millis: u16) -> Self {
+        if subsecond_millis >= 1000 {
+            panic!("invalid subsecond millisecond value");
+        }
         Self {
-            unix_seconds,
+            secs: unix_seconds,
-            subsecond_millis: 0,
+            subsec_nanos: subsecond_millis as u32 * 1_000_000,
         }
     }
 
-    pub fn subsecond_millis(&self) -> u16 {
+    pub fn new_only_secs(unix_seconds: i64) -> Self {
-        self.subsecond_millis
+        Self {
+            secs: unix_seconds,
+            subsec_nanos: 0,
+        }
+    }
+
+    #[inline]
+    pub fn subsec_millis(&self) -> u16 {
+        (self.subsec_nanos / 1_000_000) as u16
+    }
+
+    pub fn subsec_nanos(&self) -> u32 {
+        self.subsec_nanos
     }
 
     #[cfg(feature = "std")]
@@ -279,68 +345,88 @@ impl UnixTimestamp {
     pub fn from_now() -> Result<Self, SystemTimeError> {
         let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH)?;
         let epoch = now.as_secs();
-        Ok(Self::const_new(epoch as i64, now.subsec_millis() as u16))
+        Ok(Self::new(epoch as i64, now.subsec_nanos()))
     }
 
     #[inline]
-    pub fn unix_seconds_f64(&self) -> f64 {
+    pub fn unix_secs_f64(&self) -> f64 {
-        self.unix_seconds as f64 + (self.subsecond_millis as f64 / 1000.0)
+        self.secs as f64 + (self.subsec_nanos as f64 / 1_000_000_000.0)
     }
 
-    pub fn as_date_time(&self) -> LocalResult<DateTime<Utc>> {
+    pub fn secs(&self) -> i64 {
-        Utc.timestamp_opt(
+        self.secs
-            self.unix_seconds,
+    }
-            self.subsecond_millis as u32 * 10_u32.pow(6),
+
-        )
+    #[cfg(feature = "chrono")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "chrono")))]
+    pub fn chrono_date_time(&self) -> chrono::LocalResult<chrono::DateTime<chrono::Utc>> {
+        Utc.timestamp_opt(self.secs, self.subsec_nanos)
+    }
+
+    #[cfg(feature = "timelib")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "timelib")))]
+    pub fn timelib_date_time(&self) -> Result<time::OffsetDateTime, time::error::ComponentRange> {
+        Ok(time::OffsetDateTime::from_unix_timestamp(self.secs())?
+            + time::Duration::nanoseconds(self.subsec_nanos().into()))
     }
 
     // Calculate the difference in milliseconds between two UnixTimestamps
-    pub fn difference_in_millis(&self, other: &UnixTimestamp) -> i64 {
+    pub fn diff_in_millis(&self, other: &UnixTime) -> Option<i64> {
-        let seconds_difference = self.unix_seconds - other.unix_seconds;
+        let seconds_difference = self.secs.checked_sub(other.secs)?;
         // Convert seconds difference to milliseconds
-        let milliseconds_difference = seconds_difference * 1000;
+        let milliseconds_difference = seconds_difference.checked_mul(1000)?;
 
         // Calculate the difference in subsecond milliseconds directly
-        let subsecond_difference = self.subsecond_millis as i64 - other.subsecond_millis as i64;
+        let subsecond_difference_nanos = self.subsec_nanos as i64 - other.subsec_nanos as i64;
 
         // Combine the differences
-        milliseconds_difference + subsecond_difference
+        Some(milliseconds_difference + (subsecond_difference_nanos / 1_000_000))
     }
 }
 
-impl From<DateTime<Utc>> for UnixTimestamp {
+#[cfg(feature = "chrono")]
-    fn from(value: DateTime<Utc>) -> Self {
+#[cfg_attr(doc_cfg, doc(cfg(feature = "chrono")))]
-        Self::const_new(value.timestamp(), value.timestamp_subsec_millis() as u16)
+impl From<chrono::DateTime<chrono::Utc>> for UnixTime {
+    fn from(value: chrono::DateTime<chrono::Utc>) -> Self {
+        Self::new(value.timestamp(), value.timestamp_subsec_nanos())
     }
 }
 
-impl PartialOrd for UnixTimestamp {
+#[cfg(feature = "timelib")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "timelib")))]
+impl From<time::OffsetDateTime> for UnixTime {
+    fn from(value: time::OffsetDateTime) -> Self {
+        Self::new(value.unix_timestamp(), value.nanosecond())
+    }
+}
+
+impl PartialOrd for UnixTime {
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
         Some(self.cmp(other))
     }
 }
 
-impl Ord for UnixTimestamp {
+impl Ord for UnixTime {
     fn cmp(&self, other: &Self) -> Ordering {
         if self == other {
             return Ordering::Equal;
         }
-        match self.unix_seconds.cmp(&other.unix_seconds) {
+        match self.secs.cmp(&other.secs) {
             Ordering::Less => return Ordering::Less,
             Ordering::Greater => return Ordering::Greater,
             _ => (),
         }
 
-        match self.subsecond_millis().cmp(&other.subsecond_millis()) {
+        match self.subsec_millis().cmp(&other.subsec_millis()) {
             Ordering::Less => {
-                return if self.unix_seconds < 0 {
+                return if self.secs < 0 {
                     Ordering::Greater
                 } else {
                     Ordering::Less
                 }
             }
             Ordering::Greater => {
-                return if self.unix_seconds < 0 {
+                return if self.secs < 0 {
                     Ordering::Less
                 } else {
                     Ordering::Greater
@@ -360,12 +446,12 @@ pub struct StampDiff {
     pub duration_absolute: Duration,
 }
 
-impl Sub for UnixTimestamp {
+impl Sub for UnixTime {
-    type Output = StampDiff;
+    type Output = Option<StampDiff>;
 
     fn sub(self, rhs: Self) -> Self::Output {
-        let difference = self.difference_in_millis(&rhs);
+        let difference = self.diff_in_millis(&rhs)?;
-        if difference < 0 {
+        Some(if difference < 0 {
             StampDiff {
                 positive_duration: false,
                 duration_absolute: Duration::from_millis(-difference as u64),
@@ -375,16 +461,13 @@ impl Sub for UnixTimestamp {
                 positive_duration: true,
                 duration_absolute: Duration::from_millis(difference as u64),
             }
-        }
+        })
     }
 }
 
-fn get_new_stamp_after_addition(
+fn get_new_stamp_after_addition(current_stamp: &UnixTime, duration: Duration) -> UnixTime {
-    current_stamp: &UnixTimestamp,
+    let mut new_subsec_nanos = current_stamp.subsec_nanos() + duration.subsec_nanos();
-    duration: Duration,
+    let mut new_unix_seconds = current_stamp.secs;
-) -> UnixTimestamp {
-    let mut new_subsec_millis = current_stamp.subsecond_millis() + duration.subsec_millis() as u16;
-    let mut new_unix_seconds = current_stamp.unix_seconds;
     let mut increment_seconds = |value: u32| {
         if new_unix_seconds < 0 {
             new_unix_seconds = new_unix_seconds
@@ -396,8 +479,8 @@ fn get_new_stamp_after_addition(
                 .expect("new unix seconds would exceed i64::MAX");
         }
     };
-    if new_subsec_millis >= 1000 {
+    if new_subsec_nanos >= 1_000_000_000 {
-        new_subsec_millis -= 1000;
+        new_subsec_nanos -= 1_000_000_000;
         increment_seconds(1);
     }
     increment_seconds(
@@ -406,7 +489,7 @@ fn get_new_stamp_after_addition(
             .try_into()
             .expect("duration seconds exceeds u32::MAX"),
     );
-    UnixTimestamp::const_new(new_unix_seconds, new_subsec_millis)
+    UnixTime::new(new_unix_seconds, new_subsec_nanos)
 }
 
 /// Please note that this operation will panic on the following conditions:
@@ -414,7 +497,7 @@ fn get_new_stamp_after_addition(
 /// - Unix seconds after subtraction for stamps before the unix epoch exceeds [i64::MIN].
 /// - Unix seconds after addition  exceeds [i64::MAX].
 /// - Seconds from duration to add exceeds [u32::MAX].
-impl AddAssign<Duration> for UnixTimestamp {
+impl AddAssign<Duration> for UnixTime {
     fn add_assign(&mut self, duration: Duration) {
         *self = get_new_stamp_after_addition(self, duration);
     }
@@ -425,7 +508,7 @@ impl AddAssign<Duration> for UnixTimestamp {
 /// - Unix seconds after subtraction for stamps before the unix epoch exceeds [i64::MIN].
 /// - Unix seconds after addition  exceeds [i64::MAX].
 /// - Unix seconds exceeds [u32::MAX].
-impl Add<Duration> for UnixTimestamp {
+impl Add<Duration> for UnixTime {
     type Output = Self;
 
     fn add(self, duration: Duration) -> Self::Output {
@@ -433,8 +516,8 @@ impl Add<Duration> for UnixTimestamp {
     }
 }
 
-impl Add<Duration> for &UnixTimestamp {
+impl Add<Duration> for &UnixTime {
-    type Output = UnixTimestamp;
+    type Output = UnixTime;
 
     fn add(self, duration: Duration) -> Self::Output {
         get_new_stamp_after_addition(self, duration)
@@ -445,10 +528,15 @@ impl Add<Duration> for &UnixTimestamp {
 mod tests {
     use alloc::string::ToString;
     use chrono::{Datelike, Timelike};
-    use std::format;
+    use std::{format, println};
 
     use super::{cuc::CucError, *};
 
+    #[allow(dead_code)]
+    const UNIX_STAMP_CONST: UnixTime = UnixTime::new(5, 999_999_999);
+    #[allow(dead_code)]
+    const UNIX_STAMP_CONST_2: UnixTime = UnixTime::new_subsec_millis(5, 999);
+
     #[test]
     fn test_days_conversion() {
         assert_eq!(unix_to_ccsds_days(DAYS_CCSDS_TO_UNIX.into()), 0);
@@ -484,28 +572,29 @@ mod tests {
 
     #[test]
     fn basic_unix_stamp_test() {
-        let stamp = UnixTimestamp::new_only_seconds(-200);
+        let stamp = UnixTime::new_only_secs(-200);
-        assert_eq!(stamp.unix_seconds, -200);
+        assert_eq!(stamp.secs, -200);
-        assert_eq!(stamp.subsecond_millis(), 0);
+        assert_eq!(stamp.subsec_millis(), 0);
-        let stamp = UnixTimestamp::new_only_seconds(250);
+        let stamp = UnixTime::new_only_secs(250);
-        assert_eq!(stamp.unix_seconds, 250);
+        assert_eq!(stamp.secs, 250);
-        assert_eq!(stamp.subsecond_millis(), 0);
+        assert_eq!(stamp.subsec_millis(), 0);
     }
 
     #[test]
     fn basic_float_unix_stamp_test() {
-        let stamp = UnixTimestamp::new(500, 600).unwrap();
+        let stamp = UnixTime::new_subsec_millis_checked(500, 600).unwrap();
-        assert_eq!(stamp.unix_seconds, 500);
+        assert_eq!(stamp.secs, 500);
-        let subsec_millis = stamp.subsecond_millis();
+        let subsec_millis = stamp.subsec_millis();
         assert_eq!(subsec_millis, 600);
-        assert!((500.6 - stamp.unix_seconds_f64()).abs() < 0.0001);
+        println!("{:?}", (500.6 - stamp.unix_secs_f64()).to_string());
+        assert!((500.6 - stamp.unix_secs_f64()).abs() < 0.0001);
     }
 
     #[test]
     fn test_ord_larger() {
-        let stamp0 = UnixTimestamp::new_only_seconds(5);
+        let stamp0 = UnixTime::new_only_secs(5);
-        let stamp1 = UnixTimestamp::new(5, 500).unwrap();
+        let stamp1 = UnixTime::new_subsec_millis_checked(5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(6);
+        let stamp2 = UnixTime::new_only_secs(6);
         assert!(stamp1 > stamp0);
         assert!(stamp2 > stamp0);
         assert!(stamp2 > stamp1);
@@ -513,9 +602,9 @@ mod tests {
 
     #[test]
     fn test_ord_smaller() {
-        let stamp0 = UnixTimestamp::new_only_seconds(5);
+        let stamp0 = UnixTime::new_only_secs(5);
-        let stamp1 = UnixTimestamp::new(5, 500).unwrap();
+        let stamp1 = UnixTime::new_subsec_millis_checked(5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(6);
+        let stamp2 = UnixTime::new_only_secs(6);
         assert!(stamp0 < stamp1);
         assert!(stamp0 < stamp2);
         assert!(stamp1 < stamp2);
@@ -523,9 +612,9 @@ mod tests {
 
     #[test]
     fn test_ord_larger_neg_numbers() {
-        let stamp0 = UnixTimestamp::new_only_seconds(-5);
+        let stamp0 = UnixTime::new_only_secs(-5);
-        let stamp1 = UnixTimestamp::new(-5, 500).unwrap();
+        let stamp1 = UnixTime::new_subsec_millis_checked(-5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(-6);
+        let stamp2 = UnixTime::new_only_secs(-6);
         assert!(stamp0 > stamp1);
         assert!(stamp0 > stamp2);
         assert!(stamp1 > stamp2);
@@ -535,9 +624,9 @@ mod tests {
 
     #[test]
     fn test_ord_smaller_neg_numbers() {
-        let stamp0 = UnixTimestamp::new_only_seconds(-5);
+        let stamp0 = UnixTime::new_only_secs(-5);
-        let stamp1 = UnixTimestamp::new(-5, 500).unwrap();
+        let stamp1 = UnixTime::new_subsec_millis_checked(-5, 500).unwrap();
-        let stamp2 = UnixTimestamp::new_only_seconds(-6);
+        let stamp2 = UnixTime::new_only_secs(-6);
         assert!(stamp2 < stamp1);
         assert!(stamp2 < stamp0);
         assert!(stamp1 < stamp0);
@@ -548,8 +637,8 @@ mod tests {
     #[allow(clippy::nonminimal_bool)]
     #[test]
     fn test_eq() {
-        let stamp0 = UnixTimestamp::new(5, 0).unwrap();
+        let stamp0 = UnixTime::new(5, 0);
-        let stamp1 = UnixTimestamp::new_only_seconds(5);
+        let stamp1 = UnixTime::new_only_secs(5);
         assert_eq!(stamp0, stamp1);
         assert!(stamp0 <= stamp1);
         assert!(stamp0 >= stamp1);
@@ -559,27 +648,27 @@ mod tests {
 
     #[test]
     fn test_addition() {
-        let mut stamp0 = UnixTimestamp::new_only_seconds(1);
+        let mut stamp0 = UnixTime::new_only_secs(1);
         stamp0 += Duration::from_secs(5);
-        assert_eq!(stamp0.unix_seconds, 6);
+        assert_eq!(stamp0.secs(), 6);
-        assert_eq!(stamp0.subsecond_millis(), 0);
+        assert_eq!(stamp0.subsec_millis(), 0);
         let stamp1 = stamp0 + Duration::from_millis(500);
-        assert_eq!(stamp1.unix_seconds, 6);
+        assert_eq!(stamp1.secs, 6);
-        assert_eq!(stamp1.subsecond_millis(), 500);
+        assert_eq!(stamp1.subsec_millis(), 500);
     }
 
     #[test]
     fn test_addition_on_ref() {
-        let stamp0 = &UnixTimestamp::new(20, 500).unwrap();
+        let stamp0 = &UnixTime::new_subsec_millis_checked(20, 500).unwrap();
         let stamp1 = stamp0 + Duration::from_millis(2500);
-        assert_eq!(stamp1.unix_seconds, 23);
+        assert_eq!(stamp1.secs, 23);
-        assert_eq!(stamp1.subsecond_millis(), 0);
+        assert_eq!(stamp1.subsec_millis(), 0);
     }
 
     #[test]
     fn test_as_dt() {
-        let stamp = UnixTimestamp::new_only_seconds(0);
+        let stamp = UnixTime::new_only_secs(0);
-        let dt = stamp.as_date_time().unwrap();
+        let dt = stamp.chrono_date_time().unwrap();
         assert_eq!(dt.year(), 1970);
         assert_eq!(dt.month(), 1);
         assert_eq!(dt.day(), 1);
@@ -590,55 +679,55 @@ mod tests {
 
     #[test]
     fn test_from_now() {
-        let stamp_now = UnixTimestamp::from_now().unwrap();
+        let stamp_now = UnixTime::from_now().unwrap();
-        let dt_now = stamp_now.as_date_time().unwrap();
+        let dt_now = stamp_now.chrono_date_time().unwrap();
         assert!(dt_now.year() >= 2020);
     }
 
     #[test]
     fn test_stamp_diff_positive_0() {
-        let stamp_later = UnixTimestamp::new(2, 0).unwrap();
+        let stamp_later = UnixTime::new(2, 0);
         let StampDiff {
             positive_duration,
             duration_absolute,
-        } = stamp_later - UnixTimestamp::new(1, 0).unwrap();
+        } = (stamp_later - UnixTime::new(1, 0)).expect("stamp diff error");
         assert!(positive_duration);
         assert_eq!(duration_absolute, Duration::from_secs(1));
     }
 
     #[test]
     fn test_stamp_diff_positive_1() {
-        let stamp_later = UnixTimestamp::new(3, 800).unwrap();
+        let stamp_later = UnixTime::new(3, 800 * 1_000_000);
-        let stamp_earlier = UnixTimestamp::new(1, 900).unwrap();
+        let stamp_earlier = UnixTime::new_subsec_millis_checked(1, 900).unwrap();
         let StampDiff {
             positive_duration,
             duration_absolute,
-        } = stamp_later - stamp_earlier;
+        } = (stamp_later - stamp_earlier).expect("stamp diff error");
         assert!(positive_duration);
         assert_eq!(duration_absolute, Duration::from_millis(1900));
     }
 
     #[test]
     fn test_stamp_diff_negative() {
-        let stamp_later = UnixTimestamp::new(3, 800).unwrap();
+        let stamp_later = UnixTime::new_subsec_millis_checked(3, 800).unwrap();
-        let stamp_earlier = UnixTimestamp::new(1, 900).unwrap();
+        let stamp_earlier = UnixTime::new_subsec_millis_checked(1, 900).unwrap();
         let StampDiff {
             positive_duration,
             duration_absolute,
-        } = stamp_earlier - stamp_later;
+        } = (stamp_earlier - stamp_later).expect("stamp diff error");
         assert!(!positive_duration);
         assert_eq!(duration_absolute, Duration::from_millis(1900));
     }
 
     #[test]
     fn test_addition_spillover() {
-        let mut stamp0 = UnixTimestamp::new(1, 900).unwrap();
+        let mut stamp0 = UnixTime::new_subsec_millis_checked(1, 900).unwrap();
         stamp0 += Duration::from_millis(100);
-        assert_eq!(stamp0.unix_seconds, 2);
+        assert_eq!(stamp0.secs, 2);
-        assert_eq!(stamp0.subsecond_millis(), 0);
+        assert_eq!(stamp0.subsec_millis(), 0);
         stamp0 += Duration::from_millis(1100);
-        assert_eq!(stamp0.unix_seconds, 3);
+        assert_eq!(stamp0.secs, 3);
-        assert_eq!(stamp0.subsecond_millis(), 100);
+        assert_eq!(stamp0.subsec_millis(), 100);
     }
 
     #[test]
@@ -647,4 +736,26 @@ mod tests {
         let stamp_error = TimestampError::from(cuc_error);
         assert_eq!(stamp_error.to_string(), format!("cuc error: {cuc_error}"));
     }
+
+    #[test]
+    #[cfg(feature = "timelib")]
+    fn test_unix_stamp_as_timelib_datetime() {
+        let stamp_epoch = UnixTime::EPOCH;
+        let timelib_dt = stamp_epoch.timelib_date_time().unwrap();
+        assert_eq!(timelib_dt.year(), 1970);
+        assert_eq!(timelib_dt.month(), time::Month::January);
+        assert_eq!(timelib_dt.day(), 1);
+        assert_eq!(timelib_dt.hour(), 0);
+        assert_eq!(timelib_dt.minute(), 0);
+        assert_eq!(timelib_dt.second(), 0);
+    }
+
+    #[test]
+    #[cfg(feature = "timelib")]
+    fn test_unix_stamp_from_timelib_datetime() {
+        let timelib_dt = time::OffsetDateTime::UNIX_EPOCH;
+        let unix_time = UnixTime::from(timelib_dt);
+        let timelib_converted_back = unix_time.timelib_date_time().unwrap();
+        assert_eq!(timelib_dt, timelib_converted_back);
+    }
 }