v0.5.3

Added

• Introduced CivilDateTime — a proleptic Gregorian UTC datetime representation derived from Time<Utc>.
• Added bidirectional conversion API between Time<Utc> and CivilDateTime.
• Added Display implementation for ISO 8601 / RFC 3339 format with nanosecond precision.
• Added is_whole_second() helper.
• Added Unix time conversion API for Time<Utc> (seconds and nanoseconds).
• Added additional epoch constants for UTC/GPS/Unix alignment.
• Extended serde support and improved Postcard serialization test coverage.
• Added embedded-friendly serialization documentation improvements.
• Introduced new integration and round-trip test coverage across time scales.

Changed

• Refactored civil calendar conversion constants for improved clarity and symmetry.
• Improved architecture documentation consistency across crate, README, and internal modules.
• Improved days_to_unix / civil_from_days implementation readability.
• Updated feature-gated serialization strategy documentation.

Fixed

• Fixed potential overflow in as_unix_nanos conversion for large timestamps.

Removed

• Removed legacy benches directory in favor of dedicated benchmark crate.

---

This release improves correctness, clarity, and extensibility of the time conversion layer while preserving full backward compatibility within the 0.5.x series.

v0.5.2

• updated the examples in the README file, improved the code documentation
• updated the examples in the README file, improved the code documentation

v0.5.1

Updated the information in the README file

v0.5.0

Added

• Deterministic property test suite (tests/prop_deterministic.rs)

  • Fixed coverage for boundary values, all 18 leap-second transitions, uniform u64 space sampling, and real IGS epochs

  • Verified invariants for:

    • GPS ↔ TAI roundtrip
    • GPS ↔ Galileo / BeiDou roundtrips
    • GPS ↔ UTC correctness outside leap windows
    • Arithmetic laws (identity, associativity, double negation)
    • Sub-second boundary correctness
    • Leap-second ambiguity window correctness

• Randomized property tests (tests/prop_tests.rs) using proptest

  • GPS domain random sampling
  • bounded duration strategies to prevent overflow
  • ±3s leap-second boundary testing
  • strict ambiguity coverage rules (Exact outside leap windows)

• CI test orchestration in justfile

  • test-deterministic
  • test-props
  • test-all

• Compile-time leap second validation:

  • _ASSERT_FIRST_ENTRY (TAI−UTC = 19)
  • _ASSERT_TABLE_INVARIANTS (strict monotonic +1 progression)
  • _ASSERT_LAST_ENTRY (2017-01-01, TAI−UTC = 37)

• Runtime leap second subsystem:

  • RuntimeLeapSeconds (fixed-capacity, heap-free, RUNTIME_CAPACITY = 64)
  • from_builtin(), from_slice(), try_extend()
  • LeapExtendError (NotStrictlyAscending, NonUnitIncrement, BufferFull)

• Leap second API extensions:

  • LeapSeconds::last_update()
  • LeapSeconds::current_tai_minus_utc()

• Prelude expansion:

  • RuntimeLeapSeconds, LeapExtendError, LeapEntry, RUNTIME_CAPACITY
  • gps_to_utc, utc_to_gps

• Cross-verification test:

  • test_builtin_table_matches_iers_bulletin_c (full IERS Bulletin C validation)

• #[must_use] enforcement across core API:

  • Time, Duration, ConvertResult, GnssTimeError
  • all arithmetic and conversion APIs
  • all critical accessors

• #[non_exhaustive] added to:

  • GnssTimeError
  • ConvertResult
  • ConversionKind
  • ScaleId

• clippy.toml introduced as future lint extension point

Changed

• Property testing architecture split:

  • deterministic tests (no randomness, full reproducibility)
  • proptest-based randomized validation (host-only)

• proptest dependency updated:

  • default-features = false
  • features = ["std"]

• Leap second table fully validated against IERS Bulletin C (19 entries, verified)

• Documentation updated:

  • runtime extension policy
  • compile-time invariants
  • IERS monitoring notes (TAI−UTC = 37 as of 2026)

• LeapSeconds API improved:

  • from_slice alias added for clarity

• Enabled crate-wide lint:

  • #![warn(clippy::must_use_candidate)]

• Improved forward compatibility via #[non_exhaustive]

• Strengthened developer diagnostics and API safety rules

Fixed

• Corrected internal type documentation:

  • i64 → u64 for internal time representation consistency

v0.4.0

Deterministic API & Production Readiness

Release focused on determinism, correctness, and production readiness.

⚠️ Breaking Changes

• Removed all f64-based constructors
• Introduced DurationParts { seconds, nanos } for exact, deterministic input

Added

• DurationParts – deterministic replacement for f64 with validation
  • DurationParts::new() with range check
  • DurationParts::as_nanos() -> u128
• Full CI/CD pipeline (clippy, tests, docs, MSRV, cargo-deny)
• Embedded validation (no_std, Cortex-M, RISC-V)
• Automated publishing workflow
• Extended documentation:
  • architecture, invariants, leap seconds, embedded usage
• Property-based tests (roundtrip, leap seconds, ordering)
• Time::NANOS_PER_YEAR

Changed

• All constructors migrated to DurationParts
• Updated:
  • all examples (17 files)
  • integration tests
  • benchmarks
• Added strict input validation

Performance

No regressions:

Operation	Cost
Arithmetic (panicking)	~0.5 ns (≈ raw u64)
Checked ops	~4.3 ns
Fixed conversions	~0.8–1.0 ns
UTC conversions	~9–22 ns

Notes

• Type-safe time domains preserved
• Fixed conversions remain zero-cost
• UTC stays explicit and leap-second aware

Upgrade

Replace:

// Before
Time::<Gps>::from_week_tow(week, 432_000.0)

// After
Time::<Gps>::from_week_tow(week, DurationParts {
    seconds: 432_000,
    nanos: 0,
})

v0.3.0

Precision & Overflow (#TIME-11)

• Added Time::MIN constant (alias for EPOCH)
• Added documentation about value range: Time<S> covers ~584 years from epoch (Time<Gps> up to year 2554)
• Added test_time_max_behavior to verify overflow handling
• Added clippy::arithmetic_overflow lint to CI

Benchmarks (#TIME-12)

• Added benches/arithmetic_bench.rs – proves zero-cost abstractions:
  • Time<Gps> + Duration: 512 ps (raw u64 + u64: 517 ps)
  • Time<Gps> - Duration: 512 ps (raw u64 - u64: 518 ps)
• Added benches/convert_bench.rs:
  • GPS → TAI: ~0.8 ns
  • GPS → Galileo: ~0.8 ns
  • GPS → BeiDou: ~0.9 ns
  • GPS → UTC (with leap seconds): ~9.5 ns (< 10 ns target)
  • GLONASS → UTC (constant shift): ~0.8 ns
  • GLONASS → GPS (via UTC + LS): ~22.4 ns
• Uses criterion with HTML reports

Full no_std Compatibility (#TIME-10)

• All types are Copy – no allocations anywhere
• defmt::Format implementation behind defmt feature flag
• Fixed LeapSeconds::builtin() – now uses static instance instead of const fn
• Cross-compilation tests for embedded targets:
  • thumbv7em-none-eabihf (STM32F4/F7, nRF52)
  • thumbv7em-none-eabi (Cortex-M4/M7)
  • riscv32imac-unknown-none-elf (ESP32-C3, GD32VF103)
• Added .cargo/config.toml with embedded optimization settings
• Added tests/no_std_compact.rs – verifies no Drop, Copy semantics, 8-byte alignment, no allocations

CI & Project Infrastructure

• Added .github/workflows/embedded.yml – cross-compilation checks
• Added .github/workflows/semantic-pull-request.yml – validates PR titles (feat:, fix:, etc.)
• Added .github/pull_request_template.md – structured checklist
• Added .github/ISSUE_TEMPLATE/enhancement.yml – enhancement request template
• Added CODEOWNERS – automatic reviewer assignment
• Updated justfile with new commands (check-no-std, ci, etc.)
• Updated Cargo.toml with defmt feature, docs.rs metadata

Fixed

• leap.rs: LeapSeconds::builtin() now works in no_std (static instance, not const fn)
• time.rs: removed const from as_seconds_f64 (no_std compatibility)
• time.rs: fixed typo "Дипазон значений" → "Диапазон значений"

---

Full Changelog

See CHANGELOG.md

v0.2.0

Full Conversion Matrix & Typed Conversion API

This release introduces a complete 6×6 GNSS time conversion matrix,
a unified conversion API, and improved correctness around leap seconds.

Highlights:

• Full conversion matrix (30 directions)
• Runtime conversion graph inspection (ConversionMatrix)
• Typed conversion traits: IntoScale, IntoScaleWith
• Leap second–aware conversions with ambiguity handling
• GLONASS-specific time utilities
• <1 ns roundtrip accuracy (except intrinsic leap second ambiguity)

This is a foundational release: gnss-time is now a complete,
type-safe core for GNSS time transformations.

v0.1.0

Release v0.1.0 — Type‑safe GNSS time core

gnss-time is a zero‑cost, no_std‑friendly Rust library for working with time in satellite navigation systems (GPS, GLONASS, Galileo, BeiDou, TAI, UTC).

What's included

Core types

• Duration – signed nanosecond interval (i64) with arithmetic, saturating ops, and Display.
• Time<S> – parametric timestamp (u64) representing nanoseconds since the scale’s epoch.
• TimeScale sealed trait – markers for Gps, Glonass, Galileo, Beidou, Tai, Utc.

Time scales & epochs

• Epoch constants: GPS_EPOCH, GLONASS_EPOCH, GALILEO_EPOCH, BEIDOU_EPOCH, TAI_EPOCH, UNIX_EPOCH.
• CivilDate with const calendar arithmetic.
• Compile‑time verified offsets between epochs (days, seconds, nanoseconds).
• GPS: Time<Gps>::from_week_tow(week, tow_s) + accessors week(), tow_seconds(), sub_second_nanos().
• GLONASS: Time<Glonass>::from_day_tod(day, tod_s) + accessors day(), tod_seconds().

Leap seconds (contextual conversions)

• LeapSeconds – static built‑in table (19 entries, 1980–2017).
• LeapSecondsProvider trait for custom / runtime sources.
• Conversions: gps_to_utc, utc_to_gps, glonass_to_utc, utc_to_glonass, gps_to_glonass, glonass_to_gps.
• Tests for leap second boundaries (1998-12-31, 2016-12-31).

Display formatting

• WeekTow (GPS/Galileo/BeiDou): "GPS 2345:432000.000"
• DayTod (GLONASS): "GLO 10512:43200.000"
• Simple (TAI/UTC): "TAI +1000000000s 0ns"

Error handling

• GnssTimeError with Overflow, InvalidInput, LeapSecondsRequired.

Examples

• basic_usage, gps_week_tow, glonass_day_tod, scale_conversion, display_formats, and more.

Documentation & metadata

• README.md, CHANGELOG.md, #![deny(missing_docs)].
• no_std by default, optional std feature.
• All types are 8 bytes, repr(transparent) – zero overhead.

---

Full Changelog: CHANGELOG.md