t2t holds the time a program reads and carries: points on the wall, monotonic,
boot and atomic timelines, a hardware counter's readings, the spans between
them, and the clocks that read each. Every point and span is one i64, and
every timeline its own type, so a reading from one clock is never subtracted
from another's; every operator saturates rather than overflows, and every value
has a spelling it writes and reads back. Nothing reaches the operating system
unless the std feature asks.
| Crate | What it holds |
|---|
t2t | everything, the values at its root and the clocks under t2t::clock |
t2t-core | the values: points, spans, rates, the calendar, Timed; no_std |
t2t-clock | the clocks: the OS's, the CPU's counter, and clocks set by hand |
Install
cargo add t2t --features std
t2t builds with Rust 1.98 or later, on Linux and macOS, on aarch64 and
x86_64; the values and the CPU's counter build without std too.
Quick Start
use t2t::clock::{Clock, ManualClock};
use t2t::{Timed, Timedelta, Timestamp};
fn main() {
let clock = ManualClock::new(Timestamp::from_secs(1_700_000_000));
let sample = Timed::new(clock.now(), 101_u64);
clock.advance(Timedelta::from_millis(1_500));
assert!(sample.elapsed(clock.now()) > Timedelta::SECOND, "stale a second and a half on");
}
In a clone of the repository, cargo run --release -p t2t --features std --example clock-tour prints every clock's reading, and what one costs on the
machine it runs on.
Clocks
| Clock | Reads | Steps? | For |
|---|
SystemClock | Timestamp | yes | a stamp other machines compare |
CoarseSystemClock | Timestamp | yes | whether a heartbeat or expiry is due |
TaiClock (Linux) | TaiTimestamp | yes | a stamp on the timescale PTP keeps |
MonotonicClock | Uptime | never | a deadline, a timeout |
CoarseMonotonicClock | Uptime | never | a far deadline, polled often |
RawMonotonicClock | RawUptime | never | a span no time service's slewing touches |
BootClock | BootUptime | never | a timeout that runs through a suspension |
ProcessCpuClock | Timedelta | never | the CPU time the process has used |
ThreadCpuClock | Timedelta | never | the CPU time the calling thread has used |
Counter | Tickstamp | never | a stamp or a span in one instruction |
ManualClock | any point | by hand | a test or a replay on one thread |
AtomicManualClock | any point | by hand | a test or a replay shared across threads |
Features
What std adds is on 64-bit Linux and macOS.
| Feature | Adds |
|---|
std | the OS clocks, an x86_64 counter's measured rate, SystemTime conversions |
serde | every value's spelling, and the serde modules for counts in a named unit |
schemars | JsonSchema for every value with a spelling; turns serde on |
zerocopy-08 | the zerocopy traits each type can honour, native-endian |
chrono-04 | conversions to and from chrono 0.4's DateTime and TimeDelta |
jiff-02 | conversions to and from jiff 0.2's Timestamp and SignedDuration |
time-03 | conversions to and from time 0.3's OffsetDateTime and Duration |
None is on by default: cargo add t2t --features std,serde.
Documentation
Contributing
Issues and pull requests are welcome: read CONTRIBUTING.md
first, and report a vulnerability as SECURITY.md says.
License
Either the MIT License or the Apache License, Version 2.0, at
your option.
