1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163
//! # Embedded Time //! `embedded-time` provides a comprehensive library for implementing [`Clock`] abstractions over //! hardware to generate [`Instant`]s and using [`Duration`]s ([`Seconds`], [`Milliseconds`], etc) //! in embedded systems. The approach is similar to the C++ `chrono` library. A [`Duration`] //! consists of an integer (whose type is chosen by the user to be either [`i32`] or [`i64`]) as //! well as a `const` ratio where the integer value multiplied by the ratio is the [`Duration`] in //! seconds. Put another way, the ratio is the precision of the LSbit of the integer. This structure //! avoids unnecessary arithmetic. For example, if the [`Duration`] type is [`Milliseconds`], a call //! to the [`Duration::count()`] method simply returns the stored integer value directly which is //! the number of milliseconds being represented. Conversion arithmetic is only performed when //! explicitly converting between time units. //! //! [`Clock`]: trait.Clock.html //! [`Instant`]: instant::Instant //! [`Seconds`]: time_units::Seconds //! [`Milliseconds`]: time_units::Milliseconds //! //! ## Definitions //! **Clock**: Any entity that periodically counts (ie a hardware timer peripheral). Generally, //! this needs to be monotonic. A wrapping timer is considered monotonic in this context as long as //! it fulfills the other requirements. //! //! **Wrapping Timer**: A timer that when at its maximum value, the next count is the minimum //! value. //! //! **Instant**: A specific instant in time ("time-point") returned by calling `Clock::now()`. //! //! **Duration**: The difference of two instances. The duration of time elapsed from one instant //! until another. A span of time. //! //! ## Notes //! Some parts of this crate were derived from various sources: //! - [`RTFM`](https://github.com/rtfm-rs/cortex-m-rtfm) //! - [`time`](https://docs.rs/time/latest/time) (Specifically the [`time::NumbericalDuration`](https://docs.rs/time/latest/time/trait.NumericalDuration.html) //! implementations for primitive integers) //! //! # Example Usage //! ```rust,no_run //! # use embedded_time::{prelude::*, time_units::*, instant::Instant, Period}; //! # #[derive(Debug)] //! struct SomeClock; //! impl embedded_time::Clock for SomeClock { //! type Rep = i64; //! const PERIOD: Period = Period::new_raw(1, 16_000_000); //! //! fn now() -> Instant<Self> { //! // ... //! # unimplemented!() //! } //! } //! //! let instant1 = SomeClock::now(); //! // ... //! let instant2 = SomeClock::now(); //! assert!(instant1 < instant2); // instant1 is *before* instant2 //! //! // duration is the difference between the instances //! let duration: Option<Microseconds<i64>> = instant2.duration_since(&instant1); //! //! assert!(duration.is_some()); //! assert_eq!(instant1 + duration.unwrap(), instant2); //! ``` #![cfg_attr(not(test), no_std)] #![feature(associated_type_bounds)] #![deny(intra_doc_link_resolution_failure)] mod clock; pub mod duration; pub mod instant; mod numerical_duration; pub use clock::Clock; pub use duration::{time_units, Duration}; pub use numerical_duration::TimeRep; pub type Period = num::rational::Ratio<i32>; /// A collection of imports that are widely useful. /// /// Unlike the standard library, this must be explicitly imported: /// /// ```rust,no_run /// use embedded_time::prelude::*; /// ``` /// The prelude may grow in minor releases. Any removals will only occur in /// major releases. pub mod prelude { // Rename traits to `_` to avoid any potential name conflicts. pub use crate::duration::Duration as _; pub use crate::duration::TryConvertFrom as _; pub use crate::duration::TryConvertInto as _; pub use crate::numerical_duration::TimeRep as _; pub use crate::Clock as _; pub use crate::Period as _; pub use num::Integer as _; } #[cfg(test)] #[allow(unused_imports)] mod tests { use crate::instant::Instant; use crate::prelude::*; use crate::time_units::*; use crate::{Clock, Period}; #[derive(Debug, Ord, PartialOrd, Eq, PartialEq)] struct MockClock64; impl Clock for MockClock64 { type Rep = i64; const PERIOD: Period = Period::new_raw(1, 64_000_000); fn now() -> Instant<Self> { Instant::new(128_000_000) } } #[derive(Debug, Ord, PartialOrd, Eq, PartialEq)] struct MockClock32; impl Clock for MockClock32 { type Rep = i32; const PERIOD: Period = Period::new_raw(1, 16_000_000); fn now() -> Instant<Self> { Instant::new(32_000_000) } } fn get_time<M>() where M: Clock, { assert_eq!(M::now().elapsed_since_epoch(), Some(Seconds(2))); } #[test] fn common_types() { let then = MockClock32::now(); let now = MockClock32::now(); get_time::<MockClock64>(); get_time::<MockClock32>(); let then = then - Seconds(1); assert_ne!(then, now); assert!(then < now); } #[test] fn brute_force() { let mut time = 1_i64; time *= 60; assert_eq!(Hours(1), Minutes(time)); time *= 60; assert_eq!(Hours(1), Seconds(time)); time *= 1000; assert_eq!(Hours(1), Milliseconds(time)); time *= 1000; assert_eq!(Hours(1), Microseconds(time)); time *= 1000; assert_eq!(Hours(1), Nanoseconds(time)); } }