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// Copyright 2017 Thomas Schaller. // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! A small crate which allows combining //! a [`Duration`]'s seconds and nanoseconds //! into [seconds], [milliseconds] and [microseconds]. //! Additionally, it allows [easy formatting] of a //! `Duration` for performance measurements. //! //! ## Conversion to fractional //! //! ``` //! # #![allow(unused_variables)] //! //! use std::time::Duration; //! use floating_duration::TimeAsFloat; //! //! let duration = Duration::new(4, 123_456_789); //! //! let secs = duration.as_fractional_secs(); // 4.12.. //! let millis = duration.as_fractional_millis(); // 4_123.45.. //! let micros = duration.as_fractional_micros(); // 4_123_456.78.. //! ``` //! //! ## Automatic formatting //! //! ``` //! use std::time::Instant; //! use floating_duration::TimeFormat; //! //! # fn do_something() {} //! //! # fn main() { //! let start = Instant::now(); //! //! do_something(); //! //! println!("Needed {}", TimeFormat(start.elapsed())); //! # } //! ``` //! //! Output: `Needed 12.841µs` //! //! [`Duration`]: https://doc.rust-lang.org/stable/std/time/struct.Duration.html //! [seconds]: trait.TimeAsFloat.html#tymethod.as_fractional_secs //! [milliseconds]: trait.TimeAsFloat.html#tymethod.as_fractional_millis //! [microseconds]: trait.TimeAsFloat.html#tymethod.as_fractional_micros //! //! [easy formatting]: struct.TimeFormat.html use std::borrow::Borrow; use std::fmt::{Display, Error as FormatError, Formatter}; use std::time::Duration; /// Trait for providing `as_fractional_*` methods. /// /// # Examples /// /// ## Measuring a time span /// /// ``` /// use std::time::Instant; /// use floating_duration::TimeAsFloat; /// /// let start = Instant::now(); /// /// let result = (1..12).fold(1, |acc, x| acc * x); /// /// println!("Needed {} seconds", start.elapsed().as_fractional_secs()); /// // or: /// println!("Needed {:#}", start.elapsed().as_fractional_secs()); // uses the full unit name /// println!("Result: {}", result); /// ``` pub trait TimeAsFloat { /// Returns the duration in seconds. fn as_fractional_secs(&self) -> f64; /// Returns the duration in milliseconds. fn as_fractional_millis(&self) -> f64; /// Returns the duration in microseconds. fn as_fractional_micros(&self) -> f64; } impl<T: Borrow<Duration>> TimeAsFloat for T { fn as_fractional_secs(&self) -> f64 { let dur: &Duration = self.borrow(); dur.as_secs() as f64 + dur.subsec_nanos() as f64 / 1_000_000_000.0 } fn as_fractional_millis(&self) -> f64 { let dur: &Duration = self.borrow(); dur.as_secs() as f64 * 1_000.0 + dur.subsec_nanos() as f64 / 1_000_000.0 } fn as_fractional_micros(&self) -> f64 { let dur: &Duration = self.borrow(); dur.as_secs() as f64 * 1_000_000.0 + dur.subsec_nanos() as f64 / 1_000.0 } } /// A formatting newtype for providing a /// [`Display`] implementation. This format is /// meant to be used for printing performance measurements. /// /// # Behaviour /// /// * `secs > 0` => seconds with precision 3 /// * `secs > 0.001` => milliseconds with precision 3 /// * `secs > 0.000_001` => microseconds with precision 3 /// * otherwise => nanoseconds /// /// By default the duration is formatted using abbreviated units /// (e.g. `1.234ms`). /// If the the format string is specified with the [alternate flag] `{:#}`, /// the duration is formatted using the full unit name instead /// (e.g. `1.234 milliseconds`). /// /// # Examples /// /// ``` /// use std::time::Duration; /// use floating_duration::TimeFormat; /// /// let dur = Duration::new(0, 461_933); /// let formatted = format!("{}", TimeFormat(dur)); /// assert_eq!(formatted, "461.933µs"); /// let alternate = format!("{:#}", TimeFormat(dur)); /// assert_eq!(alternate, "461.933 microseconds"); /// ``` /// /// [`Display`]: https://doc.rust-lang.org/stable/std/fmt/trait.Display.html /// [alternate flag]: https://doc.rust-lang.org/stable/std/fmt/#sign0 #[derive(Clone, Copy, Debug)] pub struct TimeFormat<T: Borrow<Duration>>(pub T); impl<T: Borrow<Duration>> Display for TimeFormat<T> { fn fmt(&self, f: &mut Formatter) -> Result<(), FormatError> { let dur: &Duration = self.0.borrow(); if dur.as_secs() > 0 { if !f.alternate() { write!(f, "{:.3}s", dur.as_fractional_secs()) } else { write!(f, "{:.3} seconds", dur.as_fractional_secs()) } } else if dur.subsec_nanos() > 1_000_000 { if !f.alternate() { write!(f, "{:.3}ms", dur.as_fractional_millis()) } else { write!(f, "{:.3} milliseconds", dur.as_fractional_millis()) } } else if dur.subsec_nanos() > 1_000 { if !f.alternate() { write!(f, "{:.3}µs", dur.as_fractional_micros()) } else { write!(f, "{:.3} microseconds", dur.as_fractional_micros()) } } else { if !f.alternate() { write!(f, "{}ns", dur.subsec_nanos()) } else { write!(f, "{} nanoseconds", dur.subsec_nanos()) } } } }