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//! You've probably heard of print debugging, but maybe not the lesser known //! member of the print family: print-optimization. //! Sometimes it's interesting to measure the time some part of your code uses, //! but you won't set up everything you need for profiling your entire program //! (or you don't have that option in the environment you're working in). //! Doing this in Rust requires some boilerplate at the moment, especially if //! you want to print out an easily readable output that you can navigate. //! directly to the relevant lines of code from. This crate aims to make this //! easier to do: //! Here's an example: //! //! ```rust //! use print_perf::*; //! # use std::time::Duration; //! # use std::thread::sleep; //! fn add(a: i32, b: i32) -> i32 { //! sleep(Duration::from_millis(100)); //! a + b //! } //! //! fn main() { //! let add_p = perf!("add fn"); //! let result = add(4, 4); //! add_p.end(); //! // ^-- prints: 0.100140446 (add fn) @ [src/main.rs:9] //! //! assert_eq!(result, 8); //! } //! ``` //! //! # Stability //! //! The exact output printed by this macro should not be relied upon //! and is subject to future changes. //! //! # Panics //! //! Panics if writing to `io::stderr` fails. //! //! //! [stderr]: https://en.wikipedia.org/wiki/Standard_streams#Standard_error_(stderr) //! /// This is what you get returned from the macro. You probably won't create this directly. pub struct Perf { start: std::time::Instant, start_line: String, ident: String, } impl Perf { pub fn new(ident: String, start_line: String) -> Self { Perf { start: std::time::Instant::now(), start_line, ident, } } pub fn end(&self) { let elapsed = self.start.elapsed(); if cfg!(all(target_os="windows", not(debug_assertions))) { eprintln!( "{}.{} ({}) @ {}", elapsed.as_secs(), format!("{:09}", elapsed.subsec_nanos()), self.ident, self.start_line, ); } else { eprintln!( "\x1B[33m\x1B[1m{}.{} ({})\x1B[0m @ {}", elapsed.as_secs(), format!("{:09}", elapsed.subsec_nanos()), self.ident, self.start_line, ); } } } /// Se crate documentation for example on how to use #[macro_export] macro_rules! perf { ($val:expr) => { match $val { i => { let ident = format!("{}", i); let start_line = format!("[{}:{}]", file!(), line!()); Perf::new(ident, start_line) } } }; } #[cfg(test)] mod tests { use super::*; fn add(a: i32, b: i32) -> i32 { std::thread::sleep(std::time::Duration::from_millis(100)); a + b } #[test] fn basic_example() { // to see output use: cargo test -- --nocapture let p = perf!("add fn"); let _result = add(4, 4); p.end(); } fn add_fast(a: i32, b: i32) -> i32 { a + b } #[test] fn fast_example() { // to see output use: cargo test -- --nocapture let p = perf!("add fn"); let _result = add_fast(4, 4); p.end(); } }