5a1e5449c8
perf: improve write_fmt to handle simple strings In case format string has no arguments, simplify its implementation with a direct call to `output.write_str(value)`. This builds on `@dtolnay` original [suggestion](https://github.com/serde-rs/serde/pull/2697#issuecomment-1940376414). This does not change any expectations because the original `fn write()` implementation calls `write_str` for parts of the format string. ```rust write!(f, "text") -> f.write_str("text") ``` ```diff /// [`write!`]: crate::write! +#[inline] #[stable(feature = "rust1", since = "1.0.0")] pub fn write(output: &mut dyn Write, args: Arguments<'_>) -> Result { + if let Some(s) = args.as_str() { output.write_str(s) } else { write_internal(output, args) } +} + +/// Actual implementation of the [`write`], but without the simple string optimization. +fn write_internal(output: &mut dyn Write, args: Arguments<'_>) -> Result { let mut formatter = Formatter::new(output); let mut idx = 0; ``` * Hopefully it will improve the simple case for the https://github.com/rust-lang/rust/issues/99012 * Another related (original?) issues #10761 * Previous similar attempt to fix it by by `@Kobzol` #100700 CC: `@m-ou-se` as probably the biggest expert in everything `format!` |
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The Rust Programming Language
This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.
Note: this README is for users rather than contributors. If you wish to contribute to the compiler, you should read CONTRIBUTING.md instead.
Table of Contents
Quick Start
Read "Installation" from The Book.
Installing from Source
If you really want to install from source (though this is not recommended), see INSTALL.md.
Getting Help
See https://www.rust-lang.org/community for a list of chat platforms and forums.
Contributing
See CONTRIBUTING.md.
License
Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.
See LICENSE-APACHE, LICENSE-MIT, and COPYRIGHT for details.
Trademark
The Rust Foundation owns and protects the Rust and Cargo trademarks and logos (the "Rust Trademarks").
If you want to use these names or brands, please read the media guide.
Third-party logos may be subject to third-party copyrights and trademarks. See Licenses for details.