This is a fork of the `dtoa` crate which writes integer value floats without trailing `.0`. Fast functions for printing floating-point primitives to an io::Write.

performance, rust



github crates.io docs.rs build status

This crate provides fast functions for printing floating-point primitives to an io::Write. The implementation is a straightforward Rust port of Milo Yip's C++ implementation dtoa.h. The original C++ code of each function is included in comments.

See also itoa for printing integer primitives.

Version requirement: rustc 1.0+

dtoa = "0.4"

Performance (lower is better)



use std::io;

fn main() -> io::Result<()> {
    // Write to a vector or other io::Write.
    let mut buf = Vec::new();
    dtoa::write(&mut buf, 2.71828f64)?;
    println!("{:?}", buf);

    // Write to a stack buffer.
    let mut bytes = [b'\0'; 20];
    let n = dtoa::write(&mut bytes[..], 2.71828f64)?;
    println!("{:?}", &bytes[..n]);


The function signature is:

fn write<W: io::Write, V: dtoa::Floating>(writer: W, value: V) -> io::Result<()>;

where dtoa::Floating is implemented for f32 and f64. The return value gives the number of bytes written.


Licensed under either of Apache License, Version 2.0 or MIT license at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.