dtoa
====
[](https://github.com/dtolnay/dtoa)
[](https://crates.io/crates/dtoa)
[](https://docs.rs/dtoa)
[](https://github.com/dtolnay/dtoa/actions?query=branch%3Amaster)
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+*
[`io::Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
[Milo Yip]: https://github.com/miloyip
[dtoa.h]: https://github.com/miloyip/rapidjson/blob/master/include/rapidjson/internal/dtoa.h
[`itoa`]: https://github.com/dtolnay/itoa
```toml
[dependencies]
dtoa = "0.4"
```
## Performance (lower is better)
![performance](https://raw.githubusercontent.com/dtolnay/dtoa/master/performance.png)
## Examples
```rust
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]);
Ok(())
}
```
The function signature is:
```rust
fn write(writer: W, value: V) -> io::Result<()>;
```
where `dtoa::Floating` is implemented for f32 and f64. The return value gives
the number of bytes written.
#### License
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.