| buffer |
|
|
| common.rs |
or u32 -> u32 |
3237 |
| d2s.rs |
|
11284 |
| d2s_full_table.rs |
|
32886 |
| d2s_intrinsics.rs |
|
2567 |
| d2s_small_table.rs |
|
5370 |
| digit_table.rs |
|
1203 |
| f2s.rs |
|
6959 |
| f2s_intrinsics.rs |
|
3700 |
| lib.rs |
[![github]](https://github.com/dtolnay/ryu) [![crates-io]](https://crates.io/crates/ryu) [![docs-rs]](https://docs.rs/ryu)
[github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github
[crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust
[docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs
<br>
Pure Rust implementation of Ryū, an algorithm to quickly convert floating
point numbers to decimal strings.
The PLDI'18 paper [*Ryū: fast float-to-string conversion*][paper] by Ulf
Adams includes a complete correctness proof of the algorithm. The paper is
available under the creative commons CC-BY-SA license.
This Rust implementation is a line-by-line port of Ulf Adams' implementation
in C, [https://github.com/ulfjack/ryu][upstream].
[paper]: https://dl.acm.org/citation.cfm?id=3192369
[upstream]: https://github.com/ulfjack/ryu
# Example
```
fn main() {
let mut buffer = ryu::Buffer::new();
let printed = buffer.format(1.234);
assert_eq!(printed, "1.234");
}
```
## Performance (lower is better)
You can run upstream's benchmarks with:
```console
$ git clone https://github.com/ulfjack/ryu c-ryu
$ cd c-ryu
$ bazel run -c opt //ryu/benchmark
```
And the same benchmark against our implementation with:
```console
$ git clone https://github.com/dtolnay/ryu rust-ryu
$ cd rust-ryu
$ cargo run --example upstream_benchmark --release
```
These benchmarks measure the average time to print a 32-bit float and average
time to print a 64-bit float, where the inputs are distributed as uniform random
bit patterns 32 and 64 bits wide.
The upstream C code, the unsafe direct Rust port, and the safe pretty Rust API
all perform the same, taking around 21 nanoseconds to format a 32-bit float and
31 nanoseconds to format a 64-bit float.
There is also a Rust-specific benchmark comparing this implementation to the
standard library which you can run with:
```console
$ cargo bench
```
The benchmark shows Ryū approximately 2-5x faster than the standard library
across a range of f32 and f64 inputs. Measurements are in nanoseconds per
iteration; smaller is better.
## Formatting
This library tends to produce more human-readable output than the standard
library's to\_string, which never uses scientific notation. Here are two
examples:
- *ryu:* 1.23e40, *std:* 12300000000000000000000000000000000000000
- *ryu:* 1.23e-40, *std:* 0.000000000000000000000000000000000000000123
Both libraries print short decimals such as 0.0000123 without scientific
notation. |
4039 |
| parse.rs |
|
479 |
| pretty |
|
|
| s2d.rs |
|
7756 |
| s2f.rs |
|
8315 |