Bug: 166632747

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  1. bd0da20 Mark ab/6881855 as merged by Xin Li · 8 weeks ago master
  2. 25856d9 Copy description from Cargo.toml to METADATA am: fd17487e5f by Chih-Hung Hsieh · 3 months ago
  3. fd17487 Copy description from Cargo.toml to METADATA by Chih-Hung Hsieh · 3 months ago
  4. 6bfb67d Import 'itoa' crate version 0.4.6 am: 8884bbeb9c am: aa38c62a6a am: ac1a7b3d82 am: 262d642d67 by Yi Kong · 5 months ago
  5. 262d642 Import 'itoa' crate version 0.4.6 am: 8884bbeb9c am: aa38c62a6a am: ac1a7b3d82 by Yi Kong · 5 months ago

itoa

This crate provides fast functions for printing integer primitives to an io::Write or a fmt::Write. The implementation comes straight from libcore but avoids the performance penalty of going through fmt::Formatter.

See also dtoa for printing floating point primitives.

Version requirement: rustc 1.0+

[dependencies]
itoa = "0.4"

Performance (lower is better)

performance

Examples

use std::{fmt, io};

fn demo_itoa_write() -> io::Result<()> {
    // Write to a vector or other io::Write.
    let mut buf = Vec::new();
    itoa::write(&mut buf, 128u64)?;
    println!("{:?}", buf);

    // Write to a stack buffer.
    let mut bytes = [0u8; 20];
    let n = itoa::write(&mut bytes[..], 128u64)?;
    println!("{:?}", &bytes[..n]);

    Ok(())
}

fn demo_itoa_fmt() -> fmt::Result {
    // Write to a string.
    let mut s = String::new();
    itoa::fmt(&mut s, 128u64)?;
    println!("{}", s);

    Ok(())
}

The function signatures are:

fn write<W: io::Write, V: itoa::Integer>(writer: W, value: V) -> io::Result<usize>;

fn fmt<W: fmt::Write, V: itoa::Integer>(writer: W, value: V) -> fmt::Result;

where itoa::Integer is implemented for i8, u8, i16, u16, i32, u32, i64, u64, i128, u128, isize and usize. 128-bit integer support requires rustc 1.26+ and the i128 feature of this crate enabled.

The write function is only available when the std feature is enabled (default is enabled). The return value gives the number of bytes written.

License