NumToA

#![no_std] Compatible with Zero Heap Allocations

The standard library provides a convenient method of converting numbers into strings, but these strings are heap-allocated. If you have an application which needs to convert large volumes of numbers into strings, but don't want to pay the price of heap allocation, this crate provides an efficient no_std-compatible method of heaplessly converting numbers into their string representations, storing the representation within a reusable byte array.

Supports Multiple Bases

In addition to supporting the standard base 10 conversion, this implementation allows you to select the base of your choice. Therefore, if you want a binary representation, set the base to 2. If you want hexadecimal, set the base to 16.

Currently, there are some optimizations being done for base 10 conversions to get it closer to the performance of the competing itoa crate when doing base 10 conversions. Itoa remains slightly faster, so there is more work to be done to match the performance.

• std: 1,431,256,318 ns
• numtoa: 784,711,632 ns
• itoa: 695,028,994 ns

Base 10 Example

use numtoa::NumToA;
use std::io::{self, Write};

let stdout = io::stdout();
let mut stdout = stdout.lock();
let mut buffer = [0u8; 20];

let number: u32 = 162392;
let mut bytes_written = number.numtoa(10, &mut buffer);
let _ = stdout.write(&buffer[0..bytes_written]);
assert_eq!(&buffer[0..bytes_written], "162392".as_bytes());

let other_number: i32 = -6235;
bytes_written = other_number.numtoa(10, &mut buffer);
let _ = stdout.write(&buffer[0..bytes_written]);
assert_eq!(&buffer[0..bytes_written], "-6235".as_bytes());

let max_u64: u64 = 18446744073709551615;
bytes_written = max_u64.numtoa(10, &mut buffer);
let _ = stdout.write(&buffer[0..bytes_written]);
assert_eq!(&buffer[0..bytes_written], "18446744073709551615".as_bytes());