Crate padder

Highly efficient data and string formatting library for Rust.

Pad and format virtually any generic slice or vector efficiently with minimal memory overhead. This crate has guaranteed performance improvements over the standard library format! macro. Clone this repository and run cargo bench to see benchmark comparisons between this implementation and the standard library.

The library defines a core trait called Source which enables efficient padding on the type. It is currently implemented on three main types of datastructures:

• the string slice &str,
• the generic slice &[T],
• and the generic vector `Vec,

Note that the type T has to adhere to the trait bound T: From<Symbol>, where Symbol is the Enum representing the available characters to pad and format with. If you want to extend the padding capabilities of the Source trait with your own type T, then you need to also implement the From<Symbol> trait for your type T.

Examples

Given the below string slice and target pad width 6, with Alignment::Left and Symbol::Whitespace, the resulting output String can be seen on the right:

+—+—+—+ +—+—+—+—+—+—+ | a | b | c | –> | a | b | c | | | | +—+—+—+ +—+—+—+—+—+—+

use padder::*;

let output: String = "abc".pad(6, Alignment::Left, Symbol::Whitespace);
let expected = String::from("abc   ");
assert_eq!(expected, output);

You can also pad to an existing buffer, providing you precise control over any memory allocations performed in your program. Given the below char slice and target pad width 10, with Alignment::Right and Symbol::Hashtag, the resulting contents of the allocated buffer can be seen on the right:

+—+—+—+ +—+—+—+—+—+—+—+—+—+—+ | a | b | c | –> | # | # | # | # | # | # | # | a | b | c | +—+—+—+ +—+—+—+—+—+—+—+—+—+—+

use padder::*;

let width: usize = 10;
let source: &[char] = &['a', 'b', 'c'];

let mut buffer: Vec<char> = Vec::with_capacity(width);
pad_and_push_to_buffer(
    source,
    width,
    Alignment::Right,
    Symbol::Hashtag,
    &mut buffer,
);

let mut expected = vec!['#'; 7];
expected.extend_from_slice(source);
assert_eq!(expected, buffer);

For more inspiration and guidance on how to use this crate and its trait, please refer to the examples of the README in the project repository.

Enums

• Alignment
  Exhaustive enum for the alternative ways to pad and format data.
• Symbol
  Exhaustive enum for the supported padding symbols.

Traits

• Source
  A trait providing functions to perform padding and formatting on the implemented type.

Functions

• pad
  Wrapper for the Source trait implementation of its pad function.
• pad_and_push_to_buffer
  Wrapper for the Source trait implementation of its pad_and_push_to_buffer function.