Cu3PO42/partial-array

A rust crate providing a potentially partial-filled array

partial-array - potentially partial-filled arrays for #![no_std]

This crate provides a central new data type, similar to an [array]: the [PartialArray<N>]. It is equivalent to an array, but the number of entries might be anywhere from 0 to N. While this has similarities to a Vec<T> keep in mind, that a [PartialArray] does not grow its memory: it always takes up the memory for the fully array (with some additional counter) and it cannot ever hold more than N elements. This means that its memory is fully static and on the stack, making it usable from #![no_std] crates.

Usages

This new data type is most likely to be used for collecting iterators into arrays, when then length is not known, but has an upper bound, e.g.:

use partial_array::PartialArray;

/// Take the first 10 elements of an iterator, that match the condition.
///
/// This can return less than 10 elements if the iterator has fewer than 10
/// items or there are less than 10 matching elements.
fn first_10_matching<T, I, F>(iter: I, check: F) -> PartialArray<T, 10>
    where I: IntoIterator<Item = T>,
          F: FnMut(&T) -> bool,
{
    iter.into_iter().filter(check).take(10).collect()
}