Function collect_until

crates/utils/src/iterators.rs:18–40

Gather the first N items, and provide the count of the remaining items. The max count cannot be zero as that's a pathological case.

(it: I, max: NonZeroUsize)

/// Gather the first N items, and provide the count of the remaining items.
/// The max count cannot be zero as that's a pathological case.
pub fn collect_until<I>(it: I, max: NonZeroUsize) -> Option<(Vec<I::Item>, usize)>
where
    I: Iterator,
{
    let mut items = Vec::with_capacity(max.get());

    let mut it = it.peekable();
    // If there's nothing, just return
    let _ = it.peek()?;

    for next in it.by_ref() {
        items.push(next);

        // If we've reached max items, stop collecting
        if items.len() == max.get() {
            break;
        }
    }
    // Count remaining items
    let remaining = it.count();
    items.shrink_to_fit();
    Some((items, remaining))
}

#[cfg(test)]
mod tests {