Function pack_linear 

pub fn pack_linear(
    values: &[u64],
    width: usize,
    output: &mut Vec<u8>,
) -> Result<()>

Packs any number of values in the layout pack_tail writes.

pack_tail is this with a bound, and the bound is a statement about columns rather than about the layout: a column that has a whole unit of values has a transposed unit to put them in, so the sequential layout is for the remainder and asking for it with a full unit in hand is a bug.

A key map is the other kind of caller. It is not a column, it is never decoded as a run, and every read of it is a single tail_at out of the middle of a binary search, so the transposed layout would buy it nothing and the bound would cost it the form: the sorted key map over fifteen million orders rows is fifteen million values in one array addressed by index. The writer’s carry chain is still here and is still serial, and that is a build time cost paid once over a column that is being sorted anyway.

Errors

If width exceeds 64, or if a value does not fit in width bits.