Enum ValidityMask 

pub enum ValidityMask {
    AllPresent(u32),
    Mixed {
        present: BitVec,
        unknown: BitVec,
    },
}

Which positions of a column carry a value, and why the others do not.

The overwhelmingly common case is that every position carries one, and that case costs a length rather than two bit sets.

Examples

use molframe_core::column::{Presence, ValidityMask};

let mut mask = ValidityMask::all_present(3);
assert_eq!(mask.get(0), Presence::Present);

mask.set(1, Presence::Unknown);
assert_eq!(mask.get(1), Presence::Unknown);
assert_eq!(mask.present_count(), 2);

Variants

AllPresent(u32)

Every position carries a value.

Mixed

Positions differ, so both distinctions are tracked.

Fields

present: BitVec

Set where a value is recorded.

unknown: BitVec

Set where the value exists but was not recorded. Meaningful only where present is clear; clear there means the field does not apply.

Implementations

impl ValidityMask

pub const fn all_present(len: u32) -> Self

Creates a mask over len positions that all carry a value.

pub fn len(&self) -> u32

The number of positions covered.

pub fn is_empty(&self) -> bool

Returns true when no position is covered.

pub fn is_all_present(&self) -> bool

Returns true when every covered position carries a value.

pub fn get(&self, position: u32) -> Presence

What the column says about position.

A position past the end reads as inapplicable, because a column that does not reach that far makes no statement about it.

pub fn set(&mut self, position: u32, presence: Presence)

Records what the column says about position.

Setting anything other than present on an all-present mask materialises the bit sets, which is the only point at which they are allocated.

pub fn present_count(&self) -> u32

The number of positions carrying a value.

pub fn compact(&mut self)

Collapses back to the compact form when every position carries a value.

Worth calling once after building a column, so a file that happened to record everything does not carry two bit sets for the rest of its life.

impl ValidityMask

pub fn try_from_iter<T: IntoIterator<Item = Presence>>(iter: T) -> Option<Self>

Builds a validity mask, returning None if u32 row capacity is exceeded.

Trait Implementations

impl Clone for ValidityMask

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ValidityMask

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for ValidityMask

impl PartialEq for ValidityMask

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for ValidityMask