Struct Projection 

pub struct Projection<'a> { /* private fields */ }

The columns a scan is being asked for.

This is a list of indices and not a bitmask. A bitmask has to pick a width, and whatever width it picks becomes the maximum number of columns the format can ever describe. Wide tables are exactly where a columnar format is supposed to win, so putting a ceiling on the column count is the wrong place to save four bytes.

Implementations

impl<'a> Projection<'a>

pub const ALL: Self

An empty projection, which means every column.

pub fn from_bytes(raw: &'a [u8]) -> Result<Self>

Wraps the encoded form.

Errors

Returns Error::Malformed if the length is not a whole number of column indices.

pub const fn len(self) -> usize

How many columns are named.

pub const fn is_empty(self) -> bool

Whether the projection names no columns, which means every column.

pub fn iter(self) -> impl Iterator<Item = u32> + 'a

The column indices, in the order the caller wrote them.

pub const fn as_bytes(self) -> &'a [u8]

The encoded form.

Trait Implementations

impl<'a> Clone for Projection<'a>

fn clone(&self) -> Projection<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for Projection<'a>

impl<'a> Debug for Projection<'a>

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

Formats the value using the given formatter.

impl<'a> Eq for Projection<'a>

impl<'a> PartialEq for Projection<'a>

fn eq(&self, other: &Projection<'a>) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<'a> StructuralPartialEq for Projection<'a>