Struct vortex_flatbuffers::footer::Layout

pub struct Layout<'a> {
    pub _tab: Table<'a>,
}

A Layout is a recursive data structure that describes the physical layout of the data in a Vortex file. As a starting, concrete example, the first three Layout encodings are defined as:

1. encoding == 1, Flat -> one buffer, zero child Layouts
2. encoding == 2, Chunked -> zero buffers, one or more child Layouts (used for chunks of rows)
3. encoding == 3, Columnar -> zero buffers, one or more child Layouts (used for columns of structs)

The row_count represents the number of rows represented by this Layout. This is very useful for pruning the Layout tree based on row filters.

The metadata field is fully opaque at this layer, and allows the Layout implementation corresponding to encoding to embed additional information that may be useful for the reader. For example, the ChunkedLayout uses the first byte of the metadata array as a boolean to indicate whether the first child Layout represents the statistics table for the other chunks.

Fields

_tab: Table<'a>

Implementations

impl<'a> Layout<'a>

pub const VT_ENCODING: VOffsetT = 4u16

pub const VT_BUFFERS: VOffsetT = 6u16

pub const VT_CHILDREN: VOffsetT = 8u16

pub const VT_ROW_COUNT: VOffsetT = 10u16

pub const VT_METADATA: VOffsetT = 12u16

pub unsafe fn init_from_table(table: Table<'a>) -> Self

pub fn create<'bldr: 'args, 'args: 'mut_bldr, 'mut_bldr, A: Allocator + 'bldr>( _fbb: &'mut_bldr mut FlatBufferBuilder<'bldr, A>, args: &'args LayoutArgs<'args>, ) -> WIPOffset<Layout<'bldr>>

pub fn encoding(&self) -> u16

pub fn buffers(&self) -> Option<Vector<'a, Buffer>>

pub fn children(&self) -> Option<Vector<'a, ForwardsUOffset<Layout<'a>>>>

pub fn row_count(&self) -> u64

pub fn metadata(&self) -> Option<Vector<'a, u8>>

Trait Implementations

impl<'a> Clone for Layout<'a>

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

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Layout<'_>

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

Formats the value using the given formatter.

impl<'a> Follow<'a> for Layout<'a>

type Inner = Layout<'a>

unsafe fn follow(buf: &'a [u8], loc: usize) -> Self::Inner

Safety

impl<'a> PartialEq for Layout<'a>

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Verifiable for Layout<'_>

fn run_verifier( v: &mut Verifier<'_, '_>, pos: usize, ) -> Result<(), InvalidFlatbuffer>

Runs the verifier for this type, assuming its at position pos in the verifier’s buffer. Should not need to be called directly.

impl<'a> Copy for Layout<'a>

impl<'a> StructuralPartialEq for Layout<'a>