Struct FoRScheme 

pub struct FoRScheme { /* private fields */ }

Frame of Reference encoding.

The v1 mode subtracts one reference, the array’s minimum. The v2 mode subtracts one reference per 1024-element chunk, the chunk’s minimum. Arrays with a single reference, including v2 arrays whose references compress to a constant, serialize as fastlanes.for, while per-chunk references serialize as fastlanes.for.v2.

The default uses v1. refine picks v2 when the v2 ID is allowed and v1 otherwise.

Implementations

impl FoRScheme

pub const fn v1() -> Self

Creates a FoR scheme configured for v1, which uses a single reference.

pub const fn v2() -> Self

Creates a FoR scheme configured for v2, which may use one reference per chunk.

Trait Implementations

impl Clone for FoRScheme

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for FoRScheme

impl Debug for FoRScheme

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

Formats the value using the given formatter.

impl Default for FoRScheme

fn default() -> Self

Returns the “default value” for a type.

impl Eq for FoRScheme

impl PartialEq for FoRScheme

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

Equality operator ==.

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

Inequality operator !=.

impl Scheme for FoRScheme

fn num_children(&self) -> usize

Children: references=0 in v2 mode. The encoded child is always bit-packed.

fn ancestor_exclusions(&self) -> Vec<AncestorExclusion>

Dict codes always start at 0, so FoR (which subtracts the min) is a no-op.

fn scheme_name(&self) -> &'static str

The globally unique name for this scheme (e.g. "vortex.int.bitpacking").

fn matches(&self, canonical: &Canonical) -> bool

Whether this scheme can compress the given canonical array.

fn produced_encodings(&self) -> Vec<ArrayId>

The serialized IDs this scheme itself may write into its compressed output.

fn refine(&self, allowed: &dyn Fn(&ArrayId) -> bool) -> &dyn Scheme

Returns the variant of this scheme to use given which serialized IDs are allowed.

fn expected_compression_ratio( &self, data: &ArrayAndStats, compress_ctx: CompressorContext, exec_ctx: &mut ExecutionCtx, ) -> CompressionEstimate

Cheaply estimate the compression ratio for this scheme on the given array.

fn compress( &self, compressor: &CascadingCompressor, data: &ArrayAndStats, compress_ctx: CompressorContext, exec_ctx: &mut ExecutionCtx, ) -> VortexResult<ArrayRef>

Compress the array using this scheme.

fn stats_options(&self) -> GenerateStatsOptions

Returns the stats generation options this scheme requires. The compressor merges all eligible schemes’ options before generating stats so that a single stats pass satisfies every scheme.

fn descendant_exclusions(&self) -> Vec<DescendantExclusion>

Schemes to exclude from specific children’s subtrees (push direction).

impl StructuralPartialEq for FoRScheme