Struct FSST 

pub struct FSST;

Implementations

impl FSST

pub fn try_new( dtype: DType, symbols: Buffer<Symbol>, symbol_lengths: Buffer<u8>, codes: VarBinArray, uncompressed_lengths: ArrayRef, ) -> VortexResult<FSSTArray>

Build an FSST array from a set of symbols and codes.

The codes VarBinArray is decomposed: its bytes are stored in FSSTData, while its offsets and validity become array slots. The codes VarBinArray can be reconstructed on demand via FSSTArrayExt::codes().

Trait Implementations

impl CastReduce for FSST

fn cast( array: ArrayView<'_, Self>, dtype: &DType, ) -> VortexResult<Option<ArrayRef>>

impl Clone for FSST

fn clone(&self) -> FSST

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl CompareKernel for FSST

fn compare( lhs: ArrayView<'_, Self>, rhs: &ArrayRef, operator: CompareOperator, ctx: &mut ExecutionCtx, ) -> VortexResult<Option<ArrayRef>>

impl Debug for FSST

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

Formats the value using the given formatter.

impl FilterKernel for FSST

fn filter( array: ArrayView<'_, Self>, mask: &Mask, ctx: &mut ExecutionCtx, ) -> VortexResult<Option<ArrayRef>>

Filter an array with the provided mask, potentially reading buffers.

impl LikeKernel for FSST

fn like( array: ArrayView<'_, Self>, pattern: &ArrayRef, options: LikeOptions, _ctx: &mut ExecutionCtx, ) -> VortexResult<Option<ArrayRef>>

impl OperationsVTable<FSST> for FSST

fn scalar_at( array: ArrayView<'_, FSST>, index: usize, ctx: &mut ExecutionCtx, ) -> VortexResult<Scalar>

Fetch the scalar at the given index.

impl SliceReduce for FSST

fn slice( array: ArrayView<'_, Self>, range: Range<usize>, ) -> VortexResult<Option<ArrayRef>>

Slice an array with the provided range without reading buffers.

impl TakeExecute for FSST

fn take( array: ArrayView<'_, Self>, indices: &ArrayRef, _ctx: &mut ExecutionCtx, ) -> VortexResult<Option<ArrayRef>>

Take elements from an array at the given indices, potentially reading buffers.

impl VTable for FSST

fn deserialize( &self, dtype: &DType, len: usize, metadata: &[u8], buffers: &[BufferHandle], children: &dyn ArrayChildren, _session: &VortexSession, ) -> VortexResult<ArrayParts<Self>>

Deserializes an FSST array from its serialized components.

Supports two serialization formats:

Legacy format (2 buffers, 2 children)

The original FSST layout stored the compressed codes as a full VarBinArray child.

• Buffers: [symbols, symbol_lengths]
• Children: [codes (VarBinArray), uncompressed_lengths (Primitive)]

The codes VarBinArray child is decomposed: its bytes become the codes_bytes buffer, and its offsets/validity are extracted into slots. See FSST::deserialize_legacy.

Current format (3 buffers, 2-3 children)

The current layout stores the compressed bytes as a raw buffer alongside the symbol table, with offsets and validity as separate children.

• Buffers: [symbols, symbol_lengths, compressed_codes_bytes]
• Children: [uncompressed_lengths, codes_offsets, (optional) codes_validity]

The codes_bytes buffer is stored directly in FSSTData. A VarBinArray for the codes can be reconstructed on demand via FSSTArrayExt::codes() using the bytes from FSSTData combined with offsets and validity from the array’s slots.

type ArrayData = FSSTData

type OperationsVTable = FSST

type ValidityVTable = FSST

fn id(&self) -> ArrayId

Returns the ID of the array.

fn validate( &self, data: &Self::ArrayData, dtype: &DType, len: usize, slots: &[Option<ArrayRef>], ) -> VortexResult<()>

Validates that externally supplied logical metadata matches the array data.

fn nbuffers(_array: ArrayView<'_, Self>) -> usize

Returns the number of buffers in the array.

fn buffer(array: ArrayView<'_, Self>, idx: usize) -> BufferHandle

Returns the buffer at the given index.

fn buffer_name(_array: ArrayView<'_, Self>, idx: usize) -> Option<String>

Returns the name of the buffer at the given index, or None if unnamed.

fn serialize( array: ArrayView<'_, Self>, _session: &VortexSession, ) -> VortexResult<Option<Vec<u8>>>

Serialize metadata into a byte buffer for IPC or file storage. Return None if the array cannot be serialized.

fn slot_name(_array: ArrayView<'_, Self>, idx: usize) -> String

Returns the name of the slot at the given index.

fn execute( array: Array<Self>, ctx: &mut ExecutionCtx, ) -> VortexResult<ExecutionResult>

Execute this array by returning an ExecutionResult.

fn append_to_builder( array: ArrayView<'_, Self>, builder: &mut dyn ArrayBuilder, ctx: &mut ExecutionCtx, ) -> VortexResult<()>

Writes the array into a canonical builder.

fn execute_parent( array: ArrayView<'_, Self>, parent: &ArrayRef, child_idx: usize, ctx: &mut ExecutionCtx, ) -> VortexResult<Option<ArrayRef>>

Attempt to execute the parent of this array.

fn reduce_parent( array: ArrayView<'_, Self>, parent: &ArrayRef, child_idx: usize, ) -> VortexResult<Option<ArrayRef>>

Attempt to perform a reduction of the parent of this array.

fn nchildren(array: ArrayView<'_, Self>) -> usize

Returns the number of children in the array.

fn child(array: ArrayView<'_, Self>, idx: usize) -> ArrayRef

Returns the child at the given index.

fn child_name(array: ArrayView<'_, Self>, idx: usize) -> String

Returns the name of the child at the given index.

fn reduce(array: ArrayView<'_, Self>) -> Result<Option<ArrayRef>, VortexError>

Attempt to reduce the array to a simpler representation.

impl ValidityVTable<FSST> for FSST

fn validity(array: ArrayView<'_, FSST>) -> VortexResult<Validity>

Returns the Validity of the array.