Struct Column 

pub struct Column { /* private fields */ }

A read-only dense column.

Implementations

impl Column

pub fn file(store: &Path, name: &str) -> PathBuf

The side file the name column of the store at store is written to.

The name carries the store’s own stem, so two stores in one directory cannot write each other’s columns.

pub fn write_to<'a>( count: u32, records: impl IntoIterator<Item = (Ordinal, &'a [u8])>, out: &mut impl Write, ) -> Result<()>

Writes the column records pack, in ordinal order.

A record is placed at its ordinal, and an ordinal no record names gets an empty range. The records are borrowed rather than packed into one buffer first, so a build writes an edition’s column without holding a second copy of it.

Errors

Returns the I/O error from writing.

pub fn read_from(reader: &mut impl Read) -> Result<Self, ColumnError>

Reads a column, checking its offsets once so a read never can.

The records land in one allocation of their final size, filled from the reader, so the column arrives at the address it is served from.

Errors

Returns ColumnError when the bytes end early, an offset lies behind the one before it, or the reader fails.

pub fn read(bytes: &[u8]) -> Result<Self, ColumnError>

Reads a column from bytes already in memory.

Errors

Returns ColumnError as Self::read_from does.

pub fn size_in_bytes(&self) -> usize

The heap bytes this column holds (concept_graph::footprint).

pub fn len(&self) -> usize

How many ordinals the column holds.

pub fn is_empty(&self) -> bool

Whether the column holds no ordinals.

pub fn get(&self, ordinal: Ordinal) -> Option<&[u8]>

The record at ordinal, None beyond the column or where the build wrote none.

The offsets were checked when the column was read, so this slices without failing.

Trait Implementations

impl Clone for Column

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 Column

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

Formats the value using the given formatter.

impl Default for Column

fn default() -> Self

Returns the “default value” for a type.

impl Eq for Column

impl PartialEq for Column

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Column