Struct Flat 

pub struct Flat { /* private fields */ }

A decoded chunk as one buffer with the values laid end to end, and where each one ends in it.

This is what the decoder builds and decode is a copy out of it. The cascade is why: a nest like FRONT(LZ(FSST)) decodes three levels to produce one, and a level that hands its caller a Vec<Vec<u8>> has allocated once per value and copied every byte it holds. Three levels of that on a chunk of a thousand URLs is three thousand allocations to produce a thousand strings that the caller almost always wants back to back anyway.

It also makes the levels cheaper on their own terms. PLAIN is one memcpy of the whole payload because the values are already end to end in the file. FRONT copies a shared prefix out of the buffer it is writing into, so the previous value never has to be somewhere else. LZ replays straight into the buffer, which is what its copy offsets meant in the first place.

Implementations

impl Flat

pub fn len(&self) -> usize

How many values the chunk holds.

pub fn is_empty(&self) -> bool

Whether the chunk holds no values at all, which is not the same as holding empty ones.

pub fn bytes(&self) -> &[u8]

The values laid end to end. A caller that already knows the boundaries, which is what a global dictionary’s offsets are, needs nothing else.

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

The value at index, or None past the end.

pub fn iter(&self) -> impl Iterator<Item = &[u8]>

Every value in order.

pub fn into_bytes(self) -> Vec<u8>

The buffer on its own, for a caller that wanted the bytes rather than the values.

Trait Implementations

impl Clone for Flat

fn clone(&self) -> Flat

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Flat

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

Formats the value using the given formatter.

impl Default for Flat

fn default() -> Flat

Returns the “default value” for a type.

impl Eq for Flat

impl PartialEq for Flat

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Flat