Struct Nodes 

pub struct Nodes { /* private fields */ }

The .bt di-node array: the key at every M-th position.

Copied out of the mapping into one compact arena at first use, so the narrowing search touches only hot, contiguous heap instead of faulting .bt pages scattered across a multi-gigabyte file.

Implementations

impl Nodes

pub fn len(&self) -> usize

Number of nodes (ceil(key_count / M)).

pub fn is_empty(&self) -> bool

Whether there are no nodes.

pub fn m(&self) -> u64

The B-tree fanout M these nodes were sampled at.

pub fn heap_bytes(&self) -> usize

Heap held by the arena and (when present) the offset table.

pub fn key(&self, j: usize) -> &[u8]

The j-th node key, which is key number j * M in the file.

Panics

Panics if j >= self.len().

pub fn narrow(&self, key: &[u8]) -> (u64, u64)

Narrow a search for key to the half-open key-index range that can contain it.

Node j is key j * M, and keys are sorted, so if node[j] <= key < node[j+1] then key, if present, lies in [j*M, (j+1)*M). Returns an empty range when key sorts before the very first key, which cannot be in the file at all.