Enum KeyRep 

pub enum KeyRep {
    Default(Vec<Vec<u8>>),
    Compact {
        buf: Vec<u8>,
        slot_width: usize,
        lengths: Vec<u16>,
    },
}

T-2: node-level key array — INKeyRep.{Default,MaxKeySize} (INKeyRep.java).

The per-slot key that used to live in BinEntry/InEntry as a Vec<u8> (24-byte header + a separate heap allocation per key) is hoisted here as a node-level rep. When every (post-prefix) key in the node is <= TREE_COMPACT_MAX_KEY_LENGTH (default 16) the keys pack into ONE fixed-width byte buffer (MaxKeySize): slot_width bytes per slot, with a parallel lengths vector tracking the actual length of each key. A key longer than the threshold inflates the whole node to the Default rep (one Vec<u8> per slot), matching JE’s Default.compact / MaxKeySize.expandToDefaultRep.

As in JE, this stores the UNPREFIXED suffix (key prefixing strips the common prefix first), so the compact rep is the smaller post-prefix bytes.

Variants

Default(Vec<Vec<u8>>)

INKeyRep.Default — one owned key per slot (any length).

Compact

INKeyRep.MaxKeySize — all keys packed into one fixed-width buffer. buf.len() == slot_width * lengths.len(); slot i occupies buf[i*slot_width .. i*slot_width + lengths[i]].

Fields

buf: Vec<u8>

slot_width: usize

lengths: Vec<u16>

Implementations

impl KeyRep

pub fn new() -> Self

An empty Default rep.

pub fn from_keys(keys: Vec<Vec<u8>>) -> Self

Build a Default rep from owned keys (callers may later compact).

pub fn len(&self) -> usize

Number of slots.

pub fn is_empty(&self) -> bool

pub fn get(&self, idx: usize) -> &[u8]

INKeyRep.get(idx) / getKey — borrow the (post-prefix) key at slot idx without allocating.

pub fn set(&mut self, idx: usize, key: Vec<u8>)

Set the key at slot idx. A key longer than a Compact rep’s slot_width inflates the rep to Default first (MaxKeySize.expandToDefaultRep).

pub fn insert(&mut self, idx: usize, key: Vec<u8>)

Insert a key at slot idx, shifting later slots up (mirrors Vec::insert + INArrayRep.copy).

pub fn remove(&mut self, idx: usize) -> Vec<u8>

Remove the key at slot idx, shifting later slots down.

pub fn compact(&mut self, compact_max_key_length: i32)

INKeyRep.Default.compact(parent) (INKeyRep.java) — if every key in a Default rep fits compact_max_key_length, pack them into a MaxKeySize (Compact) rep. compact_max_key_length <= 0 disables compaction. No-op when already Compact.

pub fn is_compact(&self) -> bool

True when key-byte memory is accounted for inside this rep (Compact), vs per-slot Vec allocations (Default). INKeyRep.accountsForKeyByteMemUsage.

pub fn memory_size(&self) -> usize

Heap bytes of the rep itself (INKeyRep.calculateMemorySize + key-byte accounting). For Default this is the Vec<Vec<u8>> header plus each key’s heap allocation; for Compact it is the single buffer plus the lengths vector.

Trait Implementations

impl Clone for KeyRep

fn clone(&self) -> KeyRep

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for KeyRep

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

Formats the value using the given formatter.

impl Default for KeyRep

fn default() -> Self

Returns the “default value” for a type.