Struct ValueHeap 

pub struct ValueHeap { /* private fields */ }

Implementations

impl ValueHeap

pub fn new() -> Self

pub fn alloc(&mut self, len: u32, room: &mut Room) -> Range

Allocates a range of at least len slots, filled with Value::EMPTY. The returned length is rounded up to the class size. A growth step is charged to room.

pub fn alloc_slots(&mut self, len: u32, room: &mut Room) -> Range

ValueHeap::alloc rounded to a power of two: an object’s named property slots, which the header decodes with one shift.

pub fn growth_bytes(&self, len: u32) -> usize

Bytes the backing vector grows by if a range of len is allocated now.

pub fn grow(&mut self, range: Range, new_len: u32, room: &mut Room) -> Range

Returns a range of at least new_len holding range’s values: the same range when it is already large enough, otherwise a new one (alloc, copy, free).

pub fn grow_slots( &mut self, range: Range, new_len: u32, room: &mut Room, ) -> Range

ValueHeap::grow for named property slots, to a power of two.

pub fn free(&mut self, range: Range)

Returns a range to its class. The slots are poisoned with EMPTY.

pub fn begin_sweep(&mut self)

Starts a collection’s sweep: the free space moves into the bitmap of free slots, where ValueHeap::release records the ranges the sweep frees, and ValueHeap::finish_sweep rebuilds it from the bitmap.

pub fn release(&mut self, range: Range)

Frees a range during the sweep: poisons it with EMPTY and records it in the bitmap of free slots.

pub fn finish_sweep(&mut self)

Ends the sweep: rebuilds the free space from the maximal runs of free slots. A run shorter than [SHORT_RUN] goes on the class lists, cut from its start into the largest class ranges that fit (a run of seven becomes ranges of six and one); a longer one becomes a free run. A run that ends the heap and spans more than a quarter of its capacity is cut off instead, and the capacity past one growth step goes back to the allocator. Lower ranges and runs are reused first.

pub fn get(&self, range: Range, slot: u32) -> Value

pub fn set(&mut self, range: Range, slot: u32, value: Value)

pub fn get_or_empty(&self, range: Range, slot: u32) -> Value

The value at slot of range, or Value::EMPTY past its end.

pub fn get_at(&self, index: u32) -> Value

An absolute slot; callers check the range in debug builds.

pub fn set_at(&mut self, index: u32, value: Value)

pub fn slice(&self, range: Range) -> &[Value]

pub fn slice_mut(&mut self, range: Range) -> &mut [Value]

pub fn total_slots(&self) -> usize

Slots handed out, free or in use.

pub fn free_slots(&self) -> usize

Slots sitting in free lists.

pub fn used_slots(&self) -> usize

Slots held by live ranges.

pub fn fragmentation(&self) -> f64

Free-list slots over all handed-out slots.

pub fn bytes(&self) -> usize

pub fn free_blocks(&self) -> impl Iterator<Item = Range> + '_

Every free range of the class lists.

pub fn free_runs(&self) -> impl Iterator<Item = (u32, u32)> + '_

The free runs, the current one first, for the stress-mode verifier.

Trait Implementations

impl Default for ValueHeap

fn default() -> Self

Returns the “default value” for a type.