Struct GraphemeId 

pub struct GraphemeId(/* private fields */);

Grapheme ID: reference to an interned string in [GraphemePool].

Layout

[30-27: width (4 bits)][26-16: generation (11 bits)][15-0: pool slot (16 bits)]

Capacity

• Pool slots: 65,536 (16 bits = 64K entries)
• Generation: 2048 versions (11 bits) for stale access detection
• Width range: 0-15 (4 bits)

Design Rationale

• 16 bits for slot (64K) is sufficient for any single frame’s unique graphemes.
• 11 bits for generation allows detecting access to reused slots (fixing the ABA problem).
• 4 bits for width allows display widths 0-15.
• Total 31 bits leaves bit 31 for CellContent type discrimination.

Implementations

impl GraphemeId

pub const MAX_SLOT: u32 = 0xFFFF

Maximum slot index (16 bits).

pub const MAX_WIDTH: u8 = 15

Maximum width (4 bits).

pub const MAX_GENERATION: u16 = 2047

Maximum generation (11 bits).

pub const fn new(slot: u32, generation: u16, width: u8) -> Self

Create a new GraphemeId from slot index, generation, and display width.

Panics

Panics in debug mode if slot > MAX_SLOT or width > MAX_WIDTH.

pub const fn slot(self) -> usize

Extract the pool slot index (0-64K).

pub const fn generation(self) -> u16

Extract the generation counter (0-2047).

pub const fn width(self) -> usize

Extract the display width (0-15).

pub const fn raw(self) -> u32

Raw u32 value for storage in CellContent.

pub const fn from_raw(raw: u32) -> Self

Reconstruct from a raw u32.

Trait Implementations

impl Clone for GraphemeId

fn clone(&self) -> GraphemeId

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GraphemeId

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

Formats the value using the given formatter.

impl Default for GraphemeId

fn default() -> GraphemeId

Returns the “default value” for a type.

impl Hash for GraphemeId

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for GraphemeId

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for GraphemeId

impl Eq for GraphemeId

impl StructuralPartialEq for GraphemeId