Struct StringBackend

pub struct StringBackend<S = DefaultSymbol> { /* private fields */ }

An interner backend that accumulates all interned string contents into one string.

Note

Implementation inspired by CAD97’s research project strena.

Usage Hint

Use this backend if runtime performance is what matters most to you.

Usage

• Fill: Efficiency of filling an empty string interner.
• Resolve: Efficiency of interned string look-up given a symbol.
• Allocations: The number of allocations performed by the backend.
• Footprint: The total heap memory consumed by the backend.
• Contiguous: True if the returned symbols have contiguous values.
• Iteration: Efficiency of iterating over the interned strings.

Rating varies between bad, ok, good and best.

Scenario	Rating
Fill	good
Resolve	ok
Allocations	good
Footprint	good
Supports get_or_intern_static	no
Send + Sync	yes
Contiguous	yes
Iteration	good

Trait Implementations

impl<S> Backend for StringBackend<S>

where S: Symbol,

type Symbol = S

The symbol used by the string interner backend.

type Iter<'a> = Iter<'a, S> where Self: 'a

The iterator over the symbols and their strings.

fn with_capacity(cap: usize) -> Self

Creates a new backend for the given capacity.

fn intern(&mut self, string: &str) -> Self::Symbol

Interns the given string and returns its interned ref and symbol.

fn resolve(&self, symbol: Self::Symbol) -> Option<&str>

Resolves the given symbol to its original string contents.

fn shrink_to_fit(&mut self)

Shrink backend capacity to fit interned symbols exactly.

unsafe fn resolve_unchecked(&self, symbol: Self::Symbol) -> &str

Resolves the given symbol to its original string contents.

fn iter(&self) -> Self::Iter<'_>

Creates an iterator that yields all interned strings and their symbols.

fn intern_static(&mut self, string: &'static str) -> Self::Symbol

Interns the given static string and returns its interned ref and symbol.

impl<S> Clone for StringBackend<S>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<S: Debug> Debug for StringBackend<S>

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

Formats the value using the given formatter.

impl<S> Default for StringBackend<S>

fn default() -> Self

Returns the “default value” for a type.

impl<'a, S> IntoIterator for &'a StringBackend<S>

where S: Symbol,

type Item = (S, &'a str)

The type of the elements being iterated over.

type IntoIter = Iter<'a, S>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<S> PartialEq for StringBackend<S>

where S: Symbol,

fn eq(&self, other: &Self) -> 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<S> Eq for StringBackend<S>

where S: Symbol,