struct StackCache {
    items: [Item; 32],
    idx: [usize; 32],
}
Expand description

A very small cache of searches of a borrow stack, mapping Items to their position in said stack.

It may seem like maintaining this cache is a waste for small stacks, but (a) iterating over small fixed-size arrays is super fast, and (b) empirically this helps a lot, probably because runtime is dominated by large stacks.

Fields

items: [Item; 32]idx: [usize; 32]

Implementations

When a tag is used, we call this function to add or refresh it in the cache.

We use the position in the cache to represent how recently a tag was used; the first position is the most recently used tag. So an add shifts every element towards the end, and inserts the new element at the start. We lose the last element. This strategy is effective at keeping the most-accessed items in the cache, but it costs a linear shift across the entire cache when we add a new tag.

Trait Implementations

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 512 bytes