Struct InverseSupply 

pub struct InverseSupply<V>
where
    V: Eq + Hash,
{ /* private fields */ }

Index-based inverse variable supply.

For a chained variable where entity.previous = value, this supply answers: “Given value, which entity index has entities[idx].previous == value?”

Returns entity indices - caller accesses actual entity via solution.entities[idx].

Example

use solverforge_core::domain::supply::InverseSupply;

let mut supply: InverseSupply<i32> = InverseSupply::new();

// Entity at index 0 points to value 42
supply.insert(42, 0);

// Entity at index 1 points to value 99
supply.insert(99, 1);

assert_eq!(supply.get(&42), Some(0));
assert_eq!(supply.get(&99), Some(1));
assert_eq!(supply.get(&100), None);

Implementations

impl<V> InverseSupply<V>

where V: Eq + Hash,

pub fn new() -> Self

Creates a new empty inverse supply.

pub fn with_capacity(capacity: usize) -> Self

Creates a new inverse supply with pre-allocated capacity.

pub fn get(&self, value: &V) -> Option<usize>

Gets the entity index that points to the given value.

Returns None if no entity currently points to this value.

pub fn insert(&mut self, value: V, entity_idx: usize) -> Option<usize>

Registers that an entity index now points to a value.

Returns the previous entity index if this value was already mapped.

pub fn remove(&mut self, value: &V) -> Option<usize>

Removes the mapping for a value.

Returns the entity index that was mapped, if any.

pub fn update(&mut self, old_value: Option<&V>, new_value: V, entity_idx: usize)

Updates the mapping: removes old value, inserts new.

Use this when an entity changes which value it points to.

pub fn clear(&mut self)

Clears all mappings.

pub fn len(&self) -> usize

Returns the number of tracked mappings.

pub fn is_empty(&self) -> bool

Returns true if no mappings exist.

pub fn iter(&self) -> impl Iterator<Item = (&V, &usize)>

Returns an iterator over all (value, entity_index) pairs.

Trait Implementations

impl<V> Debug for InverseSupply<V>

where V: Eq + Hash + Debug,

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

Formats the value using the given formatter.

impl<V> Default for InverseSupply<V>

where V: Eq + Hash,

fn default() -> Self

Returns the “default value” for a type.