108 lines
2.0 KiB
Go
108 lines
2.0 KiB
Go
package cuckoo
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// An Entry is a key-value pair.
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type Entry[K, V any] struct {
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key K
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value V
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}
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type slot[K, V any] struct {
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Entry[K, V]
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occupied bool
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}
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type bucket[K, V any] struct {
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hash Hash[K]
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slots []slot[K, V]
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capacity, size uint64
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compare EqualFunc[K]
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}
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// location determines where in the bucket a certain key would be placed. If the
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// capacity is 0, this will panic.
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func (b bucket[K, V]) location(key K) uint64 {
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return b.hash(key) % b.capacity
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}
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func (b bucket[K, V]) get(key K) (value V, found bool) {
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if b.capacity == 0 {
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return
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}
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slot := b.slots[b.location(key)]
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return slot.value, slot.occupied && b.compare(slot.key, key)
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}
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func (b *bucket[K, V]) drop(key K) (occupied bool) {
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if b.capacity == 0 {
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return
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}
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slot := &b.slots[b.location(key)]
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if slot.occupied && b.compare(slot.key, key) {
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slot.occupied = false
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b.size--
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return true
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}
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return false
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}
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func (b *bucket[K, V]) resized(capacity uint64) bucket[K, V] {
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return bucket[K, V]{
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slots: make([]slot[K, V], capacity),
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capacity: capacity,
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hash: b.hash,
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compare: b.compare,
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}
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}
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func (b bucket[K, V]) update(key K, value V) (updated bool) {
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if b.capacity == 0 {
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return
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}
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slot := &b.slots[b.location(key)]
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if slot.occupied && b.compare(slot.key, key) {
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slot.value = value
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return true
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}
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return false
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}
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func (b *bucket[K, V]) insert(insertion Entry[K, V]) (evicted Entry[K, V], eviction bool) {
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if b.capacity == 0 {
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return insertion, true
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}
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slot := &b.slots[b.location(insertion.key)]
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if !slot.occupied {
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slot.Entry = insertion
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slot.occupied = true
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b.size++
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return
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}
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if b.compare(slot.key, insertion.key) {
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slot.value = insertion.value
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return
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}
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insertion, slot.Entry = slot.Entry, insertion
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return insertion, true
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}
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func newBucket[K, V any](capacity uint64, hash Hash[K], compare EqualFunc[K]) bucket[K, V] {
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return bucket[K, V]{
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hash: hash,
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capacity: capacity,
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compare: compare,
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size: 0,
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slots: make([]slot[K, V], capacity),
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}
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}
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