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lrucache.go
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lrucache.go
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package lrucache
import (
"github.com/BTCGhostdag/BTCD/domain/consensus/model/externalapi"
)
// LRUCache is a least-recently-used cache for any type
// that's able to be indexed by DomainHash
type LRUCache struct {
cache map[externalapi.DomainHash]interface{}
capacity int
}
// New creates a new LRUCache
func New(capacity int, preallocate bool) *LRUCache {
var cache map[externalapi.DomainHash]interface{}
if preallocate {
cache = make(map[externalapi.DomainHash]interface{}, capacity+1)
} else {
cache = make(map[externalapi.DomainHash]interface{})
}
return &LRUCache{
cache: cache,
capacity: capacity,
}
}
// Add adds an entry to the LRUCache
func (c *LRUCache) Add(key *externalapi.DomainHash, value interface{}) {
c.cache[*key] = value
if len(c.cache) > c.capacity {
c.evictRandom()
}
}
// Get returns the entry for the given key, or (nil, false) otherwise
func (c *LRUCache) Get(key *externalapi.DomainHash) (interface{}, bool) {
value, ok := c.cache[*key]
if !ok {
return nil, false
}
return value, true
}
// Has returns whether the LRUCache contains the given key
func (c *LRUCache) Has(key *externalapi.DomainHash) bool {
_, ok := c.cache[*key]
return ok
}
// Remove removes the entry for the the given key. Does nothing if
// the entry does not exist
func (c *LRUCache) Remove(key *externalapi.DomainHash) {
delete(c.cache, *key)
}
func (c *LRUCache) evictRandom() {
var keyToEvict externalapi.DomainHash
for key := range c.cache {
keyToEvict = key
break
}
c.Remove(&keyToEvict)
}