// NewARC creates an ARC of the given size
func NewARC(size int) (*ARCCache, error) {
// Create the sub LRUs
b1, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
b2, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
t1, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
t2, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
// Initialize the ARC
c := &ARCCache{
size: size,
p: 0,
t1: t1,
b1: b1,
t2: t2,
b2: b2,
}
return c, nil
}
// NewWithEvict constructs a fixed size cache with the given eviction
// callback.
func NewWithEvict(size int, onEvicted func(key interface{}, value interface{})) (*Cache, error) {
lru, err := simplelru.NewLRU(size, simplelru.EvictCallback(onEvicted))
if err != nil {
return nil, err
}
c := &Cache{
lru: lru,
}
return c, nil
}
// New2QParams creates a new TwoQueueCache using the provided
// parameter values.
func New2QParams(size int, recentRatio float64, ghostRatio float64) (*TwoQueueCache, error) {
if size <= 0 {
return nil, fmt.Errorf("invalid size")
}
if recentRatio < 0.0 || recentRatio > 1.0 {
return nil, fmt.Errorf("invalid recent ratio")
}
if ghostRatio < 0.0 || ghostRatio > 1.0 {
return nil, fmt.Errorf("invalid ghost ratio")
}
// Determine the sub-sizes
recentSize := int(float64(size) * recentRatio)
evictSize := int(float64(size) * ghostRatio)
// Allocate the LRUs
recent, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
frequent, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
recentEvict, err := simplelru.NewLRU(evictSize, nil)
if err != nil {
return nil, err
}
// Initialize the cache
c := &TwoQueueCache{
size: size,
recentSize: recentSize,
recent: recent,
frequent: frequent,
recentEvict: recentEvict,
}
return c, nil
}