57 lines
1005 B
Go
57 lines
1005 B
Go
|
package mutexes
|
||
|
|
|
||
|
|
type hashmap struct {
|
||
|
|
m map[string]*rwmutex
|
||
|
|
n int
|
||
|
|
}
|
||
|
|
|
||
|
|
func (m *hashmap) init(cap int) {
|
||
|
|
m.m = make(map[string]*rwmutex, cap)
|
||
|
|
m.n = cap
|
||
|
|
}
|
||
|
|
|
||
|
|
func (m *hashmap) Get(key string) *rwmutex { return m.m[key] }
|
||
|
|
|
||
|
|
func (m *hashmap) Put(key string, mu *rwmutex) {
|
||
|
|
m.m[key] = mu
|
||
|
|
if n := len(m.m); n > m.n {
|
||
|
|
m.n = n
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (m *hashmap) Delete(key string) {
|
||
|
|
delete(m.m, key)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (m *hashmap) Compact() {
|
||
|
|
// Noop when hashmap size
|
||
|
|
// is too small to matter.
|
||
|
|
if m.n < 2048 {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// Difference between maximum map
|
||
|
|
// size and the current map size.
|
||
|
|
diff := m.n - len(m.m)
|
||
|
|
|
||
|
|
// Maximum load factor before
|
||
|
|
// runtime allocates new hmap:
|
||
|
|
// maxLoad = 13 / 16
|
||
|
|
//
|
||
|
|
// So we apply the inverse/2, once
|
||
|
|
// $maxLoad/2 % of hmap is empty we
|
||
|
|
// compact the map to drop buckets.
|
||
|
|
if 2*16*diff > m.n*13 {
|
||
|
|
|
||
|
|
// Create new map only as big as required.
|
||
|
|
m2 := make(map[string]*rwmutex, len(m.m))
|
||
|
|
for k, v := range m.m {
|
||
|
|
m2[k] = v
|
||
|
|
}
|
||
|
|
|
||
|
|
// Set new.
|
||
|
|
m.m = m2
|
||
|
|
m.n = len(m2)
|
||
|
|
}
|
||
|
|
}
|