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/*
Copyright 2017 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package cache
import (
"hash/fnv"
"time"
)
// split cache lookups across N striped caches
type stripedCache struct {
stripeCount uint32
hashFunc func(string) uint32
caches []cache
}
type hashFunc func(string) uint32
type newCacheFunc func() cache
func newStripedCache(stripeCount int, hash hashFunc, newCacheFunc newCacheFunc) cache {
caches := []cache{}
for i := 0; i < stripeCount; i++ {
caches = append(caches, newCacheFunc())
}
return &stripedCache{
stripeCount: uint32(stripeCount),
hashFunc: hash,
caches: caches,
}
}
func (c *stripedCache) get(key string) (*cacheRecord, bool) {
return c.caches[c.hashFunc(key)%c.stripeCount].get(key)
}
func (c *stripedCache) set(key string, value *cacheRecord, ttl time.Duration) {
c.caches[c.hashFunc(key)%c.stripeCount].set(key, value, ttl)
}
func (c *stripedCache) remove(key string) {
c.caches[c.hashFunc(key)%c.stripeCount].remove(key)
}
func fnvHashFunc(key string) uint32 {
f := fnv.New32()
f.Write([]byte(key))
return f.Sum32()
}
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