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package utils
import (
"container/list"
)
type CacheEntry struct {
key int64
value []byte
}
type LruCache struct {
capacity int
ll *list.List
cache map[int64]*list.Element
}
func NewLRUCache(capacity int) *LruCache {
return &LruCache{
capacity: capacity,
ll: list.New(),
cache: make(map[int64]*list.Element),
}
}
func (c *LruCache) Get(key int64) ([]byte, bool) {
if ele, ok := c.cache[key]; ok {
c.ll.MoveToFront(ele)
return ele.Value.(*CacheEntry).value, true
}
return nil, false
}
func (c *LruCache) Put(key int64, value []byte) {
if ele, ok := c.cache[key]; ok {
c.ll.MoveToFront(ele)
ele.Value.(*CacheEntry).value = value
return
}
if c.ll.Len() >= c.capacity {
oldest := c.ll.Back()
if oldest != nil {
c.ll.Remove(oldest)
delete(c.cache, oldest.Value.(*CacheEntry).key)
}
}
entry := &CacheEntry{key, value}
ele := c.ll.PushFront(entry)
c.cache[key] = ele
}
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