/
ring_buffer.go
56 lines (50 loc) · 1.23 KB
/
ring_buffer.go
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package common
import (
"container/list"
"github.com/DSiSc/craft/types"
"sync"
)
// ringRecord represent a record in ring buffer
type ringRecord struct {
v interface{}
node *list.Element
}
// RingBuffer is a ring buffer implementation.
type RingBuffer struct {
elements map[types.Hash]*ringRecord
limit int
keyList *list.List
lock sync.RWMutex
}
// NewRingBuffer create a ring buffer instance
func NewRingBuffer(size int) *RingBuffer {
return &RingBuffer{
elements: make(map[types.Hash]*ringRecord),
limit: size,
keyList: list.New(),
}
}
// AddElement add a element to ring buffer
func (ring *RingBuffer) AddElement(hash types.Hash, elem interface{}) {
ring.lock.Lock()
defer ring.lock.Unlock()
if r, ok := ring.elements[hash]; ok {
ring.keyList.Remove(r.node)
}
first := ring.keyList.PushFront(hash)
ring.elements[hash] = &ringRecord{
v: elem,
node: first,
}
if len(ring.elements) > ring.limit {
last := ring.keyList.Back()
delete(ring.elements, last.Value.(types.Hash))
ring.keyList.Remove(last)
}
}
// Exist check if the element is already in the ring buffer
func (ring *RingBuffer) Exist(hash types.Hash) bool {
ring.lock.RLock()
defer ring.lock.RUnlock()
return nil != ring.elements[hash]
}