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go-zero/core/collection/ring.go

53 lines
916 B
Go

package collection
import "sync"
// A Ring can be used as fixed size ring.
type Ring struct {
elements []interface{}
index int
lock sync.RWMutex
}
// NewRing returns a Ring object with the given size n.
func NewRing(n int) *Ring {
if n < 1 {
panic("n should be greater than 0")
}
return &Ring{
elements: make([]interface{}, n),
}
}
// Add adds v into r.
func (r *Ring) Add(v interface{}) {
r.lock.Lock()
defer r.lock.Unlock()
r.elements[r.index%len(r.elements)] = v
r.index++
}
// Take takes all items from r.
func (r *Ring) Take() []interface{} {
r.lock.RLock()
defer r.lock.RUnlock()
var size int
var start int
if r.index > len(r.elements) {
size = len(r.elements)
start = r.index % len(r.elements)
} else {
size = r.index
}
elements := make([]interface{}, size)
for i := 0; i < size; i++ {
elements[i] = r.elements[(start+i)%len(r.elements)]
}
return elements
}