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ring.go
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ring.go
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package queuelistener
import "net"
type ring struct {
connections []net.Conn
next int
size int
}
func newRing(maxSize int) *ring {
return &ring{connections: make([]net.Conn, maxSize)}
}
func (r *ring) peek() net.Conn {
i := r.next - 1
if i < 0 {
i = len(r.connections) - 1
}
return r.connections[i]
}
func (r *ring) peekOldest() net.Conn {
i := r.next - r.size
if i < 0 {
i += len(r.connections)
}
return r.connections[i]
}
func (r *ring) enqueue(c net.Conn) (oldest net.Conn) {
if r.size == len(r.connections) {
oldest = r.connections[r.next]
} else {
r.size++
}
r.connections[r.next] = c
r.next++
if r.next == len(r.connections) {
r.next = 0
}
return
}
func (r *ring) dequeue() net.Conn {
r.next--
if r.next < 0 {
r.next = len(r.connections) - 1
}
var c net.Conn
c, r.connections[r.next] = r.connections[r.next], nil
r.size--
return c
}
func (r *ring) dequeueOldest() net.Conn {
i := r.next - r.size
if i < 0 {
i += len(r.connections)
}
var c net.Conn
c, r.connections[i] = r.connections[i], nil
r.size--
return c
}
func (r *ring) rangeOver(f func(net.Conn)) {
start := r.next - r.size
if start < 0 {
start = len(r.connections) + start
}
finish := start + r.size
if finish >= len(r.connections) {
finish = len(r.connections)
}
for i := start; i < finish; i++ {
f(r.connections[i])
}
finish = r.size + start - finish
start = 0
for i := start; i < finish; i++ {
f(r.connections[i])
}
}