mirror of
https://github.com/yunionio/cloudpods.git
synced 2026-05-09 15:17:23 +08:00
81 lines
1.6 KiB
Go
81 lines
1.6 KiB
Go
// Copyright 2019 Yunion
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package appsrv
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import (
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"sync"
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)
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type Ring struct {
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buffer []interface{}
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header, tail int
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lock *sync.Mutex
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}
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func NewRing(size int) *Ring {
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r := Ring{
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buffer: make([]interface{}, size+1),
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header: 0,
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tail: 0,
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lock: &sync.Mutex{},
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}
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return &r
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}
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func nextPointer(idx int, size int) int {
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idx = idx + 1
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if idx >= size {
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idx = 0
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}
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return idx
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}
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func (r *Ring) Push(val interface{}) bool {
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r.lock.Lock()
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defer r.lock.Unlock()
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if nextPointer(r.header, len(r.buffer)) == r.tail {
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return false
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}
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r.buffer[r.header] = val
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r.header = nextPointer(r.header, len(r.buffer))
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return true
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}
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func (r *Ring) Pop() interface{} {
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r.lock.Lock()
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defer r.lock.Unlock()
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if r.tail == r.header {
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return nil
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}
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ret := r.buffer[r.tail]
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r.buffer[r.tail] = nil
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r.tail = nextPointer(r.tail, len(r.buffer))
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return ret
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}
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func (r *Ring) Capacity() int {
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return len(r.buffer) - 1
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}
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func (r *Ring) Size() int {
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r.lock.Lock()
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defer r.lock.Unlock()
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if r.tail <= r.header {
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return r.header - r.tail
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} else {
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return len(r.buffer) - r.tail + r.header
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}
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}
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