/
oparray.go
60 lines (52 loc) · 1.31 KB
/
oparray.go
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// Copyright 2021 ByteDance Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package skipmap
import (
"sync/atomic"
"unsafe"
)
const (
op1 = 4
op2 = maxLevel - op1
)
type optionalArray struct {
base [op1]unsafe.Pointer
extra *([op2]unsafe.Pointer)
}
func (a *optionalArray) load(i int) unsafe.Pointer {
if i < op1 {
return a.base[i]
}
return a.extra[i-op1]
}
func (a *optionalArray) store(i int, p unsafe.Pointer) {
if i < op1 {
a.base[i] = p
return
}
a.extra[i-op1] = p
}
func (a *optionalArray) atomicLoad(i int) unsafe.Pointer {
if i < op1 {
return atomic.LoadPointer(&a.base[i])
}
return atomic.LoadPointer(&a.extra[i-op1])
}
func (a *optionalArray) atomicStore(i int, p unsafe.Pointer) {
if i < op1 {
atomic.StorePointer(&a.base[i], p)
return
}
atomic.StorePointer(&a.extra[i-op1], p)
}