github.com/songzhibin97/gkit@v1.2.13/structure/skipmap/oparray.go (about) 1 // Copyright 2021 ByteDance Inc. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package skipmap 16 17 import ( 18 "sync/atomic" 19 "unsafe" 20 ) 21 22 const ( 23 op1 = 4 24 op2 = maxLevel - op1 25 ) 26 27 type optionalArray struct { 28 base [op1]unsafe.Pointer 29 extra *([op2]unsafe.Pointer) 30 } 31 32 func (a *optionalArray) load(i int) unsafe.Pointer { 33 if i < op1 { 34 return a.base[i] 35 } 36 return a.extra[i-op1] 37 } 38 39 func (a *optionalArray) store(i int, p unsafe.Pointer) { 40 if i < op1 { 41 a.base[i] = p 42 return 43 } 44 a.extra[i-op1] = p 45 } 46 47 func (a *optionalArray) atomicLoad(i int) unsafe.Pointer { 48 if i < op1 { 49 return atomic.LoadPointer(&a.base[i]) 50 } 51 return atomic.LoadPointer(&a.extra[i-op1]) 52 } 53 54 func (a *optionalArray) atomicStore(i int, p unsafe.Pointer) { 55 if i < op1 { 56 atomic.StorePointer(&a.base[i], p) 57 return 58 } 59 atomic.StorePointer(&a.extra[i-op1], p) 60 }