github.com/songzhibin97/gkit@v1.2.13/structure/skipset/flag.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 skipset
    16  
    17  import "sync/atomic"
    18  
    19  const (
    20  	fullyLinked = 1 << iota
    21  	marked
    22  )
    23  
    24  type bitflag struct {
    25  	data uint32
    26  }
    27  
    28  func (f *bitflag) SetTrue(flags uint32) {
    29  	for {
    30  		old := atomic.LoadUint32(&f.data)
    31  		if old&flags != flags {
    32  			// Flag is 0, need set it to 1.
    33  			n := old | flags
    34  			if !atomic.CompareAndSwapUint32(&f.data, old, n) {
    35  				continue
    36  			}
    37  		}
    38  		return
    39  	}
    40  }
    41  
    42  func (f *bitflag) SetFalse(flags uint32) {
    43  	for {
    44  		old := atomic.LoadUint32(&f.data)
    45  		check := old & flags
    46  		if check != 0 {
    47  			// Flag is 1, need set it to 0.
    48  			n := old ^ check
    49  			if !atomic.CompareAndSwapUint32(&f.data, old, n) {
    50  				continue
    51  			}
    52  		}
    53  		return
    54  	}
    55  }
    56  
    57  func (f *bitflag) Get(flag uint32) bool {
    58  	return (atomic.LoadUint32(&f.data) & flag) != 0
    59  }
    60  
    61  func (f *bitflag) MGet(check, expect uint32) bool {
    62  	return (atomic.LoadUint32(&f.data) & check) == expect
    63  }