github.com/bytedance/gopkg@v0.0.0-20240514070511-01b2cbcf35e1/collection/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  				return
    36  			}
    37  			continue
    38  		}
    39  		return
    40  	}
    41  }
    42  
    43  func (f *bitflag) SetFalse(flags uint32) {
    44  	for {
    45  		old := atomic.LoadUint32(&f.data)
    46  		check := old & flags
    47  		if check != 0 {
    48  			// Flag is 1, need set it to 0.
    49  			n := old ^ check
    50  			if atomic.CompareAndSwapUint32(&f.data, old, n) {
    51  				return
    52  			}
    53  			continue
    54  		}
    55  		return
    56  	}
    57  }
    58  
    59  func (f *bitflag) Get(flag uint32) bool {
    60  	return (atomic.LoadUint32(&f.data) & flag) != 0
    61  }
    62  
    63  func (f *bitflag) MGet(check, expect uint32) bool {
    64  	return (atomic.LoadUint32(&f.data) & check) == expect
    65  }