github.com/MerlinKodo/gvisor@v0.0.0-20231110090155-957f62ecf90e/pkg/atomicbitops/bool.go (about)

     1  // Copyright 2022 The gVisor Authors.
     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 atomicbitops
    16  
    17  import "sync/atomic"
    18  
    19  // Bool is an atomic Boolean.
    20  //
    21  // It is implemented by a Uint32, with value 0 indicating false, and 1
    22  // indicating true.
    23  //
    24  // +stateify savable
    25  type Bool struct {
    26  	Uint32
    27  }
    28  
    29  // FromBool returns an Bool initialized to value val.
    30  //
    31  //go:nosplit
    32  func FromBool(val bool) Bool {
    33  	var u uint32
    34  	if val {
    35  		u = 1
    36  	}
    37  	return Bool{
    38  		Uint32{
    39  			value: u,
    40  		},
    41  	}
    42  }
    43  
    44  // Load is analogous to atomic.LoadBool, if such a thing existed.
    45  //
    46  //go:nosplit
    47  func (b *Bool) Load() bool {
    48  	return atomic.LoadUint32(&b.value) == 1
    49  }
    50  
    51  // Store is analogous to atomic.StoreBool, if such a thing existed.
    52  //
    53  //go:nosplit
    54  func (b *Bool) Store(val bool) {
    55  	var u uint32
    56  	if val {
    57  		u = 1
    58  	}
    59  	atomic.StoreUint32(&b.value, u)
    60  }
    61  
    62  // Swap is analogous to atomic.SwapBool, if such a thing existed.
    63  //
    64  //go:nosplit
    65  func (b *Bool) Swap(val bool) bool {
    66  	var u uint32
    67  	if val {
    68  		u = 1
    69  	}
    70  	return atomic.SwapUint32(&b.value, u) == 1
    71  }