atomic_bits.go

     1  // Copyright 2023 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package quic
     6  
     7  import "sync/atomic"
     8  
     9  // atomicBits is an atomic uint32 that supports setting individual bits.
    10  type atomicBits[T ~uint32] struct {
    11  	bits atomic.Uint32
    12  }
    13  
    14  // set sets the bits in mask to the corresponding bits in v.
    15  // It returns the new value.
    16  func (a *atomicBits[T]) set(v, mask T) T {
    17  	if v&^mask != 0 {
    18  		panic("BUG: bits in v are not in mask")
    19  	}
    20  	for {
    21  		o := a.bits.Load()
    22  		n := (o &^ uint32(mask)) | uint32(v)
    23  		if a.bits.CompareAndSwap(o, n) {
    24  			return T(n)
    25  		}
    26  	}
    27  }
    28  
    29  func (a *atomicBits[T]) load() T {
    30  	return T(a.bits.Load())
    31  }
    32
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