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- // Copyright (c) 2020 Uber Technologies, Inc.
- //
- // Permission is hereby granted, free of charge, to any person obtaining a copy
- // of this software and associated documentation files (the "Software"), to deal
- // in the Software without restriction, including without limitation the rights
- // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- // copies of the Software, and to permit persons to whom the Software is
- // furnished to do so, subject to the following conditions:
- //
- // The above copyright notice and this permission notice shall be included in
- // all copies or substantial portions of the Software.
- //
- // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- // THE SOFTWARE.
- package atomic
- import (
- "math"
- "strconv"
- )
- //go:generate bin/gen-atomicwrapper -name=Float64 -type=float64 -wrapped=Uint64 -pack=math.Float64bits -unpack=math.Float64frombits -swap -json -imports math -file=float64.go
- // Add atomically adds to the wrapped float64 and returns the new value.
- func (f *Float64) Add(delta float64) float64 {
- for {
- old := f.Load()
- new := old + delta
- if f.CAS(old, new) {
- return new
- }
- }
- }
- // Sub atomically subtracts from the wrapped float64 and returns the new value.
- func (f *Float64) Sub(delta float64) float64 {
- return f.Add(-delta)
- }
- // CAS is an atomic compare-and-swap for float64 values.
- //
- // Note: CAS handles NaN incorrectly. NaN != NaN using Go's inbuilt operators
- // but CAS allows a stored NaN to compare equal to a passed in NaN.
- // This avoids typical CAS loops from blocking forever, e.g.,
- //
- // for {
- // old := atom.Load()
- // new = f(old)
- // if atom.CAS(old, new) {
- // break
- // }
- // }
- //
- // If CAS did not match NaN to match, then the above would loop forever.
- func (f *Float64) CAS(old, new float64) (swapped bool) {
- return f.v.CAS(math.Float64bits(old), math.Float64bits(new))
- }
- // String encodes the wrapped value as a string.
- func (f *Float64) String() string {
- // 'g' is the behavior for floats with %v.
- return strconv.FormatFloat(f.Load(), 'g', -1, 64)
- }
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