mirror of
https://github.com/NotAShelf/catApi.git
synced 2024-11-23 07:50:43 +00:00
70 lines
2.4 KiB
Go
70 lines
2.4 KiB
Go
// 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)
|
|
}
|