You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
69 lines
2.4 KiB
69 lines
2.4 KiB
// 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) |
|
}
|
|
|