diff options
Diffstat (limited to 'vendor/go.uber.org/atomic/float64_ext.go')
| -rw-r--r-- | vendor/go.uber.org/atomic/float64_ext.go | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/vendor/go.uber.org/atomic/float64_ext.go b/vendor/go.uber.org/atomic/float64_ext.go index 927b1add..df36b010 100644 --- a/vendor/go.uber.org/atomic/float64_ext.go +++ b/vendor/go.uber.org/atomic/float64_ext.go @@ -20,15 +20,18 @@ package atomic -import "strconv" +import ( + "math" + "strconv" +) -//go:generate bin/gen-atomicwrapper -name=Float64 -type=float64 -wrapped=Uint64 -pack=math.Float64bits -unpack=math.Float64frombits -cas -json -imports math -file=float64.go +//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(s float64) float64 { +func (f *Float64) Add(delta float64) float64 { for { old := f.Load() - new := old + s + new := old + delta if f.CAS(old, new) { return new } @@ -36,8 +39,27 @@ func (f *Float64) Add(s float64) float64 { } // Sub atomically subtracts from the wrapped float64 and returns the new value. -func (f *Float64) Sub(s float64) float64 { - return f.Add(-s) +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. |