float64: Generate with gen-atomicwrapper

Generate atomic.Float64 with gen-valuewrapper by wrapping atomic.Uint64,
using math.Float64bits and math.Float64frombits to pack and unpack
float64 to uint64.

float64.go

@@ -1,3 +1,5 @@
+// @generated Code generated by gen-atomicwrapper.
+
 // Copyright (c) 2020 Uber Technologies, Inc.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -23,70 +25,52 @@ package atomic
 import (
 	"encoding/json"
 	"math"
-	"strconv"
-	"sync/atomic"
 )
 
-// Float64 is an atomic wrapper around float64.
+// Float64 is an atomic type-safe wrapper for float64 values.
 type Float64 struct {
 	nocmp // disallow non-atomic comparison
 
-	v uint64
-}
-
-// NewFloat64 creates a Float64.
-func NewFloat64(f float64) *Float64 {
-	return &Float64{v: math.Float64bits(f)}
+	v Uint64
 }
 
-// Load atomically loads the wrapped value.
-func (f *Float64) Load() float64 {
-	return math.Float64frombits(atomic.LoadUint64(&f.v))
-}
+var _zeroFloat64 float64
 
-// Store atomically stores the passed value.
-func (f *Float64) Store(s float64) {
-	atomic.StoreUint64(&f.v, math.Float64bits(s))
+// NewFloat64 creates a new Float64.
+func NewFloat64(v float64) *Float64 {
+	x := &Float64{}
+	if v != _zeroFloat64 {
+		x.Store(v)
+	}
+	return x
 }
 
-// Add atomically adds to the wrapped float64 and returns the new value.
-func (f *Float64) Add(s float64) float64 {
-	for {
-		old := f.Load()
-		new := old + s
-		if f.CAS(old, new) {
-			return new
-		}
-	}
+// Load atomically loads the wrapped float64.
+func (x *Float64) Load() float64 {
+	return math.Float64frombits(x.v.Load())
 }
 
-// Sub atomically subtracts from the wrapped float64 and returns the new value.
-func (f *Float64) Sub(s float64) float64 {
-	return f.Add(-s)
+// Store atomically stores the passed float64.
+func (x *Float64) Store(v float64) {
+	x.v.Store(math.Float64bits(v))
 }
 
-// CAS is an atomic compare-and-swap.
-func (f *Float64) CAS(old, new float64) bool {
-	return atomic.CompareAndSwapUint64(&f.v, math.Float64bits(old), math.Float64bits(new))
+// CAS is an atomic compare-and-swap for float64 values.
+func (x *Float64) CAS(o, n float64) bool {
+	return x.v.CAS(math.Float64bits(o), math.Float64bits(n))
 }
 
 // MarshalJSON encodes the wrapped float64 into JSON.
-func (f *Float64) MarshalJSON() ([]byte, error) {
-	return json.Marshal(f.Load())
+func (x *Float64) MarshalJSON() ([]byte, error) {
+	return json.Marshal(x.Load())
 }
 
-// UnmarshalJSON decodes JSON into the wrapped float64.
-func (f *Float64) UnmarshalJSON(b []byte) error {
+// UnmarshalJSON decodes a float64 from JSON.
+func (x *Float64) UnmarshalJSON(b []byte) error {
 	var v float64
 	if err := json.Unmarshal(b, &v); err != nil {
 		return err
 	}
-	f.Store(v)
+	x.Store(v)
 	return nil
 }
-
-// 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)
-}

float64_ext.go

@@ -0,0 +1,47 @@
+// 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 "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
+
+// Add atomically adds to the wrapped float64 and returns the new value.
+func (f *Float64) Add(s float64) float64 {
+	for {
+		old := f.Load()
+		new := old + s
+		if f.CAS(old, new) {
+			return new
+		}
+	}
+}
+
+// Sub atomically subtracts from the wrapped float64 and returns the new value.
+func (f *Float64) Sub(s float64) float64 {
+	return f.Add(-s)
+}
+
+// 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)
+}