Separate files for each atomic type
As in #73, separate each atomic type into its own file to ease review of
transition to generated code.
After moving every atomic to its own file, the atomic.go file serves
only as documentation, so rename it to doc.go.
diff --git a/atomic.go b/atomic.go
deleted file mode 100644
index 8bdf5d7..0000000
--- a/atomic.go
+++ /dev/null
@@ -1,238 +0,0 @@
-// Copyright (c) 2016-2020 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 provides simple wrappers around numerics to enforce atomic
-// access.
-package atomic
-
-import (
- "encoding/json"
- "math"
- "strconv"
- "sync/atomic"
- "time"
-)
-
-// Bool is an atomic Boolean.
-type Bool struct {
- nocmp // disallow non-atomic comparison
-
- v uint32
-}
-
-// NewBool creates a Bool.
-func NewBool(initial bool) *Bool {
- return &Bool{v: boolToInt(initial)}
-}
-
-// Load atomically loads the Boolean.
-func (b *Bool) Load() bool {
- return truthy(atomic.LoadUint32(&b.v))
-}
-
-// CAS is an atomic compare-and-swap.
-func (b *Bool) CAS(old, new bool) bool {
- return atomic.CompareAndSwapUint32(&b.v, boolToInt(old), boolToInt(new))
-}
-
-// Store atomically stores the passed value.
-func (b *Bool) Store(new bool) {
- atomic.StoreUint32(&b.v, boolToInt(new))
-}
-
-// Swap sets the given value and returns the previous value.
-func (b *Bool) Swap(new bool) bool {
- return truthy(atomic.SwapUint32(&b.v, boolToInt(new)))
-}
-
-// Toggle atomically negates the Boolean and returns the previous value.
-func (b *Bool) Toggle() bool {
- for {
- old := b.Load()
- if b.CAS(old, !old) {
- return old
- }
- }
-}
-
-func truthy(n uint32) bool {
- return n == 1
-}
-
-func boolToInt(b bool) uint32 {
- if b {
- return 1
- }
- return 0
-}
-
-// MarshalJSON encodes the wrapped bool into JSON.
-func (b *Bool) MarshalJSON() ([]byte, error) {
- return json.Marshal(b.Load())
-}
-
-// UnmarshalJSON decodes JSON into the wrapped bool.
-func (b *Bool) UnmarshalJSON(t []byte) error {
- var v bool
- if err := json.Unmarshal(t, &v); err != nil {
- return err
- }
- b.Store(v)
- return nil
-}
-
-// String encodes the wrapped value as a string.
-func (b *Bool) String() string {
- return strconv.FormatBool(b.Load())
-}
-
-// Float64 is an atomic wrapper around float64.
-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)}
-}
-
-// Load atomically loads the wrapped value.
-func (f *Float64) Load() float64 {
- return math.Float64frombits(atomic.LoadUint64(&f.v))
-}
-
-// Store atomically stores the passed value.
-func (f *Float64) Store(s float64) {
- atomic.StoreUint64(&f.v, math.Float64bits(s))
-}
-
-// 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)
-}
-
-// 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))
-}
-
-// MarshalJSON encodes the wrapped float64 into JSON.
-func (f *Float64) MarshalJSON() ([]byte, error) {
- return json.Marshal(f.Load())
-}
-
-// UnmarshalJSON decodes JSON into the wrapped float64.
-func (f *Float64) UnmarshalJSON(b []byte) error {
- var v float64
- if err := json.Unmarshal(b, &v); err != nil {
- return err
- }
- f.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)
-}
-
-// Duration is an atomic wrapper around time.Duration
-// https://godoc.org/time#Duration
-type Duration struct {
- nocmp // disallow non-atomic comparison
-
- v Int64
-}
-
-// NewDuration creates a Duration.
-func NewDuration(d time.Duration) *Duration {
- return &Duration{v: *NewInt64(int64(d))}
-}
-
-// Load atomically loads the wrapped value.
-func (d *Duration) Load() time.Duration {
- return time.Duration(d.v.Load())
-}
-
-// Store atomically stores the passed value.
-func (d *Duration) Store(n time.Duration) {
- d.v.Store(int64(n))
-}
-
-// Add atomically adds to the wrapped time.Duration and returns the new value.
-func (d *Duration) Add(n time.Duration) time.Duration {
- return time.Duration(d.v.Add(int64(n)))
-}
-
-// Sub atomically subtracts from the wrapped time.Duration and returns the new value.
-func (d *Duration) Sub(n time.Duration) time.Duration {
- return time.Duration(d.v.Sub(int64(n)))
-}
-
-// Swap atomically swaps the wrapped time.Duration and returns the old value.
-func (d *Duration) Swap(n time.Duration) time.Duration {
- return time.Duration(d.v.Swap(int64(n)))
-}
-
-// CAS is an atomic compare-and-swap.
-func (d *Duration) CAS(old, new time.Duration) bool {
- return d.v.CAS(int64(old), int64(new))
-}
-
-// MarshalJSON encodes the wrapped time.Duration into JSON.
-func (d *Duration) MarshalJSON() ([]byte, error) {
- return json.Marshal(d.Load())
-}
-
-// UnmarshalJSON decodes JSON into the wrapped time.Duration.
-func (d *Duration) UnmarshalJSON(b []byte) error {
- var v time.Duration
- if err := json.Unmarshal(b, &v); err != nil {
- return err
- }
- d.Store(v)
- return nil
-}
-
-// String encodes the wrapped value as a string.
-func (d *Duration) String() string {
- return d.Load().String()
-}
-
-// Value shadows the type of the same name from sync/atomic
-// https://godoc.org/sync/atomic#Value
-type Value struct {
- nocmp // disallow non-atomic comparison
- atomic.Value
-}
diff --git a/atomic_test.go b/atomic_test.go
deleted file mode 100644
index cb3768e..0000000
--- a/atomic_test.go
+++ /dev/null
@@ -1,182 +0,0 @@
-// Copyright (c) 2016-2020 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 (
- "encoding/json"
- "testing"
- "time"
-
- "github.com/stretchr/testify/assert"
- "github.com/stretchr/testify/require"
-)
-
-func TestBool(t *testing.T) {
- atom := NewBool(false)
- require.False(t, atom.Toggle(), "Expected Toggle to return previous value.")
- require.True(t, atom.Toggle(), "Expected Toggle to return previous value.")
- require.False(t, atom.Toggle(), "Expected Toggle to return previous value.")
- require.True(t, atom.Load(), "Unexpected state after swap.")
-
- require.True(t, atom.CAS(true, true), "CAS should swap when old matches")
- require.True(t, atom.Load(), "CAS should have no effect")
- require.True(t, atom.CAS(true, false), "CAS should swap when old matches")
- require.False(t, atom.Load(), "CAS should have modified the value")
- require.False(t, atom.CAS(true, false), "CAS should fail on old mismatch")
- require.False(t, atom.Load(), "CAS should not have modified the value")
-
- atom.Store(false)
- require.False(t, atom.Load(), "Unexpected state after store.")
-
- prev := atom.Swap(false)
- require.False(t, prev, "Expected Swap to return previous value.")
-
- prev = atom.Swap(true)
- require.False(t, prev, "Expected Swap to return previous value.")
-
- t.Run("JSON/Marshal", func(t *testing.T) {
- atom.Store(true)
- bytes, err := json.Marshal(atom)
- require.NoError(t, err, "json.Marshal errored unexpectedly.")
- require.Equal(t, []byte("true"), bytes, "json.Marshal encoded the wrong bytes.")
- })
-
- t.Run("JSON/Unmarshal", func(t *testing.T) {
- err := json.Unmarshal([]byte("false"), &atom)
- require.NoError(t, err, "json.Unmarshal errored unexpectedly.")
- require.False(t, atom.Load(), "json.Unmarshal didn't set the correct value.")
- })
-
- t.Run("JSON/Unmarshal/Error", func(t *testing.T) {
- err := json.Unmarshal([]byte("42"), &atom)
- require.Error(t, err, "json.Unmarshal didn't error as expected.")
- assertErrorJSONUnmarshalType(t, err,
- "json.Unmarshal failed with unexpected error %v, want UnmarshalTypeError.", err)
- })
-
- t.Run("String", func(t *testing.T) {
- t.Run("true", func(t *testing.T) {
- assert.Equal(t, "true", NewBool(true).String(),
- "String() returned an unexpected value.")
- })
-
- t.Run("false", func(t *testing.T) {
- var b Bool
- assert.Equal(t, "false", b.String(),
- "String() returned an unexpected value.")
- })
- })
-}
-
-func TestFloat64(t *testing.T) {
- atom := NewFloat64(4.2)
-
- require.Equal(t, float64(4.2), atom.Load(), "Load didn't work.")
-
- require.True(t, atom.CAS(4.2, 0.5), "CAS didn't report a swap.")
- require.Equal(t, float64(0.5), atom.Load(), "CAS didn't set the correct value.")
- require.False(t, atom.CAS(0.0, 1.5), "CAS reported a swap.")
-
- atom.Store(42.0)
- require.Equal(t, float64(42.0), atom.Load(), "Store didn't set the correct value.")
- require.Equal(t, float64(42.5), atom.Add(0.5), "Add didn't work.")
- require.Equal(t, float64(42.0), atom.Sub(0.5), "Sub didn't work.")
-
- t.Run("JSON/Marshal", func(t *testing.T) {
- atom.Store(42.5)
- bytes, err := json.Marshal(atom)
- require.NoError(t, err, "json.Marshal errored unexpectedly.")
- require.Equal(t, []byte("42.5"), bytes, "json.Marshal encoded the wrong bytes.")
- })
-
- t.Run("JSON/Unmarshal", func(t *testing.T) {
- err := json.Unmarshal([]byte("40.5"), &atom)
- require.NoError(t, err, "json.Unmarshal errored unexpectedly.")
- require.Equal(t, float64(40.5), atom.Load(), "json.Unmarshal didn't set the correct value.")
- })
-
- t.Run("JSON/Unmarshal/Error", func(t *testing.T) {
- err := json.Unmarshal([]byte("\"40.5\""), &atom)
- require.Error(t, err, "json.Unmarshal didn't error as expected.")
- assertErrorJSONUnmarshalType(t, err,
- "json.Unmarshal failed with unexpected error %v, want UnmarshalTypeError.", err)
- })
-
- t.Run("String", func(t *testing.T) {
- assert.Equal(t, "42.5", NewFloat64(42.5).String(),
- "String() returned an unexpected value.")
- })
-}
-
-func TestDuration(t *testing.T) {
- atom := NewDuration(5 * time.Minute)
-
- require.Equal(t, 5*time.Minute, atom.Load(), "Load didn't work.")
- require.Equal(t, 6*time.Minute, atom.Add(time.Minute), "Add didn't work.")
- require.Equal(t, 4*time.Minute, atom.Sub(2*time.Minute), "Sub didn't work.")
-
- require.True(t, atom.CAS(4*time.Minute, time.Minute), "CAS didn't report a swap.")
- require.Equal(t, time.Minute, atom.Load(), "CAS didn't set the correct value.")
-
- require.Equal(t, time.Minute, atom.Swap(2*time.Minute), "Swap didn't return the old value.")
- require.Equal(t, 2*time.Minute, atom.Load(), "Swap didn't set the correct value.")
-
- atom.Store(10 * time.Minute)
- require.Equal(t, 10*time.Minute, atom.Load(), "Store didn't set the correct value.")
-
- t.Run("JSON/Marshal", func(t *testing.T) {
- atom.Store(time.Second)
- bytes, err := json.Marshal(atom)
- require.NoError(t, err, "json.Marshal errored unexpectedly.")
- require.Equal(t, []byte("1000000000"), bytes, "json.Marshal encoded the wrong bytes.")
- })
-
- t.Run("JSON/Unmarshal", func(t *testing.T) {
- err := json.Unmarshal([]byte("1000000000"), &atom)
- require.NoError(t, err, "json.Unmarshal errored unexpectedly.")
- require.Equal(t, time.Second, atom.Load(), "json.Unmarshal didn't set the correct value.")
- })
-
- t.Run("JSON/Unmarshal/Error", func(t *testing.T) {
- err := json.Unmarshal([]byte("\"1000000000\""), &atom)
- require.Error(t, err, "json.Unmarshal didn't error as expected.")
- assertErrorJSONUnmarshalType(t, err,
- "json.Unmarshal failed with unexpected error %v, want UnmarshalTypeError.", err)
- })
-
- t.Run("String", func(t *testing.T) {
- assert.Equal(t, "42s", NewDuration(42*time.Second).String(),
- "String() returned an unexpected value.")
- })
-}
-
-func TestValue(t *testing.T) {
- var v Value
- assert.Nil(t, v.Load(), "initial Value is not nil")
-
- v.Store(42)
- assert.Equal(t, 42, v.Load())
-
- v.Store(84)
- assert.Equal(t, 84, v.Load())
-
- assert.Panics(t, func() { v.Store("foo") })
-}
diff --git a/bool.go b/bool.go
new file mode 100644
index 0000000..b22b97d
--- /dev/null
+++ b/bool.go
@@ -0,0 +1,100 @@
+// 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 (
+ "encoding/json"
+ "strconv"
+ "sync/atomic"
+)
+
+// Bool is an atomic Boolean.
+type Bool struct {
+ nocmp // disallow non-atomic comparison
+
+ v uint32
+}
+
+// NewBool creates a Bool.
+func NewBool(initial bool) *Bool {
+ return &Bool{v: boolToInt(initial)}
+}
+
+// Load atomically loads the Boolean.
+func (b *Bool) Load() bool {
+ return truthy(atomic.LoadUint32(&b.v))
+}
+
+// CAS is an atomic compare-and-swap.
+func (b *Bool) CAS(old, new bool) bool {
+ return atomic.CompareAndSwapUint32(&b.v, boolToInt(old), boolToInt(new))
+}
+
+// Store atomically stores the passed value.
+func (b *Bool) Store(new bool) {
+ atomic.StoreUint32(&b.v, boolToInt(new))
+}
+
+// Swap sets the given value and returns the previous value.
+func (b *Bool) Swap(new bool) bool {
+ return truthy(atomic.SwapUint32(&b.v, boolToInt(new)))
+}
+
+// Toggle atomically negates the Boolean and returns the previous value.
+func (b *Bool) Toggle() bool {
+ for {
+ old := b.Load()
+ if b.CAS(old, !old) {
+ return old
+ }
+ }
+}
+
+func truthy(n uint32) bool {
+ return n == 1
+}
+
+func boolToInt(b bool) uint32 {
+ if b {
+ return 1
+ }
+ return 0
+}
+
+// MarshalJSON encodes the wrapped bool into JSON.
+func (b *Bool) MarshalJSON() ([]byte, error) {
+ return json.Marshal(b.Load())
+}
+
+// UnmarshalJSON decodes JSON into the wrapped bool.
+func (b *Bool) UnmarshalJSON(t []byte) error {
+ var v bool
+ if err := json.Unmarshal(t, &v); err != nil {
+ return err
+ }
+ b.Store(v)
+ return nil
+}
+
+// String encodes the wrapped value as a string.
+func (b *Bool) String() string {
+ return strconv.FormatBool(b.Load())
+}
diff --git a/bool_test.go b/bool_test.go
new file mode 100644
index 0000000..bcba01d
--- /dev/null
+++ b/bool_test.go
@@ -0,0 +1,86 @@
+// 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 (
+ "encoding/json"
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+ "github.com/stretchr/testify/require"
+)
+
+func TestBool(t *testing.T) {
+ atom := NewBool(false)
+ require.False(t, atom.Toggle(), "Expected Toggle to return previous value.")
+ require.True(t, atom.Toggle(), "Expected Toggle to return previous value.")
+ require.False(t, atom.Toggle(), "Expected Toggle to return previous value.")
+ require.True(t, atom.Load(), "Unexpected state after swap.")
+
+ require.True(t, atom.CAS(true, true), "CAS should swap when old matches")
+ require.True(t, atom.Load(), "CAS should have no effect")
+ require.True(t, atom.CAS(true, false), "CAS should swap when old matches")
+ require.False(t, atom.Load(), "CAS should have modified the value")
+ require.False(t, atom.CAS(true, false), "CAS should fail on old mismatch")
+ require.False(t, atom.Load(), "CAS should not have modified the value")
+
+ atom.Store(false)
+ require.False(t, atom.Load(), "Unexpected state after store.")
+
+ prev := atom.Swap(false)
+ require.False(t, prev, "Expected Swap to return previous value.")
+
+ prev = atom.Swap(true)
+ require.False(t, prev, "Expected Swap to return previous value.")
+
+ t.Run("JSON/Marshal", func(t *testing.T) {
+ atom.Store(true)
+ bytes, err := json.Marshal(atom)
+ require.NoError(t, err, "json.Marshal errored unexpectedly.")
+ require.Equal(t, []byte("true"), bytes, "json.Marshal encoded the wrong bytes.")
+ })
+
+ t.Run("JSON/Unmarshal", func(t *testing.T) {
+ err := json.Unmarshal([]byte("false"), &atom)
+ require.NoError(t, err, "json.Unmarshal errored unexpectedly.")
+ require.False(t, atom.Load(), "json.Unmarshal didn't set the correct value.")
+ })
+
+ t.Run("JSON/Unmarshal/Error", func(t *testing.T) {
+ err := json.Unmarshal([]byte("42"), &atom)
+ require.Error(t, err, "json.Unmarshal didn't error as expected.")
+ assertErrorJSONUnmarshalType(t, err,
+ "json.Unmarshal failed with unexpected error %v, want UnmarshalTypeError.", err)
+ })
+
+ t.Run("String", func(t *testing.T) {
+ t.Run("true", func(t *testing.T) {
+ assert.Equal(t, "true", NewBool(true).String(),
+ "String() returned an unexpected value.")
+ })
+
+ t.Run("false", func(t *testing.T) {
+ var b Bool
+ assert.Equal(t, "false", b.String(),
+ "String() returned an unexpected value.")
+ })
+ })
+}
diff --git a/doc.go b/doc.go
new file mode 100644
index 0000000..ae7390e
--- /dev/null
+++ b/doc.go
@@ -0,0 +1,23 @@
+// 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 provides simple wrappers around numerics to enforce atomic
+// access.
+package atomic
diff --git a/duration.go b/duration.go
new file mode 100644
index 0000000..92d65f9
--- /dev/null
+++ b/duration.go
@@ -0,0 +1,89 @@
+// 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 (
+ "encoding/json"
+ "time"
+)
+
+// Duration is an atomic wrapper around time.Duration
+// https://godoc.org/time#Duration
+type Duration struct {
+ nocmp // disallow non-atomic comparison
+
+ v Int64
+}
+
+// NewDuration creates a Duration.
+func NewDuration(d time.Duration) *Duration {
+ return &Duration{v: *NewInt64(int64(d))}
+}
+
+// Load atomically loads the wrapped value.
+func (d *Duration) Load() time.Duration {
+ return time.Duration(d.v.Load())
+}
+
+// Store atomically stores the passed value.
+func (d *Duration) Store(n time.Duration) {
+ d.v.Store(int64(n))
+}
+
+// Add atomically adds to the wrapped time.Duration and returns the new value.
+func (d *Duration) Add(n time.Duration) time.Duration {
+ return time.Duration(d.v.Add(int64(n)))
+}
+
+// Sub atomically subtracts from the wrapped time.Duration and returns the new value.
+func (d *Duration) Sub(n time.Duration) time.Duration {
+ return time.Duration(d.v.Sub(int64(n)))
+}
+
+// Swap atomically swaps the wrapped time.Duration and returns the old value.
+func (d *Duration) Swap(n time.Duration) time.Duration {
+ return time.Duration(d.v.Swap(int64(n)))
+}
+
+// CAS is an atomic compare-and-swap.
+func (d *Duration) CAS(old, new time.Duration) bool {
+ return d.v.CAS(int64(old), int64(new))
+}
+
+// MarshalJSON encodes the wrapped time.Duration into JSON.
+func (d *Duration) MarshalJSON() ([]byte, error) {
+ return json.Marshal(d.Load())
+}
+
+// UnmarshalJSON decodes JSON into the wrapped time.Duration.
+func (d *Duration) UnmarshalJSON(b []byte) error {
+ var v time.Duration
+ if err := json.Unmarshal(b, &v); err != nil {
+ return err
+ }
+ d.Store(v)
+ return nil
+}
+
+// String encodes the wrapped value as a string.
+func (d *Duration) String() string {
+ return d.Load().String()
+}
diff --git a/duration_test.go b/duration_test.go
new file mode 100644
index 0000000..bc5cea5
--- /dev/null
+++ b/duration_test.go
@@ -0,0 +1,72 @@
+// 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 (
+ "encoding/json"
+ "testing"
+ "time"
+
+ "github.com/stretchr/testify/assert"
+ "github.com/stretchr/testify/require"
+)
+
+func TestDuration(t *testing.T) {
+ atom := NewDuration(5 * time.Minute)
+
+ require.Equal(t, 5*time.Minute, atom.Load(), "Load didn't work.")
+ require.Equal(t, 6*time.Minute, atom.Add(time.Minute), "Add didn't work.")
+ require.Equal(t, 4*time.Minute, atom.Sub(2*time.Minute), "Sub didn't work.")
+
+ require.True(t, atom.CAS(4*time.Minute, time.Minute), "CAS didn't report a swap.")
+ require.Equal(t, time.Minute, atom.Load(), "CAS didn't set the correct value.")
+
+ require.Equal(t, time.Minute, atom.Swap(2*time.Minute), "Swap didn't return the old value.")
+ require.Equal(t, 2*time.Minute, atom.Load(), "Swap didn't set the correct value.")
+
+ atom.Store(10 * time.Minute)
+ require.Equal(t, 10*time.Minute, atom.Load(), "Store didn't set the correct value.")
+
+ t.Run("JSON/Marshal", func(t *testing.T) {
+ atom.Store(time.Second)
+ bytes, err := json.Marshal(atom)
+ require.NoError(t, err, "json.Marshal errored unexpectedly.")
+ require.Equal(t, []byte("1000000000"), bytes, "json.Marshal encoded the wrong bytes.")
+ })
+
+ t.Run("JSON/Unmarshal", func(t *testing.T) {
+ err := json.Unmarshal([]byte("1000000000"), &atom)
+ require.NoError(t, err, "json.Unmarshal errored unexpectedly.")
+ require.Equal(t, time.Second, atom.Load(), "json.Unmarshal didn't set the correct value.")
+ })
+
+ t.Run("JSON/Unmarshal/Error", func(t *testing.T) {
+ err := json.Unmarshal([]byte("\"1000000000\""), &atom)
+ require.Error(t, err, "json.Unmarshal didn't error as expected.")
+ assertErrorJSONUnmarshalType(t, err,
+ "json.Unmarshal failed with unexpected error %v, want UnmarshalTypeError.", err)
+ })
+
+ t.Run("String", func(t *testing.T) {
+ assert.Equal(t, "42s", NewDuration(42*time.Second).String(),
+ "String() returned an unexpected value.")
+ })
+}
diff --git a/float64.go b/float64.go
new file mode 100644
index 0000000..fd9e250
--- /dev/null
+++ b/float64.go
@@ -0,0 +1,92 @@
+// 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 (
+ "encoding/json"
+ "math"
+ "strconv"
+ "sync/atomic"
+)
+
+// Float64 is an atomic wrapper around float64.
+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)}
+}
+
+// Load atomically loads the wrapped value.
+func (f *Float64) Load() float64 {
+ return math.Float64frombits(atomic.LoadUint64(&f.v))
+}
+
+// Store atomically stores the passed value.
+func (f *Float64) Store(s float64) {
+ atomic.StoreUint64(&f.v, math.Float64bits(s))
+}
+
+// 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)
+}
+
+// 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))
+}
+
+// MarshalJSON encodes the wrapped float64 into JSON.
+func (f *Float64) MarshalJSON() ([]byte, error) {
+ return json.Marshal(f.Load())
+}
+
+// UnmarshalJSON decodes JSON into the wrapped float64.
+func (f *Float64) UnmarshalJSON(b []byte) error {
+ var v float64
+ if err := json.Unmarshal(b, &v); err != nil {
+ return err
+ }
+ f.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)
+}
diff --git a/float64_test.go b/float64_test.go
new file mode 100644
index 0000000..bc04e77
--- /dev/null
+++ b/float64_test.go
@@ -0,0 +1,69 @@
+// 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 (
+ "encoding/json"
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+ "github.com/stretchr/testify/require"
+)
+
+func TestFloat64(t *testing.T) {
+ atom := NewFloat64(4.2)
+
+ require.Equal(t, float64(4.2), atom.Load(), "Load didn't work.")
+
+ require.True(t, atom.CAS(4.2, 0.5), "CAS didn't report a swap.")
+ require.Equal(t, float64(0.5), atom.Load(), "CAS didn't set the correct value.")
+ require.False(t, atom.CAS(0.0, 1.5), "CAS reported a swap.")
+
+ atom.Store(42.0)
+ require.Equal(t, float64(42.0), atom.Load(), "Store didn't set the correct value.")
+ require.Equal(t, float64(42.5), atom.Add(0.5), "Add didn't work.")
+ require.Equal(t, float64(42.0), atom.Sub(0.5), "Sub didn't work.")
+
+ t.Run("JSON/Marshal", func(t *testing.T) {
+ atom.Store(42.5)
+ bytes, err := json.Marshal(atom)
+ require.NoError(t, err, "json.Marshal errored unexpectedly.")
+ require.Equal(t, []byte("42.5"), bytes, "json.Marshal encoded the wrong bytes.")
+ })
+
+ t.Run("JSON/Unmarshal", func(t *testing.T) {
+ err := json.Unmarshal([]byte("40.5"), &atom)
+ require.NoError(t, err, "json.Unmarshal errored unexpectedly.")
+ require.Equal(t, float64(40.5), atom.Load(), "json.Unmarshal didn't set the correct value.")
+ })
+
+ t.Run("JSON/Unmarshal/Error", func(t *testing.T) {
+ err := json.Unmarshal([]byte("\"40.5\""), &atom)
+ require.Error(t, err, "json.Unmarshal didn't error as expected.")
+ assertErrorJSONUnmarshalType(t, err,
+ "json.Unmarshal failed with unexpected error %v, want UnmarshalTypeError.", err)
+ })
+
+ t.Run("String", func(t *testing.T) {
+ assert.Equal(t, "42.5", NewFloat64(42.5).String(),
+ "String() returned an unexpected value.")
+ })
+}
diff --git a/value.go b/value.go
new file mode 100644
index 0000000..5c32903
--- /dev/null
+++ b/value.go
@@ -0,0 +1,30 @@
+// 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 "sync/atomic"
+
+// Value shadows the type of the same name from sync/atomic
+// https://godoc.org/sync/atomic#Value
+type Value struct {
+ nocmp // disallow non-atomic comparison
+ atomic.Value
+}
diff --git a/value_test.go b/value_test.go
new file mode 100644
index 0000000..bb9f301
--- /dev/null
+++ b/value_test.go
@@ -0,0 +1,40 @@
+// 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 (
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+)
+
+func TestValue(t *testing.T) {
+ var v Value
+ assert.Nil(t, v.Load(), "initial Value is not nil")
+
+ v.Store(42)
+ assert.Equal(t, 42, v.Load())
+
+ v.Store(84)
+ assert.Equal(t, 84, v.Load())
+
+ assert.Panics(t, func() { v.Store("foo") })
+}
