From aa33b26f680d12b135ad4944d47bf90c6d77d10a Mon Sep 17 00:00:00 2001 From: whoisix <35096485+whoisix@users.noreply.github.com> Date: Fri, 6 May 2022 16:18:21 +0800 Subject: [PATCH] Provide atomic type for float32 --- float32.go | 77 +++++++++++++++++++++++++++++++++++++++++++++++++ float32_ext.go | 69 ++++++++++++++++++++++++++++++++++++++++++++ float32_test.go | 72 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 218 insertions(+) create mode 100644 float32.go create mode 100644 float32_ext.go create mode 100644 float32_test.go diff --git a/float32.go b/float32.go new file mode 100644 index 0000000..5d535a6 --- /dev/null +++ b/float32.go @@ -0,0 +1,77 @@ +// @generated Code generated by gen-atomicwrapper. + +// Copyright (c) 2020-2022 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" +) + +// Float32 is an atomic type-safe wrapper for float32 values. +type Float32 struct { + _ nocmp // disallow non-atomic comparison + + v Uint32 +} + +var _zeroFloat32 float32 + +// NewFloat32 creates a new Float32. +func NewFloat32(val float32) *Float32 { + x := &Float32{} + if val != _zeroFloat32 { + x.Store(val) + } + return x +} + +// Load atomically loads the wrapped float32. +func (x *Float32) Load() float32 { + return math.Float32frombits(x.v.Load()) +} + +// Store atomically stores the passed float32. +func (x *Float32) Store(val float32) { + x.v.Store(math.Float32bits(val)) +} + +// Swap atomically stores the given float32 and returns the old +// value. +func (x *Float32) Swap(val float32) (old float32) { + return math.Float32frombits(x.v.Swap(math.Float32bits(val))) +} + +// MarshalJSON encodes the wrapped float32 into JSON. +func (x *Float32) MarshalJSON() ([]byte, error) { + return json.Marshal(x.Load()) +} + +// UnmarshalJSON decodes a float32 from JSON. +func (x *Float32) UnmarshalJSON(b []byte) error { + var v float32 + if err := json.Unmarshal(b, &v); err != nil { + return err + } + x.Store(v) + return nil +} diff --git a/float32_ext.go b/float32_ext.go new file mode 100644 index 0000000..ed47945 --- /dev/null +++ b/float32_ext.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 ( + "math" + "strconv" +) + +//go:generate bin/gen-atomicwrapper -name=Float32 -type=float32 -wrapped=Uint32 -pack=math.Float32bits -unpack=math.Float32frombits -swap -json -imports math -file=float32.go + +// Add atomically adds to the wrapped float32 and returns the new value. +func (f *Float32) Add(delta float32) float32 { + for { + old := f.Load() + new := old + delta + if f.CAS(old, new) { + return new + } + } +} + +// Sub atomically subtracts from the wrapped float32 and returns the new value. +func (f *Float32) Sub(delta float32) float32 { + return f.Add(-delta) +} + +// CAS is an atomic compare-and-swap for float32 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 *Float32) CAS(old, new float32) (swapped bool) { + return f.v.CAS(math.Float32bits(old), math.Float32bits(new)) +} + +// String encodes the wrapped value as a string. +func (f *Float32) String() string { + // 'g' is the behavior for floats with %v. + return strconv.FormatFloat(float64(f.Load()), 'g', -1, 32) +} diff --git a/float32_test.go b/float32_test.go new file mode 100644 index 0000000..c7ff35d --- /dev/null +++ b/float32_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" + + "github.com/stretchr/testify/assert" + "github.com/stretchr/testify/require" +) + +func TestFloat32(t *testing.T) { + atom := NewFloat32(4.2) + + require.Equal(t, float32(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, float32(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, float32(42.0), atom.Load(), "Store didn't set the correct value.") + require.Equal(t, float32(42.5), atom.Add(0.5), "Add didn't work.") + require.Equal(t, float32(42.0), atom.Sub(0.5), "Sub didn't work.") + + require.Equal(t, float32(42.0), atom.Swap(45.0), "Swap didn't return the old value.") + require.Equal(t, float32(45.0), atom.Load(), "Swap didn't set the correct value.") + + 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, float32(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", NewFloat32(42.5).String(), + "String() returned an unexpected value.") + }) +}