Revert "Merge pull request #3 from barryz/add_flip_method"

Due to a regression to `SetToIf` introduced by `Toggle`

This reverts commit d91eb651d5, reversing
changes made to 9b9efcf221.

README.md

@@ -20,7 +20,6 @@ cond.UnSet()            // Sets to false
 cond.IsNotSet()         // Returns true
 cond.SetTo(any)         // Sets to whatever you want
 cond.SetToIf(new, old)  // Sets to `new` only if the Boolean matches the `old`, returns whether succeeded
-cond.Toggle()           // Inverts the boolean then returns the value before inverting
 
 
 // embedding
@@ -29,33 +28,27 @@ type Foo struct {
 }
 ```
 
-## Benchmark
+## Benchmark:
 
-- Go 1.14.3
-- Linux 4.19.0
+- Go 1.6.2
+- OS X 10.11.4
+- Intel CPU (to be specified)
 
-```bash
-goos: linux
-goarch: amd64
 
+```
 # Read
-BenchmarkMutexRead-4          	86662128	        14.2 ns/op
-BenchmarkAtomicValueRead-4    	1000000000	         0.755 ns/op
-BenchmarkAtomicBoolRead-4     	1000000000	         0.720 ns/op  # <--- This package
-
+BenchmarkMutexRead-4       	100000000	        21.0 ns/op
+BenchmarkAtomicValueRead-4 	200000000	         6.30 ns/op
+BenchmarkAtomicBoolRead-4  	300000000	         4.21 ns/op  # <--- This package
 
 # Write
-BenchmarkMutexWrite-4         	76237544	        13.6 ns/op
-BenchmarkAtomicValueWrite-4   	79471124	        14.9 ns/op
-BenchmarkAtomicBoolWrite-4    	178218270	         6.73 ns/op  # <--- This package
+BenchmarkMutexWrite-4      	100000000	        21.6 ns/op
+BenchmarkAtomicValueWrite-4	 30000000	        43.4 ns/op
+BenchmarkAtomicBoolWrite-4 	200000000	         9.87 ns/op  # <--- This package
 
 # CAS
-BenchmarkMutexCAS-4           	29416574	        34.7 ns/op
-BenchmarkAtomicBoolCAS-4      	171900002	         7.14 ns/op  # <--- This package
-
-# Toggle
-BenchmarkMutexToggle-4        	35212117	        34.5 ns/op
-BenchmarkAtomicBoolToggle-4   	169871972	         7.02 ns/op  # <--- This package
+BenchmarkMutexCAS-4        	 30000000	        44.9 ns/op
+BenchmarkAtomicBoolCAS-4   	100000000	        11.7 ns/op   # <--- This package
 ```
 
 ## Special thanks to contributors

bool.go

@@ -38,7 +38,7 @@ func (ab *AtomicBool) UnSet() {
 
 // IsSet returns whether the Boolean is true.
 func (ab *AtomicBool) IsSet() bool {
-	return atomic.LoadInt32((*int32)(ab))&1 == 1
+	return atomic.LoadInt32((*int32)(ab)) == 1
 }
 
 // IsNotSet returns whether the Boolean is false.
@@ -55,11 +55,6 @@ func (ab *AtomicBool) SetTo(yes bool) {
 	}
 }
 
-// Toggle inverts the Boolean then returns the value before inverting.
-func (ab *AtomicBool) Toggle() bool {
-	return atomic.AddInt32((*int32)(ab), 1)&1 == 0
-}
-
 // SetToIf sets the Boolean to new only if the Boolean matches the old.
 // Returns whether the set was done.
 func (ab *AtomicBool) SetToIf(old, new bool) (set bool) {

bool_test.go

@@ -2,7 +2,6 @@ package abool
 
 import (
 	"encoding/json"
-	"math"
 	"sync"
 	"sync/atomic"
 	"testing"
@@ -73,78 +72,10 @@ func TestSetTo(t *testing.T) {
 	}
 }
 
-func TestToggle(t *testing.T) {
-	t.Parallel()
-	v := New()
-
-	_ = v.Toggle()
-	if !v.IsSet() {
-		t.Fatal("AtomicBool.Toggle() to true failed")
-	}
-
-	prev := v.Toggle()
-	if v.IsSet() == prev {
-		t.Fatal("AtomicBool.Toggle() to false failed")
-	}
-}
-
-func TestToogleMultipleTimes(t *testing.T) {
-	t.Parallel()
-
-	v := New()
-	pre := !v.IsSet()
-	for i := 0; i < 100; i++ {
-		v.SetTo(false)
-		for j := 0; j < i; j++ {
-			pre = v.Toggle()
-		}
-
-		expected := i%2 != 0
-		if v.IsSet() != expected {
-			t.Fatalf("AtomicBool.Toogle() doesn't work after %d calls, expected: %v, got %v", i, expected, v.IsSet())
-		}
-
-		if pre == v.IsSet() {
-			t.Fatalf("AtomicBool.Toogle() returned wrong value at the %dth calls, expected: %v, got %v", i, !v.IsSet(), pre)
-		}
-	}
-}
-
-func TestToogleAfterOverflow(t *testing.T) {
-	t.Parallel()
-
-	var value int32 = math.MaxInt32
-	v := (*AtomicBool)(&value)
-
-	valueBeforeToggle := *(*int32)(v)
-
-	// test first toggle after overflow
-	v.Toggle()
-	expected := math.MaxInt32%2 == 0
-	if v.IsSet() != expected {
-		t.Fatalf("AtomicBool.Toogle() doesn't work after overflow, expected: %v, got %v", expected, v.IsSet())
-	}
-
-	// make sure overflow happened
-	var valueAfterToggle int32 = *(*int32)(v)
-	if valueAfterToggle >= valueBeforeToggle {
-		t.Fatalf("Overflow does not happen as expected, before %d, after: %d", valueBeforeToggle, valueAfterToggle)
-	}
-
-	// test second toggle after overflow
-	v.Toggle()
-	expected = !expected
-	if v.IsSet() != expected {
-		t.Fatalf("AtomicBool.Toogle() doesn't work after the second call after overflow, expected: %v, got %v", expected, v.IsSet())
-	}
-}
-
 func TestRace(t *testing.T) {
-	t.Parallel()
-
 	repeat := 10000
 	var wg sync.WaitGroup
-	wg.Add(repeat * 4)
+	wg.Add(repeat * 3)
 	v := New()
 
 	// Writer
@@ -170,15 +101,6 @@ func TestRace(t *testing.T) {
 			wg.Done()
 		}
 	}()
-
-	// Reader And Writer
-	go func() {
-		for i := 0; i < repeat; i++ {
-			v.Toggle()
-			wg.Done()
-		}
-	}()
-
 	wg.Wait()
 }
 
@@ -257,7 +179,6 @@ func ExampleAtomicBool() {
 	cond.IsNotSet()        // Returns true
 	cond.SetTo(any)        // Sets to whatever you want
 	cond.SetToIf(new, old) // Sets to `new` only if the Boolean matches the `old`, returns whether succeeded
-	cond.Toggle()          // Inverts the boolean then returns the value before inverting
 }
 
 // Benchmark Read
@@ -342,24 +263,3 @@ func BenchmarkAtomicBoolCAS(b *testing.B) {
 		v.SetToIf(false, true)
 	}
 }
-
-// Benchmark toggle
-
-func BenchmarkMutexToggle(b *testing.B) {
-	var m sync.RWMutex
-	var v bool
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		m.Lock()
-		v = !v
-		m.Unlock()
-	}
-}
-
-func BenchmarkAtomicBoolToggle(b *testing.B) {
-	v := New()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		v.Toggle()
-	}
-}