atomically negates boolean value with Toggle method

README.md

@@ -18,7 +18,7 @@ cond.IsSet()               // Returns true
 cond.UnSet()               // Set to false
 cond.SetTo(true)           // Set to whatever you want
 cond.SetToIf(false, true)  // Set to true if it is false, returns false(not set)
-cond.Flip()                // Flip toggles the value(replaces with its opposite value)
+cond.Toggle() bool         // Toggle the boolean value atomically and returns the previous value.
 
 
 // embedding
@@ -47,8 +47,8 @@ BenchmarkAtomicBoolWrite-4 	200000000	         9.87 ns/op  # <--- This package
 BenchmarkMutexCAS-4        	 30000000	         44.9 ns/op
 BenchmarkAtomicBoolCAS-4   	100000000	         11.7 ns/op  # <--- This package
 
-# Flip
-BenchmarkMutexFlip-4            50000000           29.7 ns/op
-BenchmarkAtomicBoolFlip-4      200000000           8.65 ns/op   # <--- This package
+# Toggle
+BenchmarkMutexToggle-4       50000000            30.7 ns/op
+BenchmarkAtomicBoolToggle-4  300000000           5.27 ns/op  # <--- This package
 ```
 

bool.go

@@ -49,13 +49,9 @@ func (ab *AtomicBool) SetTo(yes bool) {
 	}
 }
 
-// Flip toggles the Boolean (replaces with its opposite value).
-func (ab *AtomicBool) Flip() {
-	var o, n int32
-	o, n = 0, 1
-	if !atomic.CompareAndSwapInt32((*int32)(ab), o, n) {
-		atomic.CompareAndSwapInt32((*int32)(ab), n, o)
-	}
+// Toggle negates boolean atomically and returns the previous value.
+func (ab *AtomicBool) Toggle() bool {
+	return (atomic.AddInt32((*int32)(ab), 1)-1)&1 == 1
 }
 
 // SetToIf sets the Boolean to new only if the Boolean matches the old

bool_test.go

@@ -50,9 +50,9 @@ func TestBool(t *testing.T) {
 		t.Fatal("AtomicBool.SetTo(false, true) failed")
 	}
 
-	v.Flip() // expected false
+	_ = v.Toggle() // expected false
 	if v.IsSet() {
-		t.Fatal("AtomicBool.Flip() failed")
+		t.Fatal("AtomicBool.Toggle() failed")
 	}
 
 }
@@ -90,7 +90,7 @@ func TestRace(t *testing.T) {
 	// Reader And Writer
 	go func() {
 		for i := 0; i < repeat; i++ {
-			v.Flip()
+			v.Toggle()
 			wg.Done()
 		}
 	}()
@@ -104,7 +104,7 @@ func ExampleAtomicBool() {
 	cond.IsSet()     // returns true
 	cond.UnSet()     // set to false
 	cond.SetTo(true) // set to whatever you want
-	cond.Flip()      // flips the boolean value
+	cond.Toggle()    // toggles the boolean value
 }
 
 // Benchmark Read
@@ -191,9 +191,9 @@ func BenchmarkAtomicBoolCAS(b *testing.B) {
 	}
 }
 
-// Benchmark flip boolean value
+// Benchmark toggle boolean value
 
-func BenchmarkMutexFlip(b *testing.B) {
+func BenchmarkMutexToggle(b *testing.B) {
 	var m sync.RWMutex
 	var v bool
 	b.ResetTimer()
@@ -205,10 +205,10 @@ func BenchmarkMutexFlip(b *testing.B) {
 	b.StopTimer()
 }
 
-func BenchmarkAtomicBoolFlip(b *testing.B) {
+func BenchmarkAtomicBoolToggle(b *testing.B) {
 	v := New()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		v.Flip()
+		v.Toggle()
 	}
 }