Merge pull request #101 from bits-and-blooms/dlemire/issue92

Verifying and checking issue 100.
bits-and-blooms · Mar 18, 2022 · c263434 · c263434
2 parents 04f5e3f + a1cbd25
commit c263434
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/bitset.go b/bitset.go
@@ -231,7 +231,9 @@ func (b *BitSet) FlipRange(start, end uint) *BitSet {
 	for i := startWord; i < endWord; i++ {
 		b.set[i] = ^b.set[i]
 	}
-	b.set[endWord] ^= ^uint64(0) >> (-end & (wordSize - 1))
+	if end & (wordSize - 1) != 0 {
+		b.set[endWord] ^= ^uint64(0) >> (-end & (wordSize - 1))
+    }
 	return b
 }
 

diff --git a/bitset_test.go b/bitset_test.go
@@ -1409,6 +1409,18 @@ func TestFlipRange(t *testing.T) {
 		t.Error("Unexpected value: ", d.length)
 		return
 	}
+	//
+	for i := uint(0); i < 256; i++ {
+		for j := uint(0); j <= i; j++ {
+			bits := New(i)
+			bits.FlipRange(0, j)
+			c := bits.Count()
+			if c != j {
+				t.Error("Unexpected value: ", c, " expected: ", j)
+				return
+			}
+		}
+	}
 }
 
 func TestCopy(t *testing.T) {