swarm/network/bitvector: add tests, fix Get method and add Length

swarm/network/bitvector/bitvector.go

@@ -1,34 +1,48 @@
 package bitvector
 
+import "errors"
+
+var errInvalidLength = errors.New("invalid length")
+
 type BitVector struct {
 	len int
 	b   []byte
 }
 
-func New(l int) *BitVector {
+func New(l int) (bv *BitVector, err error) {
 	return NewFromBytes(make([]byte, l/8+1), l)
 }
 
-func NewFromBytes(b []byte, l int) *BitVector {
+func NewFromBytes(b []byte, l int) (bv *BitVector, err error) {
+	if l <= 0 {
+		return nil, errInvalidLength
+	}
+	if len(b)*8 < l {
+		return nil, errInvalidLength
+	}
 	return &BitVector{
 		len: l,
 		b:   b,
-	}
+	}, nil
 }
 
 func (bv *BitVector) Get(i int) bool {
 	bi := i / 8
-	return uint8(bv.b[bi])&0x1>>uint(i%8) != 0
+	return uint8(bv.b[bi])&(0x1<<uint(i%8)) != 0
 }
 
 func (bv *BitVector) Set(i int, v bool) {
 	bi := i / 8
 	cv := bv.Get(i)
 	if cv != v {
-		bv.b[bi] ^= 0x1 >> uint8(i%8)
+		bv.b[bi] ^= 0x1 << uint8(i%8)
 	}
 }
 
 func (bv *BitVector) Bytes() []byte {
 	return bv.b
 }
+
+func (bv *BitVector) Length() int {
+	return bv.len
+}

swarm/network/bitvector/bitvector_test.go

@@ -0,0 +1,88 @@
+package bitvector
+
+import "testing"
+
+func TestBitvectorNew(t *testing.T) {
+	_, err := New(0)
+	if err != errInvalidLength {
+		t.Errorf("expected err %v, got %v", errInvalidLength, err)
+	}
+
+	_, err = NewFromBytes(nil, 0)
+	if err != errInvalidLength {
+		t.Errorf("expected err %v, got %v", errInvalidLength, err)
+	}
+
+	_, err = NewFromBytes([]byte{0}, 9)
+	if err != errInvalidLength {
+		t.Errorf("expected err %v, got %v", errInvalidLength, err)
+	}
+
+	_, err = NewFromBytes(make([]byte, 8), 8)
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestBitvectorGetSet(t *testing.T) {
+	for _, length := range []int{
+		1,
+		2,
+		4,
+		8,
+		9,
+		15,
+		16,
+	} {
+		bv, err := New(length)
+		if err != nil {
+			t.Errorf("error for length %v: %v", length, err)
+		}
+
+		for i := 0; i < length; i++ {
+			if bv.Get(i) {
+				t.Errorf("expected false for element on index %v", i)
+			}
+		}
+
+		func() {
+			defer func() {
+				if err := recover(); err == nil {
+					t.Errorf("expecting panic")
+				}
+			}()
+			bv.Get(length + 8)
+		}()
+
+		for i := 0; i < length; i++ {
+			bv.Set(i, true)
+			for j := 0; j < length; j++ {
+				if j == i {
+					if bv.Get(j) != true {
+						t.Errorf("element on index %v is not set to true", i)
+					}
+				} else {
+					if bv.Get(j) != false {
+						t.Errorf("element on index %v is not false", i)
+					}
+				}
+			}
+
+			bv.Set(i, false)
+
+			if bv.Get(i) != false {
+				t.Errorf("element on index %v is not set to false", i)
+			}
+		}
+	}
+}
+
+func TestBitvectorNewFromBytesGet(t *testing.T) {
+	bv, err := NewFromBytes([]byte{8}, 8)
+	if err != nil {
+		t.Error(err)
+	}
+	if bv.Get(3) != true {
+		t.Fatalf("element 3 is not set to true: state %08b", bv.b[0])
+	}
+}