diff --git a/roaring/roaring.go b/roaring/roaring.go
index 9c4274df9..a94121dc9 100644
--- a/roaring/roaring.go
+++ b/roaring/roaring.go
@@ -3006,6 +3006,85 @@ func xorBitmapBitmap(a, b *Container) *Container {
 	return output
 }
 
+func shift(a *Container) (*Container, bool) {
+	if a.isArray() {
+		return shiftArray(a)
+	} else if a.isRun() {
+		return shiftRun(a)
+	}
+	return shiftBitmap(a)
+}
+
+func shiftArray(a *Container) (*Container, bool) {
+	statsHit("shift/Array")
+	carry := false
+	output := &Container{containerType: containerArray}
+	output.array = make([]uint16, len(a.array))
+	output.array = output.array[:0]
+	output.n = a.n
+	for _, v := range a.array {
+		fmt.Println(v,v+1)
+		if v+1 == 0 { //overflow
+			carry = true
+			output.n -= 1
+		} else {
+			output.array = append(output.array, v+1)
+		}
+	}
+	return output, carry
+}
+
+func shiftBitmap(a *Container) (*Container, bool) {
+	statsHit("shift/Bitmap")
+	carry := false
+	output := &Container{containerType: containerBitmap}
+	output.bitmap = make([]uint64, len(a.bitmap))
+	output.bitmap = output.bitmap[:0]
+	output.n = a.n
+	lastcarry:=false
+	for i, v := range a.bitmap {
+		carry = (v&(1<<63))!= 0
+		v = v << 1
+		if i != 0 {
+			if lastcarry {
+				v |= 1
+			}
+		}
+		output.bitmap = append(output.bitmap, v)
+		lastcarry = carry
+	}
+	if carry {
+		output.n -= 1
+	}
+	return output, carry
+}
+
+func shiftRun(a *Container) (*Container, bool) {
+	statsHit("shift/Run")
+	carry := false
+	output := &Container{containerType: containerRun}
+	output.runs = make([]interval16, len(a.runs))
+	output.runs = output.runs[:0]
+	for _, v := range a.runs {
+		if v.start+1 == 0 {
+			carry = true
+			output.n -= 1
+			break
+		} else if v.last+1 == 0 {
+			v.start += 1
+			carry = true
+			output.n -= 1
+		} else {
+			v.start += 1
+			v.last += 1
+			carry = false
+		}
+		output.runs = append(output.runs, v)
+	}
+
+	return output, carry
+}
+
 // opType represents a type of operation.
 type opType uint8
 
diff --git a/roaring/roaring_helpers_test.go b/roaring/roaring_helpers_test.go
index cd22978fb..36963425e 100644
--- a/roaring/roaring_helpers_test.go
+++ b/roaring/roaring_helpers_test.go
@@ -106,6 +106,25 @@ func bitmapFirstBitSet() []uint64 {
 	return bitmap
 }
 
+func bitmapSecondBitSet() []uint64 {
+	bitmap := make([]uint64, bitmapN)
+	bitmap[0] = 0x0000000000000002
+	return bitmap
+}
+
+func bitmapLastBitFirstRowSet() []uint64 {
+	bitmap := make([]uint64, bitmapN)
+	bitmap[0] = 0x8000000000000000
+	return bitmap
+}
+
+func bitmapFirstBitSecoundRowSet() []uint64 {
+	bitmap := make([]uint64, bitmapN)
+	bitmap[1] = 0x0000000000000001
+	return bitmap
+}
+
+
 func bitmapLastBitSet() []uint64 {
 	bitmap := make([]uint64, bitmapN)
 	bitmap[bitmapN-1] = 0x8000000000000000
diff --git a/roaring/roaring_internal_test.go b/roaring/roaring_internal_test.go
index 78b686371..ffa8be812 100644
--- a/roaring/roaring_internal_test.go
+++ b/roaring/roaring_internal_test.go
@@ -3289,3 +3289,115 @@ func TestEquals(t *testing.T) {
 	}
 }
 */
+func TestShiftArray(t *testing.T) {
+	a := &Container{
+		containerType: containerArray,
+}
+	tests := []struct {
+		array []uint16
+		exp   []uint16
+	}{
+		{
+			array: []uint16{1},
+			exp:   []uint16{2},
+		},
+		{
+			array: []uint16{},
+			exp:   []uint16{},
+		},
+		{
+			array: []uint16{1, 2, 3, 4, 5, 11, 12},
+			exp:   []uint16{2, 3, 4, 5, 6, 12,13}, 
+		},
+		{
+			array: []uint16{65535},
+			exp:   []uint16{},
+		},
+	}
+
+	for i, test := range tests {
+		a.array = test.array
+		a.n = int32(len(a.array))
+		ret,_ := shiftArray(a)
+		if !reflect.DeepEqual(ret.array, test.exp) {
+			t.Fatalf("test #%v expected %v, but got %v", i, test.exp, ret.array)
+		}
+	}
+}	
+
+
+func TestShiftBitmap(t *testing.T) {
+	a := &Container{
+		containerType: containerBitmap,
+	}
+	tests := []struct {
+		bitmap []uint64
+		exp   []uint64
+	}{
+		{
+			bitmap:bitmapFirstBitSet() ,
+			exp:   bitmapSecondBitSet(), 
+		},
+		{
+			bitmap:bitmapLastBitSet() ,
+			exp:   bitmapEmpty(), 
+		},
+		{
+			bitmap:bitmapLastBitFirstRowSet() ,
+			exp:  bitmapFirstBitSecoundRowSet (), 
+		},
+	}
+
+	for i, test := range tests {
+		a.bitmap = test.bitmap
+		a.n = 1
+		ret,_ := shiftBitmap(a)
+		if !reflect.DeepEqual(ret.bitmap, test.exp) {
+			t.Fatalf("test #%v expected %v, but got %v", i, test.exp, ret.bitmap)
+		}
+	}
+}	
+func TestShiftRun(t *testing.T) {
+	a := &Container{
+		containerType: containerRun,
+	}
+
+	tests := []struct {
+		runs []interval16
+		n int32
+		en int32
+		exp   []interval16
+		carry bool
+	}{
+		{
+			runs:  []interval16{{start: 5, last: 10}},
+			n:  5,
+			en: 5, 
+			exp:  []interval16{{start: 6, last: 11}},
+			carry: false,
+		},
+		{
+			runs:  []interval16{{start: 5, last:65535 }},
+			n:  65530,
+			en: 65529, 
+			exp:  []interval16{{start: 6, last: 65535}},
+			carry: true,
+		},
+		{
+			runs:  []interval16{{start: 65535, last:65535 }},
+			n:  1,
+			en: 0, 
+			exp:  []interval16{},
+			carry:  true,
+		},
+	}
+
+	for i, test := range tests {
+		a.runs = test.runs
+		a.n = test.n
+		ret,c := shiftRun(a)
+		if !reflect.DeepEqual(ret.runs, test.exp) && c == test.carry && ret.n == test.en  {
+			t.Fatalf("test #%v expected %v, but got %v %d", i, test.exp, ret.runs,ret.n)
+		}
+	}
+}