add bitmapCountRuns and arrayCountRuns

roaring/roaring.go

@@ -1164,6 +1164,27 @@ func (c *container) contains(v uint32) bool {
 	}
 }
 
+func (c *container) bitmapCountRuns() (r int) {
+	for i := 0; i < 1023; i++ {
+		v, v1 := c.bitmap[i], c.bitmap[i+1]
+		r = r + int(popcnt((v<<1)&^v)+((v>>63)&^v1))
+	}
+	vl := c.bitmap[len(c.bitmap)-1]
+	r = r + int(popcnt((vl<<1)&^vl)+vl>>63)
+	return r
+}
+
+func (c *container) arrayCountRuns() (r int) {
+	prev := -2
+	for _, v := range c.array {
+		if uint32(prev+1) != v {
+			r += 1
+		}
+		prev = int(v)
+	}
+	return r
+}
+
 func (c *container) arrayContains(v uint32) bool {
 	return search32(c.array, v) >= 0
 }

roaring/roaring_internal_test.go

@@ -872,3 +872,94 @@ func TestRunToArray(t *testing.T) {
 		}
 	}
 }
+
+func TestBitmapCountRuns(t *testing.T) {
+	c := &container{bitmap: make([]uint64, bitmapN)}
+	tests := []struct {
+		bitmap []uint64
+		exp    int
+	}{
+		{
+			bitmap: []uint64{0xFF00FF00},
+			exp:    2,
+		},
+		{
+			bitmap: []uint64{0xFF00FF0000000000, 0x1},
+			exp:    2,
+		},
+		{
+			bitmap: []uint64{0xFF00FF0000000000, 0x2, 0x100},
+			exp:    4,
+		},
+		{
+			bitmap: []uint64{0xFF00FF0000000000, 0x1010101FF0101010, 0x100},
+			exp:    10,
+		},
+	}
+
+	for i, test := range tests {
+		for j, v := range test.bitmap {
+			c.bitmap[j] = v
+		}
+
+		ret := c.bitmapCountRuns()
+		if ret != test.exp {
+			t.Fatalf("test #%v expected %v but got %v", i, test.exp, ret)
+		}
+
+		for j, _ := range test.bitmap {
+			c.bitmap[j] = 0
+		}
+	}
+
+	test := tests[3]
+	for j, v := range test.bitmap {
+		c.bitmap[1024-len(test.bitmap)+j] = v
+
+	}
+	ret := c.bitmapCountRuns()
+	if ret != test.exp {
+		t.Fatalf("test at end expected %v but got %v", test.exp, ret)
+	}
+}
+
+func TestArrayCountRuns(t *testing.T) {
+	c := &container{}
+	tests := []struct {
+		array []uint32
+		exp   int
+	}{
+		{
+			array: []uint32{},
+			exp:   0,
+		},
+		{
+			array: []uint32{0},
+			exp:   1,
+		},
+		{
+			array: []uint32{1},
+			exp:   1,
+		},
+		{
+			array: []uint32{1, 2, 3, 5},
+			exp:   2,
+		},
+		{
+			array: []uint32{0, 1, 3, 9, 2048, 4096, 4097, 65534, 65535},
+			exp:   6,
+		},
+		{
+			array: []uint32{0, 10, 11, 12},
+			exp:   2,
+		},
+	}
+
+	for i, test := range tests {
+		c.array = test.array
+		ret := c.arrayCountRuns()
+		if ret != test.exp {
+			t.Fatalf("test #%v expected %v but got %v", i, test.exp, ret)
+		}
+	}
+}