Fix mode.

Author: ncruces

ext/stats/mode.go

@@ -19,8 +19,8 @@ type mode struct {
 
 func (m mode) Value(ctx sqlite3.Context) {
 	var (
-		max = 0
 		typ = sqlite3.NULL
+		max uint
 		i64 int64
 		f64 float64
 		str string
@@ -32,7 +32,6 @@ func (m mode) Value(ctx sqlite3.Context) {
 			i64 = k
 		}
 	}
-	f64 = float64(i64)
 	for k, v := range m.reals {
 		if v > max || v == max && k < f64 {
 			typ = sqlite3.FLOAT
@@ -66,33 +65,45 @@ func (m mode) Value(ctx sqlite3.Context) {
 	}
 }
 
-func (b *mode) Step(ctx sqlite3.Context, arg ...sqlite3.Value) {
+func (m *mode) Step(ctx sqlite3.Context, arg ...sqlite3.Value) {
 	switch arg[0].Type() {
 	case sqlite3.INTEGER:
-		b.ints.add(arg[0].Int64())
+		if m.reals == nil {
+			m.ints.add(arg[0].Int64())
+			break
+		}
+		fallthrough
 	case sqlite3.FLOAT:
-		b.reals.add(arg[0].Float())
+		m.reals.add(arg[0].Float())
+		for k, v := range m.ints {
+			m.reals[float64(k)] += v
+		}
+		m.ints = nil
 	case sqlite3.TEXT:
-		b.texts.add(arg[0].Text())
+		m.texts.add(arg[0].Text())
 	case sqlite3.BLOB:
-		b.blobs.add(string(arg[0].RawBlob()))
+		m.blobs.add(string(arg[0].RawBlob()))
 	}
 }
 
-func (b *mode) Inverse(ctx sqlite3.Context, arg ...sqlite3.Value) {
+func (m *mode) Inverse(ctx sqlite3.Context, arg ...sqlite3.Value) {
 	switch arg[0].Type() {
 	case sqlite3.INTEGER:
-		b.ints.del(arg[0].Int64())
+		if m.reals == nil {
+			m.ints.del(arg[0].Int64())
+			break
+		}
+		fallthrough
 	case sqlite3.FLOAT:
-		b.reals.del(arg[0].Float())
+		m.reals.del(arg[0].Float())
 	case sqlite3.TEXT:
-		b.texts.del(arg[0].Text())
+		m.texts.del(arg[0].Text())
 	case sqlite3.BLOB:
-		b.blobs.del(string(arg[0].RawBlob()))
+		m.blobs.del(string(arg[0].RawBlob()))
 	}
 }
 
-type counter[T comparable] map[T]int
+type counter[T comparable] map[T]uint
 
 func (c *counter[T]) add(k T) {
 	if (*c) == nil {
@@ -102,11 +113,9 @@ func (c *counter[T]) add(k T) {
 }
 
 func (c counter[T]) del(k T) {
-	switch n := c[k]; n {
-	default:
-		c[k] = n - 1
-	case 1:
+	if n := c[k]; n == 1 {
 		delete(c, k)
-	case 0:
+	} else {
+		c[k] = n - 1
 	}
 }

ext/stats/mode_test.go

@@ -82,4 +82,20 @@ func TestRegister_mode(t *testing.T) {
 	for stmt.Step() {
 	}
 	stmt.Close()
+
+	stmt, _, err = db.Prepare(`SELECT mode(column1) FROM (VALUES (?), (?), (?), (?), (?))`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	stmt.BindInt(1, 1)
+	stmt.BindInt(2, 1)
+	stmt.BindInt(3, 2)
+	stmt.BindFloat(4, 2)
+	stmt.BindFloat(5, 2)
+	if stmt.Step() {
+		if got := stmt.ColumnInt(0); got != 2 {
+			t.Errorf("got %v, want 2", got)
+		}
+	}
+	stmt.Close()
 }