use reflect slices for columns

Author: mlange-42

ecs/column.go

@@ -20,8 +20,8 @@ type column struct {
 // newColumn creates a new column for a given type and capacity.
 func newColumn(index uint32, tp reflect.Type, itemSize uintptr, isRelation bool, isTrivial bool, target Entity, capacity uint32) column {
 	// TODO: should we use a slice instead of an array here?
-	data := reflect.New(reflect.ArrayOf(int(capacity), tp)).Elem()
-	pointer := data.Addr().UnsafePointer()
+	data := reflect.MakeSlice(reflect.SliceOf(tp), int(capacity), int(capacity))
+	pointer := data.Index(0).Addr().UnsafePointer()
 
 	return column{
 		pointer:    pointer,
@@ -103,7 +103,9 @@ func (c *column) Reset(ownLen uint32, zero unsafe.Pointer) {
 	if ownLen <= 64 && c.isTrivial { // A coarse estimate where manually zeroing is faster
 		c.ZeroRange(0, ownLen, zero)
 	} else {
-		c.data.SetZero()
+		for i := range ownLen {
+			zeroValueAt(c.data, int(i))
+		}
 	}
 }
 

ecs/column_test.go

@@ -9,5 +9,5 @@ func TestColumnPointer(t *testing.T) {
 	posType := reflect.TypeOf(Position{})
 	column := newColumn(0, posType, posType.Size(), false, true, Entity{}, 8)
 
-	expectEqual(t, uintptr(column.pointer), uintptr(column.data.Addr().UnsafePointer()))
+	expectEqual(t, uintptr(column.pointer), uintptr(column.data.Index(0).Addr().UnsafePointer()))
 }

ecs/internal/generate/query.go.template

@@ -197,7 +197,7 @@ func (q *Query{{.}}{{$genericsShort}}) setTable(index int32, table *table) {
 	q.table = table
 	{{- range $i, $v := $upper}}
 	column{{$v}} := q.components[{{$i}}].columns[q.table.id]
-	q.column{{$v}} = column{{$v}}.data.Slice(0, column{{$v}}.data.Len()).Interface().([]{{$v}})
+	q.column{{$v}} = column{{$v}}.data.Interface().([]{{$v}})
 	{{- end}}
 	q.cursor.index = 0
 	q.cursor.maxIndex = int64(q.table.len - 1)

ecs/query_gen.go

@@ -174,15 +174,15 @@ func (t *table) adjustCapacity(cap uint32) {
 	for i := range t.columns {
 		column := &t.columns[i]
 		old := column.data
-		column.data = reflect.New(reflect.ArrayOf(int(t.cap), column.elemType)).Elem()
+		column.data = reflect.MakeSlice(reflect.SliceOf(column.elemType), int(t.cap), int(t.cap))
 		if column.isTrivial {
-			newPtr := column.data.Addr().UnsafePointer()
+			newPtr := column.data.Index(0).Addr().UnsafePointer()
 			if t.len > 0 {
 				copyPtr(column.pointer, newPtr, uintptr(t.len)*column.itemSize)
 			}
 			column.pointer = newPtr
 		} else {
-			column.pointer = column.data.Addr().UnsafePointer()
+			column.pointer = column.data.Index(0).Addr().UnsafePointer()
 			if t.len > 0 {
 				reflect.Copy(column.data, old)
 			}