simple ecs system

server/internal/ecs/bitest.go

@@ -0,0 +1,39 @@
+package ecs
+
+type BitSet struct {
+	// TODO: this is not a bitset, I'm just testing
+	values map[Index]struct{}
+}
+
+func (b BitSet) Set(i Index) (old bool) {
+	_, old = b.values[i]
+	b.values[i] = struct{}{}
+	return
+}
+
+func (b BitSet) Unset(i Index) (old bool) {
+	_, old = b.values[i]
+	delete(b.values, i)
+	return
+}
+
+func (b BitSet) Contains(i Index) bool {
+	_, contains := b.values[i]
+	return contains
+}
+
+func (b BitSet) And(other BitSet) (result BitSet) {
+	result = BitSet{values: make(map[Index]struct{})}
+	for i := range b.values {
+		if other.Contains(i) {
+			result.values[i] = struct{}{}
+		}
+	}
+	return result
+}
+
+func (b BitSet) Range(f func(eid Index)) {
+	for i := range b.values {
+		f(i)
+	}
+}