1 files changed, 32 insertions, 0 deletions
diff --git a/lib/containers/maputil.go b/lib/containers/maputil.go
new file mode 100644
index 0000000..4d49d2a
--- /dev/null
+++ b/lib/containers/maputil.go
@@ -0,0 +1,32 @@
+// Copyright (C) 2023  Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package containers
+
+type Map[K comparable, V any] interface {
+	Store(K, V)
+	Load(K) (V, bool)
+	Has(K) bool
+	Delete(K)
+	Len() int
+}
+
+type RangeMap[K comparable, V any] interface {
+	Map[K, V]
+	Range(func(K, V) bool)
+}
+
+type SubrangeMap[K comparable, V any] interface {
+	RangeMap[K, V]
+	Subrange(rangeFn func(K, V) int, handleFn func(K, V) bool)
+}
+
+func LoadOrElse[K comparable, V any](m Map[K, V], k K, vFn func(K) V) V {
+	if v, ok := m.Load(k); ok {
+		return v
+	}
+	v := vFn(k)
+	m.Store(k, v)
+	return v
+}