Adding the challenge 0401

0401/kv.go

@@ -0,0 +1,31 @@
+package db0401
+
+type KV struct {
+	log  Log
+	keys [][]byte
+	vals [][]byte
+}
+
+func (kv *KV) Open() error
+
+func (kv *KV) Close() error { return kv.log.Close() }
+
+func (kv *KV) Get(key []byte) (val []byte, ok bool, err error)
+
+type UpdateMode int
+
+const (
+	ModeUpsert UpdateMode = 0 // insert or update
+	ModeInsert UpdateMode = 1 // insert new
+	ModeUpdate UpdateMode = 2 // update existing
+)
+
+func (kv *KV) SetEx(key []byte, val []byte, mode UpdateMode) (updated bool, err error)
+
+func (kv *KV) Set(key []byte, val []byte) (updated bool, err error) {
+	return kv.SetEx(key, val, ModeUpsert)
+}
+
+func (kv *KV) Del(key []byte) (deleted bool, err error)
+
+// QzBQWVJJOUhU https://trialofcode.org/