infer compress type before decode NBT fail

save/playerdata.go

@@ -0,0 +1,16 @@
+package save
+
+import (
+	"github.com/Tnze/go-mc/nbt"
+	"io"
+)
+
+type PlayerData struct {
+	Pos    [3]float64
+	Motion [3]float64
+}
+
+func ReadPlayerData(r io.Reader) (data PlayerData, err error) {
+	err = nbt.NewDecoder(r).Decode(&data)
+	return
+}