Add bambu-nfc dump parse, Key-A HKDF, and spool merge.

Parse filanfc-dump/v1 zip/JSON, Bambu 1K images, and merge stickers by tray UID. dump and mifare packages stay importable for a later common library.

kdf_test.go

@@ -0,0 +1,48 @@
+package bambunfc
+
+import (
+	"encoding/hex"
+	"errors"
+	"testing"
+)
+
+func TestKeysAGolden11223344(t *testing.T) {
+	t.Parallel()
+	uid, err := hex.DecodeString("11223344")
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []string{
+		"0729F3B2D37A", "2027210D85E7", "D77B2E7C92BC", "29126A53A2EE",
+		"E49850F62778", "9A9128B882BD", "45F69B980786", "90DD67095D6B",
+		"EB994746CD69", "B4AEB23473E3", "445E850D699C", "5C9BD5BD9FD7",
+		"1062AFE9F5F5", "81EE5259CF6B", "0920CEEEE2BC", "BAF630CCBFD3",
+	}
+	got, err := KeysA(uid)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for i, w := range want {
+		if h := hex.EncodeToString(got[i][:]); h != toLower(w) {
+			t.Errorf("key[%d] = %s; want %s", i, h, toLower(w))
+		}
+	}
+}
+
+func toLower(s string) string {
+	b := []byte(s)
+	for i, c := range b {
+		if c >= 'A' && c <= 'F' {
+			b[i] = c + ('a' - 'A')
+		}
+	}
+	return string(b)
+}
+
+func TestKeysAEmpty(t *testing.T) {
+	t.Parallel()
+	_, err := KeysA(nil)
+	if !errors.Is(err, ErrUID) {
+		t.Errorf("KeysA(nil) err = %v; want ErrUID", err)
+	}
+}