feat: first version of kgg support

algo/kgm/kgm_v5.go

@@ -0,0 +1,30 @@
+package kgm
+
+import (
+	"fmt"
+
+	"unlock-music.dev/cli/algo/common"
+	"unlock-music.dev/cli/algo/kgm/pc_kugou_db"
+	"unlock-music.dev/cli/algo/qmc"
+)
+
+func newKgmCryptoV5(header *header, kggDatabasePath string) (common.StreamDecoder, error) {
+	if header.AudioHash == "" {
+		return nil, fmt.Errorf("kgm v5: missing audio hash")
+	}
+
+	if kggDatabasePath == "" {
+		return nil, fmt.Errorf("kgm v5: missing kgg database path")
+	}
+
+	m, err := pc_kugou_db.CachedDumpEKey(kggDatabasePath)
+	if err != nil {
+		return nil, fmt.Errorf("kgm v5: decrypt kgg database: %w", err)
+	}
+	ekey, ok := m[header.AudioHash]
+	if !ok || ekey == "" {
+		return nil, fmt.Errorf("kgm v5: ekey missing from db (audio_hash=%s)", header.AudioHash)
+	}
+
+	return qmc.NewQmcCipherDecoderFromEKey([]byte(ekey))
+}