Implement support for parsing/interacting with NCAs. (#942)

* fs: implement support for interacting with ncas.

* spl: extend to use virtual keyslots

libraries/libstratosphere/source/fssystem/fssystem_nca_header.cpp

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+
+namespace ams::fssystem {
+
+    u8 NcaHeader::GetProperKeyGeneration() const {
+        return std::max(this->key_generation, this->key_generation_2);
+    }
+    bool NcaPatchInfo::HasIndirectTable() const {
+        return this->indirect_size != 0;
+    }
+
+    bool NcaPatchInfo::HasAesCtrExTable() const {
+        return this->aes_ctr_ex_size != 0;
+    }
+
+}