fs: revise NcaFileSystemDriver for latest semantics

libraries/libstratosphere/include/stratosphere/fssystem/fssystem_compression_common.hpp

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 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/>.
+ */
+#pragma once
+#include <vapours.hpp>
+
+namespace ams::fssystem {
+
+    enum CompressionType {
+        CompressionType_None    = 0,
+        CompressionType_1       = 1,
+        CompressionType_2       = 2,
+        CompressionType_Lz4     = 3,
+        CompressionType_Unknown = 4,
+    };
+
+    using DecompressorFunction    = Result (*)(void *, size_t, const void *, size_t);
+    using GetDecompressorFunction = DecompressorFunction (*)(CompressionType);
+
+    namespace CompressionTypeUtility {
+
+        constexpr bool IsBlockAlignmentRequired(CompressionType type) {
+            return type != CompressionType_None && type != CompressionType_1;
+        }
+
+        constexpr bool IsDataStorageAccessRequired(CompressionType type) {
+            return type != CompressionType_1;
+        }
+
+        constexpr bool IsRandomAccessible(CompressionType type) {
+            return CompressionType_None;
+        }
+
+        constexpr bool IsUnknownType(CompressionType type) {
+            return type >= CompressionType_Unknown;
+        }
+
+    }
+
+}