fs: add Sha256HashGenerator, LZ4 decompressor

libraries/libstratosphere/source/fssystem/fssystem_compression_configuration.cpp

@@ -0,0 +1,47 @@
+/*
+ * 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/>.
+ */
+#include <stratosphere.hpp>
+#include "fssystem_key_slot_cache.hpp"
+
+namespace ams::fssystem {
+
+    namespace {
+
+        Result DecompressLz4(void *dst, size_t dst_size, const void *src, size_t src_size) {
+            R_UNLESS(util::DecompressLZ4(dst, dst_size, src, src_size) == static_cast<int>(dst_size), fs::ResultUnexpectedInCompressedStorageC());
+            return ResultSuccess();
+        }
+
+        constexpr DecompressorFunction GetNcaDecompressorFunction(CompressionType type) {
+            switch (type) {
+                case CompressionType_Lz4:
+                    return DecompressLz4;
+                default:
+                    return nullptr;
+            }
+        }
+
+        constexpr NcaCompressionConfiguration g_nca_compression_configuration {
+            .get_decompressor = GetNcaDecompressorFunction,
+        };
+
+    }
+
+    const ::ams::fssystem::NcaCompressionConfiguration *GetNcaCompressionConfiguration() {
+        return std::addressof(g_nca_compression_configuration);
+    }
+
+}