1 files changed, 39 insertions, 0 deletions
diff --git a/src/core/file_sys/fssystem/fssystem_sparse_storage.cpp b/src/core/file_sys/fssystem/fssystem_sparse_storage.cpp
new file mode 100644
index 000000000..8574a11dd
--- /dev/null
+++ b/src/core/file_sys/fssystem/fssystem_sparse_storage.cpp
@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "core/file_sys/fssystem/fssystem_sparse_storage.h"
+
+namespace FileSys {
+
+size_t SparseStorage::Read(u8* buffer, size_t size, size_t offset) const {
+    // Validate preconditions.
+    ASSERT(this->IsInitialized());
+    ASSERT(buffer != nullptr);
+
+    // Allow zero size.
+    if (size == 0) {
+        return size;
+    }
+
+    SparseStorage* self = const_cast<SparseStorage*>(this);
+
+    if (self->GetEntryTable().IsEmpty()) {
+        BucketTree::Offsets table_offsets;
+        ASSERT(R_SUCCEEDED(self->GetEntryTable().GetOffsets(std::addressof(table_offsets))));
+        ASSERT(table_offsets.IsInclude(offset, size));
+
+        std::memset(buffer, 0, size);
+    } else {
+        self->OperatePerEntry<false, true>(
+            offset, size,
+            [=](VirtualFile storage, s64 data_offset, s64 cur_offset, s64 cur_size) -> Result {
+                storage->Read(reinterpret_cast<u8*>(buffer) + (cur_offset - offset),
+                              static_cast<size_t>(cur_size), data_offset);
+                R_SUCCEED();
+            });
+    }
+
+    return size;
+}
+
+} // namespace FileSys