1 files changed, 50 insertions, 0 deletions

diff --git a/src/core/file_sys/vfs/vfs_offset.h b/src/core/file_sys/vfs/vfs_offset.h
new file mode 100644
index 000000000..4abe41d8e
--- /dev/null
+++ b/src/core/file_sys/vfs/vfs_offset.h
@@ -0,0 +1,50 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <memory>
+
+#include "core/file_sys/vfs/vfs.h"
+
+namespace FileSys {
+
+// An implementation of VfsFile that wraps around another VfsFile at a certain offset.
+// Similar to seeking to an offset.
+// If the file is writable, operations that would write past the end of the offset file will expand
+// the size of this wrapper.
+class OffsetVfsFile : public VfsFile {
+public:
+    OffsetVfsFile(VirtualFile file, std::size_t size, std::size_t offset = 0,
+                  std::string new_name = "", VirtualDir new_parent = nullptr);
+    ~OffsetVfsFile() override;
+
+    std::string GetName() const override;
+    std::size_t GetSize() const override;
+    bool Resize(std::size_t new_size) override;
+    VirtualDir GetContainingDirectory() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::size_t Read(u8* data, std::size_t length, std::size_t offset) const override;
+    std::size_t Write(const u8* data, std::size_t length, std::size_t offset) override;
+    std::optional<u8> ReadByte(std::size_t offset) const override;
+    std::vector<u8> ReadBytes(std::size_t size, std::size_t offset) const override;
+    std::vector<u8> ReadAllBytes() const override;
+    bool WriteByte(u8 data, std::size_t offset) override;
+    std::size_t WriteBytes(const std::vector<u8>& data, std::size_t offset) override;
+
+    bool Rename(std::string_view new_name) override;
+
+    std::size_t GetOffset() const;
+
+private:
+    std::size_t TrimToFit(std::size_t r_size, std::size_t r_offset) const;
+
+    VirtualFile file;
+    std::size_t offset;
+    std::size_t size;
+    std::string name;
+    VirtualDir parent;
+};
+
+} // namespace FileSys