1 files changed, 98 insertions, 0 deletions
diff --git a/src/core/file_sys/vfs/vfs_offset.cpp b/src/core/file_sys/vfs/vfs_offset.cpp
new file mode 100644
index 000000000..1a37d2670
--- /dev/null
+++ b/src/core/file_sys/vfs/vfs_offset.cpp
@@ -0,0 +1,98 @@
+// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <algorithm>
+#include <utility>
+
+#include "core/file_sys/vfs/vfs_offset.h"
+
+namespace FileSys {
+
+OffsetVfsFile::OffsetVfsFile(VirtualFile file_, std::size_t size_, std::size_t offset_,
+                             std::string name_, VirtualDir parent_)
+    : file(file_), offset(offset_), size(size_), name(std::move(name_)),
+      parent(parent_ == nullptr ? file->GetContainingDirectory() : std::move(parent_)) {}
+
+OffsetVfsFile::~OffsetVfsFile() = default;
+
+std::string OffsetVfsFile::GetName() const {
+    return name.empty() ? file->GetName() : name;
+}
+
+std::size_t OffsetVfsFile::GetSize() const {
+    return size;
+}
+
+bool OffsetVfsFile::Resize(std::size_t new_size) {
+    if (offset + new_size < file->GetSize()) {
+        size = new_size;
+    } else {
+        auto res = file->Resize(offset + new_size);
+        if (!res)
+            return false;
+        size = new_size;
+    }
+
+    return true;
+}
+
+VirtualDir OffsetVfsFile::GetContainingDirectory() const {
+    return parent;
+}
+
+bool OffsetVfsFile::IsWritable() const {
+    return file->IsWritable();
+}
+
+bool OffsetVfsFile::IsReadable() const {
+    return file->IsReadable();
+}
+
+std::size_t OffsetVfsFile::Read(u8* data, std::size_t length, std::size_t r_offset) const {
+    return file->Read(data, TrimToFit(length, r_offset), offset + r_offset);
+}
+
+std::size_t OffsetVfsFile::Write(const u8* data, std::size_t length, std::size_t r_offset) {
+    return file->Write(data, TrimToFit(length, r_offset), offset + r_offset);
+}
+
+std::optional<u8> OffsetVfsFile::ReadByte(std::size_t r_offset) const {
+    if (r_offset >= size) {
+        return std::nullopt;
+    }
+
+    return file->ReadByte(offset + r_offset);
+}
+
+std::vector<u8> OffsetVfsFile::ReadBytes(std::size_t r_size, std::size_t r_offset) const {
+    return file->ReadBytes(TrimToFit(r_size, r_offset), offset + r_offset);
+}
+
+std::vector<u8> OffsetVfsFile::ReadAllBytes() const {
+    return file->ReadBytes(size, offset);
+}
+
+bool OffsetVfsFile::WriteByte(u8 data, std::size_t r_offset) {
+    if (r_offset < size)
+        return file->WriteByte(data, offset + r_offset);
+
+    return false;
+}
+
+std::size_t OffsetVfsFile::WriteBytes(const std::vector<u8>& data, std::size_t r_offset) {
+    return file->Write(data.data(), TrimToFit(data.size(), r_offset), offset + r_offset);
+}
+
+bool OffsetVfsFile::Rename(std::string_view new_name) {
+    return file->Rename(new_name);
+}
+
+std::size_t OffsetVfsFile::GetOffset() const {
+    return offset;
+}
+
+std::size_t OffsetVfsFile::TrimToFit(std::size_t r_size, std::size_t r_offset) const {
+    return std::clamp(r_size, std::size_t{0}, size - r_offset);
+}
+
+} // namespace FileSys