From 86f6b6b7b2d930e8203114332b04a5c49a780b06 Mon Sep 17 00:00:00 2001
From: Liam <byteslice@airmail.cc>
Date: Thu, 10 Aug 2023 21:34:43 -0400
Subject: vfs: expand support for NCA reading

---
 .../fssystem_aes_ctr_counter_extended_storage.h    | 114 +++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 src/core/file_sys/fssystem/fssystem_aes_ctr_counter_extended_storage.h

(limited to 'src/core/file_sys/fssystem/fssystem_aes_ctr_counter_extended_storage.h')

diff --git a/src/core/file_sys/fssystem/fssystem_aes_ctr_counter_extended_storage.h b/src/core/file_sys/fssystem/fssystem_aes_ctr_counter_extended_storage.h
new file mode 100644
index 000000000..a79904fad
--- /dev/null
+++ b/src/core/file_sys/fssystem/fssystem_aes_ctr_counter_extended_storage.h
@@ -0,0 +1,114 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <optional>
+
+#include "common/literals.h"
+#include "core/file_sys/fssystem/fs_i_storage.h"
+#include "core/file_sys/fssystem/fssystem_bucket_tree.h"
+
+namespace FileSys {
+
+using namespace Common::Literals;
+
+class AesCtrCounterExtendedStorage : public IReadOnlyStorage {
+    YUZU_NON_COPYABLE(AesCtrCounterExtendedStorage);
+    YUZU_NON_MOVEABLE(AesCtrCounterExtendedStorage);
+
+public:
+    static constexpr size_t BlockSize = 0x10;
+    static constexpr size_t KeySize = 0x10;
+    static constexpr size_t IvSize = 0x10;
+    static constexpr size_t NodeSize = 16_KiB;
+
+    class IDecryptor {
+    public:
+        virtual ~IDecryptor() {}
+        virtual void Decrypt(u8* buf, size_t buf_size, const std::array<u8, KeySize>& key,
+                             const std::array<u8, IvSize>& iv) = 0;
+    };
+
+    struct Entry {
+        enum class Encryption : u8 {
+            Encrypted = 0,
+            NotEncrypted = 1,
+        };
+
+        std::array<u8, sizeof(s64)> offset;
+        Encryption encryption_value;
+        std::array<u8, 3> reserved;
+        s32 generation;
+
+        void SetOffset(s64 value) {
+            std::memcpy(this->offset.data(), std::addressof(value), sizeof(s64));
+        }
+
+        s64 GetOffset() const {
+            s64 value;
+            std::memcpy(std::addressof(value), this->offset.data(), sizeof(s64));
+            return value;
+        }
+    };
+    static_assert(sizeof(Entry) == 0x10);
+    static_assert(alignof(Entry) == 4);
+    static_assert(std::is_trivial_v<Entry>);
+
+public:
+    static constexpr s64 QueryHeaderStorageSize() {
+        return BucketTree::QueryHeaderStorageSize();
+    }
+
+    static constexpr s64 QueryNodeStorageSize(s32 entry_count) {
+        return BucketTree::QueryNodeStorageSize(NodeSize, sizeof(Entry), entry_count);
+    }
+
+    static constexpr s64 QueryEntryStorageSize(s32 entry_count) {
+        return BucketTree::QueryEntryStorageSize(NodeSize, sizeof(Entry), entry_count);
+    }
+
+    static Result CreateSoftwareDecryptor(std::unique_ptr<IDecryptor>* out);
+
+private:
+    mutable BucketTree m_table;
+    VirtualFile m_data_storage;
+    std::array<u8, KeySize> m_key;
+    u32 m_secure_value;
+    s64 m_counter_offset;
+    std::unique_ptr<IDecryptor> m_decryptor;
+
+public:
+    AesCtrCounterExtendedStorage()
+        : m_table(), m_data_storage(), m_secure_value(), m_counter_offset(), m_decryptor() {}
+    virtual ~AesCtrCounterExtendedStorage() {
+        this->Finalize();
+    }
+
+    Result Initialize(const void* key, size_t key_size, u32 secure_value, s64 counter_offset,
+                      VirtualFile data_storage, VirtualFile node_storage, VirtualFile entry_storage,
+                      s32 entry_count, std::unique_ptr<IDecryptor>&& decryptor);
+    void Finalize();
+
+    bool IsInitialized() const {
+        return m_table.IsInitialized();
+    }
+
+    virtual size_t Read(u8* buffer, size_t size, size_t offset) const override;
+
+    virtual size_t GetSize() const override {
+        BucketTree::Offsets offsets;
+        ASSERT(R_SUCCEEDED(m_table.GetOffsets(std::addressof(offsets))));
+
+        return offsets.end_offset;
+    }
+
+    Result GetEntryList(Entry* out_entries, s32* out_entry_count, s32 entry_count, s64 offset,
+                        s64 size);
+
+private:
+    Result Initialize(const void* key, size_t key_size, u32 secure_value, VirtualFile data_storage,
+                      VirtualFile table_storage);
+};
+
+} // namespace FileSys
-- 
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