file_sys: Add support for parsing NCA metadata (CNMT)

src/core/file_sys/nca_metadata.h

@@ -0,0 +1,105 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include "core/file_sys/vfs.h"
+
+namespace FileSys {
+class CNMT;
+
+struct CNMTHeader;
+struct OptionalHeader;
+
+enum class TitleType : u8 {
+    SystemProgram = 0x01,
+    SystemDataArchive = 0x02,
+    SystemUpdate = 0x03,
+    FirmwarePackageA = 0x04,
+    FirmwarePackageB = 0x05,
+    Application = 0x80,
+    Update = 0x81,
+    AOC = 0x82,
+    DeltaTitle = 0x83,
+};
+
+enum class ContentRecordType : u8 {
+    Meta = 0,
+    Program = 1,
+    Data = 2,
+    Control = 3,
+    Manual = 4,
+    Legal = 5,
+    Patch = 6,
+};
+
+struct ContentRecord {
+    std::array<u8, 0x20> hash;
+    std::array<u8, 0x10> nca_id;
+    std::array<u8, 0x6> size;
+    ContentRecordType type;
+    INSERT_PADDING_BYTES(1);
+};
+static_assert(sizeof(ContentRecord) == 0x38, "ContentRecord has incorrect size.");
+
+constexpr ContentRecord EMPTY_META_CONTENT_RECORD{{}, {}, {}, ContentRecordType::Meta, {}};
+
+struct MetaRecord {
+    u64_le title_id;
+    u32_le title_version;
+    TitleType type;
+    u8 install_byte;
+    INSERT_PADDING_BYTES(2);
+};
+static_assert(sizeof(MetaRecord) == 0x10, "MetaRecord has incorrect size.");
+
+struct OptionalHeader {
+    u64_le title_id;
+    u64_le minimum_version;
+};
+static_assert(sizeof(OptionalHeader) == 0x10, "OptionalHeader has incorrect size.");
+
+struct CNMTHeader {
+    u64_le title_id;
+    u32_le title_version;
+    TitleType type;
+    INSERT_PADDING_BYTES(1);
+    u16_le table_offset;
+    u16_le number_content_entries;
+    u16_le number_meta_entries;
+    INSERT_PADDING_BYTES(12);
+};
+static_assert(sizeof(CNMTHeader) == 0x20, "CNMTHeader has incorrect size.");
+
+// A class representing the format used by NCA metadata files, typically named {}.cnmt.nca or
+// meta0.ncd. These describe which NCA's belong with which titles in the registered cache.
+class CNMT {
+public:
+    explicit CNMT(VirtualFile file);
+    CNMT(CNMTHeader header, OptionalHeader opt_header, std::vector<ContentRecord> content_records,
+         std::vector<MetaRecord> meta_records);
+
+    u64 GetTitleID() const;
+    u32 GetTitleVersion() const;
+    TitleType GetType() const;
+
+    const std::vector<ContentRecord>& GetContentRecords() const;
+    const std::vector<MetaRecord>& GetMetaRecords() const;
+
+    bool UnionRecords(const CNMT& other);
+    std::vector<u8> Serialize() const;
+
+private:
+    VirtualFile file;
+    std::unique_ptr<CNMTHeader> header;
+    std::unique_ptr<OptionalHeader> opt_header;
+    std::vector<ContentRecord> content_records;
+    std::vector<MetaRecord> meta_records;
+
+    // TODO(DarkLordZach): According to switchbrew, for Patch-type there is additional data
+    // after the table. This is not documented, unfortunately.
+};
+
+} // namespace FileSys