Add CIA building

Quite a lot of code, yeah.

The built CIA is almost identical to GM9, with the following differences:
1. Paddings are zeroed out
2. Title key is not written (GM9 gets it from support data/ticket db)
3. Ticket content index is slightly different (GM9 likely takes it from the legit ticket, while we are building a fake one)

The 2, 3 points can be fixed probably.

src/core/ncch/cia_builder.h

@@ -0,0 +1,112 @@
+// Copyright 2017 Citra Emulator Project / 2020 Pengfei Zhu
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <memory>
+#include <mutex>
+#include <string>
+#include "common/file_util.h"
+#include "common/swap.h"
+#include "core/ncch/ncch_container.h"
+#include "core/ncch/title_metadata.h"
+#include "core/quick_decryptor.h"
+
+namespace Core {
+
+constexpr std::size_t CIA_CONTENT_MAX_COUNT = 0x10000;
+constexpr std::size_t CIA_CONTENT_BITS_SIZE = (CIA_CONTENT_MAX_COUNT / 8);
+constexpr std::size_t CIA_HEADER_SIZE = 0x2020;
+constexpr std::size_t CIA_CERT_SIZE = 0xA00;
+constexpr std::size_t CIA_METADATA_SIZE = 0x3AC0;
+
+class HashedFile;
+
+class CIABuilder {
+public:
+    explicit CIABuilder();
+    ~CIABuilder();
+
+    /**
+     * Initializes the building of the CIA.
+     * @return true on success, false otherwise
+     */
+    bool Init(const std::string& destination, TitleMetadata tmd, const std::string& certs_db_path,
+              std::size_t total_size, const ProgressCallback& callback);
+
+    /**
+     * Adds an NCCH content to the CIA.
+     * @return true on success, false otherwise
+     */
+    bool AddContent(u16 content_id, NCCHContainer& ncch);
+
+    /**
+     * Finalizes this CIA and write remaining data.
+     * @return true on success, false otherwise
+     */
+    bool Finalize();
+
+    /**
+     * Aborts the current work. In fact, only usable during AddContent.
+     */
+    void Abort();
+
+private:
+    struct Header {
+        u32_le header_size;
+        u16_le type;
+        u16_le version;
+        u32_le cert_size;
+        u32_le tik_size;
+        u32_le tmd_size;
+        u32_le meta_size;
+        u64_le content_size;
+        std::array<u8, CIA_CONTENT_BITS_SIZE> content_present;
+
+        bool IsContentPresent(u16 index) const {
+            // The content_present is a bit array which defines which content in the TMD
+            // is included in the CIA, so check the bit for this index and add if set.
+            // The bits in the content index are arranged w/ index 0 as the MSB, 7 as the LSB, etc.
+            return (content_present[index >> 3] & (0x80 >> (index & 7)));
+        }
+
+        void SetContentPresent(u16 index) {
+            content_present[index >> 3] |= (0x80 >> (index & 7));
+        }
+    };
+
+    static_assert(sizeof(Header) == CIA_HEADER_SIZE, "CIA Header structure size is wrong");
+
+    struct Metadata {
+        std::array<u64_le, 0x30> dependencies;
+        std::array<u8, 0x180> reserved;
+        u32_le core_version;
+        std::array<u8, 0xfc> reserved_2;
+        std::array<u8, 0x36c0> icon_data;
+    };
+
+    static_assert(sizeof(Metadata) == CIA_METADATA_SIZE, "CIA Metadata structure size is wrong");
+
+    bool WriteCert(const std::string& certs_db_path);
+
+    Header header{};
+    Metadata meta{};
+
+    TitleMetadata tmd;
+
+    std::size_t cert_offset{};
+    std::size_t ticket_offset{};
+    std::size_t tmd_offset{};
+    std::size_t content_offset{};
+    std::size_t metadata_offset{};
+
+    std::shared_ptr<HashedFile> file;
+    std::size_t written{}; // size written (with alignment)
+    std::size_t total_size{};
+    ProgressCallback callback;
+
+    // The NCCH to abort on
+    std::mutex abort_ncch_mutex;
+    NCCHContainer* abort_ncch{};
+};
+
+} // namespace Core