GCF.h

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#pragma once
 
#include "../PackFile.h"
 
namespace vpkpp {
 
constexpr std::string_view GCF_EXTENSION = ".gcf";
 
class GCF : public PackFileReadOnly {
protected:
#pragma pack(push, 1)
    struct Header {
        uint32_t dummy1;
        uint32_t dummy2;
        uint32_t gcfversion;
        uint32_t appid;
        uint32_t appversion;
        uint32_t dummy3;
        uint32_t dummy4;
        uint32_t filesize;
        uint32_t blocksize;
        uint32_t blockcount;
        uint32_t dummy5;
    };
 
    // second header with info about blocks inside the file
    // appears only ONCE not before every block!
    struct BlockHeader {
        uint32_t count;
        uint32_t used;
        uint32_t dummy1;
        uint32_t dummy2;
        uint32_t dummy3;
        uint32_t dummy4;
        uint32_t dummy5;
        uint32_t checksum;
    };
 
    struct Block {
        enum class CompressionType : uint32_t {
            UNCOMPRESSED = 0,
            COMPRESSED, // compressed on the server, client automatically extracts it so not really
            COMPRESSED_AND_ENCRYPTED,
            ENCRYPTED,
        };
 
        uint16_t flags;
        uint16_t open;
        uint32_t file_data_offset;
        uint32_t file_data_size;
        uint32_t first_data_block_index;
        uint32_t next_block_entry_index;
        uint32_t prev_block_entry_index;
        uint32_t dir_index;
 
        [[nodiscard]] CompressionType getCompressionType() const {
            static constexpr std::array compressionTypeLUT = {
                CompressionType::COMPRESSED,
                CompressionType::COMPRESSED_AND_ENCRYPTED,
                CompressionType::UNCOMPRESSED,
                CompressionType::ENCRYPTED,
            };
            const auto idx = (static_cast<std::uint8_t>(flags) & 7) - 1;
            if (idx <= 3) {
                return compressionTypeLUT[idx];
            }
            return CompressionType::UNCOMPRESSED;
        }
 
        [[nodiscard]] bool isEncrypted() const {
            return static_cast<uint32_t>(this->getCompressionType()) - 2 <= 1;
        }
    };
 
    struct DirectoryHeader {
        uint32_t dummy1;
        uint32_t cacheid;
        uint32_t gcfversion;
        uint32_t itemcount;
        uint32_t filecount;
        uint32_t dummy2;
        uint32_t dirsize;
        uint32_t namesize;
        uint32_t info1count;
        uint32_t copycount;
        uint32_t localcount;
        uint32_t dummy3;
        uint32_t dummy4;
        uint32_t checksum;
    };
 
    struct DirectoryEntry {
        uint32_t nameoffset;
        uint32_t itemsize;
        uint32_t fileid;
        uint32_t dirtype;
        uint32_t parentindex;
        uint32_t nextindex;
        uint32_t firstindex;
    };
 
    struct DirectoryEntry2 {
        DirectoryEntry entry_real{};
        std::string filename;
    };
 
    struct DirectoryMapHeader {
        uint32_t dummy1;
        uint32_t dummy2;
    };
 
    struct DirectoryMapEntry {
        uint32_t firstblockindex;
    };
 
    struct DataBlockHeader {
        uint32_t appversion;
        uint32_t blockcount;
        uint32_t blocksize;
        uint32_t firstblockoffset;
        uint32_t used;
        uint32_t checksum;
    };
 
    struct ChecksumMapHeader {
        uint32_t dummy1;
        uint32_t dummy2;
        uint32_t item_count;
        uint32_t checksum_count;
    };
 
    struct ChecksumMapEntry {
        uint32_t count;
        uint32_t firstindex;
    };
#pragma pack(pop)
 
public:
    [[nodiscard]] static std::unique_ptr<PackFile> open(const std::string& path, const EntryCallback& callback = nullptr, const OpenPropertyRequest& requestProperty = nullptr);
 
    static constexpr inline std::string_view GUID = "0C088488F666451E9361297528F2446D";
 
    [[nodiscard]] constexpr std::string_view getGUID() const override {
        return GCF::GUID;
    }
 
    [[nodiscard]] constexpr bool hasEntryChecksums() const override {
        return true;
    }
 
    [[nodiscard]] std::vector<std::string> verifyEntryChecksums() const override;
 
    [[nodiscard]] constexpr bool isCaseSensitive() const override {
        return true;
    }
 
    [[nodiscard]] std::optional<std::vector<std::byte>> readEntry(const std::string& path_) const override;
 
    [[nodiscard]] Attribute getSupportedEntryAttributes() const override;
 
    [[nodiscard]] explicit operator std::string() const override;
 
    [[nodiscard]] uint32_t getVersion() const;
 
    [[nodiscard]] uint32_t getAppID() const;
 
    [[nodiscard]] uint32_t getAppVersion() const;
 
protected:
    using PackFileReadOnly::PackFileReadOnly;
 
    Header header{};
    BlockHeader blockheader{};
    std::vector<Block> blockdata{};
    std::vector<uint32_t> fragmap{};
    DirectoryHeader dirheader{};
    //std::vector<DirectoryEntry2> direntries{};
    std::vector<DirectoryMapEntry> dirmap_entries{};
    DataBlockHeader datablockheader{};
    std::vector<ChecksumMapEntry> chksum_map{};
    std::vector<uint32_t> checksums{};
    std::array<std::byte, 16> decryption_key;
private:
    VPKPP_REGISTER_PACKFILE_OPEN(GCF_EXTENSION, &GCF::open);
};
 
} // namespace vpkpp