Meta.hpp

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#pragma once
#include <Algorithm/Algorithm.hpp>
#include <Core/Core.hpp>
#include <Logger/Logger.hpp>
#include <Utility/SizeUtils.hpp>
#include "Endianness.hpp"
#include <bit>
#include <fstream>
#include <iostream>
#include <sha.h>
//#include <sha3.h>
 
NS_ENIGMA_BEGIN
class Meta final {
    ENIGMA_STATIC_CLASS(Meta);
 
  public:
    using magic_t = std::uint64_t;
    using size_type = std::size_t;
    static constexpr const magic_t ENIGMA_MAGIC = 0x456e69676d61;
    static constexpr const magic_t ENIGMA_CIPHER_CHUNK_MAGIC = 0x43456e69676d6143;
    static constexpr const size_type ENIGMA_BUFFER_DEFAULT_SIZE = ENIGMA_KB_TO_BYTES(64); // 64KB chunk size is reasonable for memory usage and efficiency.
 
#pragma pack(push, 1)
    struct EnigmaFooter {
        magic_t magic = ENIGMA_MAGIC;
        std::uint64_t version = ENIGMA_VERSION_MAJOR * 100'000 + ENIGMA_VERSION_MINOR * 1000 + ENIGMA_VERSION_PATCH;
        Algorithm::Type algo{};
        std::array<byte, CryptoPP::SHA256::DIGESTSIZE> hash{};
        std::vector<byte> iv{};
        std::vector<byte> extra{};
 
 
        [[nodiscard]] size_type sizeInBytes() const noexcept;
 
        [[nodiscard]] std::vector<byte> toBytes() const;
 
        [[nodiscard]] static EnigmaFooter fromBytes(const std::vector<byte>& bytes);
        [[nodiscard]] static EnigmaFooter fromBytes(const byte *bytes, const std::size_t bytesSize);
        [[nodiscard]] static EnigmaFooter fromBase64(const std::string& base64);
        [[nodiscard]] static EnigmaFooter fromFile(const fs::path& filename);
    };
 
    struct EnigmaCipherChunk {
        magic_t magic = ENIGMA_CIPHER_CHUNK_MAGIC;
        std::vector<byte> cipher;
        std::vector<byte> extra;
 
        [[nodiscard]] size_type sizeInBytes() const noexcept;
 
        [[nodiscard]] std::vector<byte> toBytes() const;
 
        // readCipherChunks() will read this
    };
#pragma pack(pop)
 
    // Sanity checks
    // Ensure that size of magic_t is same on all platforms,
    // so if you encrypt in Windows, you can decrypt in Linux..
    static_assert(std::endian::native == std::endian::little, "Host must be little endian");
    static_assert(sizeof(magic_t) == 8, "Magic type must be of 8 bytes");
    static_assert(sizeof(size_type) == 8, "Size type must be of 8 bytes");
 
    static bool isEnigmaFile(const fs::path& filename);
 
    static bool isEnigmaCipher(const byte *cipher, const std::size_t cipherSize);
    static bool isEnigmaCipher(const std::vector<byte>& cipher);
 
    static void readCipherChunks(const fs::path& filename, const std::function<bool(EnigmaCipherChunk&&)>& callback);
};
 
NS_ENIGMA_END