Method de

source/src/tools/code.h:14–30

	{
	public:
		static std::vector<unsigned char> de(const std::string& hex_str)
		{
			std::vector<unsigned char> result;
			if (hex_str.empty()) return {};
			if (hex_str.length() % 2 != 0) return {};
			result.reserve(hex_str.length() / 2);
			for (size_t i = 0; i < hex_str.length(); i += 2)
			{
				char c1 = static_cast<char>(std::tolower(static_cast<unsigned char>(hex_str[i])));
				char c2 = static_cast<char>(std::tolower(static_cast<unsigned char>(hex_str[i + 1])));
				if (!std::isxdigit(static_cast<unsigned char>(c1)) || !std::isxdigit(static_cast<unsigned char>(c2))) return {};
				int high = (c1 >= 'a') ? (c1 - 'a' + 10) : (c1 - '0');
				int low = (c2 >= 'a') ? (c2 - 'a' + 10) : (c2 - '0');
				result.push_back(static_cast<unsigned char>((high << 4) | low));
			}
			return result;
		}
		static std::string en(const unsigned char* data, const size_t size)
		{
			if (!data || size <= 0) return {};