trick/include/trick/var_binary_parser.hh

#include <unistd.h>
#include <vector>
#include <string>
#include <map>
#include <exception>

#include "trick/parameter_types.h"

class IncorrectUsageException : public std::exception 
{
    private:
        std::string _message;
    public:
        IncorrectUsageException(std::string msg) : _message(msg) {}
        const char * what() const noexcept override { return _message.c_str(); }
};

class ParseTypeException : public IncorrectUsageException
{
    public:
        ParseTypeException() : IncorrectUsageException("Mismatched trick type and template call") {}
};

class MalformedMessageException : public std::exception
{
    private:
        std::string _message;
    public:
        MalformedMessageException() : _message("Attempted to parse an incorrectly formed message") {}
        MalformedMessageException(std::string msg) : _message(msg) {}
        const char * what() const noexcept override { return _message.c_str(); }
};

typedef union Number {
    unsigned char raw_bytes[sizeof(long long)];     // Raw bytes 

    uint8_t unsigned_char_val;
    int8_t char_val;
    bool bool_val;

    wchar_t wchar_val;
    uint16_t unsigned_short_val;
    int16_t short_val;

    uint32_t unsigned_int_val;
    int32_t int_val;

    uint64_t unsigned_long_val;
    int64_t long_val;

    unsigned long long unsigned_long_long_val;
    long long long_long_val;

    float float_val;
    double double_val;
} Number;

const static std::map<TRICK_TYPE, unsigned int> type_size_map = {{TRICK_CHARACTER, sizeof(char)},
                                                                 {TRICK_UNSIGNED_CHARACTER, sizeof(unsigned char)},
                                                                 {TRICK_SHORT, sizeof(short)},
                                                                 {TRICK_UNSIGNED_SHORT, sizeof(unsigned short)},
                                                                 {TRICK_INTEGER, sizeof(int)},
                                                                 {TRICK_UNSIGNED_INTEGER, sizeof(unsigned int)},
                                                                 {TRICK_LONG, sizeof(long)},
                                                                 {TRICK_UNSIGNED_LONG, sizeof(unsigned long)},
                                                                 {TRICK_LONG_LONG, sizeof(long long)},
                                                                 {TRICK_UNSIGNED_LONG_LONG, sizeof(unsigned long)},
                                                                 {TRICK_FLOAT, sizeof (float)},
                                                                 {TRICK_DOUBLE, sizeof (double)},
                                                                 {TRICK_BOOLEAN, sizeof (bool)},
                                                                 {TRICK_WCHAR, sizeof (wchar_t)}
                                                                };

    
class Var {
    public:
        Var () : _has_name(false) {};
        void setValue(const std::vector<unsigned char>& bytes, size_t size, TRICK_TYPE type, bool byteswap = false);
        void setName(size_t name_size, const std::vector<unsigned char>& name_data);

        // The closest to runtime return type polymorphism that I can think of
        // There won't be a general case
        template <typename T>
        T getValue() const;
        std::vector<unsigned char> getRawBytes() const;
        
        int getArraySize() const;
        std::string getName() const;
        TRICK_TYPE getType() const;


    private:
        std::vector<unsigned char> value_bytes;
        Number getInterpreter () const;

        bool _has_name;
        unsigned int _name_length;
        std::string _name;

        bool _byteswap;

        TRICK_TYPE _trick_type;
        unsigned int _var_size;
        unsigned int _arr_length;
};

class ParsedBinaryMessage {
    public:
        ParsedBinaryMessage() : ParsedBinaryMessage(false, false)  {}
        ParsedBinaryMessage (bool byteswap, bool nonames) : _message_type(0), _message_size(0), _num_vars(0), _byteswap(byteswap), _nonames(nonames) {}

        void combine (const ParsedBinaryMessage& message);
        
        int parse (const std::vector<unsigned char>& bytes);

        int getMessageType() const;
        unsigned int getMessageSize() const;
        unsigned int getNumVars() const;
        Var getVariable(const std::string& name);
        Var getVariable(unsigned int index);

        std::vector<Var> variables;

    private:
        static bool validateMessageType(int message_type);

        int _message_type;
        unsigned int _message_size;
        unsigned int _num_vars;

        bool _byteswap;
        bool _nonames;

        const static size_t header_size;
        const static size_t message_indicator_size;
        const static size_t variable_num_size;
        const static size_t message_size_size;
        const static size_t variable_name_length_size;
        const static size_t variable_type_size;
        const static size_t variable_size_size;
};