sMQTTMessage.h

#ifndef SMQTTMESSAGE_FILE
#define SMQTTMESSAGE_FILE
 
#include<vector>
#include<string>
 
#if (__cplusplus >= 201703L)
#define MAYBE_UNUSED [[maybe_unused]]
#else
#define MAYBE_UNUSED
#endif
 
enum sMQTTError
{
    sMQTTOk = 0,
    sMQTTNowhereToSend = 1,
    sMQTTInvalidMessage = 2,
};
 
MAYBE_UNUSED static const char *debugMessageType[] = {
    "Unknown",
    "Connect",
    "ConnAck",
    "Publish",
    "PubAck",
    "PubRec",
    "PubRel",
    "PubComp",
    "Subscribe",
    "SubAck",
    "UnSubscribe",
    "UnSuback",
    "PingReq",
    "PingResp",
    "Disconnect"
};
 
class sMQTTClient;
class sMQTTMessage
{
public:
    enum Type
    {
        Unknown = 0,
        Connect = 0x10,
        ConnAck = 0x20,
        Publish = 0x30,
        PubAck = 0x40,
        PubRec = 0x50,
        PubRel = 0x60,
        PubComp=0x70,
        Subscribe = 0x80,
        SubAck = 0x90,
        UnSubscribe = 0xA0,
        UnSuback = 0xB0,
        PingReq = 0xC0,
        PingResp = 0xD0,
        Disconnect = 0xE0
    };
    enum State
    {
        FixedHeader = 0,
        Length = 1,
        VariableHeader = 2,
        PayLoad = 3,
        Complete = 4,
        Error = 5,
        Create = 6
    };
    sMQTTMessage();
    sMQTTMessage(Type t, unsigned char bits_d3_d0 = 0);
    void incoming(char byte);
    void add(char byte) { incoming(byte); }
    void add(const char* p, size_t len, bool addLength = true)
    {
        if (addLength)
        {
            buffer.reserve(buffer.size() + len + 2);
            incoming(len >> 8);
            incoming(len & 0xFF);
        }
        while (len--) incoming(*p++);
    }
    void add(const std::string &str) { add(str.c_str(), str.size()); }
    const char* end() const { return &buffer[0] + buffer.size(); }
    const char* getVHeader() const { return &buffer[vheader]; }
    void reset();
    Type type() const
    {
        return state == Complete ? static_cast<Type>(buffer[0] & 0XF0) : Unknown;
    }
    unsigned char QoS() {
        return (buffer[0] & 0x6)>>1;
    }
    bool isRetained() {
        return buffer[0] & 0x1;
    }
    sMQTTError sendTo(sMQTTClient *, bool needRecalc=true);
    // buff is MSB/LSB/STRING
    // output buff+=2, len=length(str)
    static void getString(const char* &buff, unsigned short &len);
private:
    void create(Type type)
    {
        buffer.push_back((char)type);
        buffer.push_back('\0');     // reserved for msg length
        vheader = 2;
        size = 0;
        state = Create;
    }
    int encodeLength(char* msb, int length) const;
 
    std::vector<char> buffer;
    State state;
    unsigned short multiplyer;
    unsigned short size;
    unsigned char vheader;
};
#endif