protocol.cpp

/* SPDX-License-Identifier: GPLv3-or-later */
/* Copyright (c) 2019 Project WomoLIN */
/* Author Myron Franze <myronfranze@web.de> */

#include "protocol.h"
#include "interface/helper.h"

#include <iostream>

namespace siguni
{

   CProtocol::CProtocol( interface::IControlbus & attControlbus ) 
      : controlbus( attControlbus ) 
   {
   }

   bool CProtocol::GetKeyValue( std::string & attKey, std::string & attValue)
   {
      // if no key or value found, then send empty strings
      attKey.clear();
      attValue.clear();

      // read bytes to buffer 
      std::string buffer;
      if ( 0 >= controlbus.ReadData( buffer ) && 
           0 == messageBuffer.size()
         )
      {
          return false;
      }

      // add read bytes to internal message buffer
      messageBuffer += buffer;

      // search startbyte within messagebuffer, if not found then clear messagebuffer 
      auto pos = helper::CSignalStrings::FindFirstCharacter( messageBuffer, STARTBYTE ); 
      if( pos < 0 )
      {
         messageBuffer.clear(); 
         return false;
      }

      // remove all bytes left from startbyte
      messageBuffer = messageBuffer.substr( pos ); 

      // search first endbyte after first startbyte
      pos = helper::CSignalStrings::FindFirstCharacter( messageBuffer, ENDBYTE ); 
      if( pos < 0 )
      {
         // we have a max size of input messages 
         if( messageBuffer.size() > MESSAGE_BUFFER_MAX_SIZE )
         {
            // clear buffer to prevent a memory overflow for invalid messages 
            messageBuffer.clear(); 
         }
         return false;
      }
      
      // copy a full raw message without start and end byte
      auto protocolString = messageBuffer.substr( 1, pos-1 );

      // remove this message from buffer 
      messageBuffer = messageBuffer.substr( pos+1 );

      // if there is more than one start byte, delete all previous start bytes     
      pos = helper::CSignalStrings::FindLastCharacter( protocolString, STARTBYTE ); 
      if( pos >= 0)
      {
         protocolString = protocolString.substr( pos+1 );
      }
 
      return helper::CSignalStrings::SplitKeyValue( 
                     protocolString, SEPARATOR, attKey, attValue ); 

   }

   void CProtocol::SendKeyValue( std::string & attKey, std::string & attValue )
   {
      std::string message;
      message = STARTBYTE + attKey + SEPARATOR + attValue + ENDBYTE + LINEBREAK;
      controlbus.WriteData( message );
   }


}