CMD_Interpreter.cpp

00001 // *****************************************************************
00002 // Handle all the LEDs with some general function wrappers functions
00003 // *****************************************************************
00004 #include "CMD_Interpreter.h"
00005 
00006 //************************************
00007 // Interpreter Class Creation 
00008 //************************************
00009 // Strategy: the interpreter accumulates characters in its input buffer
00010 // it flags the presence of complete lines
00011 // it also flags Overflow of the buffer in which case all subsequent characters 
00012 //       are lost until the queue is emptied, and a CR-LF is received
00013 // Defined States of the interpreter: 
00014 //     MyState = isStartNew, isLineFilling, isOverflow, isWaitNewLine};
00015 
00016 // #define DEBUG(...) { snprintf(buff, sizeof(buff), __VA_ARGS__);   DataLog( buff );  }
00017 
00018 Interpreter::Interpreter( void ) 
00019 { Reinit( );
00020   MyState = isStartNew;
00021   AllCommands = NULL;
00022   NumCommands = 0;
00023 }
00024 
00025 void Interpreter::FillCommands( int aNumCommands, const  EXE_CMD_TYPE *ACommands  )
00026 {   int cnt;
00027     AllCommands = new EXE_CMD_TYPE[ aNumCommands ];
00028     for( cnt=0; cnt<aNumCommands; cnt++)
00029       { AllCommands[cnt] = ACommands[cnt]; } ;
00030     NumCommands = aNumCommands;
00031 }
00032 
00033 void Interpreter::Reinit( void ) {
00034     MyState = isWaitNewLine; // indicates no buffer overflow
00035     WriteIndex = 0;  // points to next index to write to
00036     LinesComplete = 0; // indicates that no complete line is currently available 
00037     // Start Scanning at the start
00038     ScanIndex = 0;
00039     BufAvail = BuffLen;// the full buffer size is available 
00040  }
00041 
00042 // Barebone function, assumes that checks havee been performed by writeBuf!
00043 void Interpreter::AddChar( char aChar ) {
00044     if (aChar == 8) // is it a backspace code, then remove one character:
00045       { if (BufAvail<BuffLen) { // there's actually a character to be removed
00046             BufAvail++; // Buffer regrows
00047             if (WriteIndex == 0) {WriteIndex=BuffLen-1;}
00048                else {WriteIndex--;} // recoil the write index
00049           }
00050       }
00051     else {
00052         if (WriteIndex == BuffLen-1) {WriteIndex=0;}
00053            else {WriteIndex++;}
00054         RingBuf[WriteIndex]=aChar; // all right, buffer it!
00055         BufAvail--; // Buffer is shrinking
00056         if (BufAvail==0) { MyState = isOverflow; }
00057      }
00058 }                 
00059 
00060 // High level method to add a Char to the buffer,
00061 // Separates at Chars 10, 13, 0; replaced by a single 0 char
00062 // Blocking write when buffer has overflowed
00063 void Interpreter::writeBuf(char aChar) {
00064   bool LineEnds = aChar==10 || aChar==13 || aChar==0;
00065   switch (MyState) {
00066     case isOverflow: break;
00067     case isStartNew:  // ready for the next line to start
00068         // avoid that consecutive CR LF are counted as multiple lines 
00069         if (!LineEnds) {AddChar(aChar ); MyState = isLineFilling; } 
00070         break;
00071     case isLineFilling:// New line has started filling
00072         if (!LineEnds)  {AddChar(aChar);} 
00073           else 
00074             {MyState = isStartNew; // ready for the next line
00075              // Between consecutive commands, the endstring=NULL character is inserted
00076              // this is to indicate that line was already counted as completed
00077              AddChar(0 ); // append a line end char, will detect bufferFull!
00078              LinesComplete++; } // count completed lines        
00079         break;
00080     case isWaitNewLine: // waiting for a new line end to arrive after an overflow
00081         if (LineEnds) { MyState = isStartNew; }
00082         break;
00083     default: MyState = isOverflow; // goes into error state, should never happen though
00084     }   
00085 } // writeBuf
00086 
00087 // Barebone function, that performs the checks to be performed!
00088 // Passes back the actC, and reads already the nextChar into actC
00089 char Interpreter::GetAChar( void ) {
00090 char oldC = actC;
00091     if (BufAvail==BuffLen) { actC = 0; LinesComplete=0; } // buffer is empty, no more lines!!
00092     else // something is in the buffer 
00093       { if (ScanIndex == BuffLen) {ScanIndex=0;}
00094            else {ScanIndex++;}
00095         actC=RingBuf[ScanIndex]; // all right, get it
00096         if (actC==0) {LinesComplete--; } // now there is one line less in the storage
00097         BufAvail++; // Buffer is increasing
00098       } // something is in the buffer 
00099     return oldC;
00100 }                 
00101 
00102 // skip true blank, but also Tab characters
00103 void Interpreter::SkipBlanks( void ) {
00104     while(BufAvail<BuffLen && (actC==' ' || actC==9|| actC==0)) { GetAChar(); }
00105 } // SkipBlanks
00106 
00107 int Interpreter::ReadAnInt( void ) {
00108 bool Negative = false;
00109 int  Result = 0;
00110     if (actC=='-') {Negative = true; GetAChar(); }
00111     else if (actC=='+') {Negative = false; GetAChar(); }
00112     while(BufAvail<BuffLen  && actC>='0' && actC<='9') 
00113         { Result = Result * 10 + (GetAChar()-'0') ; }
00114     return Negative? -Result : Result;
00115 } // ReadAnInt
00116 
00117 
00118 RD_CMD_TYPE Interpreter::ParseCommand( void ) {
00119   RD_CMD_TYPE cmd; // locally built command
00120     actC=RingBuf[ScanIndex]; // initialiye the actC variable, as the first char to use
00121     SkipBlanks();
00122     // Next Character is the command
00123     cmd.Command = GetAChar();
00124     // Next Blanks are to be omitted, but are not even mandatory
00125     SkipBlanks();
00126     if ((actC>='0' && actC<='9') || actC=='-' || actC=='+' )
00127            { cmd.Parameter= ReadAnInt(); cmd.NumParam = 1; }
00128       else { cmd.Parameter= 0;           cmd.NumParam = 0; }
00129     SkipBlanks( ); // There should be at least a trailing NUL character to be removed
00130     return cmd; // return the built command
00131 }
00132 
00133 bool Interpreter::executeCommand(RD_CMD_TYPE cmd) {
00134     int CmdNr;
00135     bool Found;
00136     CmdNr = 0;
00137     Found = false; 
00138     // DEBUG("Com '%c'=%d %d NPar=%d \n\r",cmd.Command, cmd.Command, cmd.Parameter, cmd.NumParam);
00139     // While not found go through all the commands, linear; they are not sorted by alphabet.
00140     while(CmdNr<NumCommands && !Found) 
00141       { // DEBUG("NR:%d \n\r", CmdNr);
00142         if (AllCommands[CmdNr].cmd == cmd.Command) 
00143             { // the command character matches
00144               if (cmd.NumParam == AllCommands[CmdNr].Npar) 
00145                   { // DEBUG("Execute: %s \n\r", AllCommands[CmdNr].help);
00146                     AllCommands[CmdNr].Handler( cmd.Parameter ); // then call the handler 
00147                   }
00148                //  else { DataLog("Param Mismatch!\n\r");  } // Inform about Parameter error
00149             Found = true; // and mark as found 
00150             }
00151         else { CmdNr++; } // go on serarching
00152       } // while   
00153     // if ( !Found )  { CmdInval(cmd.Command) ;  } // call invalid command function
00154     return Found;
00155 }
00156 
00157 bool Interpreter::ProcessPresentCommands( void )
00158 {   RD_CMD_TYPE Readcmd;
00159     if (MyState==isOverflow)   { Reinit(); } 
00160     if(LinesComplete>0) 
00161        { // DEBUG("X: Scan=%d ", Interp.ScanIndex); 
00162          Readcmd = ParseCommand();
00163          executeCommand( Readcmd ); 
00164          //DEBUG("state=%d; wix=%d; rix=%d; buf=%s ", Interp.MyState, Interp.WriteIndex, Interp.ScanIndex, &Interp.RingBuf[Interp.ScanIndex]); 
00165          return true;
00166         } 
00167       else { return false; }
00168 }
00169 
00170 char *ParamHelp[] = {"     ", "<param>", "<par><par>"};
00171 
00172 void Interpreter::PrtCmdHelp  (Serial *aSerial ) // Display list of Commands
00173 {   EXE_CMD_TYPE *com;
00174     int CmdNr;
00175     char *parStr;
00176     // DataLog("List of commands: \n\r"); 
00177     // Go Through all commands in the table
00178     for (CmdNr = 0; CmdNr<NumCommands; CmdNr++ )
00179       { com = &AllCommands[CmdNr]; // get a pointer to the command
00180         parStr = ParamHelp[com->Npar]; // Get the string that represents the number of parameters
00181         aSerial->printf( " %c %s => %s \n\r", com->cmd, parStr, com->help.c_str() );  // output the full command help
00182       }   
00183 }
00184 
00185 /*
00186 void Interpreter::CmdInval( int param ) // Feedback that the command is invalid
00187 { DEBUG( " Invalid command %d = '%c'; use: 'h' for help. \n\r",  param, char(param) ) ; 
00188 }
00189 
00190 string Interpreter::GetLastMessage( void )
00191 { string LastMsg = LastMessage;
00192   LastMessage = ""; // Empty the old Message
00193   return LastMsg;
00194 }
00195 
00196 void Interpreter::DataLog( char *DebugMessage )
00197 { if (LastMessage=="" ) { LastMessage = DebugMessage; }
00198     else { LastMessage = LastMessage + "\n\r" + DebugMessage; }
00199 };
00200 */