/***************************************************************************\
	Dynamic C MODBus ASCII/RTU Slave
		Copyright (c) 2002 Z-World, Inc.
		Copyright (c) 1997, CFControls.
\***************************************************************************/

/*** BeginHeader */
#ifndef __MS_RAB_LIB
#define __MS_RAB_LIB

//	Supported MODBus Exceptions
#define	MS_BADFUNC		0x01		//	Illegal Function
#define	MS_BADADDR		0x02		//	Illegal Data Address
#define	MS_BADDATA		0x03		//	Illegal Data Value
/*** EndHeader */

/***************************************************************************\
	MODBus Packet Utilities & Globals
\***************************************************************************/

/*** BeginHeader msInit */
extern
shared char		*pcMSCmd,*pcMSRep;
extern
char				acMSCmd[256],acMSRep[256];
extern
unsigned			wMSAddr;

unsigned msCmdWord ( unsigned wOff );

void msError ( void );
void msRecv ( int nByte );
int msSend ( char *pcMess,unsigned wLen );

void msRun ( void );
void msInit ( unsigned wAddr );
/*** EndHeader */

unsigned			wMSAddr;						//	Network Address
unsigned			wMSComm;						//	Communication Counters
unsigned			wMSCmd;						//	Command Opcode
													//	Don't Change Order
shared char		*pcMSCmd;						//	Command Pointer
char				acMSCmd[256];					//	Command Buffer
shared char		*pcMSRep;						//	Reply Pointer
char				acMSRep[256];					//	Reply Buffer

/*=========================================================================*\
	Extract Word (MSB First) from Command Body
\*=========================================================================*/

nodebug
unsigned msCmdWord(unsigned wOff)
{
	return(acMSCmd[wOff] << 8) + acMSCmd[wOff + 1];
}

/*=========================================================================*\
	Add Byte to Reply Body
\*=========================================================================*/

nodebug
int msRepByte(char cByte)
{
	if(&acMSRep[sizeof(acMSRep) - 1] <= pcMSRep)
		return 0;
	*pcMSRep++ = cByte;
	return 1;
}

/*=========================================================================*\
	Add Word to Reply (MSB First)
\*=========================================================================*/

nodebug
int msRepWord(unsigned wWord)
{
	return msRepByte(wWord >> 8) && msRepByte(wWord);
}

/*=========================================================================*\
	Start New Reply
\*=========================================================================*/

nodebug
void msRepNew(unsigned wCmd)
{
	pcMSRep = acMSRep;					//	Reset Reply Pointer
	msRepByte ( wMSAddr );				//	Slave Address
	msRepByte ( wCmd );					//	Command Opcode
}

/*=========================================================================*\
	Complete Reply Body
\*=========================================================================*/

nodebug
int msRepDone()
{
	++wMSComm;								//	Inc Comm Counter
	return 1;								//	Success
}

/*=========================================================================*\
	Compose Exception Reply
\*=========================================================================*/

nodebug
int msRepErr(unsigned wCode)
{
	msRepNew ( 0x80|wMSCmd );			//	Start Reply (Set Error Flag)
	msRepByte ( wCode );					//	Error Code
	--wMSComm;								//	Adjust Comm Counter
	return msRepDone ();					//	Complete Reply
}

/***************************************************************************\
	MODBus I/O Utilities
\***************************************************************************/

/*=========================================================================*\
	Read Coils (Output or Input)
\*=========================================================================*/

nodebug
int msCoilRd(int (*pxRd)())
{
	unsigned wCoil, wCount;
	int nState, nErr;
	char cAcc, cMask;

	if (!acMSCmd[0])									//	Broadcast Not Supported
		return 0;

	wCoil = msCmdWord(2);							//	Starting Address
	wCount = msCmdWord(4);							//	Count
	msRepNew(wMSCmd);									//	Start Reply
	msRepByte((wCount + 7) >> 3);					//	Byte Count
	while (wCount) {
		cAcc = 0;										// Read Coils
		for (cMask = 0x01; cMask && wCount; cMask <<= 1, wCount--) {
			if (nErr = pxRd(wCoil++, &nState))
				return msRepErr(nErr);
			if (nState)
				cAcc |= cMask;
		}
		msRepByte(cAcc);								//	Add Coil to Packet
	}
	return msRepDone();								//	Complete & Send Reply
}

/*=========================================================================*\
	Read Registers (Input or Holding)
\*=========================================================================*/

nodebug
int msRegRd(int (*pxRd)())
{
	unsigned wAddr, wCount, wData;
	int nErr;

	if (!acMSCmd[0])									//	Broadcast Not Supported
		return 0;

	wAddr = msCmdWord(2);							//	Starting Address
	wCount = msCmdWord(4);							//	Count
	msRepNew(wMSCmd);									//	Start Reply
	msRepByte(2 * wCount);							//	Byte Count
	while (wCount--) {								//	Read Registers
		if (nErr = pxRd(wAddr++, &wData))
			return msRepErr(nErr);
		msRepWord(wData);								//	Add Word to Packet
	}
	return msRepDone();								//	Complete & Send Reply
}

/*=========================================================================*\
	Write Registers (No Reply)
\*=========================================================================*/

nodebug
int msRegWr(unsigned wOff)
{
	unsigned wAddr, wCount;
	int nErr;

	wAddr = msCmdWord(wOff);						//	Register Address
	wCount = msCmdWord(wOff += 2);				//	Register Count
	++wOff;												//	Skip Byte Count
	while (wCount--) {								//	Write Registers
		if (nErr = msWrite(wAddr++, msCmdWord(wOff += 2))) {
			msRepErr(nErr);
			return 0;
		}
	}
	return 1;
}

/***************************************************************************\
	MODBus Command/Reply Processors
\***************************************************************************/

/*=========================================================================*\
	[0x01] Read Output Coil Status
\*=========================================================================*/

nodebug
int
msCmdOutRd		(	void
					)

{
	return msCoilRd ( msOutRd );
}

/*=========================================================================*\
	[0x02] Read Input Coils
\*=========================================================================*/

nodebug
int
msCmdIn			(	void
					)
					
{
	return msCoilRd ( msIn );
}

/*=========================================================================*\
	[0x03] Read Holding Registers
\*=========================================================================*/

nodebug
int
msCmdRead		(	void
					)
					
{
	return msRegRd ( msRead );
}

/*=========================================================================*\
	[0x04] Read Input Registers
\*=========================================================================*/

nodebug
int
msCmdInput		(	void
					)
					
{
	return msRegRd ( msInput );
}

/*=========================================================================*\
	[0x05] Force Single Coil
\*=========================================================================*/

nodebug
int
msForceCoil	(	void
					)
					
{	unsigned		wCoil,wData;
	int			nErr;

	nErr = MS_BADDATA;
	wCoil = msCmdWord ( 2 );				//	Coil Number
	wData = msCmdWord ( 4 );				//	Coil State
	switch ( wData ) {
		case	0x0000	:						//	Force Coil Off
			nErr = msOutWr ( wCoil,0 );
			break;
		case	0xFF00	:						//	Force Coil On
			nErr = msOutWr ( wCoil,1 );
			break;
	}
	if (nErr)
		return msRepErr ( nErr );
	msRepNew ( wMSCmd );						//	Start Reply
	msRepWord ( wCoil );						//	Coil Number
	msRepWord ( wData );						//	Coil State
	return msRepDone ();						//	Complete & Send Reply
}

/*=========================================================================*\
	[0x06] Preset Single Register
\*=========================================================================*/

nodebug
int
msPresetReg	(	void
					)
					
{	unsigned		wAddr,wData;
	int			nErr;

	wAddr = msCmdWord ( 2 );			//	Register Address
	wData = msCmdWord ( 4 );			//	Register Value
	nErr = msWrite ( wAddr,wData );	//	Write Register
	if (nErr)
		return msRepErr ( nErr );
	msRepNew ( wMSCmd );					//	Start Reply
	msRepWord ( wAddr );					//	Register Address
	msRepWord ( wData );					//	Register Data
	return msRepDone ();					//	Complete & Send Reply
}

/*=========================================================================*\
	[0x0B] Fetch Comm Event Counter
\*=========================================================================*/

nodebug
int
msFetchComm	(	void
					)
					
{
	if (!acMSCmd[0])			//	Broadcast Not Supported
		return 0;

	msRepNew ( wMSCmd );		//	Start Reply
	msRepWord ( 0x0000 );	//	Slave Not Busy
	msRepWord ( wMSComm );	//	Comm Counter
	return msRepDone ();		//	Complete & Send Reply
}

/*=========================================================================*\
	[0x0F] Force Multiple Coils
\*=========================================================================*/

nodebug
int
msForceCoils	(	void
					)
					
{
	unsigned		wCoil,wCount,wState,wBit;
	char			*pcState;