Tooltron

/* 

 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.

 * Copyright (c) 2006 Christian Walter <wolti@sil.at>

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. The name of the author may not be used to endorse or promote products

 *    derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * File: $Id: mbfuncinput.c,v 1.10 2007/09/12 10:15:56 wolti Exp $

 */

/* ----------------------- System includes ----------------------------------*/

#include "stdlib.h"

#include "string.h"

/* ----------------------- Platform includes --------------------------------*/

#include "port.h"

/* ----------------------- Modbus includes ----------------------------------*/

#include "mb.h"

#include "mbframe.h"

#include "mbproto.h"

#include "mbconfig.h"

/* ----------------------- Defines ------------------------------------------*/

#define MB_PDU_FUNC_READ_ADDR_OFF           ( MB_PDU_DATA_OFF )

#define MB_PDU_FUNC_READ_REGCNT_OFF         ( MB_PDU_DATA_OFF + 2 )

#define MB_PDU_FUNC_READ_SIZE               ( 4 )

#define MB_PDU_FUNC_READ_REGCNT_MAX         ( 0x007D )

#define MB_PDU_FUNC_READ_RSP_BYTECNT_OFF    ( MB_PDU_DATA_OFF )

/* ----------------------- Static functions ---------------------------------*/

eMBException    prveMBError2Exception( eMBErrorCode eErrorCode );

/* ----------------------- Start implementation -----------------------------*/

#if MB_FUNC_READ_INPUT_ENABLED > 0

eMBException

eMBFuncReadInputRegister( UCHAR * pucFrame, USHORT * usLen )

{

    USHORT          usRegAddress;

    USHORT          usRegCount;

    UCHAR          *pucFrameCur;

    eMBException    eStatus = MB_EX_NONE;

    eMBErrorCode    eRegStatus;

    if( *usLen == ( MB_PDU_FUNC_READ_SIZE + MB_PDU_SIZE_MIN ) )

    {

        usRegAddress = ( USHORT )( pucFrame[MB_PDU_FUNC_READ_ADDR_OFF] << 8 );

        usRegAddress |= ( USHORT )( pucFrame[MB_PDU_FUNC_READ_ADDR_OFF + 1] );

        usRegAddress++;

        usRegCount = ( USHORT )( pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF] << 8 );

        usRegCount |= ( USHORT )( pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF + 1] );

        /* Check if the number of registers to read is valid. If not

         * return Modbus illegal data value exception. 

         */

        if( ( usRegCount >= 1 )

            && ( usRegCount < MB_PDU_FUNC_READ_REGCNT_MAX ) )

        {

            /* Set the current PDU data pointer to the beginning. */

            pucFrameCur = &pucFrame[MB_PDU_FUNC_OFF];

            *usLen = MB_PDU_FUNC_OFF;

            /* First byte contains the function code. */

            *pucFrameCur++ = MB_FUNC_READ_INPUT_REGISTER;

            *usLen += 1;

            /* Second byte in the response contain the number of bytes. */

            *pucFrameCur++ = ( UCHAR )( usRegCount * 2 );

            *usLen += 1;

            eRegStatus =

                eMBRegInputCB( pucFrameCur, usRegAddress, usRegCount );

            /* If an error occured convert it into a Modbus exception. */

            if( eRegStatus != MB_ENOERR )

            {

                eStatus = prveMBError2Exception( eRegStatus );

            }

            else

            {

                *usLen += usRegCount * 2;

            }

        }

        else

        {

            eStatus = MB_EX_ILLEGAL_DATA_VALUE;

        }

    }

    else

    {

        /* Can't be a valid read input register request because the length

         * is incorrect. */

        eStatus = MB_EX_ILLEGAL_DATA_VALUE;

    }

    return eStatus;

}

#endif