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/* 
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 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
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 * Copyright (c) 2006 Christian Walter <wolti@sil.at>
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. The name of the author may not be used to endorse or promote products
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 *    derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 *
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 * File: $Id: mbfuncinput.c,v 1.10 2007/09/12 10:15:56 wolti Exp $
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 */
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/* ----------------------- System includes ----------------------------------*/
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#include "stdlib.h"
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#include "string.h"
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/* ----------------------- Platform includes --------------------------------*/
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#include "port.h"
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/* ----------------------- Modbus includes ----------------------------------*/
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#include "mb.h"
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#include "mbframe.h"
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#include "mbproto.h"
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#include "mbconfig.h"
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/* ----------------------- Defines ------------------------------------------*/
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#define MB_PDU_FUNC_READ_ADDR_OFF           ( MB_PDU_DATA_OFF )
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#define MB_PDU_FUNC_READ_REGCNT_OFF         ( MB_PDU_DATA_OFF + 2 )
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#define MB_PDU_FUNC_READ_SIZE               ( 4 )
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#define MB_PDU_FUNC_READ_REGCNT_MAX         ( 0x007D )
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#define MB_PDU_FUNC_READ_RSP_BYTECNT_OFF    ( MB_PDU_DATA_OFF )
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/* ----------------------- Static functions ---------------------------------*/
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eMBException    prveMBError2Exception( eMBErrorCode eErrorCode );
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/* ----------------------- Start implementation -----------------------------*/
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#if MB_FUNC_READ_INPUT_ENABLED > 0
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eMBException
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eMBFuncReadInputRegister( UCHAR * pucFrame, USHORT * usLen )
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{
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    USHORT          usRegAddress;
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    USHORT          usRegCount;
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    UCHAR          *pucFrameCur;
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    eMBException    eStatus = MB_EX_NONE;
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    eMBErrorCode    eRegStatus;
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    if( *usLen == ( MB_PDU_FUNC_READ_SIZE + MB_PDU_SIZE_MIN ) )
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    {
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        usRegAddress = ( USHORT )( pucFrame[MB_PDU_FUNC_READ_ADDR_OFF] << 8 );
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        usRegAddress |= ( USHORT )( pucFrame[MB_PDU_FUNC_READ_ADDR_OFF + 1] );
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        usRegAddress++;
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        usRegCount = ( USHORT )( pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF] << 8 );
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        usRegCount |= ( USHORT )( pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF + 1] );
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        /* Check if the number of registers to read is valid. If not
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         * return Modbus illegal data value exception. 
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         */
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        if( ( usRegCount >= 1 )
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            && ( usRegCount < MB_PDU_FUNC_READ_REGCNT_MAX ) )
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        {
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            /* Set the current PDU data pointer to the beginning. */
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            pucFrameCur = &pucFrame[MB_PDU_FUNC_OFF];
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            *usLen = MB_PDU_FUNC_OFF;
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            /* First byte contains the function code. */
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            *pucFrameCur++ = MB_FUNC_READ_INPUT_REGISTER;
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            *usLen += 1;
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            /* Second byte in the response contain the number of bytes. */
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            *pucFrameCur++ = ( UCHAR )( usRegCount * 2 );
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            *usLen += 1;
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            eRegStatus =
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                eMBRegInputCB( pucFrameCur, usRegAddress, usRegCount );
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            /* If an error occured convert it into a Modbus exception. */
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            if( eRegStatus != MB_ENOERR )
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            {
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                eStatus = prveMBError2Exception( eRegStatus );
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            }
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            else
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            {
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                *usLen += usRegCount * 2;
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            }
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        }
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        else
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        {
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            eStatus = MB_EX_ILLEGAL_DATA_VALUE;
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        }
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    }
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    else
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    {
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        /* Can't be a valid read input register request because the length
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         * is incorrect. */
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        eStatus = MB_EX_ILLEGAL_DATA_VALUE;
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    }
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    return eStatus;
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}
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#endif