/* 
 * 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: mbfuncholding.c,v 1.12 2007/02/18 23:48:22 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 + 0)
#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_WRITE_ADDR_OFF              ( MB_PDU_DATA_OFF + 0)
#define MB_PDU_FUNC_WRITE_VALUE_OFF             ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_WRITE_SIZE                  ( 4 )

#define MB_PDU_FUNC_WRITE_MUL_ADDR_OFF          ( MB_PDU_DATA_OFF + 0 )
#define MB_PDU_FUNC_WRITE_MUL_REGCNT_OFF        ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF       ( MB_PDU_DATA_OFF + 4 )
#define MB_PDU_FUNC_WRITE_MUL_VALUES_OFF        ( MB_PDU_DATA_OFF + 5 )
#define MB_PDU_FUNC_WRITE_MUL_SIZE_MIN          ( 5 )
#define MB_PDU_FUNC_WRITE_MUL_REGCNT_MAX        ( 0x0078 )

#define MB_PDU_FUNC_READWRITE_READ_ADDR_OFF     ( MB_PDU_DATA_OFF + 0 )
#define MB_PDU_FUNC_READWRITE_READ_REGCNT_OFF   ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_READWRITE_WRITE_ADDR_OFF    ( MB_PDU_DATA_OFF + 4 )
#define MB_PDU_FUNC_READWRITE_WRITE_REGCNT_OFF  ( MB_PDU_DATA_OFF + 6 )
#define MB_PDU_FUNC_READWRITE_BYTECNT_OFF       ( MB_PDU_DATA_OFF + 8 )
#define MB_PDU_FUNC_READWRITE_WRITE_VALUES_OFF  ( MB_PDU_DATA_OFF + 9 )
#define MB_PDU_FUNC_READWRITE_SIZE_MIN          ( 9 )

/* ----------------------- Static functions ---------------------------------*/
eMBException    prveMBError2Exception( eMBErrorCode eErrorCode );

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

#if MB_FUNC_WRITE_HOLDING_ENABLED > 0

eMBException
eMBFuncWriteHoldingRegister( UCHAR * pucFrame, USHORT * usLen )
{
    USHORT          usRegAddress;
    eMBException    eStatus = MB_EX_NONE;
    eMBErrorCode    eRegStatus;

    if( *usLen == ( MB_PDU_FUNC_WRITE_SIZE + MB_PDU_SIZE_MIN ) )
    {
        usRegAddress = ( USHORT )( pucFrame[MB_PDU_FUNC_WRITE_ADDR_OFF] << 8 );
        usRegAddress |= ( USHORT )( pucFrame[MB_PDU_FUNC_WRITE_ADDR_OFF + 1] );
        usRegAddress++;

        /* Make callback to update the value. */
        eRegStatus = eMBRegHoldingCB( &pucFrame[MB_PDU_FUNC_WRITE_VALUE_OFF],
                                      usRegAddress, 1, MB_REG_WRITE );

        /* If an error occured convert it into a Modbus exception. */
        if( eRegStatus != MB_ENOERR )
        {
            eStatus = prveMBError2Exception( eRegStatus );
        }
    }
    else
    {
        /* Can't be a valid request because the length is incorrect. */
        eStatus = MB_EX_ILLEGAL_DATA_VALUE;
    }
    return eStatus;
}
#endif

#if MB_FUNC_WRITE_MULTIPLE_HOLDING_ENABLED > 0
eMBException
eMBFuncWriteMultipleHoldingRegister( UCHAR * pucFrame, USHORT * usLen )
{
    USHORT          usRegAddress;
    USHORT          usRegCount;
    UCHAR           ucRegByteCount;

    eMBException    eStatus = MB_EX_NONE;
    eMBErrorCode    eRegStatus;

    if( *usLen >= ( MB_PDU_FUNC_WRITE_MUL_SIZE_MIN + MB_PDU_SIZE_MIN ) )
    {
        usRegAddress = ( USHORT )( pucFrame[MB_PDU_FUNC_WRITE_MUL_ADDR_OFF] << 8 );
        usRegAddress |= ( USHORT )( pucFrame[MB_PDU_FUNC_WRITE_MUL_ADDR_OFF + 1] );
        usRegAddress++;

        usRegCount = ( USHORT )( pucFrame[MB_PDU_FUNC_WRITE_MUL_REGCNT_OFF] << 8 );
        usRegCount |= ( USHORT )( pucFrame[MB_PDU_FUNC_WRITE_MUL_REGCNT_OFF + 1] );

        ucRegByteCount = pucFrame[MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF];

        if( ( usRegCount >= 1 ) &&
            ( usRegCount <= MB_PDU_FUNC_WRITE_MUL_REGCNT_MAX ) &&
            ( ucRegByteCount == ( UCHAR ) ( 2 * usRegCount ) ) )
        {
            /* Make callback to update the register values. */
            eRegStatus =
                eMBRegHoldingCB( &pucFrame[MB_PDU_FUNC_WRITE_MUL_VALUES_OFF],
                                 usRegAddress, usRegCount, MB_REG_WRITE );

            /* If an error occured convert it into a Modbus exception. */
            if( eRegStatus != MB_ENOERR )
            {
                eStatus = prveMBError2Exception( eRegStatus );
            }
            else
            {
                /* The response contains the function code, the starting
                 * address and the quantity of registers. We reuse the
                 * old values in the buffer because they are still valid.
                 */
                *usLen = MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF;
            }
        }
        else
        {
            eStatus = MB_EX_ILLEGAL_DATA_VALUE;
        }
    }
    else
    {
        /* Can't be a valid request because the length is incorrect. */
        eStatus = MB_EX_ILLEGAL_DATA_VALUE;
    }
    return eStatus;
}
#endif

#if MB_FUNC_READ_HOLDING_ENABLED > 0

eMBException
eMBFuncReadHoldingRegister( 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_HOLDING_REGISTER;
            *usLen += 1;

            /* Second byte in the response contain the number of bytes. */
            *pucFrameCur++ = ( UCHAR ) ( usRegCount * 2 );
            *usLen += 1;

            /* Make callback to fill the buffer. */
            eRegStatus = eMBRegHoldingCB( pucFrameCur, usRegAddress, usRegCount, MB_REG_READ );
            /* 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 request because the length is incorrect. */
        eStatus = MB_EX_ILLEGAL_DATA_VALUE;
    }
    return eStatus;
}

#endif

#if MB_FUNC_READWRITE_HOLDING_ENABLED > 0

eMBException
eMBFuncReadWriteMultipleHoldingRegister( UCHAR * pucFrame, USHORT * usLen )
{
    USHORT          usRegReadAddress;
    USHORT          usRegReadCount;
    USHORT          usRegWriteAddress;
    USHORT          usRegWriteCount;
    UCHAR           ucRegWriteByteCount;
    UCHAR          *pucFrameCur;

    eMBException    eStatus = MB_EX_NONE;
    eMBErrorCode    eRegStatus;

    if( *usLen >= ( MB_PDU_FUNC_READWRITE_SIZE_MIN + MB_PDU_SIZE_MIN ) )
    {
        usRegReadAddress = ( USHORT )( pucFrame[MB_PDU_FUNC_READWRITE_READ_ADDR_OFF] << 8U );
        usRegReadAddress |= ( USHORT )( pucFrame[MB_PDU_FUNC_READWRITE_READ_ADDR_OFF + 1] );
        usRegReadAddress++;

        usRegReadCount = ( USHORT )( pucFrame[MB_PDU_FUNC_READWRITE_READ_REGCNT_OFF] << 8U );
        usRegReadCount |= ( USHORT )( pucFrame[MB_PDU_FUNC_READWRITE_READ_REGCNT_OFF + 1] );

        usRegWriteAddress = ( USHORT )( pucFrame[MB_PDU_FUNC_READWRITE_WRITE_ADDR_OFF] << 8U );
        usRegWriteAddress |= ( USHORT )( pucFrame[MB_PDU_FUNC_READWRITE_WRITE_ADDR_OFF + 1] );
        usRegWriteAddress++;

        usRegWriteCount = ( USHORT )( pucFrame[MB_PDU_FUNC_READWRITE_WRITE_REGCNT_OFF] << 8U );
        usRegWriteCount |= ( USHORT )( pucFrame[MB_PDU_FUNC_READWRITE_WRITE_REGCNT_OFF + 1] );

        ucRegWriteByteCount = pucFrame[MB_PDU_FUNC_READWRITE_BYTECNT_OFF];

        if( ( usRegReadCount >= 1 ) && ( usRegReadCount <= 0x7D ) &&
            ( usRegWriteCount >= 1 ) && ( usRegWriteCount <= 0x79 ) &&
            ( ( 2 * usRegWriteCount ) == ucRegWriteByteCount ) )
        {
            /* Make callback to update the register values. */
            eRegStatus = eMBRegHoldingCB( &pucFrame[MB_PDU_FUNC_READWRITE_WRITE_VALUES_OFF],
                                          usRegWriteAddress, usRegWriteCount, MB_REG_WRITE );

            if( eRegStatus == MB_ENOERR )
            {
                /* 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_READWRITE_MULTIPLE_REGISTERS;
                *usLen += 1;

                /* Second byte in the response contain the number of bytes. */
                *pucFrameCur++ = ( UCHAR ) ( usRegReadCount * 2 );
                *usLen += 1;

                /* Make the read callback. */
                eRegStatus =
                    eMBRegHoldingCB( pucFrameCur, usRegReadAddress, usRegReadCount, MB_REG_READ );
                if( eRegStatus == MB_ENOERR )
                {
                    *usLen += 2 * usRegReadCount;
                }
            }
            if( eRegStatus != MB_ENOERR )
            {
                eStatus = prveMBError2Exception( eRegStatus );
            }
        }
        else
        {
            eStatus = MB_EX_ILLEGAL_DATA_VALUE;
        }
    }
    return eStatus;
}

#endif
