CheckSum.cpp

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#include "CheckSum.h"

/****************************************************************************
*        CheckSum::add
* Inputs:
*   unsigned int d: word to add
* Result: void
* 
* Effect: 
*   Adds the bytes of the unsigned int to the CheckSum
****************************************************************************/

void CheckSum::Add ( unsigned int value )
{
        union
        {
                unsigned int value;
                unsigned char bytes[ 4 ];
        }

        data;
        data.value = value;

        for ( unsigned int i = 0; i < sizeof( data.bytes ); i++ )
                Add ( data.bytes[ i ] )

                ;
} // CheckSum::add(unsigned int)

/****************************************************************************
*       CheckSum::add
* Inputs:
*   unsigned short value:
* Result: void
* 
* Effect: 
*   Adds the bytes of the unsigned short value to the CheckSum
****************************************************************************/

void CheckSum::Add ( unsigned short value )
{
        union
        {
                unsigned short value;
                unsigned char bytes[ 2 ];
        }

        data;
        data.value = value;

        for ( unsigned int i = 0; i < sizeof( data.bytes ); i++ )
                Add ( data.bytes[ i ] )

                ;
} // CheckSum::add(unsigned short)

/****************************************************************************
*       CheckSum::add
* Inputs:
*   unsigned char value:
* Result: void
* 
* Effect: 
*   Adds the byte to the CheckSum
****************************************************************************/

void CheckSum::Add ( unsigned char value )
{
        unsigned char cipher = (unsigned char)( value ^ ( r >> 8 ) );
        r = ( cipher + r ) * c1 + c2;
        sum += cipher;
} // CheckSum::add(unsigned char)


/****************************************************************************
*       CheckSum::add
* Inputs:
*   LPunsigned char b: pointer to byte array
*   unsigned int length: count
* Result: void
* 
* Effect: 
*   Adds the bytes to the CheckSum
****************************************************************************/

void CheckSum::Add ( unsigned char *b, unsigned int length )
{
        for ( unsigned int i = 0; i < length; i++ )
                Add ( b[ i ] )

                ;
} // CheckSum::add(LPunsigned char, unsigned int)