DarkflameServer/thirdparty/raknet/Source/CheckSum.cpp

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/**
* @file
* @brief CheckSum implementation from http://www.flounder.com/checksum.htm
*
*/
#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)