crc.h

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//======================================================================
//======================================================================
 
#ifndef CRC_h_
#define CRC_h_
 
#include "sdhlibrary_settings.h"
 
//----------------------------------------------------------------------
// System Includes - include with <>
//----------------------------------------------------------------------
 
 
//----------------------------------------------------------------------
// Project Includes - include with ""
//----------------------------------------------------------------------
 
#include "basisdef.h"
 
//----------------------------------------------------------------------
// Defines, enums, unions, structs
//----------------------------------------------------------------------
 
NAMESPACE_SDH_START
 
 
typedef UInt16 tCRCValue;   
 
//----------------------------------------------------------------------
// Global variables (declarations)
//----------------------------------------------------------------------
 
 
//----------------------------------------------------------------------
// External functions (function declarations)
//----------------------------------------------------------------------
 
 
//----------------------------------------------------------------------
// Function prototypes (function declarations)
//----------------------------------------------------------------------
 
 
//----------------------------------------------------------------------
// Class declarations
//----------------------------------------------------------------------
 
class VCC_EXPORT cCRC
{
 protected:
    tCRCValue current_crc;
 
    tCRCValue initial_value;
 
    tCRCValue const* crc_table;
 
 public:
    cCRC( tCRCValue const* _crc_table, tCRCValue _initial_value )
    {
        crc_table     = _crc_table;
        initial_value = _initial_value;
        current_crc   = initial_value;
    }
 
    tCRCValue AddByte( unsigned char byte )
    {
        current_crc = ( (current_crc & 0xFF00) >> 8 ) ^ crc_table[ ( current_crc & 0x00FF ) ^ (byte & 0x00FF)];
        return current_crc;
    }
 
    tCRCValue AddBytes( unsigned char* bytes, int nb_bytes )
    {
        for ( int i=0; i<nb_bytes; i++ )
            current_crc = ( (current_crc & 0xFF00) >> 8 ) ^ crc_table[ ( current_crc & 0x00FF ) ^ (bytes[i] & 0x00FF)];
        return current_crc;
    }
 
    inline tCRCValue GetCRC()
    {
        return current_crc;
    }
 
    inline UInt8 GetCRC_LB()
    {
        return current_crc & 0x00ff;
    }
 
    inline UInt8 GetCRC_HB()
    {
        return (current_crc >> 8) & 0x00ff;
    }
 
    inline tCRCValue Reset()
    {
        current_crc = initial_value;
        return current_crc;
    }
};
//----------------------------------------------------------------------
//----------------------------------------------------------------------
 
class VCC_EXPORT cCRC_DSACON32m : public cCRC
{
 protected:
    static tCRCValue const crc_table_dsacon32m[256];
 
 public:
    inline cCRC_DSACON32m( void )
        : cCRC( crc_table_dsacon32m, 0xffff )
    {
        // nothing more to do
    }
};
//----------------------------------------------------------------------
//----------------------------------------------------------------------
 
class VCC_EXPORT cCRC_SDH : public cCRC_DSACON32m
{
 public:
    inline cCRC_SDH( void )
        : cCRC_DSACON32m()
    {
        // nothing more to do
    }
};
//----------------------------------------------------------------------
//----------------------------------------------------------------------
 
NAMESPACE_SDH_END
 
#endif
 
 
//======================================================================
/*
  Here are some settings for the emacs/xemacs editor (and can be safely ignored):
  (e.g. to explicitely set C++ mode for *.h header files)
 
  Local Variables:
  mode:C
  mode:ELSE
  End:
*/
//======================================================================}