crc.h

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/*
 * Copyright (c) 2008 SCHUNK GmbH & Co. KG
 * Copyright (c) 2017 Fraunhofer Institute for Manufacturing Engineering and Automation (IPA)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0

 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

//======================================================================
//======================================================================

#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:
*/
//======================================================================}