crc.h

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/**********************************************************************
 *
 * Filename:    crc.h
 * 
 * Description: A header file describing the various CRC standards.
 *
 * Notes:       
 *
 * 
 * Copyright (c) 2000 by Michael Barr.  This software is placed into
 * the public domain and may be used for any purpose.  However, this
 * notice must not be changed or removed and no warranty is either
 * expressed or implied by its publication or distribution.
 **********************************************************************/

#ifndef _crc_h
#define _crc_h


#define FALSE   0
#define TRUE    !FALSE

/*
 * Select the CRC standard from the list that follows.
 */
#define CRC32


#if defined(CRC_CCITT)

typedef unsigned short  crc;

#define CRC_NAME            "CRC-CCITT"
#define POLYNOMIAL          0x1021
#define INITIAL_REMAINDER   0xFFFF
#define FINAL_XOR_VALUE     0x0000
#define REFLECT_DATA        FALSE
#define REFLECT_REMAINDER   FALSE
#define CHECK_VALUE         0x29B1

#elif defined(CRC16)

typedef unsigned short  crc;

#define CRC_NAME            "CRC-16"
#define POLYNOMIAL          0x8005
#define INITIAL_REMAINDER   0x0000
#define FINAL_XOR_VALUE     0x0000
#define REFLECT_DATA        TRUE
#define REFLECT_REMAINDER   TRUE
#define CHECK_VALUE         0xBB3D

#elif defined(CRC32)

typedef unsigned long  crc;

#define CRC_NAME            "CRC-32"
#define POLYNOMIAL          0x04C11DB7
#define INITIAL_REMAINDER   0xFFFFFFFF
#define FINAL_XOR_VALUE     0xFFFFFFFF
#define REFLECT_DATA        TRUE
#define REFLECT_REMAINDER   TRUE
#define CHECK_VALUE         0xCBF43926

#else

#error "One of CRC_CCITT, CRC16, or CRC32 must be #define'd."

#endif


void  crcInit(void);
crc   crcSlow(unsigned char const message[], int nBytes);
crc   crcFast(unsigned char const message[], int nBytes);


#endif /* _crc_h */