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/*
* Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved.
*
* This software may be freely used, copied, modified, and distributed
* provided that the above copyright notice is preserved in all copies of the
* software.
*/
/* -*-C-*-
*
* $Revision$
* $Date$
*
*
* crc.h - describes some "standard" CRC calculation routines.
*/
#ifndef angel_crc_h
#define angel_crc_h
/*
* manifests
*/
/*
* When using "crc32" or "crc16" these initial CRC values must be given to
* the respective function the first time it is called. The function can
* then be called with the return value from the last call of the function
* to generate a running CRC over multiple data blocks.
* When the last data block has been processed using the "crc32" algorithm
* the CRC value should be inverted to produce the final CRC value:
* e.g. CRC = ~CRC
*/
#define startCRC32 (0xFFFFFFFF) /* CRC initialised to all 1s */
#define startCRC16 (0x0000) /* CRC initialised to all 0s */
/*
* For the CRC-32 residual to be calculated correctly requires that the CRC
* value is in memory little-endian due to the byte read, bit-ordering
* nature of the algorithm.
*/
#define CRC32residual (0xDEBB20E3) /* good CRC-32 residual */
/**********************************************************************/
/*
* exported functions
*/
/*
* Function: crc32
* Purpose: Provides a table driven implementation of the IEEE-802.3
* 32-bit CRC algorithm for byte data.
*
* Params:
* Input: address pointer to the byte data
* size number of bytes of data to be processed
* crc initial CRC value to be used (can be the output
* from a previous call to this function).
* Returns:
* OK: 32-bit CRC value for the specified data
*/
extern unsigned int crc32(unsigned char *address, unsigned int size,
unsigned int crc);
/**********************************************************************/
/*
*
* Function: crc16
* Purpose: Generates a table driven 16-bit CRC-CCITT for byte data
*
* Params:
* Input: address pointer to the byte data
* size number of bytes of data to be processed
* crc initial CRC value to be used (can be the output
* from a previous call to this function).
*
* Returns:
* OK: 16-bit CRC value for the specified data
*/
extern unsigned short crc16(unsigned char *address, unsigned int size,
unsigned short crc);
/**********************************************************************/
#endif /* !defined(angel_crc_h) */
/* EOF crc.h */
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