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