/* * 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-*- * * 1.1.1.1 * 1999/04/16 01:34:27 * * * 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 */