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crc32.h

/*
 * 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.
 */

/*
 * When using "crc32" this initial CRC value 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 */

/*
 * 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);

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