hash_crc32.c   [plain text]

/*
 * Copyright (C) 1998 by the FundsXpress, INC.
 * 
 * All rights reserved.
 * 
 * Export of this software from the United States of America may require
 * a specific license from the United States Government.  It is the
 * responsibility of any person or organization contemplating export to
 * obtain such a license before exporting.
 * 
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of FundsXpress. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  FundsXpress makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include "k5-int.h"
#include "crc-32.h"
#include "hash_provider.h"

static void
k5_crc32_hash_size(size_t *output)
{
    *output = CRC32_CKSUM_LENGTH;
}

static void
k5_crc32_block_size(size_t *output)
{
    *output = 1;
}

static krb5_error_code
k5_crc32_hash(unsigned int icount, const krb5_data *input,
	      krb5_data *output)
{
    unsigned long c, cn;
    int i;
    
    if (output->length != CRC32_CKSUM_LENGTH)
	return(KRB5_CRYPTO_INTERNAL);

    c = 0;
    for (i=0; i<icount; i++) {
	mit_crc32(input[i].data, input[i].length, &cn);
	c ^= cn;
    }

    output->data[0] = c&0xff;
    output->data[1] = (c>>8)&0xff;
    output->data[2] = (c>>16)&0xff;
    output->data[3] = (c>>24)&0xff;

    return(0);
}

const struct krb5_hash_provider krb5int_hash_crc32 = {
    k5_crc32_hash_size,
    k5_crc32_block_size,
    k5_crc32_hash
};