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/*
* Copyright (c) 1997 - 2000 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "krb5_locl.h"
RCSID("$Id: crc.c,v 1.9 2000/08/03 01:45:14 assar Exp $");
static u_long table[256];
#define CRC_GEN 0xEDB88320L
void
_krb5_crc_init_table(void)
{
static int flag = 0;
unsigned long crc, poly;
int i, j;
if(flag) return;
poly = CRC_GEN;
for (i = 0; i < 256; i++) {
crc = i;
for (j = 8; j > 0; j--) {
if (crc & 1) {
crc = (crc >> 1) ^ poly;
} else {
crc >>= 1;
}
}
table[i] = crc;
}
flag = 1;
}
u_int32_t
_krb5_crc_update (const char *p, size_t len, u_int32_t res)
{
while (len--)
res = table[(res ^ *p++) & 0xFF] ^ (res >> 8);
return res & 0xFFFFFFFF;
}
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