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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 1998-2016. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*
*/
#include "hash.h"
/* this is a general prime factoring function
* we get one prime factor each time we call it
* we only use it here to determine if n is prime,
* by checking if factor(n) == n .
*/
static int factor(int n)
{
/* FIXME problem for threaded?! */
static int a[] = { 0, 4, 1, 2, 0, 2 };
static int m = 0;
static int d = 0;
if (n) {
m = n;
d = 2;
}
while ((d*d) <= m) {
if (!(m%d)) {
m /= d;
return d;
}
d += a[d%6];
}
n = m;
m = 0;
return n;
}
/* true if n prime */
int ei_isprime(int n)
{
return (n == factor(n));
}
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