You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
166 lines
2.2 KiB
166 lines
2.2 KiB
2 months ago
|
/*
|
||
|
|
* UCW Library -- Prime Number Table
|
||
|
|
*
|
||
|
|
* (c) 2005 Martin Mares <mj@ucw.cz>
|
||
|
|
*
|
||
|
|
* This software may be freely distributed and used according to the terms
|
||
|
|
* of the GNU Lesser General Public License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <ucw/lib.h>
|
||
|
|
#include <ucw/prime.h>
|
||
|
|
#include <ucw/binsearch.h>
|
||
|
|
|
||
|
|
/* A table of odd primes, each is about 1.2 times the previous one */
|
||
|
|
static uint prime_table[] = {
|
||
|
|
3,
|
||
|
|
7,
|
||
|
|
13,
|
||
|
|
19,
|
||
|
|
29,
|
||
|
|
37,
|
||
|
|
53,
|
||
|
|
67,
|
||
|
|
89,
|
||
|
|
109,
|
||
|
|
137,
|
||
|
|
173,
|
||
|
|
211,
|
||
|
|
263,
|
||
|
|
331,
|
||
|
|
409,
|
||
|
|
499,
|
||
|
|
601,
|
||
|
|
727,
|
||
|
|
877,
|
||
|
|
1061,
|
||
|
|
1279,
|
||
|
|
1543,
|
||
|
|
1861,
|
||
|
|
2239,
|
||
|
|
2689,
|
||
|
|
3229,
|
||
|
|
3877,
|
||
|
|
4657,
|
||
|
|
5623,
|
||
|
|
6761,
|
||
|
|
8123,
|
||
|
|
9767,
|
||
|
|
11731,
|
||
|
|
14083,
|
||
|
|
16903,
|
||
|
|
20287,
|
||
|
|
24359,
|
||
|
|
29243,
|
||
|
|
35099,
|
||
|
|
42131,
|
||
|
|
50581,
|
||
|
|
60703,
|
||
|
|
72859,
|
||
|
|
87433,
|
||
|
|
104933,
|
||
|
|
125927,
|
||
|
|
151121,
|
||
|
|
181361,
|
||
|
|
217643,
|
||
|
|
261223,
|
||
|
|
313471,
|
||
|
|
376171,
|
||
|
|
451411,
|
||
|
|
541699,
|
||
|
|
650059,
|
||
|
|
780119,
|
||
|
|
936151,
|
||
|
|
1123391,
|
||
|
|
1348111,
|
||
|
|
1617739,
|
||
|
|
1941293,
|
||
|
|
2329559,
|
||
|
|
2795477,
|
||
|
|
3354581,
|
||
|
|
4025507,
|
||
|
|
4830619,
|
||
|
|
5796797,
|
||
|
|
6956203,
|
||
|
|
8347483,
|
||
|
|
10017011,
|
||
|
|
12020431,
|
||
|
|
14424539,
|
||
|
|
17309471,
|
||
|
|
20771371,
|
||
|
|
24925661,
|
||
|
|
29910821,
|
||
|
|
35892991,
|
||
|
|
43071601,
|
||
|
|
51685939,
|
||
|
|
62023139,
|
||
|
|
74427803,
|
||
|
|
89313379,
|
||
|
|
107176057,
|
||
|
|
128611313,
|
||
|
|
154333591,
|
||
|
|
185200339,
|
||
|
|
222240413,
|
||
|
|
266688509,
|
||
|
|
320026249,
|
||
|
|
384031507,
|
||
|
|
460837813,
|
||
|
|
553005391,
|
||
|
|
663606499,
|
||
|
|
796327811,
|
||
|
|
955593439,
|
||
|
|
1146712139,
|
||
|
|
1376054569,
|
||
|
|
1651265507,
|
||
|
|
1981518631,
|
||
|
|
2377822387,
|
||
|
|
2853386881,
|
||
|
|
3424064269,
|
||
|
|
4108877153,
|
||
|
|
4294967291
|
||
|
|
};
|
||
|
|
|
||
|
|
#define NPRIMES ARRAY_SIZE(prime_table)
|
||
|
|
|
||
|
|
uint
|
||
|
|
next_table_prime(uint x)
|
||
|
|
{
|
||
|
|
if (x >= prime_table[NPRIMES-1])
|
||
|
|
return 0;
|
||
|
|
else
|
||
|
|
return prime_table[BIN_SEARCH_FIRST_GE(prime_table, NPRIMES, x+1)];
|
||
|
|
}
|
||
|
|
|
||
|
|
uint
|
||
|
|
prev_table_prime(uint x)
|
||
|
|
{
|
||
|
|
int i = BIN_SEARCH_FIRST_GE(prime_table, NPRIMES, x);
|
||
|
|
return i ? prime_table[i-1] : 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
#ifdef TEST
|
||
|
|
|
||
|
|
#include <stdio.h>
|
||
|
|
|
||
|
|
int main(void)
|
||
|
|
{
|
||
|
|
#if 0 /* Generate the table */
|
||
|
|
uint x = 3, xx;
|
||
|
|
do
|
||
|
|
{
|
||
|
|
printf(" %u,\n", x);
|
||
|
|
xx = x;
|
||
|
|
x = nextprime(1.2*x);
|
||
|
|
}
|
||
|
|
while (x > xx);
|
||
|
|
#else
|
||
|
|
for (int i=1; i<=100; i++)
|
||
|
|
printf("%d\t%d\t%d\n", i, next_table_prime(i), prev_table_prime(i));
|
||
|
|
for (uint i=0xfffffff0; i; i++)
|
||
|
|
printf("%u\t%u\t%u\n", i, next_table_prime(i), prev_table_prime(i));
|
||
|
|
return 0;
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif
|