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122 lines
3.6 KiB
C
122 lines
3.6 KiB
C
/*
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* isprime.c
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*
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* Probabilistic primality tester command-line tool
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is the MPI Arbitrary Precision Integer Arithmetic library.
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*
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* The Initial Developer of the Original Code is
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* Michael J. Fromberger.
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* Portions created by the Initial Developer are Copyright (C) 1998
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/* $Id: isprime.c,v 1.3 2004/04/27 23:04:37 gerv%gerv.net Exp $ */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "mpi.h"
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#include "mpprime.h"
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#define RM_TESTS 15 /* how many iterations of Rabin-Miller? */
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#define MINIMUM 1024 /* don't bother us with a < this */
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int g_tests = RM_TESTS;
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char *g_prog = NULL;
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int main(int argc, char *argv[])
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{
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mp_int a;
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mp_digit np = prime_tab_size; /* from mpprime.h */
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int res = 0;
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g_prog = argv[0];
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if(argc < 2) {
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fprintf(stderr, "Usage: %s <a>, where <a> is a decimal integer\n"
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"Use '0x' prefix for a hexadecimal value\n", g_prog);
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return 1;
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}
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/* Read number of tests from environment, if present */
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{
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char *tmp;
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if((tmp = getenv("RM_TESTS")) != NULL) {
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if((g_tests = atoi(tmp)) <= 0)
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g_tests = RM_TESTS;
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}
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}
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mp_init(&a);
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if(argv[1][0] == '0' && argv[1][1] == 'x')
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mp_read_radix(&a, argv[1] + 2, 16);
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else
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mp_read_radix(&a, argv[1], 10);
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if(mp_cmp_d(&a, MINIMUM) <= 0) {
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fprintf(stderr, "%s: please use a value greater than %d\n",
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g_prog, MINIMUM);
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mp_clear(&a);
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return 1;
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}
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/* Test for divisibility by small primes */
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if(mpp_divis_primes(&a, &np) != MP_NO) {
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printf("Not prime (divisible by small prime %d)\n", np);
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res = 2;
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goto CLEANUP;
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}
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/* Test with Fermat's test, using 2 as a witness */
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if(mpp_fermat(&a, 2) != MP_YES) {
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printf("Not prime (failed Fermat test)\n");
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res = 2;
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goto CLEANUP;
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}
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/* Test with Rabin-Miller probabilistic test */
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if(mpp_pprime(&a, g_tests) == MP_NO) {
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printf("Not prime (failed pseudoprime test)\n");
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res = 2;
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goto CLEANUP;
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}
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printf("Probably prime, 1 in 4^%d chance of false positive\n", g_tests);
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CLEANUP:
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mp_clear(&a);
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return res;
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}
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