/security/nss/lib/freebl/mpi/utils/makeprime.c
http://github.com/zpao/v8monkey · C · 147 lines · 58 code · 25 blank · 64 comment · 27 complexity · 8c177707a4c8ea6e99dfd9e98060df41 MD5 · raw file
- /*
- * makeprime.c
- *
- * A simple prime generator function (and test driver). Prints out the
- * first prime it finds greater than or equal to the starting value.
- *
- * Usage: makeprime <start>
- *
- * ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (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.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is the MPI Arbitrary Precision Integer Arithmetic library.
- *
- * The Initial Developer of the Original Code is
- * Michael J. Fromberger.
- * Portions created by the Initial Developer are Copyright (C) 1998
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
- /* $Id: makeprime.c,v 1.3 2004/04/27 23:04:37 gerv%gerv.net Exp $ */
- #include <stdio.h>
- #include <stdlib.h>
- #include <ctype.h>
- /* These two must be included for make_prime() to work */
- #include "mpi.h"
- #include "mpprime.h"
- /*
- make_prime(p, nr)
- Find the smallest prime integer greater than or equal to p, where
- primality is verified by 'nr' iterations of the Rabin-Miller
- probabilistic primality test. The caller is responsible for
- generating the initial value of p.
- Returns MP_OKAY if a prime has been generated, otherwise the error
- code indicates some other problem. The value of p is clobbered; the
- caller should keep a copy if the value is needed.
- */
- mp_err make_prime(mp_int *p, int nr);
- /* The main() is not required -- it's just a test driver */
- int main(int argc, char *argv[])
- {
- mp_int start;
- mp_err res;
- if(argc < 2) {
- fprintf(stderr, "Usage: %s <start-value>\n", argv[0]);
- return 1;
- }
-
- mp_init(&start);
- if(argv[1][0] == '0' && tolower(argv[1][1]) == 'x') {
- mp_read_radix(&start, argv[1] + 2, 16);
- } else {
- mp_read_radix(&start, argv[1], 10);
- }
- mp_abs(&start, &start);
- if((res = make_prime(&start, 5)) != MP_OKAY) {
- fprintf(stderr, "%s: error: %s\n", argv[0], mp_strerror(res));
- mp_clear(&start);
- return 1;
- } else {
- char *buf = malloc(mp_radix_size(&start, 10));
- mp_todecimal(&start, buf);
- printf("%s\n", buf);
- free(buf);
-
- mp_clear(&start);
- return 0;
- }
-
- } /* end main() */
- /*------------------------------------------------------------------------*/
- mp_err make_prime(mp_int *p, int nr)
- {
- mp_err res;
- if(mp_iseven(p)) {
- mp_add_d(p, 1, p);
- }
- do {
- mp_digit which = prime_tab_size;
- /* First test for divisibility by a few small primes */
- if((res = mpp_divis_primes(p, &which)) == MP_YES)
- continue;
- else if(res != MP_NO)
- goto CLEANUP;
- /* If that passes, try one iteration of Fermat's test */
- if((res = mpp_fermat(p, 2)) == MP_NO)
- continue;
- else if(res != MP_YES)
- goto CLEANUP;
- /* If that passes, run Rabin-Miller as often as requested */
- if((res = mpp_pprime(p, nr)) == MP_YES)
- break;
- else if(res != MP_NO)
- goto CLEANUP;
-
- } while((res = mp_add_d(p, 2, p)) == MP_OKAY);
- CLEANUP:
- return res;
- } /* end make_prime() */
- /*------------------------------------------------------------------------*/
- /* HERE THERE BE DRAGONS */