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/*
* gcd.c
*
* Greatest common divisor
*
* 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 Michael J. Fromberger are
* Copyright (C) 1998, 1999, 2000 Michael J. Fromberger.
* All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License Version 2 or later (the
* "GPL"), in which case the provisions of the GPL are applicable
* instead of those above. If you wish to allow use of your
* version of this file only under the terms of the GPL and not to
* allow others to use your version of this file under the MPL,
* indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by
* the GPL. If you do not delete the provisions above, a recipient
* may use your version of this file under either the MPL or the GPL.
*
* $Id$
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "mpi.h"
char *g_prog = NULL;
void print_mp_int(mp_int *mp, FILE *ofp);
int main(int argc, char *argv[])
{
mp_int a, b, x, y;
mp_err res;
int ext = 0;
g_prog = argv[0];
if(argc < 3) {
fprintf(stderr, "Usage: %s <a> <b>\n", g_prog);
return 1;
}
mp_init(&a); mp_read_radix(&a, argv[1], 10);
mp_init(&b); mp_read_radix(&b, argv[2], 10);
/* If we were called 'xgcd', compute x, y so that g = ax + by */
if(strcmp(g_prog, "xgcd") == 0) {
ext = 1;
mp_init(&x); mp_init(&y);
}
if(ext) {
if((res = mp_xgcd(&a, &b, &a, &x, &y)) != MP_OKAY) {
fprintf(stderr, "%s: error: %s\n", g_prog, mp_strerror(res));
mp_clear(&a); mp_clear(&b);
mp_clear(&x); mp_clear(&y);
return 1;
}
} else {
if((res = mp_gcd(&a, &b, &a)) != MP_OKAY) {
fprintf(stderr, "%s: error: %s\n", g_prog,
mp_strerror(res));
mp_clear(&a); mp_clear(&b);
return 1;
}
}
print_mp_int(&a, stdout);
if(ext) {
fputs("x = ", stdout); print_mp_int(&x, stdout);
fputs("y = ", stdout); print_mp_int(&y, stdout);
}
mp_clear(&a); mp_clear(&b);
if(ext) {
mp_clear(&x);
mp_clear(&y);
}
return 0;
}
void print_mp_int(mp_int *mp, FILE *ofp)
{
char *buf;
int len;
len = mp_radix_size(mp, 10);
buf = calloc(len, sizeof(char));
mp_todecimal(mp, buf);
fprintf(ofp, "%s\n", buf);
free(buf);
}
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