mirror of
https://github.com/rn10950/RetroZilla.git
synced 2024-11-14 03:30:17 +01:00
87 lines
1.7 KiB
C
87 lines
1.7 KiB
C
/*
|
|
* gcd.c
|
|
*
|
|
* Greatest common divisor
|
|
*
|
|
* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#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);
|
|
|
|
}
|