mirror of
https://github.com/rn10950/RetroZilla.git
synced 2024-11-14 11:40:13 +01:00
87 lines
1.7 KiB
C
87 lines
1.7 KiB
C
/*
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* gcd.c
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*
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* Greatest common divisor
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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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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char *g_prog = NULL;
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void print_mp_int(mp_int *mp, FILE *ofp);
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int main(int argc, char *argv[])
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{
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mp_int a, b, x, y;
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mp_err res;
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int ext = 0;
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g_prog = argv[0];
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if(argc < 3) {
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fprintf(stderr, "Usage: %s <a> <b>\n", g_prog);
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return 1;
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}
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mp_init(&a); mp_read_radix(&a, argv[1], 10);
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mp_init(&b); mp_read_radix(&b, argv[2], 10);
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/* If we were called 'xgcd', compute x, y so that g = ax + by */
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if(strcmp(g_prog, "xgcd") == 0) {
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ext = 1;
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mp_init(&x); mp_init(&y);
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}
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if(ext) {
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if((res = mp_xgcd(&a, &b, &a, &x, &y)) != MP_OKAY) {
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fprintf(stderr, "%s: error: %s\n", g_prog, mp_strerror(res));
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mp_clear(&a); mp_clear(&b);
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mp_clear(&x); mp_clear(&y);
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return 1;
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}
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} else {
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if((res = mp_gcd(&a, &b, &a)) != MP_OKAY) {
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fprintf(stderr, "%s: error: %s\n", g_prog,
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mp_strerror(res));
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mp_clear(&a); mp_clear(&b);
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return 1;
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}
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}
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print_mp_int(&a, stdout);
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if(ext) {
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fputs("x = ", stdout); print_mp_int(&x, stdout);
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fputs("y = ", stdout); print_mp_int(&y, stdout);
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}
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mp_clear(&a); mp_clear(&b);
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if(ext) {
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mp_clear(&x);
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mp_clear(&y);
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}
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return 0;
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}
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void print_mp_int(mp_int *mp, FILE *ofp)
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{
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char *buf;
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int len;
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len = mp_radix_size(mp, 10);
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buf = calloc(len, sizeof(char));
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mp_todecimal(mp, buf);
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fprintf(ofp, "%s\n", buf);
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free(buf);
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}
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