The Tor Browser: security/nss/lib/freebl/mpi/utils/gcd.c@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 /*

     2  *  gcd.c

     3  *

     4  *  Greatest common divisor

     5  *

     6  * This Source Code Form is subject to the terms of the Mozilla Public

     7  * License, v. 2.0. If a copy of the MPL was not distributed with this

     8  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

    10 #include <stdio.h>

    11 #include <stdlib.h>

    12 #include <string.h>

    14 #include "mpi.h"

    16 char     *g_prog = NULL;

    18 void print_mp_int(mp_int *mp, FILE *ofp);

    20 int main(int argc, char *argv[])

    21 {

    22   mp_int   a, b, x, y;

    23   mp_err   res;

    24   int      ext = 0;

    26   g_prog = argv[0];

    28   if(argc < 3) {

    29     fprintf(stderr, "Usage: %s <a> <b>\n", g_prog);

    30     return 1;

    31   }

    33   mp_init(&a); mp_read_radix(&a, argv[1], 10);

    34   mp_init(&b); mp_read_radix(&b, argv[2], 10);

    36   /* If we were called 'xgcd', compute x, y so that g = ax + by */

    37   if(strcmp(g_prog, "xgcd") == 0) {

    38     ext = 1;

    39     mp_init(&x); mp_init(&y);

    40   }

    42   if(ext) {

    43     if((res = mp_xgcd(&a, &b, &a, &x, &y)) != MP_OKAY) {

    44       fprintf(stderr, "%s: error: %s\n", g_prog, mp_strerror(res));

    45       mp_clear(&a); mp_clear(&b);

    46       mp_clear(&x); mp_clear(&y);

    47       return 1;

    48     }

    49   } else {

    50     if((res = mp_gcd(&a, &b, &a)) != MP_OKAY) {

    51       fprintf(stderr, "%s: error: %s\n", g_prog,

    52 	      mp_strerror(res));

    53       mp_clear(&a); mp_clear(&b);

    54       return 1;

    55     }

    56   }

    58   print_mp_int(&a, stdout);

    59   if(ext) {

    60     fputs("x = ", stdout); print_mp_int(&x, stdout);

    61     fputs("y = ", stdout); print_mp_int(&y, stdout);

    62   }

    64   mp_clear(&a); mp_clear(&b);

    66   if(ext) {

    67     mp_clear(&x);

    68     mp_clear(&y);

    69   }

    71   return 0;

    73 }

    75 void print_mp_int(mp_int *mp, FILE *ofp)

    76 {

    77   char  *buf;

    78   int    len;

    80   len = mp_radix_size(mp, 10);

    81   buf = calloc(len, sizeof(char));

    82   mp_todecimal(mp, buf);

    83   fprintf(ofp, "%s\n", buf);

    84   free(buf);

    86 }

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