view libtommath/bn_mp_lcm.c @ 340:454a34b2dfd1

Fixes from Erik Hovland: cli-authpubkey.c: fix leak of keybuf cli-kex.c: fix leak of fingerprint fp cli-service.c: remove commented out code dropbearkey.c: don't attepmt to free NULL key on failure common-kex.c: only free key if it is initialised keyimport.c: remove dead encrypted-key code don't leak a FILE* loading OpenSSH keys rsa.c, dss.c: check return values for some libtommath functions svr-kex.c: check return value retrieving DH kex mpint svr-tcpfwd.c: fix null-dereference if remote tcp forward request fails tcp-accept.c: don't incorrectly free the tcpinfo var
author Matt Johnston <matt@ucc.asn.au>
date Fri, 07 Jul 2006 09:17:18 +0000
parents eed26cff980b
children 5ff8218bcee9
line wrap: on
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#include <tommath.h>
#ifdef BN_MP_LCM_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
 *
 * LibTomMath is a library that provides multiple-precision
 * integer arithmetic as well as number theoretic functionality.
 *
 * The library was designed directly after the MPI library by
 * Michael Fromberger but has been written from scratch with
 * additional optimizations in place.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, [email protected], http://math.libtomcrypt.org
 */

/* computes least common multiple as |a*b|/(a, b) */
int mp_lcm (mp_int * a, mp_int * b, mp_int * c)
{
  int     res;
  mp_int  t1, t2;


  if ((res = mp_init_multi (&t1, &t2, NULL)) != MP_OKAY) {
    return res;
  }

  /* t1 = get the GCD of the two inputs */
  if ((res = mp_gcd (a, b, &t1)) != MP_OKAY) {
    goto LBL_T;
  }

  /* divide the smallest by the GCD */
  if (mp_cmp_mag(a, b) == MP_LT) {
     /* store quotient in t2 such that t2 * b is the LCM */
     if ((res = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) {
        goto LBL_T;
     }
     res = mp_mul(b, &t2, c);
  } else {
     /* store quotient in t2 such that t2 * a is the LCM */
     if ((res = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) {
        goto LBL_T;
     }
     res = mp_mul(a, &t2, c);
  }

  /* fix the sign to positive */
  c->sign = MP_ZPOS;

LBL_T:
  mp_clear_multi (&t1, &t2, NULL);
  return res;
}
#endif