/* mpc_mul_i -- Multiply a complex number by plus or minus i.

Copyright (C) 2005, 2009, 2010, 2011, 2012 INRIA

This file is part of GNU MPC.

GNU MPC is free software; you can redistribute it and/or modify it under

the terms of the GNU Lesser General Public License as published by the

Free Software Foundation; either version 3 of the License, or (at your

option) any later version.

GNU MPC is distributed in the hope that it will be useful, but WITHOUT ANY

WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for

more details.

You should have received a copy of the GNU Lesser General Public License

along with this program. If not, see http://www.gnu.org/licenses/ .

*/

#include "mpc-impl.h"

int

mpc_mul_i (mpc_ptr a, mpc_srcptr b, int sign, mpc_rnd_t rnd)

/* if sign is >= 0, multiply by i, otherwise by -i */

{

  int   inex_re, inex_im;

  mpfr_t tmp;

  /* Treat the most probable case of compatible precisions first */

  if (     MPC_PREC_RE (b) == MPC_PREC_IM (a)

        && MPC_PREC_IM (b) == MPC_PREC_RE (a))

  {

     if (a == b)

        mpfr_swap (mpc_realref (a), mpc_imagref (a));

     else

     {

        mpfr_set (mpc_realref (a), mpc_imagref (b), MPFR_RNDN);

        mpfr_set (mpc_imagref (a), mpc_realref (b), MPFR_RNDN);

     }

     if (sign >= 0)

        MPFR_CHANGE_SIGN (mpc_realref (a));

     else

        MPFR_CHANGE_SIGN (mpc_imagref (a));

     inex_re = 0;

     inex_im = 0;

  }

  else

  {

     if (a == b)

     {

        mpfr_init2 (tmp, MPC_PREC_RE (a));

        if (sign >= 0)

        {

           inex_re = mpfr_neg (tmp, mpc_imagref (b), MPC_RND_RE (rnd));

           inex_im = mpfr_set (mpc_imagref (a), mpc_realref (b), MPC_RND_IM (rnd));

        }

        else

        {

           inex_re = mpfr_set (tmp, mpc_imagref (b), MPC_RND_RE (rnd));

           inex_im = mpfr_neg (mpc_imagref (a), mpc_realref (b), MPC_RND_IM (rnd));

        }

        mpfr_clear (mpc_realref (a));

        mpc_realref (a)[0] = tmp [0];

     }

     else

        if (sign >= 0)

        {

           inex_re = mpfr_neg (mpc_realref (a), mpc_imagref (b), MPC_RND_RE (rnd));

           inex_im = mpfr_set (mpc_imagref (a), mpc_realref (b), MPC_RND_IM (rnd));

        }

        else

        {

           inex_re = mpfr_set (mpc_realref (a), mpc_imagref (b), MPC_RND_RE (rnd));

           inex_im = mpfr_neg (mpc_imagref (a), mpc_realref (b), MPC_RND_IM (rnd));

        }

  }

  return MPC_INEX(inex_re, inex_im);

}