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

Copyright (C) INRIA, 2005, 2009, 2010

This file is part of the MPC Library.

The MPC Library 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 2.1 of the License, or (at your

option) any later version.

The MPC Library 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 the MPC Library; see the file COPYING.LIB.  If not, write to

the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,

MA 02111-1307, USA. */

#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_RE (a), MPC_IM (a));

     else

     {

        mpfr_set (MPC_RE (a), MPC_IM (b), GMP_RNDN);

        mpfr_set (MPC_IM (a), MPC_RE (b), GMP_RNDN);

     }

     if (sign >= 0)

        MPFR_CHANGE_SIGN (MPC_RE (a));

     else

        MPFR_CHANGE_SIGN (MPC_IM (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_IM (b), MPC_RND_RE (rnd));

           inex_im = mpfr_set (MPC_IM (a), MPC_RE (b), MPC_RND_IM (rnd));

        }

        else

        {

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

           inex_im = mpfr_neg (MPC_IM (a), MPC_RE (b), MPC_RND_IM (rnd));

        }

        mpfr_clear (MPC_RE (a));

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

     }

     else

        if (sign >= 0)

        {

           inex_re = mpfr_neg (MPC_RE (a), MPC_IM (b), MPC_RND_RE (rnd));

           inex_im = mpfr_set (MPC_IM (a), MPC_RE (b), MPC_RND_IM (rnd));

        }

        else

        {

           inex_re = mpfr_set (MPC_RE (a), MPC_IM (b), MPC_RND_RE (rnd));

           inex_im = mpfr_neg (MPC_IM (a), MPC_RE (b), MPC_RND_IM (rnd));

        }

  }

  return MPC_INEX(inex_re, inex_im);

}