complex_t.h

// Compiler implementation of the D programming language
// Copyright (c) 1999-2006 by Digital Mars
// All Rights Reserved
// written by Walter Bright and Burton Radons
// http://www.digitalmars.com
// License for redistribution is by either the Artistic License
// in artistic.txt, or the GNU General Public License in gnu.txt.
// See the included readme.txt for details.

#ifndef DMD_COMPLEX_T_H
#define DMD_COMPLEX_T_H

/* Roll our own complex type for compilers that don't support complex
 */

struct complex_t
{
    long double re;
    long double im;

    complex_t() { this->re = 0; this->im = 0; }
    complex_t(long double re) { this->re = re; this->im = 0; }
    complex_t(long double re, long double im) { this->re = re; this->im = im; }

    complex_t operator + (complex_t y) { complex_t r; r.re = re + y.re; r.im = im + y.im; return r; }
    complex_t operator - (complex_t y) { complex_t r; r.re = re - y.re; r.im = im - y.im; return r; }
    complex_t operator - () { complex_t r; r.re = -re; r.im = -im; return r; }
    complex_t operator * (complex_t y) { return complex_t(re * y.re - im * y.im, im * y.re + re * y.im); }

    complex_t operator / (complex_t y)
    {
        long double abs_y_re = y.re < 0 ? -y.re : y.re;
        long double abs_y_im = y.im < 0 ? -y.im : y.im;
        long double r, den;

        if (abs_y_re < abs_y_im)
        {
            r = y.re / y.im;
            den = y.im + r * y.re;
            return complex_t((re * r + im) / den,
                             (im * r - re) / den);
        }
        else
        {
            r = y.im / y.re;
            den = y.re + r * y.im;
            return complex_t((re + r * im) / den,
                             (im - r * re) / den);
        }
    }

    operator bool () { return re || im; }

    int operator == (complex_t y) { return re == y.re && im == y.im; }
    int operator != (complex_t y) { return re != y.re || im != y.im; }
};

inline complex_t operator * (long double x, complex_t y) { return complex_t(x) * y; }
inline complex_t operator * (complex_t x, long double y) { return x * complex_t(y); }
inline complex_t operator / (complex_t x, long double y) { return x / complex_t(y); }


inline long double creall(complex_t x)
{
    return x.re;
}

inline long double cimagl(complex_t x)
{
    return x.im;
}

#endif