///////////////////////////////////////////////////////////////////////////

//

// Copyright (c) 2006, Industrial Light & Magic, a division of Lucas

// Digital Ltd. LLC

// 

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

// *       Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

// *       Redistributions in binary form must reproduce the above

// copyright notice, this list of conditions and the following disclaimer

// in the documentation and/or other materials provided with the

// distribution.

// *       Neither the name of Industrial Light & Magic nor the names of

// its contributors may be used to endorse or promote products derived

// from this software without specific prior written permission. 

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

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///////////////////////////////////////////////////////////////////////////

//-----------------------------------------------------------------------------

//

//	Rational numbers

//

//	The double-to-Rational conversion code below

//	was contributed to OpenEXR by Greg Ward.

//

//-----------------------------------------------------------------------------

#include <ImfRational.h>

#include <cmath>

using namespace std;

#include "ImfNamespace.h"

OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_ENTER

namespace {

double

frac (double x, double e)

{

    return x - floor (x + e);

}

double

square (double x)

{

    return x * x;

}

double

denom (double x, double e)

{

    if (e > frac (x, e))

    {

        return 1;

    }

    else

    {

	double r = frac (1 / x, e);

        if (e > r)

        {

            return floor (1 / x + e);

        }

        else

        {

            return denom (frac (1 / r, e), e / square (x * r)) +

                   floor (1 / x + e) * denom (frac (1 / x, e), e / square (x));

        }

    }

}

} // namespace

Rational::Rational (double x)

{

    int sign;

    if (x >= 0)

    {

	sign = 1;	// positive

    }

    else if (x < 0)

    {

	sign = -1;	// negative

	x = -x;

    }

    else

    {

	n = 0;		// NaN

	d = 0;

	return;

    }

    if (x >= (1U << 31) - 0.5)

    {

	n = sign;	// infinity

	d = 0;

	return;

    }

    double e = (x < 1? 1: x) / (1U << 30);

    d = (unsigned int) denom (x, e);

    n = sign * (int) floor (x * d + 0.5);

}

OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT