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///////////////////////////////////////////////////////////////////////////
//
// 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
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
///////////////////////////////////////////////////////////////////////////
//-----------------------------------------------------------------------------
//
// 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
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