mirror of
https://github.com/opencv/opencv.git
synced 2024-12-27 11:28:14 +08:00
126 lines
3.1 KiB
C++
126 lines
3.1 KiB
C++
///////////////////////////////////////////////////////////////////////////
|
|
//
|
|
// 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;
|
|
|
|
namespace Imf {
|
|
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);
|
|
}
|
|
|
|
|
|
} // namespace Imf
|