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/*
Copyright (C) 2012 Paul Davis
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* Taken from
* http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm
*
* Code assumed to be in the public domain.
*/
#ifndef __libpbd__floating_h__
#define __libpbd__floating_h__
#include <stdint.h>
#include <cstdlib> // abs(int)
#include <cmath>
#include "pbd/libpbd_visibility.h"
namespace PBD {
union /*LIBPBD_API*/ Float_t
{
Float_t (float num = 0.0f) : f(num) {}
// Portable extraction of components.
bool negative() const { return (i >> 31) != 0; }
int32_t raw_mantissa() const { return i & ((1 << 23) - 1); }
int32_t raw_exponent() const { return (i >> 23) & 0xFF; }
int32_t i;
float f;
};
/* Note: ULPS = Units in the Last Place */
static inline bool floateq (float a, float b, int max_ulps_diff)
{
Float_t ua (a);
Float_t ub (b);
if (a == b) {
return true;
}
// Different signs means they do not match.
if (ua.negative() != ub.negative()) {
return false;
}
// Find the difference in ULPs.
int ulps_diff = abs (ua.i - ub.i);
if (ulps_diff <= max_ulps_diff) {
return true;
}
return false;
}
} /* namespace */
#endif /* __libpbd__floating_h__ */
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