79 lines
1.9 KiB
C++
79 lines
1.9 KiB
C++
/*
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Copyright (C) 2012 Paul Davis
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/* Taken from
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* http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm
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*
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* Code assumed to be in the public domain.
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*/
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#ifndef __libpbd__floating_h__
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#define __libpbd__floating_h__
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#include <stdint.h>
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#include <cmath>
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#include "pbd/libpbd_visibility.h"
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namespace PBD {
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union /*LIBPBD_API*/ Float_t
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{
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Float_t (float num = 0.0f) : f(num) {}
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// Portable extraction of components.
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bool negative() const { return (i >> 31) != 0; }
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int32_t raw_mantissa() const { return i & ((1 << 23) - 1); }
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int32_t raw_exponent() const { return (i >> 23) & 0xFF; }
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int32_t i;
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float f;
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};
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/* Note: ULPS = Units in the Last Place */
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static inline bool floateq (float a, float b, int max_ulps_diff)
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{
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Float_t ua (a);
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Float_t ub (b);
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if (a == b) {
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return true;
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}
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// Different signs means they do not match.
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if (ua.negative() != ub.negative()) {
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return false;
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}
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// Find the difference in ULPs.
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int ulps_diff = abs (ua.i - ub.i);
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if (ulps_diff <= max_ulps_diff) {
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return true;
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}
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return false;
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}
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} /* namespace */
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#endif /* __libpbd__floating_h__ */
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