mirror of
https://github.com/brl/mutter.git
synced 2024-11-30 12:00:44 -05:00
ff4d87727b
Dropped obsolete Free Software Foundation address pointing to the FSF website instead as suggested by https://www.gnu.org/licenses/gpl-howto.html keeping intact the important part of the historical notice as requested by the license. Resolving rpmlint reported issue E: incorrect-fsf-address. Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com> Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3155>
133 lines
2.9 KiB
C
133 lines
2.9 KiB
C
/*
|
|
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
|
|
* 2000 Wim Taymans <wtay@chello.be>
|
|
* 2002 Thomas Vander Stichele <thomas@apestaart.org>
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Library General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library 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
|
|
* Library General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Library General Public
|
|
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
* Fraction utility functions in this file comes from gstutils.c in gstreamer.
|
|
*/
|
|
|
|
#include "config.h"
|
|
|
|
#include "core/meta-fraction.h"
|
|
|
|
#include <glib.h>
|
|
#include <math.h>
|
|
|
|
#define MAX_TERMS 30
|
|
#define MIN_DIVISOR 1.0e-10
|
|
#define MAX_ERROR 1.0e-20
|
|
|
|
static int
|
|
greatest_common_divisor (int a,
|
|
int b)
|
|
{
|
|
while (b != 0)
|
|
{
|
|
int temp = a;
|
|
|
|
a = b;
|
|
b = temp % b;
|
|
}
|
|
|
|
return ABS (a);
|
|
}
|
|
|
|
MetaFraction
|
|
meta_fraction_from_double (double src)
|
|
{
|
|
double V, F; /* double being converted */
|
|
int N, D; /* will contain the result */
|
|
int A; /* current term in continued fraction */
|
|
int64_t N1, D1; /* numerator, denominator of last approx */
|
|
int64_t N2, D2; /* numerator, denominator of previous approx */
|
|
int i;
|
|
int gcd;
|
|
gboolean negative = FALSE;
|
|
|
|
/* initialize fraction being converted */
|
|
F = src;
|
|
if (F < 0.0)
|
|
{
|
|
F = -F;
|
|
negative = TRUE;
|
|
}
|
|
|
|
V = F;
|
|
/* initialize fractions with 1/0, 0/1 */
|
|
N1 = 1;
|
|
D1 = 0;
|
|
N2 = 0;
|
|
D2 = 1;
|
|
N = 1;
|
|
D = 1;
|
|
|
|
for (i = 0; i < MAX_TERMS; i++)
|
|
{
|
|
/* get next term */
|
|
A = (gint) F; /* no floor() needed, F is always >= 0 */
|
|
/* get new divisor */
|
|
F = F - A;
|
|
|
|
/* calculate new fraction in temp */
|
|
N2 = N1 * A + N2;
|
|
D2 = D1 * A + D2;
|
|
|
|
/* guard against overflow */
|
|
if (N2 > G_MAXINT || D2 > G_MAXINT)
|
|
break;
|
|
|
|
N = N2;
|
|
D = D2;
|
|
|
|
/* save last two fractions */
|
|
N2 = N1;
|
|
D2 = D1;
|
|
N1 = N;
|
|
D1 = D;
|
|
|
|
/* quit if dividing by zero or close enough to target */
|
|
if (F < MIN_DIVISOR || fabs (V - ((gdouble) N) / D) < MAX_ERROR)
|
|
break;
|
|
|
|
/* Take reciprocal */
|
|
F = 1 / F;
|
|
}
|
|
|
|
/* fix for overflow */
|
|
if (D == 0)
|
|
{
|
|
N = G_MAXINT;
|
|
D = 1;
|
|
}
|
|
|
|
/* fix for negative */
|
|
if (negative)
|
|
N = -N;
|
|
|
|
/* simplify */
|
|
gcd = greatest_common_divisor (N, D);
|
|
if (gcd)
|
|
{
|
|
N /= gcd;
|
|
D /= gcd;
|
|
}
|
|
|
|
return (MetaFraction) {
|
|
.num = N,
|
|
.denom = D
|
|
};
|
|
}
|