| -rw-r--r-- | library/qmath.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/library/qmath.c b/library/qmath.c new file mode 100644 index 0000000..7af8706 --- a/dev/null +++ b/library/qmath.c @@ -0,0 +1,157 @@ +/********************************************************************** +** Copyright (C) 2000 Trolltech AS. All rights reserved. +** +** This file is part of Qtopia Environment. +** +** This file may be distributed and/or modified under the terms of the +** GNU General Public License version 2 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. +** +** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE +** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. +** +** See http://www.trolltech.com/gpl/ for GPL licensing information. +** +** Contact info@trolltech.com if any conditions of this licensing are +** not clear to you. +** +**********************************************************************/ + +#include <math.h> +#include <float.h> +#include "qmath.h" + +#ifdef QT_QWS_CASSIOPEIA + +double qFabs( double a ) +{ + if ( a < 0.0 ) + return -a; + return a; +} + +double qSqrt( double value ) +{ + const double tol = 0.000005; // relative error tolerance + double old_app, new_app; + if (value == 0.0) + return 0.0; + old_app = value; // take value as first approximation + new_app = (old_app + value/old_app)/2; + while (qFabs((new_app-old_app)/new_app) > tol) + { + old_app = new_app; + new_app = (old_app + value/old_app)/2; + } + + return new_app; +} + +const double Q_PI = 3.14159265358979323846; // pi +const double Q_2PI = 6.28318530717958647693; // 2*pi +const double Q_PI2 = 1.57079632679489661923; // pi/2 + +static double qsincos( double a, int calcCos ) +{ + int sign; + double a2; + double a3; + double a5; + double a7; + double a9; + double a11; + + if ( calcCos ) // calculate cosine + a -= Q_PI2; + if ( a >= Q_2PI || a <= -Q_2PI ) { // fix range: -2*pi < a < 2*pi + int m = (int)(a/Q_2PI); + a -= Q_2PI*m; + } + if ( a < 0.0 ) // 0 <= a < 2*pi + a += Q_2PI; + sign = a > Q_PI ? -1 : 1; + if ( a >= Q_PI ) + a = Q_2PI - a; + if ( a >= Q_PI2 ) + a = Q_PI - a; + if ( calcCos ) + sign = -sign; + a2 = a*a; // here: 0 <= a < pi/4 + a3 = a2*a; // make taylor sin sum + a5 = a3*a2; + a7 = a5*a2; + a9 = a7*a2; + a11 = a9*a2; + return (a-a3/6+a5/120-a7/5040+a9/362880-a11/39916800)*sign; +} + +double qSin( double a ) { return qsincos(a,0); } +double qCos( double a ) { return qsincos(a,1); } + +//atan2 returns values from -PI to PI, so we have to do the same +double qATan2( double y, double x ) +{ + double r; + if ( x != 0.0 ) { + double a = qFabs(y/x); + if ( a <= 1 ) + r = a/(1+ 0.28*a*a); + else + r = Q_PI2 - a/(a*a + 0.28); + } else { + r = Q_PI2; + } + + if ( y >= 0.0 ) { + if ( x >= 0.0 ) + return r; + else + return Q_PI - r; + } else { + if ( x >= 0.0 ) + return 0.0 - r; + else + return -Q_PI + r; + } +} + +double qATan( double a ) +{ + return qATan2( a, 1.0 ); +} + +double qASin( double a ) +{ + return qATan2( a, qSqrt(1-a*a) ); +} + +double qTan( double a ) +{ + double ca = qCos(a); + if ( ca != 0.0 ) + return qSin( a ) / ca; + + return MAXDOUBLE; +} + +double qFloor( double a ) +{ + long i = (long) a; + return (double) i; +} + +#else + +double qSqrt( double value ) { return sqrt( value ); } +double qSin( double a ) { return sin(a); } +double qCos( double a ) { return cos(a); } +double qATan2( double y, double x ) { return atan2(y,x); } +double qATan( double a ) { return atan(a); } +double qASin( double a ) { return asin(a); } +double qTan( double a ) { return tan(a); } +double qFloor( double a ) { return floor(a); } +double qFabs( double a ) { return fabs(a); } + +#endif + |