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#ifndef LIB2GEOM_UTILS_HEADER

#define LIB2GEOM_UTILS_HEADER

/** Various utility functions.

*

* Copyright 2007 Johan Engelen <goejendaagh@zonnet.nl>

* Copyright 2006 Michael G. Sloan <mgsloan@gmail.com>

*

* This library is free software; you can redistribute it and/or

* modify it either under the terms of the GNU Lesser General Public

* License version 2.1 as published by the Free Software Foundation

* (the "LGPL") or, at your option, under the terms of the Mozilla

* Public License Version 1.1 (the "MPL"). If you do not alter this

* notice, a recipient may use your version of this file under either

* the MPL or the LGPL.

*

* You should have received a copy of the LGPL along with this library

* in the file COPYING-LGPL-2.1; if not, write to the Free Software

* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

* You should have received a copy of the MPL along with this library

* in the file COPYING-MPL-1.1

*

* The contents of this file are subject to the Mozilla Public License

* Version 1.1 (the "License"); you may not use this file except in

* compliance with the License. You may obtain a copy of the License at

* http://www.mozilla.org/MPL/

*

* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY

* OF ANY KIND, either express or implied. See the LGPL or the MPL for

* the specific language governing rights and limitations.

*

*/

#include <cmath>

namespace Geom {

// proper logical xor

inline bool logical_xor (bool a, bool b) { return (a || b) && !(a && b); }

/** Sign function - indicates the sign of a numeric type. -1 indicates negative, 1 indicates

* positive, and 0 indicates, well, 0. Mathsy people will know this is basically the derivative

* of abs, except for the fact that it is defined on 0.

*/

template <class T> inline int sgn(const T& x) {return (x < 0 ? -1 : (x > 0 ? 1 : 0) );}

template <class T> inline T sqr(const T& x) {return x * x;}

template <class T> inline T cube(const T& x) {return x * x * x;}

/** Between function - returns true if a number x is within a range. The values delimiting the

* range and the number must have the same type.

*/

template <class T> inline const T& between (const T& min, const T& max, const T& x)

{ return min < x && max > x; }

/** Returns x rounded to the nearest integer. It is unspecified what happens

* if x is half way between two integers: we may in future use rint/round

* on platforms that have them.

*/

inline double round(double const x) { return std::floor(x + .5); }

/** Returns x rounded to the nearest \a places decimal places.

Implemented in terms of round, i.e. we make no guarantees as to what happens if x is

half way between two rounded numbers.

Note: places is the number of decimal places without using scientific (e) notation, not the

number of significant figures. This function may not be suitable for values of x whose

magnitude is so far from 1 that one would want to use scientific (e) notation.

places may be negative: e.g. places = -2 means rounding to a multiple of .01

**/

inline double decimal_round(double const x, int const places) {

//TODO: possibly implement with modulus instead?

double const multiplier = std::pow(10.0, places);

return round( x * multiplier ) / multiplier;

}

}

#endif

#define LIB2GEOM_UTILS_HEADER

/** Various utility functions.

*

* Copyright 2007 Johan Engelen <goejendaagh@zonnet.nl>

* Copyright 2006 Michael G. Sloan <mgsloan@gmail.com>

*

* This library is free software; you can redistribute it and/or

* modify it either under the terms of the GNU Lesser General Public

* License version 2.1 as published by the Free Software Foundation

* (the "LGPL") or, at your option, under the terms of the Mozilla

* Public License Version 1.1 (the "MPL"). If you do not alter this

* notice, a recipient may use your version of this file under either

* the MPL or the LGPL.

*

* You should have received a copy of the LGPL along with this library

* in the file COPYING-LGPL-2.1; if not, write to the Free Software

* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

* You should have received a copy of the MPL along with this library

* in the file COPYING-MPL-1.1

*

* The contents of this file are subject to the Mozilla Public License

* Version 1.1 (the "License"); you may not use this file except in

* compliance with the License. You may obtain a copy of the License at

* http://www.mozilla.org/MPL/

*

* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY

* OF ANY KIND, either express or implied. See the LGPL or the MPL for

* the specific language governing rights and limitations.

*

*/

#include <cmath>

namespace Geom {

// proper logical xor

inline bool logical_xor (bool a, bool b) { return (a || b) && !(a && b); }

/** Sign function - indicates the sign of a numeric type. -1 indicates negative, 1 indicates

* positive, and 0 indicates, well, 0. Mathsy people will know this is basically the derivative

* of abs, except for the fact that it is defined on 0.

*/

template <class T> inline int sgn(const T& x) {return (x < 0 ? -1 : (x > 0 ? 1 : 0) );}

template <class T> inline T sqr(const T& x) {return x * x;}

template <class T> inline T cube(const T& x) {return x * x * x;}

/** Between function - returns true if a number x is within a range. The values delimiting the

* range and the number must have the same type.

*/

template <class T> inline const T& between (const T& min, const T& max, const T& x)

{ return min < x && max > x; }

/** Returns x rounded to the nearest integer. It is unspecified what happens

* if x is half way between two integers: we may in future use rint/round

* on platforms that have them.

*/

inline double round(double const x) { return std::floor(x + .5); }

/** Returns x rounded to the nearest \a places decimal places.

Implemented in terms of round, i.e. we make no guarantees as to what happens if x is

half way between two rounded numbers.

Note: places is the number of decimal places without using scientific (e) notation, not the

number of significant figures. This function may not be suitable for values of x whose

magnitude is so far from 1 that one would want to use scientific (e) notation.

places may be negative: e.g. places = -2 means rounding to a multiple of .01

**/

inline double decimal_round(double const x, int const places) {

//TODO: possibly implement with modulus instead?

double const multiplier = std::pow(10.0, places);

return round( x * multiplier ) / multiplier;

}

}

#endif