#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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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. */ 00045 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. */ 00053 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. */ 00060 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 **/ 00073 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

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