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12065 | fschmid | 1 | #ifndef LIB2GEOM_UTILS_HEADER |
2 | #define LIB2GEOM_UTILS_HEADER |
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3 | |||
15347 | fschmid | 4 | /** Various utility functions. |
12065 | fschmid | 5 | * |
6 | * Copyright 2007 Johan Engelen <goejendaagh@zonnet.nl> |
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7 | * Copyright 2006 Michael G. Sloan <mgsloan@gmail.com> |
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8 | * |
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9 | * This library is free software; you can redistribute it and/or |
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10 | * modify it either under the terms of the GNU Lesser General Public |
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11 | * License version 2.1 as published by the Free Software Foundation |
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12 | * (the "LGPL") or, at your option, under the terms of the Mozilla |
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13 | * Public License Version 1.1 (the "MPL"). If you do not alter this |
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14 | * notice, a recipient may use your version of this file under either |
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15 | * the MPL or the LGPL. |
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16 | * |
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17 | * You should have received a copy of the LGPL along with this library |
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18 | * in the file COPYING-LGPL-2.1; if not, write to the Free Software |
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18122 | mrdocs | 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
12065 | fschmid | 20 | * You should have received a copy of the MPL along with this library |
21 | * in the file COPYING-MPL-1.1 |
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22 | * |
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23 | * The contents of this file are subject to the Mozilla Public License |
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24 | * Version 1.1 (the "License"); you may not use this file except in |
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25 | * compliance with the License. You may obtain a copy of the License at |
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26 | * http://www.mozilla.org/MPL/ |
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27 | * |
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28 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY |
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29 | * OF ANY KIND, either express or implied. See the LGPL or the MPL for |
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30 | * the specific language governing rights and limitations. |
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31 | * |
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32 | */ |
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33 | |||
15347 | fschmid | 34 | #include <cmath> |
12065 | fschmid | 35 | |
36 | namespace Geom { |
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37 | |||
38 | // proper logical xor |
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39 | inline bool logical_xor (bool a, bool b) { return (a || b) && !(a && b); } |
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40 | |||
15347 | fschmid | 41 | /** Sign function - indicates the sign of a numeric type. -1 indicates negative, 1 indicates |
42 | * positive, and 0 indicates, well, 0. Mathsy people will know this is basically the derivative |
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43 | * of abs, except for the fact that it is defined on 0. |
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44 | */ |
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45 | template <class T> inline int sgn(const T& x) {return (x < 0 ? -1 : (x > 0 ? 1 : 0) );} |
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12065 | fschmid | 46 | |
15347 | fschmid | 47 | template <class T> inline T sqr(const T& x) {return x * x;} |
48 | template <class T> inline T cube(const T& x) {return x * x * x;} |
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49 | |||
50 | /** Between function - returns true if a number x is within a range. The values delimiting the |
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51 | * range and the number must have the same type. |
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52 | */ |
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53 | template <class T> inline const T& between (const T& min, const T& max, const T& x) |
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54 | { return min < x && max > x; } |
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55 | |||
56 | /** Returns x rounded to the nearest integer. It is unspecified what happens |
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57 | * if x is half way between two integers: we may in future use rint/round |
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58 | * on platforms that have them. |
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59 | */ |
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60 | inline double round(double const x) { return std::floor(x + .5); } |
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61 | |||
62 | /** Returns x rounded to the nearest \a places decimal places. |
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63 | |||
64 | Implemented in terms of round, i.e. we make no guarantees as to what happens if x is |
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65 | half way between two rounded numbers. |
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66 | |||
67 | Note: places is the number of decimal places without using scientific (e) notation, not the |
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68 | number of significant figures. This function may not be suitable for values of x whose |
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69 | magnitude is so far from 1 that one would want to use scientific (e) notation. |
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70 | |||
71 | places may be negative: e.g. places = -2 means rounding to a multiple of .01 |
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72 | **/ |
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73 | inline double decimal_round(double const x, int const places) { |
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74 | //TODO: possibly implement with modulus instead? |
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75 | double const multiplier = std::pow(10.0, places); |
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76 | return round( x * multiplier ) / multiplier; |
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12065 | fschmid | 77 | } |
78 | |||
15347 | fschmid | 79 | } |
80 | |||
15344 | fschmid | 81 | #endif |