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/**
* \file
* \brief 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.
*
*/
#ifndef LIB2GEOM_SEEN_UTILS_H
#define LIB2GEOM_SEEN_UTILS_H
#include <cstddef>
#include <vector>
#include <boost/operators.hpp>
namespace Geom {
// Throw these errors instead of aserting so code can handle them if needed.
using ErrorCode = int;
enum Errors : ErrorCode {
GEOM_ERR_INTERSECGRAPH,
};
// proper logical xor
inline bool logical_xor (bool a, bool b) { return (a || b) && !(a && b); }
void binomial_coefficients(std::vector<size_t>& bc, std::size_t n);
struct EmptyClass {};
/**
* @brief Noncommutative multiplication helper.
* Generates operator*(T, U) from operator*=(T, U). Does not generate operator*(U, T)
* like boost::multipliable does. This makes it suitable for noncommutative cases,
* such as transforms.
*/
template <class T, class U, class B = EmptyClass>
struct MultipliableNoncommutative : B
{
friend T operator*(T const &lhs, U const &rhs) {
T nrv(lhs); nrv *= rhs; return nrv;
}
};
/** @brief Null output iterator
* Use this if you want to discard a result returned through an output iterator. */
struct NullIterator
: public boost::output_iterator_helper<NullIterator>
{
NullIterator() {}
template <typename T>
void operator=(T const &) {}
};
/** @brief Get the next iterator in the container with wrap-around.
* If the iterator would become the end iterator after incrementing,
* return the begin iterator instead. */
template <typename Iter, typename Container>
Iter cyclic_next(Iter i, Container &c) {
++i;
if (i == c.end()) {
i = c.begin();
}
return i;
}
/** @brief Get the previous iterator in the container with wrap-around.
* If the passed iterator is the begin iterator, return the iterator
* just before the end iterator instead. */
template <typename Iter, typename Container>
Iter cyclic_prior(Iter i, Container &c) {
if (i == c.begin()) {
i = c.end();
}
--i;
return i;
}
} // end namespace Geom
#endif // LIB2GEOM_SEEN_UTILS_H
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
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