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/*************************************************************************
** NumericRanges.hpp **
** **
** This file is part of dvisvgm -- a fast DVI to SVG converter **
** Copyright (C) 2005-2020 Martin Gieseking <martin.gieseking@uos.de> **
** **
** This program is free software; you can redistribute it and/or **
** modify it under the terms of the GNU General Public License as **
** published by the Free Software Foundation; either version 3 of **
** the License, or (at your option) any later version. **
** **
** This program is distributed in the hope that it will be useful, but **
** WITHOUT ANY WARRANTY; without even the implied warranty of **
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the **
** GNU General Public License for more details. **
** **
** You should have received a copy of the GNU General Public License **
** along with this program; if not, see <http://www.gnu.org/licenses/>. **
*************************************************************************/
#ifndef NUMERICRANGES_HPP
#define NUMERICRANGES_HPP
#include <algorithm>
#include <list>
#include <utility>
template <class T>
class NumericRanges
{
public:
using Range = std::pair<T,T>;
using Container = std::list<Range>;
using ConstIterator = typename Container::const_iterator;
public:
void addRange (T value) {addRange(value, value);}
void addRange (T first, T last);
bool valueExists (T value) const;
size_t size () const {return _ranges.size();}
ConstIterator begin () const {return _ranges.begin();}
ConstIterator end () const {return _ranges.end();}
const Container& ranges () const {return _ranges;}
private:
Container _ranges;
};
/** Adds a numeric range to the collection.
* @param[in] first left bound of new range
* @param[in] last right bound of new range */
template <class T>
void NumericRanges<T>::addRange (T first, T last) {
if (first > last)
std::swap(first, last);
typename Container::iterator it = _ranges.begin();
while (it != _ranges.end() && first > it->first+1 && first > it->second+1)
++it;
if (it == _ranges.end() || last < it->first-1 || first > it->second+1)
it = _ranges.insert(it, Range(first, last));
else if ((first < it->first && last >= it->first-1) || (first <= it->second+1 && last > it->second)) {
it->first = std::min(it->first, first);
it->second = std::max(it->second, last);
}
// merge adjacent ranges
if (it != _ranges.end()) {
typename Container::iterator l = it;
typename Container::iterator r = it;
if (l == _ranges.begin())
l = _ranges.end();
else
--l;
++r;
bool l_modified = false;
bool r_modified = false;
if (l != _ranges.end() && l->second >= it->first-1) {
l->first = std::min(l->first, it->first);
l->second = std::max(l->second, it->second);
l_modified = true;
}
if (r != _ranges.end() && r->first <= it->second+1) {
r->first = std::min(r->first, it->first);
r->second = std::max(r->second, it->second);
r_modified = true;
}
if (l_modified || r_modified) {
_ranges.erase(it);
if (l_modified && r_modified && l->second >= r->first-1) {
l->first = std::min(l->first, r->first);
l->second = std::max(l->second, r->second);
_ranges.erase(r);
}
}
}
}
template <class T>
bool NumericRanges<T>::valueExists (T value) const {
auto it = std::lower_bound(_ranges.begin(), _ranges.end(), Range(value, 0),
[](const Range &r1, const Range &r2) {
return r1.first < r2.first;
});
return (it != _ranges.end() && it->first <= value && it->second >= value);
}
#endif
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