Clusters.h
/**********************************************************************
*
* GEOS - Geometry Engine Open Source
* http://geos.osgeo.org
*
* Copyright (C) 2021-2022 Daniel Baston
*
* This is free software; you can redistribute and/or modify it under
* the terms of the GNU Lesser General Public Licence as published
* by the Free Software Foundation.
* See the COPYING file for more information.
*
**********************************************************************/
#pragma once
#include <geos/export.h>
#include <limits>
#include <vector>
namespace geos {
namespace operation {
namespace cluster {
class UnionFind;
class GEOS_DLL Clusters {
private:
std::vector<std::size_t> m_elemsInCluster; // The IDs of elements that are included in a cluster
std::vector<std::size_t> m_starts; // Start position of each cluster in m_elemsInCluster
std::size_t m_numElems; // The number of elements from which clusters were generated
public:
using const_iterator = decltype(m_elemsInCluster)::const_iterator;
explicit Clusters(UnionFind & uf, std::vector<std::size_t> elemsInCluster, std::size_t numElems);
// Get the number of clusters available
std::size_t getNumClusters() const {
return m_starts.size();
}
// Get the size of a given cluster
std::size_t getSize(std::size_t cluster) const {
return static_cast<std::size_t>(std::distance(begin(cluster), end(cluster)));
}
// Get a vector containing the cluster ID for each item in `elems`
std::vector<std::size_t> getClusterIds(std::size_t noClusterValue = std::numeric_limits<std::size_t>::max()) const;
// Get an iterator to the first element in a given cluster
const_iterator begin(std::size_t cluster) const {
return std::next(m_elemsInCluster.begin(), static_cast<std::ptrdiff_t>(m_starts[cluster]));
}
// Get an iterator beyond the last element in a given cluster
const_iterator end(std::size_t cluster) const {
if (cluster == static_cast<std::size_t>(m_starts.size() - 1)) {
return m_elemsInCluster.end();
}
return begin(cluster + 1);
}
};
}
}
}
geos::operation::cluster::UnionFind
Definition UnionFind.h:32
geos::operation
Provides classes for implementing operations on geometries.
Definition CleanCoverage.h:34
geos
Basic namespace for all GEOS functionalities.
Definition geos.h:38