InducedSubgraph.h

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#pragma once
 
#include <ogdf/basic/Graph.h>
#include <ogdf/basic/GraphList.h>
#include <ogdf/basic/List.h>
#include <ogdf/basic/basic.h>
#include <ogdf/basic/internal/config_autogen.h>
#include <ogdf/basic/internal/graph_iterators.h>
 
#include <algorithm>
#include <cstddef>
#include <iterator>
#include <type_traits>
#include <utility>
 
namespace ogdf {
 
namespace internal {
template<class T, class = void>
struct is_iterator : std::false_type { };
 
template<class T>
struct is_iterator<T, std::void_t<typename std::iterator_traits<T>::iterator_category>>
    : std::true_type { };
 
template<typename Iterator>
typename std::enable_if<!is_iterator<Iterator>::value, size_t>::type guess_dist(Iterator, Iterator) {
    return 0;
}
 
template<typename Iterator>
typename std::enable_if<is_iterator<Iterator>::value,
        typename std::iterator_traits<Iterator>::difference_type>::type
guess_dist([[maybe_unused]] Iterator begin, [[maybe_unused]] Iterator end) {
    if constexpr (std::is_same<typename std::iterator_traits<Iterator>::iterator_category,
                          std::random_access_iterator_tag>::value) {
        return end - begin;
    } else {
        return 0;
    }
}
}
 
template<OGDF_NODE_ITER NI, bool notifyObservers, bool copyIDs>
void Graph::insertNodes(const NI& nodesBegin, const NI& nodesEnd, NodeArray<node, true>& nodeMap,
        int& newNodes, void* cbData) {
    int guessedNodes = internal::guess_dist(nodesBegin, nodesEnd);
    if (guessedNodes > 0 && notifyObservers) {
        m_regNodeArrays.reserveSpace(guessedNodes);
    }
 
    for (auto it = nodesBegin; it != nodesEnd; ++it) {
        node vG = *it;
        if (copyIDs) {
            m_nodeIdCount = max(m_nodeIdCount, vG->index() + 1);
        }
        // nodeMap[vG] is overwritten if it is != nullptr
        node v = nodeMap[vG] = pureNewNode(copyIDs ? vG->index() : m_nodeIdCount++);
        newNodes++;
        if (notifyObservers) {
            m_regNodeArrays.keyAdded(v);
            nodeInserted(cbData, vG, v);
            for (GraphObserver* obs : getObservers()) {
                obs->nodeAdded(v);
            }
        }
    }
}
 
template<OGDF_NODE_ITER NI, OGDF_EDGE_ITER EI, bool copyEmbedding, bool copyIDs, bool notifyObservers>
std::pair<int, int> Graph::insert(const NI& nodesBegin, const NI& nodesEnd, const EI& edgesBegin,
        const EI& edgesEnd, NodeArray<node>& nodeMap, EdgeArray<edge>& edgeMap) {
    OGDF_ASSERT(nodeMap.valid());
    OGDF_ASSERT(edgeMap.valid());
    OGDF_ASSERT(nodeMap.graphOf() == edgeMap.graphOf());
    int newNodes = 0, newEdges = 0;
    void* cbData = preInsert(copyEmbedding, copyIDs, notifyObservers, false, nodeMap, edgeMap,
            &newNodes, &newEdges);
    if (nodesBegin == nodesEnd) {
        postInsert(cbData, newNodes, newEdges);
        return {newNodes, newEdges};
    }
    insertNodes<NI, notifyObservers, copyIDs>(nodesBegin, nodesEnd, nodeMap, newNodes, cbData);
 
    if (edgesBegin == edgesEnd) {
        postInsert(cbData, newNodes, newEdges);
        return {newNodes, newEdges};
    }
 
    if (!copyEmbedding && notifyObservers) {
        int guessedEdges = internal::guess_dist(edgesBegin, edgesEnd);
        if (guessedEdges > 0) {
            m_regEdgeArrays.reserveSpace(guessedEdges);
            m_regAdjArrays.reserveSpace(guessedEdges); // registry adds factor 2 in calculateArraySize
        }
    }
 
    for (auto it = edgesBegin; it != edgesEnd; ++it) {
        edge eG = *it;
        node src = nodeMap[eG->source()];
        node tgt = nodeMap[eG->target()];
        if (src == nullptr || tgt == nullptr) {
            continue;
        }
        if (copyIDs) {
            m_edgeIdCount = max(m_edgeIdCount, eG->index() + 1);
        }
        // edgeMap[eG] is overwritten, even if it is != nullptr
        edge e = edgeMap[eG] = pureNewEdge(src, tgt, copyIDs ? eG->index() : m_edgeIdCount++);
        newEdges++;
        if (!copyEmbedding) {
            src->adjEntries.pushBack(e->m_adjSrc);
            tgt->adjEntries.pushBack(e->m_adjTgt);
            if (notifyObservers) {
                m_regEdgeArrays.keyAdded(e);
                m_regAdjArrays.keyAdded(e->adjSource());
                edgeInserted(cbData, eG, e);
                for (GraphObserver* obs : getObservers()) {
                    obs->edgeAdded(e);
                }
            }
        }
    }
 
    if (!copyEmbedding) {
#ifdef OGDF_HEAVY_DEBUG
        consistencyCheck();
#endif
        postInsert(cbData, newNodes, newEdges);
        return {newNodes, newEdges};
    }
 
    for (auto it = nodesBegin; it != nodesEnd; ++it) {
        node vG = *it;
        node v = nodeMap[vG];
        for (adjEntry adjG : vG->adjEntries) {
            edge eG = adjG->theEdge();
            edge e = edgeMap[eG];
            if (e == nullptr) {
                continue;
            }
            adjEntry adj = adjG->isSource() ? e->adjSource() : e->adjTarget();
            // edgeMap[eG] might be an old entry that was already inserted into the list
            // so check whether adj is already in the list, indicated by having succ or pred,
            // or being the only entry in the list
            if (adj->succ() != nullptr || adj->pred() != nullptr || v->adjEntries.head() == adj) {
                continue;
            }
            v->adjEntries.pushBack(adj);
        }
    }
 
    // notify observers of added edges after adjEntries are initialized
    if (notifyObservers) {
        m_regEdgeArrays.reserveSpace(newEdges);
        m_regAdjArrays.reserveSpace(newEdges); // registry adds factor 2 in calculateArraySize
 
        for (auto it = edgesBegin; it != edgesEnd; ++it) {
            edge eG = *it;
            edge e = edgeMap[eG];
            if (nodeMap[eG->source()] == nullptr || nodeMap[eG->target()] == nullptr) {
                continue;
            }
            OGDF_ASSERT(e != nullptr);
            m_regEdgeArrays.keyAdded(e);
            m_regAdjArrays.keyAdded(e->adjSource());
            edgeInserted(cbData, eG, e);
            for (GraphObserver* obs : getObservers()) {
                obs->edgeAdded(e);
            }
        }
    }
 
#ifdef OGDF_HEAVY_DEBUG
    consistencyCheck();
#endif
 
    postInsert(cbData, newNodes, newEdges);
    return {newNodes, newEdges};
}
 
template<OGDF_NODE_ITER NI, OGDF_EDGE_FILTER EF, bool copyIDs, bool notifyObservers>
std::pair<int, int> Graph::insert(const NI& nodesBegin, const NI& nodesEnd, const EF& edgeFilter,
        NodeArray<node>& nodeMap, EdgeArray<edge>& edgeMap) {
    OGDF_ASSERT(nodeMap.valid());
    OGDF_ASSERT(edgeMap.valid());
    OGDF_ASSERT(nodeMap.graphOf() == edgeMap.graphOf());
    int newNodes = 0, newEdges = 0;
    void* cbData =
            preInsert(true, copyIDs, notifyObservers, true, nodeMap, edgeMap, &newNodes, &newEdges);
    if (nodesBegin == nodesEnd) {
        postInsert(cbData, newNodes, newEdges);
        return {newNodes, newEdges};
    }
    insertNodes<NI, notifyObservers, copyIDs>(nodesBegin, nodesEnd, nodeMap, newNodes, cbData);
 
    for (auto it = nodesBegin; it != nodesEnd; ++it) {
        node vG = *it;
        node v = nodeMap[vG];
        for (adjEntry adjG : vG->adjEntries) {
            edge eG = adjG->theEdge();
            if (!edgeFilter(eG)) {
                continue;
            }
            // edgeMap[eG] is *not* overwritten if it is != nullptr
            edge e = edgeMap[eG];
            if (e == nullptr) {
                // add the first adjEntry of the edge
                node twin = nodeMap[adjG->twinNode()];
                if (twin == nullptr) {
                    // we can be sure that the other adjEntry wasn't selected and
                    // we thus cannot add this (selected) edge
                    continue;
                }
                if (copyIDs) {
                    m_edgeIdCount = max(m_edgeIdCount, eG->index() + 1);
                }
                if (adjG->isSource()) {
                    e = edgeMap[eG] = pureNewEdge(v, twin, copyIDs ? eG->index() : m_edgeIdCount++);
                    v->adjEntries.pushBack(e->m_adjSrc);
                } else {
                    e = edgeMap[eG] = pureNewEdge(twin, v, copyIDs ? eG->index() : m_edgeIdCount++);
                    v->adjEntries.pushBack(e->m_adjTgt);
                }
                newEdges++;
            } else {
                // complete the edge with its second adjEntry
                adjEntry adj = adjG->isSource() ? e->adjSource() : e->adjTarget();
                // edgeMap[eG] might be an old entry that was already inserted into the list
                // so check whether adj is already in the list, indicated by having succ or pred,
                // or being the only entry in the list
                if (adj->succ() == nullptr && adj->pred() == nullptr && v->adjEntries.head() != adj) {
                    v->adjEntries.pushBack(adj);
                    // at this point, other edges might still be incomplete, so we cannot call observers
                }
            }
        }
    }
 
    // notify observers of added edges after all adjEntries are initialized
    if (notifyObservers) {
        m_regEdgeArrays.reserveSpace(newEdges);
        m_regAdjArrays.reserveSpace(newEdges); // registry adds factor 2 in calculateArraySize
 
        for (auto it = nodesBegin; it != nodesEnd; ++it) {
            node vG = *it;
            for (adjEntry adjG : vG->adjEntries) {
                if (!adjG->isSource()) {
                    continue;
                }
                edge eG = adjG->theEdge();
                edge e = edgeMap[eG];
                // we will call Observers for *all* edgeMap entries
                if (e == nullptr) {
                    continue;
                }
                m_regEdgeArrays.keyAdded(e);
                m_regAdjArrays.keyAdded(e->adjSource());
                edgeInserted(cbData, eG, e);
                for (GraphObserver* obs : getObservers()) {
                    obs->edgeAdded(e);
                }
            }
        }
    }
 
#ifdef OGDF_HEAVY_DEBUG
    consistencyCheck();
#endif
 
    postInsert(cbData, newNodes, newEdges);
    return {newNodes, newEdges};
}
 
}