mvrtree/Index.cc

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/******************************************************************************
 * Project:  libspatialindex - A C++ library for spatial indexing
 * Author:   Marios Hadjieleftheriou, mhadji@gmail.com
 ******************************************************************************
 * Copyright (c) 2002, Marios Hadjieleftheriou
 *
 * All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
******************************************************************************/
 
#include <limits>
 
#include <spatialindex/SpatialIndex.h>
 
#include "MVRTree.h"
#include "Node.h"
#include "Leaf.h"
#include "Index.h"
 
using namespace SpatialIndex;
using namespace SpatialIndex::MVRTree;
 
Index::~Index()
= default;
 
Index::Index(SpatialIndex::MVRTree::MVRTree* pTree, id_type id, uint32_t level) : Node(pTree, id, level, pTree->m_indexCapacity)
{
}
 
NodePtr Index::chooseSubtree(const TimeRegion& mbr, uint32_t insertionLevel, std::stack<id_type>& pathBuffer)
{
    if (m_level == insertionLevel) return NodePtr(this, &(m_pTree->m_indexPool));
 
    pathBuffer.push(m_identifier);
 
    uint32_t child = 0;
 
    switch (m_pTree->m_treeVariant)
    {
        case RV_LINEAR:
        case RV_QUADRATIC:
            child = findLeastEnlargement(mbr);
            break;
        case RV_RSTAR:
            if (m_level == 1)
            {
                // if this node points to leaves...
                child = findLeastOverlap(mbr);
            }
            else
            {
                child = findLeastEnlargement(mbr);
            }
        break;
        default:
            throw Tools::NotSupportedException("Index::chooseSubtree: Tree variant not supported.");
    }
    assert (child != std::numeric_limits<uint32_t>::max());
 
    NodePtr n = m_pTree->readNode(m_pIdentifier[child]);
    NodePtr ret = n->chooseSubtree(mbr, insertionLevel, pathBuffer);
    assert(n.unique());
    if (ret.get() == n.get()) n.relinquish();
 
    return ret;
}
 
NodePtr Index::findLeaf(const TimeRegion& mbr, id_type id, std::stack<id_type>& pathBuffer)
{
    pathBuffer.push(m_identifier);
 
    for (uint32_t cChild = 0; cChild < m_children; ++cChild)
    {
        // check live nodes only.
        if (m_ptrMBR[cChild]->m_endTime < std::numeric_limits<double>::max()) continue;
        //if (m_ptrMBR[cChild]->m_endTime < std::numeric_limits<double>::max() ||
        //      m_ptrMBR[cChild]->m_startTime > mbr.m_startTime) continue;
 
        if (m_ptrMBR[cChild]->containsRegion(mbr))
        {
            NodePtr n = m_pTree->readNode(m_pIdentifier[cChild]);
            NodePtr l = n->findLeaf(mbr, id, pathBuffer);
            if (n.get() == l.get()) n.relinquish();
            if (l.get() != nullptr) return l;
        }
    }
 
    pathBuffer.pop();
 
    return NodePtr();
}
 
void Index::split(
    uint32_t dataLength, uint8_t* pData, TimeRegion& mbr, id_type id, NodePtr& pLeft, NodePtr& pRight,
    TimeRegion& mbr2, id_type id2, bool bInsertMbr2)
{
    ++(m_pTree->m_stats.m_u64Splits);
 
    std::vector<uint32_t> g1, g2;
 
    switch (m_pTree->m_treeVariant)
    {
        case RV_LINEAR:
        case RV_QUADRATIC:
            rtreeSplit(dataLength, pData, mbr, id, g1, g2, mbr2, id2, bInsertMbr2);
            break;
        case RV_RSTAR:
            rstarSplit(dataLength, pData, mbr, id, g1, g2, mbr2, id2, bInsertMbr2);
            break;
        default:
            throw Tools::NotSupportedException("Index::split: Tree variant not supported.");
    }
 
    pLeft = m_pTree->m_indexPool.acquire();
    pRight = m_pTree->m_indexPool.acquire();
 
    if (pLeft.get() == nullptr) pLeft = NodePtr(new Index(m_pTree, m_identifier, m_level), &(m_pTree->m_indexPool));
    if (pRight.get() == nullptr) pRight = NodePtr(new Index(m_pTree, -1, m_level), &(m_pTree->m_indexPool));
 
    pLeft->m_nodeMBR = m_pTree->m_infiniteRegion;
    pRight->m_nodeMBR = m_pTree->m_infiniteRegion;
 
    uint32_t cIndex;
 
    for (cIndex = 0; cIndex < g1.size(); ++cIndex)
    {
        pLeft->insertEntry(0, nullptr, *(m_ptrMBR[g1[cIndex]]), m_pIdentifier[g1[cIndex]]);
    }
 
    for (cIndex = 0; cIndex < g2.size(); ++cIndex)
    {
        pRight->insertEntry(0, nullptr, *(m_ptrMBR[g2[cIndex]]), m_pIdentifier[g2[cIndex]]);
    }
}
 
uint32_t Index::findLeastEnlargement(const TimeRegion& r) const
{
    double area = std::numeric_limits<double>::max();
    uint32_t best = std::numeric_limits<uint32_t>::max();
 
    TimeRegionPtr t = m_pTree->m_regionPool.acquire();
 
    for (uint32_t cChild = 0; cChild < m_children; ++cChild)
    {
        // if this child is already dead do not consider it.
        if (m_ptrMBR[cChild]->m_endTime <= r.m_startTime) continue;
 
        m_ptrMBR[cChild]->getCombinedRegion(*t, r);
 
        double a = m_ptrMBR[cChild]->getArea();
        double enl = t->getArea() - a;
 
        if (enl < area)
        {
            area = enl;
            best = cChild;
        }
        else if (
                enl > area - std::numeric_limits<double>::epsilon() &&
                enl < area + std::numeric_limits<double>::epsilon())
        {
            if (a < m_ptrMBR[best]->getArea()) best = cChild;
        }
    }
 
    return best;
}
 
uint32_t Index::findLeastOverlap(const TimeRegion& r) const
{
    OverlapEntry** entries = new OverlapEntry*[m_children];
 
    double leastOverlap = std::numeric_limits<double>::max();
    double me = std::numeric_limits<double>::max();
    OverlapEntry* best = nullptr;
    uint32_t cLiveEntries = 0;
 
    // find combined region and enlargement of every entry and store it.
    for (uint32_t cChild = 0; cChild < m_children; ++cChild)
    {
        if (m_ptrMBR[cChild]->m_endTime <= r.m_startTime) continue;
 
        try
        {
            entries[cLiveEntries] = new OverlapEntry();
        }
        catch (...)
        {
            for (uint32_t i = 0; i < cLiveEntries; ++i) delete entries[i];
            delete[] entries;
            throw;
        }
 
        entries[cLiveEntries]->m_index = cChild;
        entries[cLiveEntries]->m_original = m_ptrMBR[cChild];
        entries[cLiveEntries]->m_combined = m_pTree->m_regionPool.acquire();
        m_ptrMBR[cChild]->getCombinedRegion(*(entries[cLiveEntries]->m_combined), r);
        entries[cLiveEntries]->m_oa = entries[cLiveEntries]->m_original->getArea();
        entries[cLiveEntries]->m_ca = entries[cLiveEntries]->m_combined->getArea();
        entries[cLiveEntries]->m_enlargement = entries[cLiveEntries]->m_ca - entries[cLiveEntries]->m_oa;
 
        if (entries[cLiveEntries]->m_enlargement < me)
        {
            me = entries[cLiveEntries]->m_enlargement;
            best = entries[cLiveEntries];
        }
        else if (entries[cLiveEntries]->m_enlargement == me && entries[cLiveEntries]->m_oa < best->m_oa)
        {
            best = entries[cLiveEntries];
        }
        ++cLiveEntries;
    }
 
    if (me < -std::numeric_limits<double>::epsilon() || me > std::numeric_limits<double>::epsilon())
    {
        uint32_t cIterations;
 
        if (cLiveEntries > m_pTree->m_nearMinimumOverlapFactor)
        {
            // sort entries in increasing order of enlargement.
            ::qsort(entries, cLiveEntries,
                            sizeof(OverlapEntry*),
                            OverlapEntry::compareEntries);
            assert(entries[0]->m_enlargement <= entries[m_children - 1]->m_enlargement);
 
            cIterations = m_pTree->m_nearMinimumOverlapFactor;
        }
        else
        {
            cIterations = cLiveEntries;
        }
 
        // calculate overlap of most important original entries (near minimum overlap cost).
        for (uint32_t cIndex = 0; cIndex < cIterations; ++cIndex)
        {
            double dif = 0.0;
            OverlapEntry* e = entries[cIndex];
 
            for (uint32_t cChild = 0; cChild < cLiveEntries; ++cChild)
            {
                if (cIndex != cChild)
                {
                    double f = e->m_combined->getIntersectingArea(*(entries[cChild]->m_original));
                    if (f != 0.0) dif += f - e->m_original->getIntersectingArea(*(entries[cChild]->m_original));
                }
            } // for (cChild)
 
            if (dif < leastOverlap)
            {
                leastOverlap = dif;
                best = e;
            }
            else if (dif == leastOverlap)
            {
                if (e->m_enlargement == best->m_enlargement)
                {
                    // keep the one with least area.
                    if (e->m_original->getArea() < best->m_original->getArea()) best = e;
                }
                else
                {
                    // keep the one with least enlargement.
                    if (e->m_enlargement < best->m_enlargement) best = e;
                }
            }
        } // for (cIndex)
    }
 
    uint32_t ret = best->m_index;
 
    for (uint32_t cChild = 0; cChild < cLiveEntries; ++cChild)
    {
        delete entries[cChild];
    }
    delete[] entries;
 
    return ret;
}
 
void Index::adjustTree(Node* n, std::stack<id_type>& pathBuffer)
{
    ++(m_pTree->m_stats.m_u64Adjustments);
 
    // find entry pointing to old node;
    uint32_t child;
    for (child = 0; child < m_children; ++child)
    {
        if (m_pIdentifier[child] == n->m_identifier) break;
    }
 
    // MBR needs recalculation if either:
    //   1. the NEW child MBR is not contained.
    //   2. the OLD child MBR is touching.
    bool bContained = m_nodeMBR.containsRegion(n->m_nodeMBR);
    bool bTouches = m_nodeMBR.touchesRegion(*(m_ptrMBR[child]));
    bool bRecompute = (! bContained || (bTouches && m_pTree->m_bTightMBRs));
 
    // we should not adjust time here
    double st = m_ptrMBR[child]->m_startTime;
    double en = m_ptrMBR[child]->m_endTime;
    *(m_ptrMBR[child]) = n->m_nodeMBR;
    m_ptrMBR[child]->m_startTime = st;
    m_ptrMBR[child]->m_endTime = en;
 
    if (bRecompute)
    {
        // no need to update times here. The inserted MBR is younger than all nodes.
 
        for (uint32_t cDim = 0; cDim < m_nodeMBR.m_dimension; ++cDim)
        {
            m_nodeMBR.m_pLow[cDim] = std::numeric_limits<double>::max();
            m_nodeMBR.m_pHigh[cDim] = -std::numeric_limits<double>::max();
 
            for (uint32_t cChild = 0; cChild < m_children; ++cChild)
            {
                m_nodeMBR.m_pLow[cDim] = std::min(m_nodeMBR.m_pLow[cDim], m_ptrMBR[cChild]->m_pLow[cDim]);
                m_nodeMBR.m_pHigh[cDim] = std::max(m_nodeMBR.m_pHigh[cDim], m_ptrMBR[cChild]->m_pHigh[cDim]);
            }
        }
    }
 
    m_pTree->writeNode(this);
 
    if (bRecompute && (! pathBuffer.empty()))
    {
        id_type cParent = pathBuffer.top(); pathBuffer.pop();
        NodePtr ptrN = m_pTree->readNode(cParent);
        Index* p = static_cast<Index*>(ptrN.get());
        p->adjustTree(this, pathBuffer);
    }
}
 
void Index::adjustTree(Node* n, Node* nn, std::stack<id_type>& pathBuffer)
{
    ++(m_pTree->m_stats.m_u64Adjustments);
 
    // find entry pointing to old node;
    uint32_t child, child2 = m_capacity;
    for (child = 0; child < m_children; ++child)
    {
        if (m_pIdentifier[child] == nn->m_identifier) child2 = child;
        if (m_pIdentifier[child] == n->m_identifier) break;
    }
 
    if (child2 == m_capacity)
    {
        for (child2 = child + 1; child2 < m_children; ++child2)
        {
            if (m_pIdentifier[child2] == nn->m_identifier) break;
        }
    }
 
    // MBR needs recalculation if either:
    //   1. the NEW child MBR is not contained.
    //   2. the OLD child MBR is touching.
    //   3. the SIBLING MBR is touching.
    bool b1 = m_nodeMBR.containsRegion(n->m_nodeMBR);
    bool b2 = m_nodeMBR.touchesRegion(*(m_ptrMBR[child]));
    bool b3 = m_nodeMBR.touchesRegion(*(m_ptrMBR[child2]));
    bool bRecompute = (! b1) || ((b2 || b3) && m_pTree->m_bTightMBRs);
 
    // we should not adjust time here
    double st = m_ptrMBR[child]->m_startTime;
    double en = m_ptrMBR[child]->m_endTime;
    *(m_ptrMBR[child]) = n->m_nodeMBR;
    m_ptrMBR[child]->m_startTime = st;
    m_ptrMBR[child]->m_endTime = en;
 
    st = m_ptrMBR[child2]->m_startTime;
    en = m_ptrMBR[child2]->m_endTime;
    *(m_ptrMBR[child2]) = nn->m_nodeMBR;
    m_ptrMBR[child2]->m_startTime = st;
    m_ptrMBR[child2]->m_endTime = en;
 
    if (bRecompute)
    {
        // no need to update times here. The inserted MBR is younger than all nodes.
 
        for (uint32_t cDim = 0; cDim < m_nodeMBR.m_dimension; ++cDim)
        {
            m_nodeMBR.m_pLow[cDim] = std::numeric_limits<double>::max();
            m_nodeMBR.m_pHigh[cDim] = -std::numeric_limits<double>::max();
 
            for (uint32_t cChild = 0; cChild < m_children; ++cChild)
            {
                m_nodeMBR.m_pLow[cDim] = std::min(m_nodeMBR.m_pLow[cDim], m_ptrMBR[cChild]->m_pLow[cDim]);
                m_nodeMBR.m_pHigh[cDim] = std::max(m_nodeMBR.m_pHigh[cDim], m_ptrMBR[cChild]->m_pHigh[cDim]);
            }
        }
    }
 
    m_pTree->writeNode(this);
 
    if (bRecompute && (! pathBuffer.empty()))
    {
        id_type cParent = pathBuffer.top(); pathBuffer.pop();
        NodePtr ptrN = m_pTree->readNode(cParent);
        Index* p = static_cast<Index*>(ptrN.get());
        p->adjustTree(this, pathBuffer);
    }
}