Function readElements

src/Mod/Fem/App/FemVTKTools.cpp:1731–1800

fill elements and fill cell array

// fill elements and fill cell array
std::vector<int> readElements(
    std::ifstream& ifstr,
    const std::string& lines,
    const std::map<int, int>& mapNodes,
    vtkCellArray* cellArray,
    vtkIntArray* material,
    vtkIntArray* group
)
{
    std::string line;
    std::string keyCode = "    3C";
    std::string keyCodeType = " -1";
    std::string keyCodeNodes = " -2";
    long numElem;
    int indicator;
    int elem;
    long elemID = 0;
    // element info: {type, group, material}
    std::vector<int> info(3);
    std::map<int, int> mapElem;
    std::vector<int> topoElem;
    std::vector<int> vtkType;

    material->SetNumberOfComponents(1);
    material->SetName("Material");

    group->SetNumberOfComponents(1);
    group->SetName("Group");

    std::string_view view {lines};

    std::string_view sub = view.substr(keyCode.length() + 18);
    valueFromLine(sub.begin(), 12, numElem);

    sub = sub.substr(12 + 37);
    valueFromLine(sub.begin(), 1, indicator);
    int digits = getDigits(static_cast<Indicator>(indicator));
    while (elemID < numElem && std::getline(ifstr, line)) {
        std::string_view view {line};
        if (view.rfind(keyCodeType, 0) == 0) {
            std::string_view v(line.data() + keyCodeType.length());
            valueFromLine(v.begin(), digits, elem);
            v = v.substr(digits);
            std::string_view::iterator it1;
            std::vector<int>::iterator it2;
            for (it1 = v.begin(), it2 = info.begin(); it1 != v.end() && it2 != info.end();
                 it1 += 5, ++it2) {
                valueFromLine(it1, 5, *it2);
            }
        }
        if (view.rfind(keyCodeNodes, 0) == 0) {
            std::string_view vi = view.substr(keyCodeNodes.length());
            int node;
            for (auto it = vi.begin(); it != vi.end(); it += digits) {
                valueFromLine(it, digits, node);
                topoElem.emplace_back(mapNodes.at(node));
            }