Method get_inverse_indices

src/ifcparse/IfcParse.cpp:2524–2579

}

std::vector<int> IfcFile::get_inverse_indices(int instance_id) {
    std::vector<int> return_value;

    // Mapping of instance id to attribute offset.
    std::map<int, std::vector<int>> mapping;

    std::visit([&mapping, instance_id](const auto& x) {
        if constexpr (std::is_same_v<std::decay_t<decltype(x)>, std::monostate>) {
        } else if constexpr (std::is_same_v<std::decay_t<decltype(x)>, impl::in_memory_file_storage>) {
            auto lower = x.byref_excl_.lower_bound({ instance_id, -1, -1 });
            auto upper = x.byref_excl_.upper_bound({ instance_id, std::numeric_limits<short>::max(), std::numeric_limits<short>::max() });
            for (auto it = lower; it != upper; ++it) {
                for (auto& i : it->second) {
                    mapping[i].push_back(std::get<2>(it->first));
                }
            }
        } else if constexpr (std::is_same_v<std::decay_t<decltype(x)>, impl::rocks_db_file_storage>) {
#ifdef IFOPSH_WITH_ROCKSDB
            // @todo no lower/upper_bounds() implemented yet
            auto prefix = "v|" + std::to_string(instance_id) + "|";
            auto it = std::unique_ptr<rocksdb::Iterator>(x.db->NewIterator(rocksdb::ReadOptions()));
            it->Seek(prefix);
            while (it->Valid() && it->key().starts_with(prefix)) {
                std::vector<uint32_t> vals(it->value().size() / sizeof(uint32_t));
                memcpy(vals.data(), it->value().data(), it->value().size());
                auto tuple = key_from_string<std::tuple<int, int, int>>(it->key().ToString().substr(2));
                for (auto& i : vals) {
                    mapping[i].push_back(std::get<2>(tuple));
                }
                it->Next();
            }
#endif
        }
    }, storage_);

    auto refs = instances_by_reference(instance_id);

    for (const auto& ref : *refs) {
        auto it = mapping.find(ref->id());
        if (it == mapping.end() || it->second.empty()) {
            throw IfcException("Internal error");
        }
        return_value.push_back(it->second.front());
        it->second.erase(it->second.begin());
        if (it->second.empty()) {
            mapping.erase(it);
        }
    }

    // Test whether all mappings where indeed used.
    if (!mapping.empty()) {
        throw IfcException("Internal error");
    }

    return return_value;
}

aggregate_of_instance::ptr IfcFile::getInverse(int instance_id, const IfcParse::declaration* type, int attribute_index) {