osrm-backend/include/engine/api/table_api.hpp

#ifndef ENGINE_API_TABLE_HPP
#define ENGINE_API_TABLE_HPP

#include "engine/api/base_api.hpp"
#include "engine/api/base_result.hpp"
#include "engine/api/json_factory.hpp"
#include "engine/api/table_parameters.hpp"

#include "engine/datafacade/datafacade_base.hpp"

#include "engine/guidance/assemble_geometry.hpp"
#include "engine/guidance/assemble_leg.hpp"
#include "engine/guidance/assemble_overview.hpp"
#include "engine/guidance/assemble_route.hpp"
#include "engine/guidance/assemble_steps.hpp"

#include "engine/internal_route_result.hpp"

#include "util/integer_range.hpp"

#include <boost/range/algorithm/transform.hpp>

#include <iterator>

namespace osrm::engine::api
{

class TableAPI final : public BaseAPI
{
  public:
    virtual ~TableAPI() = default;

    struct TableCellRef
    {
        TableCellRef(const std::size_t &row, const std::size_t &column) : row{row}, column{column}
        {
        }
        std::size_t row;
        std::size_t column;
    };

    TableAPI(const datafacade::BaseDataFacade &facade_, const TableParameters &parameters_)
        : BaseAPI(facade_, parameters_), parameters(parameters_)
    {
    }

    virtual void
    MakeResponse(const std::pair<std::vector<EdgeDuration>, std::vector<EdgeDistance>> &tables,
                 const std::vector<PhantomNodeCandidates> &candidates,
                 const std::vector<TableCellRef> &fallback_speed_cells,
                 osrm::engine::api::ResultT &response) const
    {
        if (std::holds_alternative<flatbuffers::FlatBufferBuilder>(response))
        {
            auto &fb_result = std::get<flatbuffers::FlatBufferBuilder>(response);
            MakeResponse(tables, candidates, fallback_speed_cells, fb_result);
        }
        else
        {
            auto &json_result = std::get<util::json::Object>(response);
            MakeResponse(tables, candidates, fallback_speed_cells, json_result);
        }
    }

    virtual void
    MakeResponse(const std::pair<std::vector<EdgeDuration>, std::vector<EdgeDistance>> &tables,
                 const std::vector<PhantomNodeCandidates> &candidates,
                 const std::vector<TableCellRef> &fallback_speed_cells,
                 flatbuffers::FlatBufferBuilder &fb_result) const
    {
        auto number_of_sources = parameters.sources.size();
        auto number_of_destinations = parameters.destinations.size();

        auto data_timestamp = facade.GetTimestamp();
        flatbuffers::Offset<flatbuffers::String> data_version_string;
        if (!data_timestamp.empty())
        {
            data_version_string = fb_result.CreateString(data_timestamp);
        }

        // symmetric case
        flatbuffers::Offset<flatbuffers::Vector<flatbuffers::Offset<fbresult::Waypoint>>> sources;
        if (parameters.sources.empty())
        {
            if (!parameters.skip_waypoints)
            {
                sources = MakeWaypoints(fb_result, candidates);
            }
            number_of_sources = candidates.size();
        }
        else
        {
            if (!parameters.skip_waypoints)
            {
                sources = MakeWaypoints(fb_result, candidates, parameters.sources);
            }
        }

        flatbuffers::Offset<flatbuffers::Vector<flatbuffers::Offset<fbresult::Waypoint>>>
            destinations;
        if (parameters.destinations.empty())
        {
            if (!parameters.skip_waypoints)
            {
                destinations = MakeWaypoints(fb_result, candidates);
            }
            number_of_destinations = candidates.size();
        }
        else
        {
            if (!parameters.skip_waypoints)
            {
                destinations = MakeWaypoints(fb_result, candidates, parameters.destinations);
            }
        }

        bool use_durations = parameters.annotations & TableParameters::AnnotationsType::Duration;
        flatbuffers::Offset<flatbuffers::Vector<float>> durations;
        if (use_durations)
        {
            durations = MakeDurationTable(fb_result, tables.first);
        }

        bool use_distances = parameters.annotations & TableParameters::AnnotationsType::Distance;
        flatbuffers::Offset<flatbuffers::Vector<float>> distances;
        if (use_distances)
        {
            distances = MakeDistanceTable(fb_result, tables.second);
        }

        bool have_speed_cells =
            parameters.fallback_speed != from_alias<double>(INVALID_FALLBACK_SPEED) &&
            parameters.fallback_speed > 0;
        flatbuffers::Offset<flatbuffers::Vector<uint32_t>> speed_cells;
        if (have_speed_cells)
        {
            speed_cells = MakeEstimatesTable(fb_result, fallback_speed_cells);
        }

        fbresult::TableBuilder table(fb_result);
        table.add_destinations(destinations);
        table.add_rows(number_of_sources);
        table.add_cols(number_of_destinations);
        if (use_durations)
        {
            table.add_durations(durations);
        }
        if (use_distances)
        {
            table.add_distances(distances);
        }
        if (have_speed_cells)
        {
            table.add_fallback_speed_cells(speed_cells);
        }
        auto table_buffer = table.Finish();

        fbresult::FBResultBuilder response(fb_result);
        if (!data_timestamp.empty())
        {
            response.add_data_version(data_version_string);
        }
        response.add_table(table_buffer);
        response.add_waypoints(sources);
        fb_result.Finish(response.Finish());
    }

    virtual void
    MakeResponse(const std::pair<std::vector<EdgeDuration>, std::vector<EdgeDistance>> &tables,
                 const std::vector<PhantomNodeCandidates> &candidates,
                 const std::vector<TableCellRef> &fallback_speed_cells,
                 util::json::Object &response) const
    {
        auto number_of_sources = parameters.sources.size();
        auto number_of_destinations = parameters.destinations.size();

        // symmetric case
        if (parameters.sources.empty())
        {
            if (!parameters.skip_waypoints)
            {
                response.values.emplace("sources", MakeWaypoints(candidates));
            }
            number_of_sources = candidates.size();
        }
        else
        {
            if (!parameters.skip_waypoints)
            {
                response.values.emplace("sources", MakeWaypoints(candidates, parameters.sources));
            }
        }

        if (parameters.destinations.empty())
        {
            if (!parameters.skip_waypoints)
            {
                response.values.emplace("destinations", MakeWaypoints(candidates));
            }
            number_of_destinations = candidates.size();
        }
        else
        {
            if (!parameters.skip_waypoints)
            {
                response.values.emplace("destinations",
                                        MakeWaypoints(candidates, parameters.destinations));
            }
        }

        if (parameters.annotations & TableParameters::AnnotationsType::Duration)
        {
            response.values.emplace(
                "durations",
                MakeDurationTable(tables.first, number_of_sources, number_of_destinations));
        }

        if (parameters.annotations & TableParameters::AnnotationsType::Distance)
        {
            response.values.emplace(
                "distances",
                MakeDistanceTable(tables.second, number_of_sources, number_of_destinations));
        }

        if (parameters.fallback_speed != from_alias<double>(INVALID_FALLBACK_SPEED) &&
            parameters.fallback_speed > 0)
        {
            response.values.emplace("fallback_speed_cells",
                                    MakeEstimatesTable(fallback_speed_cells));
        }

        response.values.emplace("code", "Ok");
        auto data_timestamp = facade.GetTimestamp();
        if (!data_timestamp.empty())
        {
            response.values.emplace("data_version", data_timestamp);
        }
    }

  protected:
    virtual flatbuffers::Offset<flatbuffers::Vector<flatbuffers::Offset<fbresult::Waypoint>>>
    MakeWaypoints(flatbuffers::FlatBufferBuilder &builder,
                  const std::vector<PhantomNodeCandidates> &candidates) const
    {
        std::vector<flatbuffers::Offset<fbresult::Waypoint>> waypoints;
        waypoints.reserve(candidates.size());
        BOOST_ASSERT(candidates.size() == parameters.coordinates.size());

        boost::range::transform(candidates,
                                std::back_inserter(waypoints),
                                [this, &builder](const PhantomNodeCandidates &candidates)
                                { return BaseAPI::MakeWaypoint(&builder, candidates)->Finish(); });
        return builder.CreateVector(waypoints);
    }

    virtual flatbuffers::Offset<flatbuffers::Vector<flatbuffers::Offset<fbresult::Waypoint>>>
    MakeWaypoints(flatbuffers::FlatBufferBuilder &builder,
                  const std::vector<PhantomNodeCandidates> &candidates,
                  const std::vector<std::size_t> &indices) const
    {
        std::vector<flatbuffers::Offset<fbresult::Waypoint>> waypoints;
        waypoints.reserve(indices.size());
        boost::range::transform(
            indices,
            std::back_inserter(waypoints),
            [this, &builder, &candidates](const std::size_t idx)
            {
                BOOST_ASSERT(idx < candidates.size());
                return BaseAPI::MakeWaypoint(&builder, candidates[idx])->Finish();
            });
        return builder.CreateVector(waypoints);
    }

    virtual flatbuffers::Offset<flatbuffers::Vector<float>>
    MakeDurationTable(flatbuffers::FlatBufferBuilder &builder,
                      const std::vector<EdgeDuration> &values) const
    {
        std::vector<float> distance_table;
        distance_table.resize(values.size());
        std::transform(values.begin(),
                       values.end(),
                       distance_table.begin(),
                       [](const EdgeDuration duration)
                       {
                           if (duration == MAXIMAL_EDGE_DURATION)
                           {
                               return 0.;
                           }
                           return from_alias<double>(duration) / 10.;
                       });
        return builder.CreateVector(distance_table);
    }

    virtual flatbuffers::Offset<flatbuffers::Vector<float>>
    MakeDistanceTable(flatbuffers::FlatBufferBuilder &builder,
                      const std::vector<EdgeDistance> &values) const
    {
        std::vector<float> duration_table;
        duration_table.resize(values.size());
        std::transform(values.begin(),
                       values.end(),
                       duration_table.begin(),
                       [](const EdgeDistance distance)
                       {
                           if (distance == INVALID_EDGE_DISTANCE)
                           {
                               return 0.;
                           }
                           return std::round(from_alias<double>(distance) * 10) / 10.;
                       });
        return builder.CreateVector(duration_table);
    }

    virtual flatbuffers::Offset<flatbuffers::Vector<uint32_t>>
    MakeEstimatesTable(flatbuffers::FlatBufferBuilder &builder,
                       const std::vector<TableCellRef> &fallback_speed_cells) const
    {
        std::vector<uint32_t> fb_table;
        fb_table.reserve(fallback_speed_cells.size());
        std::for_each(fallback_speed_cells.begin(),
                      fallback_speed_cells.end(),
                      [&](const auto &cell)
                      {
                          fb_table.push_back(cell.row);
                          fb_table.push_back(cell.column);
                      });
        return builder.CreateVector(fb_table);
    }

    virtual util::json::Array
    MakeWaypoints(const std::vector<PhantomNodeCandidates> &candidates) const
    {
        util::json::Array json_waypoints;
        json_waypoints.values.reserve(candidates.size());
        BOOST_ASSERT(candidates.size() == parameters.coordinates.size());

        boost::range::transform(candidates,
                                std::back_inserter(json_waypoints.values),
                                [this](const PhantomNodeCandidates &candidates)
                                { return BaseAPI::MakeWaypoint(candidates); });
        return json_waypoints;
    }

    virtual util::json::Array MakeWaypoints(const std::vector<PhantomNodeCandidates> &candidates,
                                            const std::vector<std::size_t> &indices) const
    {
        util::json::Array json_waypoints;
        json_waypoints.values.reserve(indices.size());
        boost::range::transform(indices,
                                std::back_inserter(json_waypoints.values),
                                [this, &candidates](const std::size_t idx)
                                {
                                    BOOST_ASSERT(idx < candidates.size());
                                    return BaseAPI::MakeWaypoint(candidates[idx]);
                                });
        return json_waypoints;
    }

    virtual util::json::Array MakeDurationTable(const std::vector<EdgeDuration> &values,
                                                std::size_t number_of_rows,
                                                std::size_t number_of_columns) const
    {
        util::json::Array json_table;
        for (const auto row : util::irange<std::size_t>(0UL, number_of_rows))
        {
            util::json::Array json_row;
            auto row_begin_iterator = values.begin() + (row * number_of_columns);
            auto row_end_iterator = values.begin() + ((row + 1) * number_of_columns);
            json_row.values.resize(number_of_columns);
            std::transform(row_begin_iterator,
                           row_end_iterator,
                           json_row.values.begin(),
                           [](const EdgeDuration duration)
                           {
                               if (duration == MAXIMAL_EDGE_DURATION)
                               {
                                   return util::json::Value(util::json::Null());
                               }
                               // division by 10 because the duration is in deciseconds (10s)
                               return util::json::Value(
                                   util::json::Number(from_alias<double>(duration) / 10.));
                           });

            json_table.values.push_back(util::json::Value{json_row});
        }
        return json_table;
    }

    virtual util::json::Array MakeDistanceTable(const std::vector<EdgeDistance> &values,
                                                std::size_t number_of_rows,
                                                std::size_t number_of_columns) const
    {
        util::json::Array json_table;
        for (const auto row : util::irange<std::size_t>(0UL, number_of_rows))
        {
            util::json::Array json_row;
            auto row_begin_iterator = values.begin() + (row * number_of_columns);
            auto row_end_iterator = values.begin() + ((row + 1) * number_of_columns);
            json_row.values.resize(number_of_columns);
            std::transform(row_begin_iterator,
                           row_end_iterator,
                           json_row.values.begin(),
                           [](const EdgeDistance distance)
                           {
                               if (distance == INVALID_EDGE_DISTANCE)
                               {
                                   return util::json::Value(util::json::Null());
                               }
                               // round to single decimal place
                               return util::json::Value(util::json::Number(
                                   std::round(from_alias<double>(distance) * 10) / 10.));
                           });
            json_table.values.push_back(util::json::Value{json_row});
        }
        return json_table;
    }

    virtual util::json::Array
    MakeEstimatesTable(const std::vector<TableCellRef> &fallback_speed_cells) const
    {
        util::json::Array json_table;
        std::for_each(
            fallback_speed_cells.begin(),
            fallback_speed_cells.end(),
            [&](const auto &cell)
            {
                util::json::Array row;
                util::json::Value jCellRow{util::json::Number(static_cast<double>(cell.row))};
                util::json::Value jCellColumn{util::json::Number(static_cast<double>(cell.column))};
                row.values.push_back(jCellRow);
                row.values.push_back(jCellColumn);
                json_table.values.push_back(util::json::Value{row});
            });
        return json_table;
    }

    const TableParameters &parameters;
};

} // namespace osrm::engine::api

#endif