trajectory.hpp

Go to the documentation of this file.

#pragma once

 
#include <cstdint>
#include <filesystem>
#include <fstream>
#include <span>
#include <string_view>
#include <vector>
 
#include "orrery/core/particle_data.hpp"
#include "orrery/core/types.hpp"
#include "orrery/core/vec3_array.hpp"
 
namespace orrery::sim {

inline constexpr std::string_view kTrajectoryMagic = "ORRERYTJ";

inline constexpr std::uint32_t kTrajectoryVersion = 1;

struct TrajectoryInfo {
    core::Index particle_count = 0;

    core::Real timestep = 0;
 
    bool has_velocities = false;

    bool single_precision = false;
};

struct TrajectoryFrame {
    core::Index step = 0;

    core::Real time = 0;
 
    core::Vec3Array positions;

    core::Vec3Array velocities;
};

class TrajectoryWriter {
public:
    TrajectoryWriter(const std::filesystem::path& path, std::span<const core::Real> masses,
                     core::Real timestep, bool with_velocities);

    void write_frame(core::Index step, core::Real time, const core::ParticleData& data);

    [[nodiscard]] core::Index frame_count() const noexcept { return frame_count_; }

    [[nodiscard]] bool ok() const { return file_.good(); }

    void flush() { file_.flush(); }
 
private:
    std::ofstream file_;
    core::Index particle_count_;
    bool has_velocities_;
    core::Index frame_count_ = 0;
};

class TrajectoryReader {
public:
    explicit TrajectoryReader(const std::filesystem::path& path);
 
    [[nodiscard]] const TrajectoryInfo& info() const noexcept { return info_; }

    [[nodiscard]] std::span<const core::Real> masses() const noexcept { return masses_; }

    [[nodiscard]] bool read_frame(TrajectoryFrame& frame);
 
private:
    std::ifstream file_;
    std::filesystem::path path_;
    TrajectoryInfo info_;
    std::vector<core::Real> masses_;
    core::Index frames_read_ = 0;
};
 
} // namespace orrery::sim