smf_reader.hpp

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#pragma once
 
#include <cstdint>
#include <filesystem>
#include <optional>
#include <span>
#include <string_view>
#include <vector>
 
namespace ts {

enum class MidiEventKind {
    channel,
    sysex,
};

struct MidiEvent {
    std::int64_t position = 0;
    MidiEventKind kind = MidiEventKind::channel;
    int status = 0;
    int data1 = 0;
    int data2 = 0;
    std::vector<std::uint8_t> sysex;

    int port = 0;

    [[nodiscard]] int channel() const noexcept { return status & 0x0F; }

    [[nodiscard]] int message_type() const noexcept { return status & 0xF0; }
};

namespace smf {

inline constexpr int block_grid = 32;

inline constexpr int default_tempo = 500'000;

struct SongLoop {
    std::int64_t start = 0;
    std::int64_t end = 0;
    bool soft = false;
};

struct Song {
    std::vector<MidiEvent> events;
    std::optional<SongLoop> loop;
};

[[nodiscard]] Song load(const std::filesystem::path& path, int sample_rate = 32000);

[[nodiscard]] Song load(std::span<const std::uint8_t> data,
                        int sample_rate = 32000,
                        std::string_view name = {});

[[nodiscard]] std::vector<MidiEvent> read(const std::filesystem::path& path,
                                          int sample_rate = 32000);

[[nodiscard]] std::vector<MidiEvent> parse(std::span<const std::uint8_t> data,
                                           int sample_rate = 32000);

[[nodiscard]] std::int64_t quantise(double samples) noexcept;
 
} // namespace smf
} // namespace ts