very, very simple WP with midi CC out
This commit is contained in:
Sebastian
@@ -0,0 +1,350 @@
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#pragma once
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#include <libremidi/backends/alsa_raw/config.hpp>
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#include <libremidi/backends/alsa_raw/helpers.hpp>
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#include <libremidi/backends/linux/helpers.hpp>
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#include <libremidi/detail/midi_in.hpp>
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#include <libremidi/detail/midi_stream_decoder.hpp>
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#include <alsa/asoundlib.h>
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#include <chrono>
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#include <thread>
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namespace libremidi::alsa_raw
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{
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class midi_in_impl
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: public midi1::in_api
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, public error_handler
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{
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public:
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struct
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: input_configuration
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, alsa_raw_input_configuration
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{
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} configuration;
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const libasound& snd = libasound::instance();
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explicit midi_in_impl(input_configuration&& conf, alsa_raw_input_configuration&& apiconf)
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: configuration{std::move(conf), std::move(apiconf)}
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{
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fds_.reserve(4);
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}
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~midi_in_impl() override { }
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bool open_virtual_port(std::string_view) override
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{
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warning(configuration, "midi_in_alsa_raw: open_virtual_port unsupported");
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return false;
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}
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void set_client_name(std::string_view) override
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{
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warning(configuration, "midi_in_alsa_raw: set_client_name unsupported");
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}
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void set_port_name(std::string_view) override
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{
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warning(configuration, "midi_in_alsa_raw: set_port_name unsupported");
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}
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libremidi::API get_current_api() const noexcept override { return libremidi::API::ALSA_RAW; }
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// Must be a string such as: "hw:2,4,1"
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[[nodiscard]] int do_init_port(const char* portname)
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{
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constexpr int mode = SND_RAWMIDI_NONBLOCK;
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if (const int err = snd.rawmidi.open(&midiport_, nullptr, portname, mode); err < 0)
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{
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error<driver_error>(this->configuration, "midi_in_alsa_raw::open_port: cannot open device.");
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return err;
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}
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snd_rawmidi_params_t* params{};
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snd_rawmidi_params_alloca(¶ms);
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if (const int err = snd.rawmidi.params_current(midiport_, params); err < 0)
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return err;
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if (const int err = snd.rawmidi.params_set_no_active_sensing(midiport_, params, 1); err < 0)
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return err;
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#if LIBREMIDI_ALSA_HAS_RAWMIDI_TREAD
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if (configuration.timestamps == timestamp_mode::NoTimestamp)
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{
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if (const int err
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= snd.rawmidi.params_set_read_mode(midiport_, params, SND_RAWMIDI_READ_STANDARD);
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err < 0)
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return err;
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if (const int err
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= snd.rawmidi.params_set_clock_type(midiport_, params, SND_RAWMIDI_CLOCK_NONE);
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err < 0)
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return err;
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}
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else
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{
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if (const int err
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= snd.rawmidi.params_set_read_mode(midiport_, params, SND_RAWMIDI_READ_TSTAMP);
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err < 0)
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return err;
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if (const int err
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= snd.rawmidi.params_set_clock_type(midiport_, params, SND_RAWMIDI_CLOCK_MONOTONIC);
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err < 0)
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return err;
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}
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#endif
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if (const int err = snd.rawmidi.params(midiport_, params); err < 0)
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return err;
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return init_pollfd();
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}
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[[nodiscard]] int init_port(const port_information& p)
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{
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return do_init_port(raw_from_port_handle(p.port).to_string().c_str());
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}
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[[nodiscard]] int init_pollfd()
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{
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const int num_fds = snd.rawmidi.poll_descriptors_count(this->midiport_);
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this->fds_.clear();
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this->fds_.resize(num_fds);
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return snd.rawmidi.poll_descriptors(this->midiport_, fds_.data(), num_fds);
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}
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ssize_t do_read_events(auto parse_func, std::span<pollfd> fds)
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{
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// Read events
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if (fds.empty())
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{
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return (this->*parse_func)();
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}
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else
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{
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unsigned short res{};
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const int err = snd.rawmidi.poll_descriptors_revents(
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this->midiport_, fds.data(), static_cast<unsigned int>(fds.size()), &res);
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if (err < 0)
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return err;
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// Did we encounter an error during polling
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if (res & (POLLERR | POLLHUP))
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return -EIO;
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// Is there data to read
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if (res & POLLIN)
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return (this->*parse_func)();
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}
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return 0;
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}
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ssize_t read_input_buffer()
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{
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static const constexpr int nbytes = 1024;
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static constexpr timestamp_backend_info timestamp_info{
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.has_absolute_timestamps = false,
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.absolute_is_monotonic = false,
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.has_samples = false,
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};
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unsigned char bytes[nbytes];
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ssize_t err = 0;
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// err is the amount of bytes read
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while ((err = snd.rawmidi.read(this->midiport_, bytes, nbytes)) > 0)
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{
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const auto to_ns = [this] { return absolute_timestamp(); };
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decoder_.on_bytes({bytes, bytes + err}, decoder_.timestamp<timestamp_info>(to_ns, 0));
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}
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return err;
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}
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#if LIBREMIDI_ALSA_HAS_RAWMIDI_TREAD
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ssize_t read_input_buffer_with_timestamps()
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{
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static constexpr int nbytes = 1024;
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static constexpr timestamp_backend_info timestamp_info{
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.has_absolute_timestamps = true,
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.absolute_is_monotonic = true,
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.has_samples = false,
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};
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unsigned char bytes[nbytes];
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struct timespec ts;
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ssize_t err = 0;
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// err is the amount of bytes read
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while ((err = snd.rawmidi.tread(this->midiport_, &ts, bytes, nbytes)) > 0)
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{
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const auto to_ns = [ts] {
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return static_cast<int64_t>(ts.tv_sec) * 1'000'000'000 + static_cast<int64_t>(ts.tv_nsec);
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};
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decoder_.on_bytes({bytes, bytes + err}, decoder_.timestamp<timestamp_info>(to_ns, 0));
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}
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return err;
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}
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#else
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ssize_t read_input_buffer_with_timestamps() { return read_input_buffer(); }
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#endif
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void close_port() override
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{
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if (midiport_)
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snd.rawmidi.close(midiport_);
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midiport_ = nullptr;
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}
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timestamp absolute_timestamp() const noexcept final override { return system_ns(); }
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snd_rawmidi_t* midiport_{};
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std::vector<pollfd> fds_;
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midi1::input_state_machine decoder_{this->configuration};
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};
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class midi_in_alsa_raw_threaded : public midi_in_impl
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{
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public:
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midi_in_alsa_raw_threaded(input_configuration&& conf, alsa_raw_input_configuration&& apiconf)
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: midi_in_impl{std::move(conf), std::move(apiconf)}
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{
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if (this->termination_event < 0)
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{
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error<driver_error>(
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this->configuration, "midi_in_alsa::initialize: error creating eventfd.");
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}
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}
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~midi_in_alsa_raw_threaded() override
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{
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// Close a connection if it exists.
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this->midi_in_alsa_raw_threaded::close_port();
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}
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private:
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void run_thread(auto parse_func)
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{
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fds_.push_back(this->termination_event);
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for (;;)
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{
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// Poll
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ssize_t err = poll(fds_.data(), fds_.size(), -1);
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if (err == -EAGAIN)
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continue;
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else if (err < 0)
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return;
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else if (termination_event.ready(fds_.back()))
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break;
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err = do_read_events(parse_func, {fds_.data(), fds_.size() - 1});
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if (err == -EAGAIN)
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continue;
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else if (err < 0)
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return;
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}
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}
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[[nodiscard]] ssize_t start_thread()
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{
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try
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{
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if (configuration.timestamps == timestamp_mode::NoTimestamp)
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{
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this->thread_ = std::thread{[this] { run_thread(&midi_in_impl::read_input_buffer); }};
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}
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else
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{
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this->thread_ = std::thread{
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[this] { run_thread(&midi_in_impl::read_input_buffer_with_timestamps); }};
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}
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}
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catch (const std::system_error& e)
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{
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using namespace std::literals;
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error<thread_error>(
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this->configuration,
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"midi_in_alsa::start_thread: error starting MIDI input thread: "s + e.what());
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return false;
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}
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return true;
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}
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bool open_port(const input_port& port, std::string_view /*name*/) override
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{
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if (const int err = midi_in_impl::init_port(port); err < 0)
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return false;
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if (!start_thread())
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return false;
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return true;
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}
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void close_port() override
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{
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termination_event.notify();
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if (thread_.joinable())
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thread_.join();
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termination_event.consume(); // Reset to zero
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midi_in_impl::close_port();
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}
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std::thread thread_;
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eventfd_notifier termination_event{};
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};
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class midi_in_alsa_raw_manual : public midi_in_impl
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{
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public:
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using midi_in_impl::midi_in_impl;
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~midi_in_alsa_raw_manual()
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{
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// Close a connection if it exists.
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this->close_port();
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}
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private:
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void send_poll_callback()
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{
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if (configuration.timestamps == timestamp_mode::NoTimestamp)
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{
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configuration.manual_poll(manual_poll_parameters{
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.fds = {this->fds_.data(), this->fds_.size()},
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.callback = [this](std::span<pollfd> fds) {
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return do_read_events(&midi_in_impl::read_input_buffer, fds);
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}});
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}
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else
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{
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configuration.manual_poll(manual_poll_parameters{
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.fds = {this->fds_.data(), this->fds_.size()},
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.callback = [this](std::span<pollfd> fds) {
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return do_read_events(&midi_in_impl::read_input_buffer_with_timestamps, fds);
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}});
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}
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}
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bool open_port(const input_port& p, std::string_view /*name*/) override
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{
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if (midi_in_impl::init_port(p) < 0)
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return false;
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send_poll_callback();
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return true;
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}
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};
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}
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namespace libremidi
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{
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template <>
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inline std::unique_ptr<midi_in_api> make<alsa_raw::midi_in_impl>(
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libremidi::input_configuration&& conf, libremidi::alsa_raw_input_configuration&& api)
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{
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if (api.manual_poll)
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return std::make_unique<alsa_raw::midi_in_alsa_raw_manual>(std::move(conf), std::move(api));
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else
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return std::make_unique<alsa_raw::midi_in_alsa_raw_threaded>(std::move(conf), std::move(api));
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}
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}
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