keychron_qmk_firmware/protocol/lufa/midi/midi_device.c

//midi for embedded chips,
//Copyright 2010 Alex Norman
//
//This file is part of avr-midi.
//
//avr-midi is free software: you can redistribute it and/or modify
//it under the terms of the GNU General Public License as published by
//the Free Software Foundation, either version 3 of the License, or
//(at your option) any later version.
//
//avr-midi is distributed in the hope that it will be useful,
//but WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//GNU General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with avr-midi.  If not, see <http://www.gnu.org/licenses/>.

#include "midi_device.h"
#include "midi.h"

#ifndef NULL
#define NULL 0
#endif

//forward declarations, internally used to call the callbacks
void midi_input_callbacks(MidiDevice * device, uint16_t cnt, uint8_t byte0, uint8_t byte1, uint8_t byte2);
void midi_process_byte(MidiDevice * device, uint8_t input);

void midi_device_init(MidiDevice * device){
  device->input_state = IDLE;
  device->input_count = 0;
  bytequeue_init(&device->input_queue, device->input_queue_data, MIDI_INPUT_QUEUE_LENGTH);

  //three byte funcs
  device->input_cc_callback = NULL;
  device->input_noteon_callback = NULL;
  device->input_noteoff_callback = NULL;
  device->input_aftertouch_callback = NULL;
  device->input_pitchbend_callback = NULL;
  device->input_songposition_callback = NULL;

  //two byte funcs
  device->input_progchange_callback = NULL;
  device->input_chanpressure_callback = NULL;
  device->input_songselect_callback = NULL;
  device->input_tc_quarterframe_callback = NULL;

  //one byte funcs
  device->input_realtime_callback = NULL;
  device->input_tunerequest_callback = NULL;

  //var byte functions
  device->input_sysex_callback = NULL;
  device->input_fallthrough_callback = NULL;
  device->input_catchall_callback = NULL;

  device->pre_input_process_callback = NULL;
}

void midi_device_input(MidiDevice * device, uint8_t cnt, uint8_t * input) {
  uint8_t i;
  for (i = 0; i < cnt; i++)
    bytequeue_enqueue(&device->input_queue, input[i]);
}

void midi_device_set_send_func(MidiDevice * device, midi_var_byte_func_t send_func){
  device->send_func = send_func;
}

void midi_device_set_pre_input_process_func(MidiDevice * device, midi_no_byte_func_t pre_process_func){
  device->pre_input_process_callback = pre_process_func;
}

void midi_device_process(MidiDevice * device) {
  //call the pre_input_process_callback if there is one
  if(device->pre_input_process_callback)
    device->pre_input_process_callback(device);

  //pull stuff off the queue and process
  byteQueueIndex_t len = bytequeue_length(&device->input_queue);
  uint16_t i;
  //TODO limit number of bytes processed?
  for(i = 0; i < len; i++) {
    uint8_t val = bytequeue_get(&device->input_queue, 0);
    midi_process_byte(device, val);
    bytequeue_remove(&device->input_queue, 1);
  }
}

void midi_process_byte(MidiDevice * device, uint8_t input) {
  if (midi_is_realtime(input)) {
    //call callback, store and restore state
    input_state_t state = device->input_state;
    device->input_state = ONE_BYTE_MESSAGE;
    midi_input_callbacks(device, 1, input, 0, 0);
    device->input_state = state;
  } else if (midi_is_statusbyte(input)) {
    //store the byte
    if (device->input_state != SYSEX_MESSAGE) {
      device->input_buffer[0] = input;
      device->input_count = 1;
    }
    switch (midi_packet_length(input)) {
      case ONE:
        device->input_state = ONE_BYTE_MESSAGE;;
        midi_input_callbacks(device, 1, input, 0, 0);
        device->input_state = IDLE;
        break;
      case TWO:
        device->input_state = TWO_BYTE_MESSAGE;
        break;
      case THREE:
        device->input_state = THREE_BYTE_MESSAGE;
        break;
      case UNDEFINED:
        switch(input) {
          case SYSEX_BEGIN:
            device->input_state = SYSEX_MESSAGE;
            device->input_buffer[0] = input;
            device->input_count = 1;
            break;
          case SYSEX_END:
            //send what is left in the input buffer, set idle
            device->input_buffer[device->input_count % 3] = input;
            device->input_count += 1;
            //call the callback
            midi_input_callbacks(device, device->input_count, 
                device->input_buffer[0], device->input_buffer[1], device->input_buffer[2]);
            device->input_state = IDLE;
            break;
          default:
            device->input_state = IDLE;
            device->input_count = 0;
        }

        break;
      default:
        device->input_state = IDLE;
        device->input_count = 0;
        break;
    }
  } else {
    if (device->input_state != IDLE) {
      //store the byte
      device->input_buffer[device->input_count % 3] = input;
      //increment count
      uint16_t prev = device->input_count;
      device->input_count += 1;

      switch(prev % 3) {
        case 2:
          //call callback
          midi_input_callbacks(device, device->input_count,
              device->input_buffer[0], device->input_buffer[1], device->input_buffer[2]);
          if (device->input_state != SYSEX_MESSAGE) {
            //set to 1, keeping status byte, allowing for running status
            device->input_count = 1;
          }
          break;
        case 1:
          if (device->input_state == TWO_BYTE_MESSAGE) {
            //call callback
            midi_input_callbacks(device, device->input_count,
                device->input_buffer[0], device->input_buffer[1], 0);
            if (device->input_state != SYSEX_MESSAGE) {
              //set to 1, keeping status byte, allowing for running status
              device->input_count = 1;
            }
          }
          break;
        case 0:
        default:
          //one byte messages are dealt with directly
          break;
      }
    }
  }
}

void midi_input_callbacks(MidiDevice * device, uint16_t cnt, uint8_t byte0, uint8_t byte1, uint8_t byte2) {
  //did we end up calling a callback?
  bool called = false;
  if (device->input_state == SYSEX_MESSAGE) {
    if (device->input_sysex_callback) {
      const uint16_t start = ((cnt - 1) / 3) * 3;
      const uint8_t length = (cnt - start);
      uint8_t data[3];
      data[0] = byte0;
      data[1] = byte1;
      data[2] = byte2;
      device->input_sysex_callback(device, start, length, data);
      called = true;
    }
  } else {
    switch (cnt) {
      case 3:
        {
          midi_three_byte_func_t func = NULL;
          switch (byte0 & 0xF0) {
            case MIDI_CC:
              func = device->input_cc_callback;
              break;
            case MIDI_NOTEON:
              func = device->input_noteon_callback;
              break;
            case MIDI_NOTEOFF:
              func = device->input_noteoff_callback;
              break;
            case MIDI_AFTERTOUCH:
              func = device->input_aftertouch_callback;
              break;
            case MIDI_PITCHBEND:
              func = device->input_pitchbend_callback;
              break;
            case 0xF0:
              if (byte0 == MIDI_SONGPOSITION)
                func = device->input_songposition_callback;
              break;
            default:
              break;
          }
          if(func) {
            //mask off the channel for non song position functions
            if (byte0 == MIDI_SONGPOSITION)
              func(device, byte0, byte1, byte2);
            else
              func(device, byte0 & 0x0F, byte1, byte2);
            called = true;
          }
        }
        break;
      case 2:
        {
          midi_two_byte_func_t func = NULL;
          switch (byte0 & 0xF0) {
            case MIDI_PROGCHANGE:
              func = device->input_progchange_callback;
              break;
            case MIDI_CHANPRESSURE:
              func = device->input_chanpressure_callback;
              break;
            case 0xF0:
              if (byte0 == MIDI_SONGSELECT)
                func = device->input_songselect_callback;
              else if (byte0 == MIDI_TC_QUARTERFRAME)
                func = device->input_tc_quarterframe_callback;
              break;
            default:
              break;
          }
          if(func) {
            //mask off the channel
            if (byte0 == MIDI_SONGSELECT || byte0 == MIDI_TC_QUARTERFRAME)
              func(device, byte0, byte1);
            else
              func(device, byte0 & 0x0F, byte1);
            called = true;
          }
        }
        break;
      case 1:
        {
          midi_one_byte_func_t func = NULL;
          if (midi_is_realtime(byte0))
            func = device->input_realtime_callback;
          else if (byte0 == MIDI_TUNEREQUEST)
            func = device->input_tunerequest_callback;
          if (func) {
            func(device, byte0);
            called = true;
          }
        }
        break;
      default:
        //just in case
        if (cnt > 3)
          cnt = 0;
        break;
    }
  }

  //if there is fallthrough default callback and we haven't called a more specific one, 
  //call the fallthrough
  if (!called && device->input_fallthrough_callback)
    device->input_fallthrough_callback(device, cnt, byte0, byte1, byte2);
  //always call the catch all if it exists
  if (device->input_catchall_callback)
    device->input_catchall_callback(device, cnt, byte0, byte1, byte2);
}