midi_driver.c

/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2018 The RetroArch team
 *
 *  RetroArch 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 Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch 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 RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#include <string.h>
#include <string/stdstring.h>
#include <lists/string_list.h>
#include <retro_miscellaneous.h>

#include "../configuration.h"
#include "../verbosity.h"

#include "midi_driver.h"

#define MIDI_DRIVER_BUF_SIZE 4096

extern midi_driver_t midi_null;
extern midi_driver_t midi_winmm;
extern midi_driver_t midi_alsa;

static midi_driver_t *midi_drivers[] = {
#ifdef HAVE_ALSA
   &midi_alsa,
#endif
#ifdef HAVE_WINMM
   &midi_winmm,
#endif
   &midi_null
};

static midi_driver_t *midi_drv = &midi_null;
static void *midi_drv_data;
static struct string_list *midi_drv_inputs;
static struct string_list *midi_drv_outputs;
static bool midi_drv_input_enabled;
static bool midi_drv_output_enabled;
static uint8_t *midi_drv_input_buffer;
static uint8_t *midi_drv_output_buffer;
static midi_event_t midi_drv_input_event;
static midi_event_t midi_drv_output_event;
static bool midi_drv_output_pending;

static const uint8_t midi_drv_ev_sizes[128] =
{
   3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
   3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
   3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
   3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
   2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
   2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
   3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
   0, 2, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
};

static midi_driver_t *midi_driver_find_driver(const char *ident)
{
   unsigned i;

   for (i = 0; i < ARRAY_SIZE(midi_drivers); ++i)
   {
      if (string_is_equal(midi_drivers[i]->ident, ident))
         return midi_drivers[i];
   }

   RARCH_ERR("[MIDI]: Unknown driver \"%s\", falling back to \"null\" driver.\n");

   return &midi_null;
}

const void *midi_driver_find_handle(int index)
{
   if (index < 0 || index >= ARRAY_SIZE(midi_drivers))
      return NULL;

   return midi_drivers[index];
}

const char *midi_driver_find_ident(int index)
{
   if (index < 0 || index >= ARRAY_SIZE(midi_drivers))
      return NULL;

   return midi_drivers[index]->ident;
}

struct string_list *midi_driver_get_avail_inputs(void)
{
   return midi_drv_inputs;
}

struct string_list *midi_driver_get_avail_outputs(void)
{
   return midi_drv_outputs;
}
bool midi_driver_set_all_sounds_off(void)
{
   midi_event_t event;
   uint8_t i;
   uint8_t data[3]     = { 0xB0, 120, 0 };
   bool result         = true;

   if (!midi_drv_data || !midi_drv_output_enabled)
      return false;

   event.data       = data;
   event.data_size  = sizeof(data);
   event.delta_time = 0;

   for (i = 0; i < 16; ++i)
   {
      data[0] = 0xB0 | i;

      if (!midi_drv->write(midi_drv_data, &event))
         result = false;
   }

   if (!midi_drv->flush(midi_drv_data))
      result = false;

   if (!result)
      RARCH_ERR("[MIDI]: All sounds off failed.\n");

   return result;
}

bool midi_driver_set_volume(unsigned volume)
{
   midi_event_t event;
   uint8_t data[8]     = { 0xF0, 0x7F, 0x7F, 0x04, 0x01, 0, 0, 0xF7 };

   if (!midi_drv_data || !midi_drv_output_enabled)
      return false;

   volume = (unsigned)(163.83 * volume + 0.5);
   if (volume > 16383)
      volume = 16383;

   data[5] = (uint8_t)(volume & 0x7F);
   data[6] = (uint8_t)(volume >> 7);

   event.data = data;
   event.data_size = sizeof(data);
   event.delta_time = 0;

   if (!midi_drv->write(midi_drv_data, &event))
   {
      RARCH_ERR("[MIDI]: Volume change failed.\n");
      return false;
   }

   return true;
}

bool midi_driver_init_io_buffers(void)
{
   midi_drv_input_buffer  = (uint8_t*)malloc(MIDI_DRIVER_BUF_SIZE);
   midi_drv_output_buffer = (uint8_t*)malloc(MIDI_DRIVER_BUF_SIZE);

   if (!midi_drv_input_buffer || !midi_drv_output_buffer)
      return false;

   midi_drv_input_event.data = midi_drv_input_buffer;
   midi_drv_input_event.data_size = 0;

   midi_drv_output_event.data = midi_drv_output_buffer;
   midi_drv_output_event.data_size = 0;

   return true;
}

bool midi_driver_init(void)
{
   settings_t *settings             = config_get_ptr();
   union string_list_elem_attr attr = {0};
   const char *err_str              = NULL;

   midi_drv_inputs                  = string_list_new();
   midi_drv_outputs                 = string_list_new();

   RARCH_LOG("[MIDI]: Initializing ...\n");

   if (!settings)
      err_str = "settings unavailable";
   else if (!midi_drv_inputs || !midi_drv_outputs)
      err_str = "string_list_new failed";
   else if (!string_list_append(midi_drv_inputs, "Off", attr) ||
         !string_list_append(midi_drv_outputs, "Off", attr))
      err_str = "string_list_append failed";
   else
   {
      char * input  = NULL;
      char * output = NULL;

      midi_drv = midi_driver_find_driver(settings->arrays.midi_driver);
      if (strcmp(midi_drv->ident, settings->arrays.midi_driver))
         strlcpy(settings->arrays.midi_driver, midi_drv->ident,
               sizeof(settings->arrays.midi_driver));

      if (!midi_drv->get_avail_inputs(midi_drv_inputs))
         err_str = "list of input devices unavailable";
      else if (!midi_drv->get_avail_outputs(midi_drv_outputs))
         err_str = "list of output devices unavailable";
      else
      {
         if (string_is_not_equal(settings->arrays.midi_input, "Off"))
         {
            if (string_list_find_elem(midi_drv_inputs, settings->arrays.midi_input))
               input = settings->arrays.midi_input;
            else
            {
               RARCH_WARN("[MIDI]: Input device \"%s\" unavailable.\n",
                     settings->arrays.midi_input);
               strlcpy(settings->arrays.midi_input, "Off",
                     sizeof(settings->arrays.midi_input));
            }
         }

         if (string_is_not_equal(settings->arrays.midi_output, "Off"))
         {
            if (string_list_find_elem(midi_drv_outputs, settings->arrays.midi_output))
               output = settings->arrays.midi_output;
            else
            {
               RARCH_WARN("[MIDI]: Output device \"%s\" unavailable.\n",
                     settings->arrays.midi_output);
               strlcpy(settings->arrays.midi_output, "Off",
                     sizeof(settings->arrays.midi_output));
            }
         }

         midi_drv_data = midi_drv->init(input, output);
         if (!midi_drv_data)
            err_str = "driver init failed";
         else
         {
            midi_drv_input_enabled = input != NULL;
            midi_drv_output_enabled = output != NULL;

            if (!midi_driver_init_io_buffers())
               err_str = "out of memory";
            else
            {
               if (input)
                  RARCH_LOG("[MIDI]: Input device \"%s\".\n", input);
               else
                  RARCH_LOG("[MIDI]: Input disabled.\n");
               if (output)
               {
                  RARCH_LOG("[MIDI]: Output device \"%s\".\n", output);
                  midi_driver_set_volume(settings->uints.midi_volume);
               }
               else
                  RARCH_LOG("[MIDI]: Output disabled.\n");
            }
         }
      }
   }

   if (err_str)
   {
      midi_driver_free();
      RARCH_ERR("[MIDI]: Initialization failed (%s).\n", err_str);
   }
   else
      RARCH_LOG("[MIDI]: Initialized \"%s\" driver.\n", midi_drv->ident);

   return err_str == NULL;
}

void midi_driver_free(void)
{
   if (midi_drv_data)
   {
      midi_drv->free(midi_drv_data);
      midi_drv_data = NULL;
   }

   if (midi_drv_inputs)
   {
      string_list_free(midi_drv_inputs);
      midi_drv_inputs = NULL;
   }
   if (midi_drv_outputs)
   {
      string_list_free(midi_drv_outputs);
      midi_drv_outputs = NULL;
   }

   if (midi_drv_input_buffer)
   {
      free(midi_drv_input_buffer);
      midi_drv_input_buffer = NULL;
   }
   if (midi_drv_output_buffer)
   {
      free(midi_drv_output_buffer);
      midi_drv_output_buffer = NULL;
   }

   midi_drv_input_enabled  = false;
   midi_drv_output_enabled = false;
}

bool midi_driver_set_input(const char *input)
{
   if (!midi_drv_data)
   {
#ifdef DEBUG
      RARCH_ERR("[MIDI]: midi_driver_set_input called on uninitialized driver.\n");
#endif
      return false;
   }

   if (string_is_equal(input, "Off"))
      input = NULL;

   if (!midi_drv->set_input(midi_drv_data, input))
   {
      if (input)
         RARCH_ERR("[MIDI]: Failed to change input device to \"%s\".\n", input);
      else
         RARCH_ERR("[MIDI]: Failed to disable input.\n");
      return false;
   }

   if (input)
      RARCH_LOG("[MIDI]: Input device changed to \"%s\".\n", input);
   else
      RARCH_LOG("[MIDI]: Input disabled.\n");

   midi_drv_input_enabled = input != NULL;

   return true;
}

bool midi_driver_set_output(const char *output)
{
   if (!midi_drv_data)
   {
#ifdef DEBUG
      RARCH_ERR("[MIDI]: midi_driver_set_output called on uninitialized driver.\n");
#endif
      return false;
   }

   if (string_is_equal(output, "Off"))
      output = NULL;

   if (!midi_drv->set_output(midi_drv_data, output))
   {
      if (output)
         RARCH_ERR("[MIDI]: Failed to change output device to \"%s\".\n", output);
      else
         RARCH_ERR("[MIDI]: Failed to disable output.\n");
      return false;
   }

   if (output)
   {
      settings_t *settings = config_get_ptr();

      midi_drv_output_enabled = true;
      RARCH_LOG("[MIDI]: Output device changed to \"%s\".\n", output);

      if (settings)
         midi_driver_set_volume(settings->uints.midi_volume);
      else
         RARCH_ERR("[MIDI]: Volume change failed (settings unavailable).\n");
   }
   else
   {
      midi_drv_output_enabled = false;
      RARCH_LOG("[MIDI]: Output disabled.\n");
   }

   return true;
}

bool midi_driver_input_enabled(void)
{
   return midi_drv_input_enabled;
}

bool midi_driver_output_enabled(void)
{
   return midi_drv_output_enabled;
}

bool midi_driver_read(uint8_t *byte)
{
   static int i;

   if (!midi_drv_data || !midi_drv_input_enabled || !byte)
   {
#ifdef DEBUG
      if (!midi_drv_data)
         RARCH_ERR("[MIDI]: midi_driver_read called on uninitialized driver.\n");
      else if (!midi_drv_input_enabled)
         RARCH_ERR("[MIDI]: midi_driver_read called when input is disabled.\n");
      else
         RARCH_ERR("[MIDI]: midi_driver_read called with null pointer.\n");
#endif
      return false;
   }

   if (i == midi_drv_input_event.data_size)
   {
      midi_drv_input_event.data_size = MIDI_DRIVER_BUF_SIZE;
      if (!midi_drv->read(midi_drv_data, &midi_drv_input_event))
      {
         midi_drv_input_event.data_size = i;
         return false;
      }

      i = 0;

#ifdef DEBUG
      if (midi_drv_input_event.data_size == 1)
         RARCH_LOG("[MIDI]: In [0x%02X].\n",
               midi_drv_input_event.data[0]);
      else if (midi_drv_input_event.data_size == 2)
         RARCH_LOG("[MIDI]: In [0x%02X, 0x%02X].\n",
               midi_drv_input_event.data[0],
               midi_drv_input_event.data[1]);
      else if (midi_drv_input_event.data_size == 3)
         RARCH_LOG("[MIDI]: In [0x%02X, 0x%02X, 0x%02X].\n",
               midi_drv_input_event.data[0],
               midi_drv_input_event.data[1],
               midi_drv_input_event.data[2]);
      else
         RARCH_LOG("[MIDI]: In [0x%02X, ...], size %u.\n",
               midi_drv_input_event.data[0],
               midi_drv_input_event.data_size);
#endif
   }

   *byte = midi_drv_input_event.data[i++];

   return true;
}

bool midi_driver_write(uint8_t byte, uint32_t delta_time)
{
   static int event_size;

   if (!midi_drv_data || !midi_drv_output_enabled)
   {
#ifdef DEBUG
      if (!midi_drv_data)
         RARCH_ERR("[MIDI]: midi_driver_write called on uninitialized driver.\n");
      else
         RARCH_ERR("[MIDI]: midi_driver_write called when output is disabled.\n");
#endif
      return false;
   }

   if (byte >= 0x80)
   {
      if (midi_drv_output_event.data_size &&
            midi_drv_output_event.data[0] == 0xF0)
      {
         if (byte == 0xF7)
            event_size = (int)midi_drv_output_event.data_size + 1;
         else
         {
            if (!midi_drv->write(midi_drv_data, &midi_drv_output_event))
               return false;

#ifdef DEBUG
            if (midi_drv_output_event.data_size == 1)
               RARCH_LOG("[MIDI]: Out [0x%02X].\n",
                     midi_drv_output_event.data[0]);
            else if (midi_drv_output_event.data_size == 2)
               RARCH_LOG("[MIDI]: Out [0x%02X, 0x%02X].\n",
                     midi_drv_output_event.data[0],
                     midi_drv_output_event.data[1]);
            else if (midi_drv_output_event.data_size == 3)
               RARCH_LOG("[MIDI]: Out [0x%02X, 0x%02X, 0x%02X].\n",
                     midi_drv_output_event.data[0],
                     midi_drv_output_event.data[1],
                     midi_drv_output_event.data[2]);
            else
               RARCH_LOG("[MIDI]: Out [0x%02X, ...], size %u.\n",
                     midi_drv_output_event.data[0],
                     midi_drv_output_event.data_size);
#endif

            midi_drv_output_pending          = true;
            event_size                       = (int)midi_driver_get_event_size(byte);
            midi_drv_output_event.data_size  = 0;
            midi_drv_output_event.delta_time = 0;
         }
      }
      else
      {
         event_size                          = (int)midi_driver_get_event_size(byte);
         midi_drv_output_event.data_size     = 0;
         midi_drv_output_event.delta_time    = 0;
      }
   }

   if (midi_drv_output_event.data_size < MIDI_DRIVER_BUF_SIZE)
   {
      midi_drv_output_event.data[midi_drv_output_event.data_size] = byte;
      ++midi_drv_output_event.data_size;
      midi_drv_output_event.delta_time += delta_time;
   }
   else
   {
#ifdef DEBUG
      RARCH_ERR("[MIDI]: Output event dropped.\n");
#endif
      return false;
   }

   if (midi_drv_output_event.data_size == event_size)
   {
      if (!midi_drv->write(midi_drv_data, &midi_drv_output_event))
         return false;

#ifdef DEBUG
      if (midi_drv_output_event.data_size == 1)
         RARCH_LOG("[MIDI]: Out [0x%02X].\n",
               midi_drv_output_event.data[0]);
      else if (midi_drv_output_event.data_size == 2)
         RARCH_LOG("[MIDI]: Out [0x%02X, 0x%02X].\n",
               midi_drv_output_event.data[0],
               midi_drv_output_event.data[1]);
      else if (midi_drv_output_event.data_size == 3)
         RARCH_LOG("[MIDI]: Out [0x%02X, 0x%02X, 0x%02X].\n",
               midi_drv_output_event.data[0],
               midi_drv_output_event.data[1],
               midi_drv_output_event.data[2]);
      else
         RARCH_LOG("[MIDI]: Out [0x%02X, ...], size %u.\n",
               midi_drv_output_event.data[0],
               midi_drv_output_event.data_size);
#endif

      midi_drv_output_pending = true;
   }

   return true;
}

bool midi_driver_flush(void)
{
   if (!midi_drv_data)
   {
#ifdef DEBUG
      RARCH_ERR("[MIDI]: midi_driver_flush called on uninitialized driver.\n");
#endif
      return false;
   }

   if (midi_drv_output_pending)
      midi_drv_output_pending = !midi_drv->flush(midi_drv_data);

   return !midi_drv_output_pending;
}

size_t midi_driver_get_event_size(uint8_t status)
{
   if (status < 0x80)
   {
#ifdef DEBUG
      RARCH_ERR("[MIDI]: midi_driver_get_event_size called with invalid status.\n");
#endif
      return 0;
   }

   return midi_drv_ev_sizes[status - 0x80];
}