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alsa.cpp

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 */

// Disable symbol overrides so that we can use system headers.
#define FORBIDDEN_SYMBOL_ALLOW_ALL

#include "common/scummsys.h"

#if defined(USE_ALSA)

#include "common/config-manager.h"
#include "common/error.h"
#include "common/textconsole.h"
#include "common/util.h"
#include "audio/musicplugin.h"
#include "audio/mpu401.h"

#include <alsa/asoundlib.h>

/*
 *     ALSA sequencer driver
 * Mostly cut'n'pasted from Virtual Tiny Keyboard (vkeybd) by Takashi Iwai
 *                                      (you really rox, you know?)
 */

#if SND_LIB_MAJOR >= 1 || SND_LIB_MINOR >= 6
#define snd_seq_flush_output(x) snd_seq_drain_output(x)
#define snd_seq_set_client_group(x,name)    /*nop */
#define my_snd_seq_open(seqp) snd_seq_open(seqp, "hw", SND_SEQ_OPEN_DUPLEX, 0)
#else
/* SND_SEQ_OPEN_OUT causes oops on early version of ALSA */
#define my_snd_seq_open(seqp) snd_seq_open(seqp, SND_SEQ_OPEN)
#endif

#define perm_ok(pinfo,bits) ((snd_seq_port_info_get_capability(pinfo) & (bits)) == (bits))

static int check_permission(snd_seq_port_info_t *pinfo) {
      if (perm_ok(pinfo, SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE)) {
            if (!(snd_seq_port_info_get_capability(pinfo) & SND_SEQ_PORT_CAP_NO_EXPORT))
                  return 1;
      }
      return 0;
}

/*
 * parse address string
 */

#define ADDR_DELIM      ".:"

class MidiDriver_ALSA : public MidiDriver_MPU401 {
public:
      MidiDriver_ALSA(int client, int port);
      int open();
      bool isOpen() const { return _isOpen; }
      void close();
      void send(uint32 b);
      void sysEx(const byte *msg, uint16 length);

private:
      void send_event(int do_flush);
      bool _isOpen;
      snd_seq_event_t ev;
      snd_seq_t *seq_handle;
      int seq_client, seq_port;
      int my_client, my_port;
      // The volume controller value of the first MIDI channel
      int8 _channel0Volume;
};

MidiDriver_ALSA::MidiDriver_ALSA(int client, int port)
      : _isOpen(false), seq_handle(0), seq_client(client), seq_port(port), my_client(0), my_port(0), _channel0Volume(127) {
      memset(&ev, 0, sizeof(ev));
}

int MidiDriver_ALSA::open() {
      if (_isOpen)
            return MERR_ALREADY_OPEN;
      _isOpen = true;

      if (my_snd_seq_open(&seq_handle) < 0) {
            error("Can't open sequencer");
            return -1;
      }

      my_client = snd_seq_client_id(seq_handle);
      if (snd_seq_set_client_name(seq_handle, "SCUMMVM") < 0) {
            error("Can't set sequencer client name");
      }
      snd_seq_set_client_group(seq_handle, "input");

      // According to http://www.alsa-project.org/~tiwai/alsa-subs.html
      // you can set read or write capabilities to allow other clients to
      // read or write the port. I don't think we need that, unless maybe
      // to be able to record the sound, but I can't get that to work even
      // with those capabilities.

      my_port = snd_seq_create_simple_port(seq_handle, "SCUMMVM port 0", 0,
                                           SND_SEQ_PORT_TYPE_MIDI_GENERIC | SND_SEQ_PORT_TYPE_APPLICATION);

      if (my_port < 0) {
            snd_seq_close(seq_handle);
            error("Can't create port");
            return -1;
      }

      if (seq_client != SND_SEQ_ADDRESS_SUBSCRIBERS) {
            // Subscribe to MIDI port. Prefer one that doesn't already have
            // any connections, unless we've forced a port number already.
            if (seq_port == -1) {
                  snd_seq_client_info_t *cinfo;
                  snd_seq_port_info_t *pinfo;

                  snd_seq_client_info_alloca(&cinfo);
                  snd_seq_port_info_alloca(&pinfo);

                  snd_seq_get_any_client_info(seq_handle, seq_client, cinfo);

                  int first_port = -1;
                  int found_port = -1;

                  snd_seq_port_info_set_client(pinfo, seq_client);
                  snd_seq_port_info_set_port(pinfo, -1);
                  while (found_port == -1 && snd_seq_query_next_port(seq_handle, pinfo) >= 0) {
                        if (check_permission(pinfo)) {
                              if (first_port == -1)
                                    first_port = snd_seq_port_info_get_port(pinfo);
                              if (found_port == -1 && snd_seq_port_info_get_write_use(pinfo) == 0)
                                    found_port = snd_seq_port_info_get_port(pinfo);
                        }
                  }

                  if (found_port == -1) {
                        // Should we abort here? For now, use the first
                        // available port.
                        seq_port = first_port;
                        warning("MidiDriver_ALSA: All ports on client %d (%s) are already in use", seq_client, snd_seq_client_info_get_name(cinfo));
                  } else {
                        seq_port = found_port;
                  }
            }

            if (snd_seq_connect_to(seq_handle, my_port, seq_client, seq_port) < 0) {
                  error("Can't subscribe to MIDI port (%d:%d) see README for help", seq_client, seq_port);
            }
      }

      printf("Connected to Alsa sequencer client [%d:%d]\n", seq_client, seq_port);
      printf("ALSA client initialised [%d:0]\n", my_client);

      return 0;
}

void MidiDriver_ALSA::close() {
      if (_isOpen) {
            _isOpen = false;
            MidiDriver_MPU401::close();
            if (seq_handle)
                  snd_seq_close(seq_handle);
      } else
            warning("MidiDriver_ALSA: Closing the driver before opening it");
}

void MidiDriver_ALSA::send(uint32 b) {
      unsigned int midiCmd[4];
      ev.type = SND_SEQ_EVENT_OSS;

      midiCmd[3] = (b & 0xFF000000) >> 24;
      midiCmd[2] = (b & 0x00FF0000) >> 16;
      midiCmd[1] = (b & 0x0000FF00) >> 8;
      midiCmd[0] = (b & 0x000000FF);
      ev.data.raw32.d[0] = midiCmd[0];
      ev.data.raw32.d[1] = midiCmd[1];
      ev.data.raw32.d[2] = midiCmd[2];

      unsigned char chanID = midiCmd[0] & 0x0F;
      switch (midiCmd[0] & 0xF0) {
      case 0x80:
            snd_seq_ev_set_noteoff(&ev, chanID, midiCmd[1], midiCmd[2]);
            send_event(1);
            break;
      case 0x90:
            snd_seq_ev_set_noteon(&ev, chanID, midiCmd[1], midiCmd[2]);
            send_event(1);
            break;
      case 0xA0:
            snd_seq_ev_set_keypress(&ev, chanID, midiCmd[1], midiCmd[2]);
            send_event(1);
            break;
      case 0xB0:
            /* is it this simple ? Wow... */
            snd_seq_ev_set_controller(&ev, chanID, midiCmd[1], midiCmd[2]);

            // We save the volume of the first MIDI channel here to utilize it in
            // our workaround for broken USB-MIDI cables.
            if (chanID == 0 && midiCmd[1] == 0x07)
                  _channel0Volume = midiCmd[2];

            send_event(1);
            break;
      case 0xC0:
            snd_seq_ev_set_pgmchange(&ev, chanID, midiCmd[1]);
            send_event(0);

            // Send a volume change command to work around a firmware bug in common
            // USB-MIDI cables. If the first MIDI command in a USB packet is a
            // Cx or Dx command, the second command in the packet is dropped
            // somewhere.
            send(0x07B0 | (_channel0Volume << 16));
            break;
      case 0xD0:
            snd_seq_ev_set_chanpress(&ev, chanID, midiCmd[1]);
            send_event(1);

            // Send a volume change command to work around a firmware bug in common
            // USB-MIDI cables. If the first MIDI command in a USB packet is a
            // Cx or Dx command, the second command in the packet is dropped
            // somewhere.
            send(0x07B0 | (_channel0Volume << 16));
            break;
      case 0xE0: {
            // long theBend = ((((long)midiCmd[1] + (long)(midiCmd[2] << 7))) - 0x2000) / 4;
            // snd_seq_ev_set_pitchbend(&ev, chanID, theBend);
            long theBend = ((long)midiCmd[1] + (long)(midiCmd[2] << 7)) - 0x2000;
            snd_seq_ev_set_pitchbend(&ev, chanID, theBend);
            send_event(1);
            } break;

      default:
            warning("Unknown MIDI Command: %08x", (int)b);
            /* I don't know if this works but, well... */
            send_event(1);
            break;
      }
}

void MidiDriver_ALSA::sysEx(const byte *msg, uint16 length) {
      unsigned char buf[266];

      assert(length + 2 <= ARRAYSIZE(buf));

      // Add SysEx frame
      buf[0] = 0xF0;
      memcpy(buf + 1, msg, length);
      buf[length + 1] = 0xF7;

      // Send it
      snd_seq_ev_set_sysex(&ev, length + 2, &buf);
      send_event(1);
}

void MidiDriver_ALSA::send_event(int do_flush) {
      snd_seq_ev_set_direct(&ev);
      snd_seq_ev_set_source(&ev, my_port);
      snd_seq_ev_set_dest(&ev, seq_client, seq_port);

      snd_seq_event_output(seq_handle, &ev);
      if (do_flush)
            snd_seq_flush_output(seq_handle);
}


// Plugin interface

class AlsaDevice {
public:
      AlsaDevice(Common::String name, MusicType mt, int client);
      Common::String getName();
      MusicType getType();
      int getClient();

private:
      Common::String _name;
      MusicType _type;
      int _client;
};

typedef Common::List<AlsaDevice> AlsaDevices;

AlsaDevice::AlsaDevice(Common::String name, MusicType mt, int client)
      : _name(name), _type(mt), _client(client) {
      // Make sure we do not get any trailing spaces to avoid problems when
      // storing the name in the configuration file.
      _name.trim();
}

Common::String AlsaDevice::getName() {
      return _name;
}

MusicType AlsaDevice::getType() {
      return _type;
}

int AlsaDevice::getClient() {
      return _client;
}

class AlsaMusicPlugin : public MusicPluginObject {
public:
      const char *getName() const {
            return "ALSA";
      }

      const char *getId() const {
            return "alsa";
      }

      AlsaDevices getAlsaDevices() const;
      MusicDevices getDevices() const;
      Common::Error createInstance(MidiDriver **mididriver, MidiDriver::DeviceHandle = 0) const;

private:
      static int parse_addr(const char *arg, int *client, int *port);
};

AlsaDevices AlsaMusicPlugin::getAlsaDevices() const {
      AlsaDevices devices;
      snd_seq_t *seq_handle;
      if (my_snd_seq_open(&seq_handle) < 0)
            return devices; // can't open sequencer

      snd_seq_client_info_t *cinfo;
      snd_seq_client_info_alloca(&cinfo);
      snd_seq_port_info_t *pinfo;
      snd_seq_port_info_alloca(&pinfo);
      snd_seq_client_info_set_client(cinfo, -1);
      while (snd_seq_query_next_client(seq_handle, cinfo) >= 0) {
            bool found_valid_port = false;

            /* reset query info */
            snd_seq_port_info_set_client(pinfo, snd_seq_client_info_get_client(cinfo));
            snd_seq_port_info_set_port(pinfo, -1);
            while (!found_valid_port && snd_seq_query_next_port(seq_handle, pinfo) >= 0) {
                  if (check_permission(pinfo)) {
                        found_valid_port = true;

                        const char *name = snd_seq_client_info_get_name(cinfo);
                        // TODO: Can we figure out the appropriate music type?
                        MusicType type = MT_GM;
                        int client = snd_seq_client_info_get_client(cinfo);
                        devices.push_back(AlsaDevice(name, type, client));
                  }
            }
      }
      snd_seq_close(seq_handle);

      return devices;
}

MusicDevices AlsaMusicPlugin::getDevices() const {
      MusicDevices devices;
      AlsaDevices::iterator d;

      AlsaDevices alsaDevices = getAlsaDevices();

      // Since the default behaviour is to use the first device in the list,
      // try to put something sensible there. We used to have 17:0 and 65:0
      // as defaults.

      for (d = alsaDevices.begin(); d != alsaDevices.end();) {
            const int client = d->getClient();

            if (client == 17 || client == 65) {
                  devices.push_back(MusicDevice(this, d->getName(), d->getType()));
                  d = alsaDevices.erase(d);
            } else {
                  ++d;
            }
      }

      // 128:0 is probably TiMidity, or something like that, so that's
      // probably a good second choice.

      for (d = alsaDevices.begin(); d != alsaDevices.end();) {
            if (d->getClient() == 128) {
                  devices.push_back(MusicDevice(this, d->getName(), d->getType()));
                  d = alsaDevices.erase(d);
            } else {
                  ++d;
            }
      }

      // Add the remaining devices in the order they were found.

      for (d = alsaDevices.begin(); d != alsaDevices.end(); ++d)
            devices.push_back(MusicDevice(this, d->getName(), d->getType()));

      return devices;
}

Common::Error AlsaMusicPlugin::createInstance(MidiDriver **mididriver, MidiDriver::DeviceHandle dev) const {
      bool found = false;
      int seq_client, seq_port;

      const char *var = NULL;

      // TODO: Upgrade from old alsa_port setting. This probably isn't the
      // right place to do that, though.

      if (ConfMan.hasKey("alsa_port")) {
            warning("AlsaMusicPlugin: Found old 'alsa_port' setting, which will be ignored");
      }

      // The SCUMMVM_PORT environment variable can still be used to override
      // any config setting.

      var = getenv("SCUMMVM_PORT");
      if (var) {
            warning("AlsaMusicPlugin: SCUMMVM_PORT environment variable overrides config settings");
            if (parse_addr(var, &seq_client, &seq_port) >= 0) {
                  found = true;
            } else {
                  warning("AlsaMusicPlugin: Invalid port %s, using config settings instead", var);
            }
      }

      // Try to match the setting to an available ALSA device.

      if (!found && dev) {
            AlsaDevices alsaDevices = getAlsaDevices();

            for (AlsaDevices::iterator d = alsaDevices.begin(); d != alsaDevices.end(); ++d) {
                  MusicDevice device(this, d->getName(), d->getType());

                  if (device.getCompleteId().equals(MidiDriver::getDeviceString(dev, MidiDriver::kDeviceId))) {
                        found = true;
                        seq_client = d->getClient();
                        seq_port = -1;
                        break;
                  }
            }
      }

      // Still nothing? Try a sensible default.

      if (!found) {
            // TODO: What's a sensible default anyway? And exactly when do
            // we get to this case?

            warning("AlsaMusicPlugin: Using 17:0 as default ALSA port");
            seq_client = 17;
            seq_port = 0;
      }

      *mididriver = new MidiDriver_ALSA(seq_client, seq_port);

      return Common::kNoError;
}

int AlsaMusicPlugin::parse_addr(const char *arg, int *client, int *port) {
      const char *p;

      if (isdigit(*arg)) {
            if ((p = strpbrk(arg, ADDR_DELIM)) == NULL)
                  return -1;
            *client = atoi(arg);
            *port = atoi(p + 1);
      } else {
            if (*arg == 's' || *arg == 'S') {
                  *client = SND_SEQ_ADDRESS_SUBSCRIBERS;
                  *port = 0;
            } else
                  return -1;
      }
      return 0;
}

//#if PLUGIN_ENABLED_DYNAMIC(ALSA)
      //REGISTER_PLUGIN_DYNAMIC(ALSA, PLUGIN_TYPE_MUSIC, AlsaMusicPlugin);
//#else
      REGISTER_PLUGIN_STATIC(ALSA, PLUGIN_TYPE_MUSIC, AlsaMusicPlugin);
//#endif

#endif

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