merged app sources to single folder

16 files changed, 2156 insertions, 0 deletions

diff --git a/app/Makefile b/app/Makefile
new file mode 100644
index 0000000..d1c2af2
--- /dev/null
+++ b/app/Makefile
@@ -0,0 +1,107 @@
+##
+##  dolmetschctl
+##
+##
+##  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+##
+##  This file is part of dolmetschctl.
+##
+##  dolmetschctl 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
+##  any later version.
+##
+##  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+##
+
+ifneq ($(MAKECMDGOALS),distclean)
+include include.mk
+endif
+
+EXECUTABLE_SERVER := dolmetschctl
+EXECUTABLE_CLIENT := dolmetschctl-client
+
+C_OBJS_SERVER :=  slist.o \
+  osc_server.o \
+  midi_server.o \
+  mixer.o \
+  dolmetschctl.o
+
+C_OBJS_CLIENT :=  slist.o \
+  osc_client.o \
+  midi_client.o \
+  dolmetschctl-client.o
+
+C_SRCS := $(C_OBJS_SERVER:%.o=%.c) $(C_OBJS_CLIENT:%.o=%.c)
+
+.PHONY: clean distclean install install-bin install-etc uninstall remove remove-bin remove-etc purge
+
+all: $(EXECUTABLE_SERVER) $(EXECUTABLE_CLIENT)
+
+%.d: %.c
+	@set -e; rm -f $@; \
+  $(CC) -MM $(CFLAGS) $< > $@.$$$$; \
+  sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
+  rm -f $@.$$$$; echo '(re)building $@'
+
+ifneq ($(MAKECMDGOALS),distclean)
+-include $(C_SRCS:%.c=%.d)
+endif
+
+$(EXECUTABLE_SERVER): $(C_OBJS_SERVER)
+	$(CC) $(C_OBJS_SERVER) -o $@ $(LDFLAGS)
+
+$(EXECUTABLE_CLIENT): $(C_OBJS_CLIENT)
+	$(CC) $(C_OBJS_CLIENT) -o $@ $(LDFLAGS)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $<
+
+strip: $(EXECUTABLE_SERVER) $(EXECUTABLE_CLIENT)
+	$(STRIP) -s $(EXECUTABLE_SERVER)
+	$(STRIP) -s $(EXECUTABLE_CLIENT)
+
+
+distclean: clean
+	find . -name *.o -exec rm -f {} \;
+	find . -name "*.\~*" -exec rm -rf {} \;
+	rm -f include.mk
+	rm -f config.h
+
+clean:
+	rm -f *.o
+	rm -f *.d
+	rm -f *.d.*
+	rm -f $(EXECUTABLE_SERVER)
+	rm -f $(EXECUTABLE_CLIENT)
+
+INSTALL_TARGETS := install-bin install-etc
+REMOVE_TARGETS := remove-bin remove-etc
+
+install: all $(INSTALL_TARGETS)
+
+install-bin: $(EXECUTABLE_SERVER) $(EXECUTABLE_CLIENT)
+	$(INSTALL) -d $(DESTDIR)$(BINDIR)
+	$(INSTALL) -m 755 $(EXECUTABLE_SERVER) $(DESTDIR)$(BINDIR)
+	$(INSTALL) -m 755 $(EXECUTABLE_CLIENT) $(DESTDIR)$(BINDIR)
+
+install-etc:
+
+uninstall: remove
+
+remove: $(REMOVE_TARGETS)
+
+remove-bin:
+	rm -f $(DESTDIR)$(BINDIR)/$(EXECUTABLE_SERVER)
+	rm -f $(DESTDIR)$(BINDIR)/$(EXECUTABLE_CLIENT)
+
+remove-etc:
+
+purge: remove
+	rm -rf $(DESTDIR)$(ETCDIR)/dolmetschctl/
diff --git a/app/configure b/app/configure
new file mode 100755
index 0000000..9809caa
--- /dev/null
+++ b/app/configure
@@ -0,0 +1,163 @@
+#!/bin/sh
+#
+#  dolmetschctl
+#
+#
+#  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+#
+#  This file is part of dolmetschctl.
+#
+#  dolmetschctl 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
+#  any later version.
+#
+#  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+#
+
+TARGET=`uname -s`
+EBUILD_COMPAT=0
+
+USE_CLANG=0
+
+PREFIX='/usr/local'
+BINDIR=''
+ETCDIR=''
+
+print_usage() {
+  echo "configure --help                    print this"
+  echo "          --target=<TARGET>         build target i.e. Linux (default: autodetect)"
+  echo "          --prefix=<PREFIX>         the installation prefix (default: /usr/local)"
+  echo "          --bindir=<DIR>            the path to the bin directory (default: $PREFIX/bin)"
+  echo "          --sysconfdir=<DIR>        the path to the system configuration directory (default: $PREFIX/etc"
+  echo "          --use-clang               use clang/llvm as compiler/linker"
+}
+
+for arg
+do
+  case $arg in
+  --target=*)
+    TARGET=${arg#--target=}
+  ;;
+  --use-clang)
+    USE_CLANG=1
+  ;;
+  --prefix=*)
+    PREFIX=${arg#--prefix=}
+  ;;
+  --bindir=*)
+    BINDIR=${arg#--bindir=}
+  ;;
+  --sysconfdir=*)
+    ETCDIR=${arg#--sysconfdir=}
+  ;;
+  --ebuild-compat)
+    EBUILD_COMPAT=1
+  ;;
+  --help)
+    print_usage
+    exit 0
+  ;;
+  *)
+    ERRORS="$ERRORS $arg"
+  ;;
+  esac
+done
+
+if [ -n "$ERRORS" ] && [ $EBUILD_COMPAT -ne 1 ]; then
+  for error in $ERRORS; do
+    echo "Unknown argument: $error"
+  done
+
+  print_usage
+  exit 1
+fi
+
+if [ $USE_CLANG -eq 0 ]; then
+  CFLAGS='-g -Wall -O2'
+  LDFLAGS='-g -Wall -O2'
+  COMPILER='gcc'
+else
+  CFLAGS='-g -O2'
+  LDFLAGS='-g -O2'
+  COMPILER='clang'
+fi
+
+rm -f config.h
+rm -f include.mk
+case $TARGET in
+  Linux)
+    LDFLAGS=$LD_FLAGS' -lasound -llo'
+  ;;
+  *)
+    echo "platform not supported"
+    exit 1;
+  ;;
+esac
+
+if [ -z "$BINDIR" ]; then
+  BINDIR=$PREFIX/bin
+fi
+
+if [ -z "$ETCDIR" ]; then
+  ETCDIR=$PREFIX/etc
+fi
+
+cat > include.mk <<EOF
+# this file was created automatically
+# do not edit this file directly
+# use ./configure instead
+
+TARGET := $TARGET
+CC := $COMPILER
+CFLAGS := $CFLAGS
+LDFLAGS := $LDFLAGS
+STRIP := strip
+INSTALL := install
+
+prefix := '$PREFIX'
+BINDIR := '$BINDIR'
+ETCDIR := '$ETCDIR'
+EOF
+
+VERSION=`cat ../version`
+if which git >/dev/null; then
+    GIT_HASH=`git rev-parse HEAD 2> /dev/null`
+    if [ -n "$GIT_HASH" ]; then
+        VERSION="$VERSION (git $GIT_HASH)"
+    fi
+fi
+
+HOSTNAME=`hostname`
+DATE=`date +"%d.%m.%Y %H:%M:%S %Z"`
+
+cat > config.h <<EOF
+/*
+ * dolmetschctl config header
+ *
+ * this file was created automatically
+ * do not edit this file directly
+ * use ./configure instead
+ */
+
+#ifndef DOLMETSCHCTL_config_h_INCLUDED
+#define DOLMETSCHCTL_config_h_INCLUDED
+
+#define VERSION_STRING_0 "dolmetschctl version $VERSION"
+#define VERSION_STRING_1 "built on $HOSTNAME, $DATE"
+
+#define TARGET "$TARGET"
+#define PREFIX "$PREFIX"
+#define BINDIR "$BINDIR"
+#define ETCDIR "$ETCDIR"
+
+#endif
+EOF
+
+exit 0
diff --git a/app/dolmetschctl-client.c b/app/dolmetschctl-client.c
new file mode 100644
index 0000000..9815924
--- /dev/null
+++ b/app/dolmetschctl-client.c
@@ -0,0 +1,192 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <error.h>
+
+#include <lo/lo.h>
+#include <alsa/asoundlib.h>
+
+#include "midi_client.h"
+#include "osc_client.h"
+
+
+void print_version()
+{
+  printf("%s\n", VERSION_STRING_0);
+#if defined(__clang__)
+  printf("%s, using CLANG %s\n", VERSION_STRING_1, __clang_version__);
+#elif defined(__GNUC__)
+  printf("%s, using GCC %d.%d.%d\n", VERSION_STRING_1, __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__);
+#else
+  printf("%s\n", VERSION_STRING_1);
+#endif
+
+  printf("linked against alsa-lib Version %s\n", snd_asoundlib_version());
+  char verstr[32];
+  lo_version(verstr, sizeof(verstr), 0, 0, 0, 0, 0, 0, 0);
+  printf("linked against liblo Version %s\n", verstr);
+}
+
+void print_usage()
+{
+  printf("\ndolmetschctl-client <options>\n");
+  printf("    -h                 print this and exit\n");
+  printf("    -v                 print version information and exit\n");
+  printf("    -m <dev>           the MIDI control device name to use, i.e. hw:2,0,0\n");
+  printf("                       (use `amidi -l` to list all available devices)'\n");
+  printf("    -o <host>:<port>   the UDP host/port to send OSC messages to\n");
+}
+
+int main_loop(midi_t* m, osc_t* o)
+{
+  int ret = 0;
+
+  printf("main_loop just started\n");
+
+  int midi_npfds_offset = 0;
+  int midi_npfds = midi_get_poll_fd_count(m);
+  assert(midi_npfds > 0);
+
+  int osc_npfds_offset = midi_npfds_offset + midi_npfds;
+  int osc_npfds = osc_get_poll_fd_count(o);
+  assert(osc_npfds > 0);
+
+  int npfds = midi_npfds + osc_npfds;
+  struct pollfd *pfds = alloca(npfds * sizeof(struct pollfd));
+  if(!pfds) {
+    error(0, 0, "error while allocating poll fds - stack corrupted??");
+    return -1;
+  }
+
+  printf("main_loop running with %d pollfds...\n", npfds);
+  for (;;) {
+    midi_get_poll_fds(m, &(pfds[midi_npfds_offset]), midi_npfds);
+    osc_get_poll_fds(o, &(pfds[osc_npfds_offset]), osc_npfds);
+
+    int err = poll(pfds, npfds, 200);
+    if(err < 0 && errno != EINTR) {
+      error(0, errno, "poll failed");
+      break;
+    }
+    if(err <= 0) {
+          // timeout or EINTR
+      continue;
+    }
+
+    ret = midi_handle_revents(m, &(pfds[midi_npfds_offset]), midi_npfds, o);
+    if(ret)
+      break;
+
+//    ret = osc_handle_revents(o, &(pfds[osc_npfds_offset]), osc_npfds, m);
+    ret = osc_handle_revents(o, &(pfds[osc_npfds_offset]), osc_npfds);
+    if(ret)
+      break;
+  }
+
+  return ret;
+}
+
+int main(int argc, char* argv[])
+{
+  int helpflag = 0;
+  int versionflag = 0;
+  char* midi_dev = NULL;
+  char* osc_target = NULL;
+
+  int c;
+  opterr = 0;
+  while ((c = getopt (argc, argv, "vhm:o:")) != -1) {
+    switch (c) {
+    case 'h':
+      helpflag = 1;
+      break;
+    case 'v':
+      versionflag = 1;
+      break;
+    case 'm':
+      midi_dev = optarg;
+      break;
+    case 'o':
+      osc_target = optarg;
+      break;
+    case '?':
+      if (optopt == 'm' || optopt == 'o')
+        error(0, 0, "Option -%c requires an argument.\n", optopt);
+      else if (isprint (optopt))
+        error(0, 0, "Unknown option `-%c'.\n", optopt);
+      else
+        error(0, 0, "Unknown option character `\\x%x'.\n", optopt);
+      return -1;
+    default:
+      return -1;
+    }
+  }
+
+  if(helpflag) {
+    print_usage();
+    return 0;
+  }
+
+  if(versionflag) {
+    print_version();
+    return 0;
+  }
+
+  if(!midi_dev){
+    error(0, 0, "MIDI device name must be set");
+    print_usage();
+    return -1;
+  }
+
+  if(!osc_target){
+    error(0, 0, "OSC target (host/port) name must be set");
+    print_usage();
+    return -1;
+  }
+
+  char* port = osc_target;
+  char* host = strsep(&port, ":");
+  char* remain = port;
+  strsep(&remain, ":");
+  if(!host || !port || remain) {
+    error(0, 0, "'%s' is not a valid targets, must be in the format <host>:<port>", osc_target);
+    print_usage();
+    return -1;
+  }
+
+  midi_t m;
+  if(midi_init(&m, midi_dev))
+    return -1;
+
+  osc_t o;
+  if(osc_init(&o, &m, host, port))
+    return -1;
+
+  int ret = main_loop(&m, &o);
+
+  return ret;
+}
diff --git a/app/dolmetschctl.c b/app/dolmetschctl.c
new file mode 100644
index 0000000..3b20cb6
--- /dev/null
+++ b/app/dolmetschctl.c
@@ -0,0 +1,214 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <error.h>
+
+#include <lo/lo.h>
+#include <alsa/asoundlib.h>
+
+#include "mixer.h"
+#include "midi_server.h"
+#include "osc_server.h"
+
+
+void print_version()
+{
+  printf("%s\n", VERSION_STRING_0);
+#if defined(__clang__)
+  printf("%s, using CLANG %s\n", VERSION_STRING_1, __clang_version__);
+#elif defined(__GNUC__)
+  printf("%s, using GCC %d.%d.%d\n", VERSION_STRING_1, __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__);
+#else
+  printf("%s\n", VERSION_STRING_1);
+#endif
+
+  printf("linked against alsa-lib Version %s\n", snd_asoundlib_version());
+  char verstr[32];
+  lo_version(verstr, sizeof(verstr), 0, 0, 0, 0, 0, 0, 0);
+  printf("linked against liblo Version %s\n", verstr);
+}
+
+void print_usage()
+{
+  printf("\ndolmetschctl <options>\n");
+  printf("    -h          print this and exit\n");
+  printf("    -v          print version information and exit\n");
+  printf("    -x <name>   the name of the mixer, dolmetschctl will look for\n");
+  printf("                language files inside '%s/<name>/'\n", ETCDIR);
+  printf("    -d <dev>    the mixer MIDI device name to use, i.e. hw:2,0,0\n");
+  printf("                (use `amidi -l` to list all available devices)'\n");
+  printf("    -m <dev>    the MIDI control device name to use, this can be omitted to\n");
+  printf("                only wait for OSC messages'\n");
+  printf("    -o <port>   the UDP port to listen on for OSC messages, this can be omitted\n");
+  printf("                to only use the control MIDI interface'\n");
+}
+
+int main_loop(mixer_t* x, midi_t* m, osc_t* o)
+{
+  int ret = 0;
+
+  printf("main_loop just started\n");
+
+  int mixer_npfds_offset = 0;
+  int mixer_npfds = mixer_get_poll_fd_count(x);
+  assert(mixer_npfds > 0);
+
+  int midi_npfds_offset = mixer_npfds_offset + mixer_npfds;
+  int midi_npfds = midi_get_poll_fd_count(m);
+  assert(midi_npfds >= 0);
+
+  int osc_npfds_offset = midi_npfds_offset + midi_npfds;
+  int osc_npfds = osc_get_poll_fd_count(o);
+  assert(osc_npfds >= 0);
+
+  int npfds = midi_npfds + osc_npfds + mixer_npfds;
+  struct pollfd *pfds = alloca(npfds * sizeof(struct pollfd));
+  if(!pfds) {
+    error(0, 0, "error while allocating poll fds - stack corrupted??");
+    return -1;
+  }
+
+  printf("main_loop running with %d pollfds...\n", npfds);
+  for (;;) {
+    mixer_get_poll_fds(x, &(pfds[mixer_npfds_offset]), mixer_npfds);
+    midi_get_poll_fds(m, &(pfds[midi_npfds_offset]), midi_npfds);
+    osc_get_poll_fds(o, &(pfds[osc_npfds_offset]), osc_npfds);
+
+    int err = poll(pfds, npfds, 200);
+    if(err < 0 && errno != EINTR) {
+      error(0, errno, "poll failed");
+      break;
+    }
+    if(err <= 0) {
+          // timeout or EINTR
+      continue;
+    }
+
+    ret = mixer_handle_revents(x, &(pfds[mixer_npfds_offset]), mixer_npfds);
+    if(ret)
+      break;
+
+    ret = midi_handle_revents(m, &(pfds[midi_npfds_offset]), midi_npfds, x);
+    if(ret)
+      break;
+
+    ret = osc_handle_revents(o, &(pfds[osc_npfds_offset]), osc_npfds, x);
+    if(ret)
+      break;
+  }
+
+  return ret;
+}
+
+int main(int argc, char* argv[])
+{
+  int helpflag = 0;
+  int versionflag = 0;
+  char* mixer_name = NULL;
+  char* mixer_dev = NULL;
+  char* midi_dev = NULL;
+  char* osc_port = NULL;
+
+  int c;
+  opterr = 0;
+  while ((c = getopt (argc, argv, "vhx:d:m:o:")) != -1) {
+    switch (c) {
+    case 'h':
+      helpflag = 1;
+      break;
+    case 'v':
+      versionflag = 1;
+      break;
+    case 'x':
+      mixer_name = optarg;
+      break;
+    case 'd':
+      mixer_dev = optarg;
+      break;
+    case 'm':
+      midi_dev = optarg;
+      break;
+    case 'o':
+      osc_port = optarg;
+      break;
+    case '?':
+      if (optopt == 'x' || optopt == 'd' || optopt == 'm' || optopt == 'o')
+        error(0, 0, "Option -%c requires an argument.\n", optopt);
+      else if (isprint (optopt))
+        error(0, 0, "Unknown option `-%c'.\n", optopt);
+      else
+        error(0, 0, "Unknown option character `\\x%x'.\n", optopt);
+      return -1;
+    default:
+      return -1;
+    }
+  }
+
+  if(helpflag) {
+    print_usage();
+    return 0;
+  }
+
+  if(versionflag) {
+    print_version();
+    return 0;
+  }
+
+  if(!mixer_name){
+    error(0, 0, "mixer name must be set");
+    print_usage();
+    return -1;
+  }
+
+  if(!mixer_dev){
+    error(0, 0, "mixer device name must be set");
+    print_usage();
+    return -1;
+  }
+
+  if(!midi_dev && !osc_port) {
+    error(0, 0, "either midi or osc (or both) must be specified");
+    print_usage();
+    return -1;
+  }
+
+  mixer_t x;
+  if(mixer_init(&x, mixer_name, mixer_dev))
+    return -1;
+
+  midi_t m;
+  if(midi_init(&m, midi_dev))
+    return -1;
+
+  osc_t o;
+  if(osc_init(&o, osc_port))
+    return -1;
+
+  int ret = main_loop(&x, &m, &o);
+
+  return ret;
+}
diff --git a/app/midi_client.c b/app/midi_client.c
new file mode 100644
index 0000000..456ec7d
--- /dev/null
+++ b/app/midi_client.c
@@ -0,0 +1,242 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <error.h>
+#include <poll.h>
+#include <assert.h>
+
+#include "midi_client.h"
+
+#define NOTE_EN 0x00
+#define NOTE_DE 0x01
+u_int8_t led_cmd_en[] = { 0xB0, NOTE_EN, 0x01, 0xB0, NOTE_DE, 0x00 };
+u_int8_t led_cmd_de[] = { 0xB0, NOTE_EN, 0x00, 0xB0, NOTE_DE, 0x01 };
+
+static void free_cmd_entry(void* ptr)
+{
+  cmd_t* c = ptr;
+  assert(c);
+  free(c->buf_);
+  free(c);
+}
+
+int midi_init(midi_t* m, const char* device)
+{
+  assert(m != NULL);
+
+  m->input_ = NULL;
+  m->output_ = NULL;
+  memset(m->buf_, 0, sizeof(m->buf_));
+  m->read_idx_ = 0;
+  slist_init(&(m->cmds_), free_cmd_entry);
+
+  int ret = snd_rawmidi_open(&(m->input_), &(m->output_), device, SND_RAWMIDI_NONBLOCK);
+  if(ret < 0) {
+    error(0, 0, "MIDI: cannot open port '%s': %s", device, snd_strerror(ret));
+    return ret;
+  }
+
+  return 0;
+}
+
+int midi_enqueue_cmd(midi_t* m, const char* lang)
+{
+  assert(m && lang);
+
+  int len;
+  const u_int8_t* src;
+  if(!strcmp(lang, "en")) {
+    len = sizeof(led_cmd_en);
+    src = led_cmd_en;
+  }
+  else if(!strcmp(lang, "de")) {
+    len = sizeof(led_cmd_de);
+    src = led_cmd_de;
+  }
+  else
+    return 0;
+
+  cmd_t* cmd = malloc(sizeof(cmd_t));
+  assert(cmd);
+  cmd->len_ = len;
+  assert((cmd->buf_ = malloc(cmd->len_)));
+  memcpy(cmd->buf_, src, cmd->len_);
+  cmd->write_idx_ = 0;
+
+  slist_add(&(m->cmds_), cmd);
+
+  return 0;
+}
+
+int midi_get_poll_fd_count(midi_t* m)
+{
+  assert(m);
+
+  m->in_pfds_cnt_ = snd_rawmidi_poll_descriptors_count(m->input_);
+  assert(m->in_pfds_cnt_ > 0);
+  m->out_pfds_cnt_ = snd_rawmidi_poll_descriptors_count(m->output_);
+  assert(m->out_pfds_cnt_ > 0);
+
+  return (m->in_pfds_cnt_ + m->out_pfds_cnt_);
+}
+
+int midi_get_poll_fds(midi_t* m, struct pollfd *pfds, int npfds)
+{
+  assert(m && pfds && npfds);
+
+  snd_rawmidi_poll_descriptors(m->input_, pfds, m->in_pfds_cnt_);
+  snd_rawmidi_poll_descriptors(m->output_, &(pfds[m->in_pfds_cnt_]), npfds - m->in_pfds_cnt_);
+
+  if(!slist_length(&(m->cmds_))) {
+    int i;
+    for(i = m->in_pfds_cnt_; i < npfds; ++i)
+      pfds[i].events = 0;
+  }
+  return (m->in_pfds_cnt_ + m->out_pfds_cnt_);
+}
+
+static int midi_enqueue_lang_switch(midi_t* m, osc_t* o, const char* lang)
+{
+  return osc_switch_lang(o, lang);
+}
+
+static int midi_handle_note_on(midi_t* m, osc_t* o)
+{
+  int ret = 0;
+  switch(m->buf_[1]) {
+  case NOTE_EN: ret = midi_enqueue_lang_switch(m, o,"en"); break;
+  case NOTE_DE: ret = midi_enqueue_lang_switch(m, o, "de"); break;
+  default: printf("ignoring unknown note\n"); break;
+  }
+  return ret;
+}
+
+static int midi_handle_note_off(midi_t* m, osc_t* o)
+{
+  return 0;
+}
+
+static int midi_handle_message(midi_t* m, osc_t* o)
+{
+  /* int i; */
+  /* printf("MIDI: "); */
+  /* for (i = 0; i < sizeof(m->buf_); ++i) */
+  /*   printf("%02X%c", m->buf_[i], (i >= (sizeof(m->buf_)-1)) ? '\n' : ' '); */
+
+  int ret = 0;
+  switch(m->buf_[0]) {
+  case 0x90: ret = midi_handle_note_on(m, o); break;
+  case 0x80: ret = midi_handle_note_off(m, o); break;
+  default: printf("ignoring unknown midi command\n"); break;
+  }
+
+  return ret;
+}
+
+static int midi_handle_in_revents(midi_t* m, struct pollfd *pfds, int npfds, osc_t* o)
+{
+  int err;
+  unsigned short revents;
+  if((err = snd_rawmidi_poll_descriptors_revents(m->input_, pfds, npfds, &revents)) < 0) {
+    error(0, 0, "MIDI: cannot get poll events: %s", snd_strerror(errno));
+    return -1;
+  }
+  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
+    error(0, 0, "MIDI: got POLLERR, POLLHUP or POLLNVAL");
+    return -1;
+  }
+  if(!(revents & POLLIN))
+    return 0;
+
+  int ret = snd_rawmidi_read(m->input_, &(m->buf_[m->read_idx_]), sizeof(m->buf_) - m->read_idx_);
+  if(ret == -EAGAIN)
+    return 0;
+  if(ret < 0) {
+    error(0, 0, "MIDI: cannot read from midi port: %s", snd_strerror(ret));
+    return -1;
+  }
+  m->read_idx_ += ret;
+  if(m->read_idx_ >= sizeof(m->buf_)) {
+    ret = midi_handle_message(m, o);
+    memset(m->buf_, 0, sizeof(m->buf_));
+    m->read_idx_ = 0;
+    return ret;
+  }
+
+  return ret;
+}
+
+static int midi_handle_out_revents(midi_t* m, struct pollfd *pfds, int npfds)
+{
+  int err;
+  unsigned short revents;
+  if((err = snd_rawmidi_poll_descriptors_revents(m->output_, pfds, npfds, &revents)) < 0) {
+    error(0, 0, "MIDI: cannot get poll events: %s", snd_strerror(errno));
+    return -1;
+  }
+  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
+    error(0, 0, "MIDI: got POLLERR, POLLHUP or POLLNVAL");
+    return -1;
+  }
+  if(!(revents & POLLOUT))
+    return 0;
+
+  assert(m->cmds_.first_);
+  cmd_t* cmd = (cmd_t*)(m->cmds_.first_->data_);
+  assert(cmd);
+  assert(cmd->buf_);
+
+  int ret = snd_rawmidi_write(m->output_, &(cmd->buf_[cmd->write_idx_]), cmd->len_ - cmd->write_idx_);
+  if(ret == -EAGAIN)
+    return 0;
+  if(ret < 0) {
+    error(0, 0, "MIDI: cannot write to port: %s", snd_strerror(ret));
+    return -1;
+  }
+  cmd->write_idx_ += ret;
+  if(cmd->write_idx_ >= cmd->len_) {
+    if((err = snd_rawmidi_drain(m->output_)) < 0) {
+      error(0, 0, "MIDI: cannot drain output: %s", snd_strerror(err));
+      return -1;
+    }
+    slist_remove(&(m->cmds_), cmd);
+  }
+
+  return 0;
+}
+
+int midi_handle_revents(midi_t* m, struct pollfd *pfds, int npfds, osc_t* o)
+{
+  assert(m);
+
+  if(!m->input_ || !m->output_)
+    return 0;
+
+  int ret = midi_handle_in_revents(m, pfds, m->in_pfds_cnt_, o);
+  if(ret)
+    return ret;
+
+  return midi_handle_out_revents(m, &(pfds[m->in_pfds_cnt_]), m->out_pfds_cnt_);
+}
diff --git a/app/midi_client.h b/app/midi_client.h
new file mode 100644
index 0000000..7ae65bd
--- /dev/null
+++ b/app/midi_client.h
@@ -0,0 +1,54 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DOLMETSCHCTL_midi_h_INCLUDED
+#define DOLMETSCHCTL_midi_h_INCLUDED
+
+#include <alsa/asoundlib.h>
+#include <poll.h>
+
+#include "slist.h"
+#include "osc_client.h"
+
+typedef struct {
+  u_int8_t* buf_;
+  int len_;
+  int write_idx_;
+} cmd_t;
+
+typedef struct {
+  snd_rawmidi_t* input_;
+  int in_pfds_cnt_;
+  snd_rawmidi_t* output_;
+  int out_pfds_cnt_;
+  u_int8_t buf_[3];
+  int read_idx_;
+  slist_t cmds_;
+} midi_t;
+
+int midi_init(midi_t* m, const char* device);
+int midi_enqueue_cmd(midi_t* m, const char* lang);
+int midi_get_poll_fd_count(midi_t* m);
+int midi_get_poll_fds(midi_t* m, struct pollfd *pfds, int npfds);
+int midi_handle_revents(midi_t* m, struct pollfd *pfds, int npfds, osc_t* o);
+
+#endif
diff --git a/app/midi_server.c b/app/midi_server.c
new file mode 100644
index 0000000..dbbf222
--- /dev/null
+++ b/app/midi_server.c
@@ -0,0 +1,237 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <error.h>
+#include <poll.h>
+#include <assert.h>
+
+#include "midi_server.h"
+
+#define NOTE_EN 0x00
+#define NOTE_DE 0x01
+u_int8_t done_data_en[] = { 0xB0, NOTE_EN, 0x01, 0xB0, NOTE_DE, 0x00 };
+u_int8_t done_data_de[] = { 0xB0, NOTE_EN, 0x00, 0xB0, NOTE_DE, 0x01 };
+
+int midi_init(midi_t* m, const char* device)
+{
+  assert(m != NULL);
+
+  m->input_ = NULL;
+  m->output_ = NULL;
+  memset(m->buf_, 0, sizeof(m->buf_));
+  m->read_idx_ = 0;
+
+  slist_init(&(m->done_data_), free);
+
+  if(device) {
+    int ret = snd_rawmidi_open(&(m->input_), &(m->output_), device, SND_RAWMIDI_NONBLOCK);
+    if(ret < 0) {
+      error(0, 0, "MIDI: cannot open port '%s': %s", device, snd_strerror(ret));
+      return ret;
+    }
+  }
+
+  return 0;
+}
+
+int midi_get_poll_fd_count(midi_t* m)
+{
+  assert(m);
+
+  if(!m->input_ || !m->output_)
+    return 0;
+
+  m->in_pfds_cnt_ = snd_rawmidi_poll_descriptors_count(m->input_);
+  assert(m->in_pfds_cnt_ > 0);
+  m->out_pfds_cnt_ = snd_rawmidi_poll_descriptors_count(m->output_);
+  assert(m->out_pfds_cnt_ > 0);
+
+  return (m->in_pfds_cnt_ + m->out_pfds_cnt_);
+}
+
+int midi_get_poll_fds(midi_t* m, struct pollfd *pfds, int npfds)
+{
+  assert(m);
+
+  if(!m->input_ || !m->output_)
+    return 0;
+
+  snd_rawmidi_poll_descriptors(m->input_, pfds, m->in_pfds_cnt_);
+  snd_rawmidi_poll_descriptors(m->output_, &(pfds[m->in_pfds_cnt_]), npfds - m->in_pfds_cnt_);
+
+  int pending_data = 0;
+  if(m->done_data_.first_) {
+    midi_done_data_t* d = (midi_done_data_t*)(m->done_data_.first_->data_);
+    if(d->active_)
+      pending_data = 1;
+  }
+  if(!pending_data) {
+    int i;
+    for(i = m->in_pfds_cnt_; i < npfds; ++i)
+      pfds[i].events = 0;
+  }
+  return (m->in_pfds_cnt_ + m->out_pfds_cnt_);
+}
+
+void midi_lang_switch_done(void* data)
+{
+  assert(data);
+  midi_done_data_t* d = data;
+  d->active_ = 1;
+}
+
+static int midi_enqueue_lang_switch(midi_t* m, mixer_t* x, const char* lang, const u_int8_t* buf, int len)
+{
+  midi_done_data_t* done_data = malloc(sizeof(midi_done_data_t));
+  assert(done_data);
+  done_data->self_ = m;
+  done_data->active_ = 0;
+  done_data->buf_ = buf;
+  done_data->len_ = len;
+  done_data->write_idx_ = 0;
+  assert(slist_add(&(m->done_data_), done_data));
+
+  return mixer_switch_lang(x, lang, &midi_lang_switch_done, done_data);
+}
+
+static int midi_handle_note_on(midi_t* m, mixer_t* x)
+{
+  int ret = 0;
+  switch(m->buf_[1]) {
+  case NOTE_EN: ret = midi_enqueue_lang_switch(m, x, "en", done_data_en, sizeof(done_data_en)); break;
+  case NOTE_DE: ret = midi_enqueue_lang_switch(m, x, "de", done_data_de, sizeof(done_data_de)); break;
+  default: printf("ignoring unknown note\n"); break;
+  }
+  return ret;
+}
+
+static int midi_handle_note_off(midi_t* m, mixer_t* x)
+{
+  return 0;
+}
+
+static int midi_handle_message(midi_t* m, mixer_t* x)
+{
+  /* int i; */
+  /* printf("MIDI: "); */
+  /* for (i = 0; i < sizeof(m->buf_); ++i) */
+  /*   printf("%02X%c", m->buf_[i], (i >= (sizeof(m->buf_)-1)) ? '\n' : ' '); */
+
+  int ret = 0;
+  switch(m->buf_[0]) {
+  case 0x90: ret = midi_handle_note_on(m, x); break;
+  case 0x80: ret = midi_handle_note_off(m, x); break;
+  default: printf("ignoring unknown midi command\n"); break;
+  }
+
+  return ret;
+}
+
+static int midi_handle_in_revents(midi_t* m, struct pollfd *pfds, int npfds, mixer_t* x)
+{
+  int err;
+  unsigned short revents;
+  if((err = snd_rawmidi_poll_descriptors_revents(m->input_, pfds, npfds, &revents)) < 0) {
+    error(0, 0, "MIDI: cannot get poll events: %s", snd_strerror(errno));
+    return -1;
+  }
+  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
+    error(0, 0, "MIDI: got POLLERR, POLLHUP or POLLNVAL");
+    return -1;
+  }
+  if(!(revents & POLLIN))
+    return 0;
+
+  int ret = snd_rawmidi_read(m->input_, &(m->buf_[m->read_idx_]), sizeof(m->buf_) - m->read_idx_);
+  if(ret == -EAGAIN)
+    return 0;
+  if(ret < 0) {
+    error(0, 0, "MIDI: cannot read from midi port: %s", snd_strerror(ret));
+    return -1;
+  }
+  m->read_idx_ += ret;
+  if(m->read_idx_ >= sizeof(m->buf_)) {
+    ret = midi_handle_message(m, x);
+    memset(m->buf_, 0, sizeof(m->buf_));
+    m->read_idx_ = 0;
+    return ret;
+  }
+
+  return ret;
+}
+
+static int midi_handle_out_revents(midi_t* m, struct pollfd *pfds, int npfds)
+{
+  int err;
+  unsigned short revents;
+  if((err = snd_rawmidi_poll_descriptors_revents(m->output_, pfds, npfds, &revents)) < 0) {
+    error(0, 0, "MIDI: cannot get poll events: %s", snd_strerror(errno));
+    return -1;
+  }
+  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
+    error(0, 0, "MIDI: got POLLERR, POLLHUP or POLLNVAL");
+    return -1;
+  }
+  if(!(revents & POLLOUT))
+    return 0;
+
+  assert(m->done_data_.first_);
+  midi_done_data_t* done_data = (midi_done_data_t*)(m->done_data_.first_->data_);
+  assert(done_data);
+  assert(done_data->active_);
+  assert(done_data->buf_);
+
+  int ret = snd_rawmidi_write(m->output_, &(done_data->buf_[done_data->write_idx_]), done_data->len_ - done_data->write_idx_);
+  if(ret == -EAGAIN)
+    return 0;
+  if(ret < 0) {
+    error(0, 0, "MIDI: cannot write to port: %s", snd_strerror(ret));
+    return -1;
+  }
+  done_data->write_idx_ += ret;
+  if(done_data->write_idx_ >= done_data->len_) {
+    if((err = snd_rawmidi_drain(m->output_)) < 0) {
+      error(0, 0, "MIDI: cannot drain output: %s", snd_strerror(err));
+      return -1;
+    }
+    slist_remove(&(m->done_data_), done_data);
+  }
+
+  return 0;
+}
+
+int midi_handle_revents(midi_t* m, struct pollfd *pfds, int npfds, mixer_t* x)
+{
+  assert(m);
+
+  if(!m->input_ || !m->output_)
+    return 0;
+
+  int ret = midi_handle_in_revents(m, pfds, m->in_pfds_cnt_, x);
+  if(ret)
+    return ret;
+
+  return midi_handle_out_revents(m, &(pfds[m->in_pfds_cnt_]), m->out_pfds_cnt_);
+}
diff --git a/app/midi_server.h b/app/midi_server.h
new file mode 100644
index 0000000..537c356
--- /dev/null
+++ b/app/midi_server.h
@@ -0,0 +1,55 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DOLMETSCHCTL_midi_h_INCLUDED
+#define DOLMETSCHCTL_midi_h_INCLUDED
+
+#include <alsa/asoundlib.h>
+#include <poll.h>
+
+#include "slist.h"
+#include "mixer.h"
+
+typedef struct {
+  snd_rawmidi_t* input_;
+  int in_pfds_cnt_;
+  snd_rawmidi_t* output_;
+  int out_pfds_cnt_;
+  u_int8_t buf_[3];
+  int read_idx_;
+  slist_t done_data_;
+} midi_t;
+
+typedef struct {
+  midi_t* self_;
+  int active_;
+  const u_int8_t* buf_;
+  int len_;
+  int write_idx_;
+} midi_done_data_t;
+
+int midi_init(midi_t* m, const char* device);
+int midi_get_poll_fd_count(midi_t* m);
+int midi_get_poll_fds(midi_t* m, struct pollfd *pfds, int npfds);
+int midi_handle_revents(midi_t* m, struct pollfd *pfds, int npfds, mixer_t* x);
+
+#endif
diff --git a/app/mixer.c b/app/mixer.c
new file mode 100644
index 0000000..54df1b4
--- /dev/null
+++ b/app/mixer.c
@@ -0,0 +1,284 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <error.h>
+#include <poll.h>
+#include <assert.h>
+#include <sys/types.h>
+#include <dirent.h>
+
+#include "mixer.h"
+
+static void free_lang_entry(void* ptr)
+{
+  lang_t* l = ptr;
+  assert(l);
+  free(l->name_);
+  slist_clear(&(l->cmds_));
+  free(l);
+}
+
+static void free_task_entry(void* ptr)
+{
+  task_t* t = ptr;
+  assert(t);
+  free(t->buf_);
+  free(t);
+}
+
+static int mixer_read_config_file(mixer_t* x, int dirfd, const char* filename)
+{
+  assert(dirfd > 0);
+
+  int fd = openat(dirfd, filename, O_RDONLY);
+  if(fd < 0) {
+    error(0, errno, "erorr open('%s')", filename);
+    return -1;
+  }
+  FILE* conf = fdopen(fd, "r");
+  if(conf == NULL) {
+    error(0, errno, "erorr fdopen('%s')", filename);
+    return -1;
+  }
+
+  lang_t* lang = malloc(sizeof(lang_t));
+  assert(lang);
+  assert((lang->name_ = strdup(filename)));
+  slist_init(&(lang->cmds_), free);
+  assert(slist_add(&(x->langs_), lang));
+
+  char buf[256];
+  while(fgets(buf, sizeof(buf), conf) != NULL) {
+    midi_cmd_t* cmd = malloc(sizeof(midi_cmd_t));
+    if(!cmd) {
+      error(0, ENOMEM, "can't create midi command stucture");
+      break;
+    }
+    if(sscanf(buf, "%02hhx %02hhx %02hhx", &((*cmd)[0]), &((*cmd)[1]), &((*cmd)[2])) != 3) {
+      continue;
+    }
+    assert(slist_add(&(lang->cmds_), cmd));
+  }
+
+  fclose(conf);
+  return 0;
+}
+
+static int mixer_read_config(mixer_t* x)
+{
+  char path[1024];
+  int ret = snprintf(path, sizeof(path), "%s/%s", ETCDIR, x->name_);
+  assert(ret < sizeof(path));
+
+  DIR* d = opendir(path);
+  if(d == NULL) {
+    error(0, errno, "MIXER: cannot open config directory '%s'", path);
+    return -1;
+  }
+
+  struct dirent* entry;
+  while((entry = readdir(d))) {
+    if(entry->d_type == DT_REG) {
+      if((ret = mixer_read_config_file(x, dirfd(d), entry->d_name)))
+        break;
+    }
+  }
+
+  if(closedir(d) < 0) {
+    error(0, errno, "MIXER: cannot closeconfig directory '%s'", path);
+    return -1;
+  }
+
+  return ret;
+}
+
+int mixer_init(mixer_t* x, const char* name, const char* device)
+{
+  assert(x != NULL);
+
+  x->name_ = name;
+  x->output_ = NULL;
+  slist_init(&(x->langs_), free_lang_entry);
+  slist_init(&(x->tasks_), free_task_entry);
+  int ret = snd_rawmidi_open(NULL, &(x->output_), device, SND_RAWMIDI_NONBLOCK);
+  if(ret < 0) {
+    error(0, 0, "MIXER: cannot open midi port '%s': %s", device, snd_strerror(ret));
+    return ret;
+  }
+
+  return mixer_read_config(x);;
+}
+
+static void mixer_print_midi_cmds(slist_t cmds)
+{
+  if(!slist_length(&(cmds)))
+    printf("<no commands>\n");
+  else {
+    slist_element_t* tmp;
+    for(tmp = cmds.first_; tmp; tmp = tmp->next_) {
+      midi_cmd_t* c = (midi_cmd_t*)(tmp->data_);
+      printf("  0x%02X 0x%02X 0x%02X\n", (*c)[0], (*c)[1], (*c)[2]);
+    }
+  }
+}
+
+void mixer_print_langs(mixer_t* x)
+{
+  assert(x);
+
+  printf("languages:\n");
+  if(!slist_length(&(x->langs_)))
+    printf(" <no languages>\n");
+  else {
+    slist_element_t* tmp;
+    for(tmp = x->langs_.first_; tmp; tmp = tmp->next_) {
+      lang_t* l = (lang_t*)(tmp->data_);
+      printf(" %s:\n", l->name_);
+      mixer_print_midi_cmds(l->cmds_);
+    }
+  }
+}
+
+static u_int8_t* mixer_create_task_buf(slist_t cmds, int len)
+{
+  u_int8_t* buf = malloc(len);
+  slist_element_t* tmp;
+  int i;
+  for(tmp = cmds.first_, i=0; tmp; tmp = tmp->next_, i+=sizeof(midi_cmd_t)) {
+    midi_cmd_t* c = (midi_cmd_t*)(tmp->data_);
+    memcpy(&(buf[i]), (*c), sizeof(midi_cmd_t));
+  }
+  return buf;
+}
+
+int mixer_switch_lang(mixer_t* x, const char* lang, void (*done_cb)(void*), void* done_data)
+{
+  slist_element_t* tmp;
+  for(tmp = x->langs_.first_; tmp; tmp = tmp->next_) {
+    lang_t* l = (lang_t*)(tmp->data_);
+    if(!strcmp(lang, l->name_)) {
+      int len = slist_length(&(l->cmds_));
+      if(len > 0) {
+        task_t* task = malloc(sizeof(task_t));
+        assert(task);
+        task->len_ = sizeof(midi_cmd_t) * len;
+        assert((task->buf_ = mixer_create_task_buf(l->cmds_, task->len_)));
+        task->write_idx_ = 0;
+        task->done_cb_ = done_cb;
+        task->done_data_ = done_data;
+        assert(slist_add(&(x->tasks_), task));
+      }
+      return 0;
+    }
+  }
+  error(0, 0, "requested language '%s' not found ... ignoring request", lang);
+  return 0;
+}
+
+void mixer_print_tasks(mixer_t* x)
+{
+  assert(x);
+
+  printf("tasks:\n");
+  if(!slist_length(&(x->tasks_)))
+    printf(" <no tasks>\n");
+  else {
+    slist_element_t* tmp;
+    for(tmp = x->tasks_.first_; tmp; tmp = tmp->next_) {
+      task_t* t = (task_t*)(tmp->data_);
+      int i;
+      printf(" buf(%d) = ", t->len_);
+      for(i = 0; i < t->len_; ++i) {
+        printf("0x%02X%s", t->buf_[i], (i && !((i+1) % 3)) ? ", " : " ");
+      }
+      printf("\n write_idx = %d\n done = %016lX ( %016lX )\n\n", t->write_idx_, (int64_t)(t->done_cb_), (int64_t)(t->done_data_));
+    }
+  }
+}
+
+int mixer_get_poll_fd_count(mixer_t* x)
+{
+	assert(x);
+
+  return snd_rawmidi_poll_descriptors_count(x->output_);
+}
+
+int mixer_get_poll_fds(mixer_t* x, struct pollfd *pfds, int npfds)
+{
+	assert(x && pfds && npfds);
+
+  int ret = snd_rawmidi_poll_descriptors(x->output_, pfds, npfds);
+  if(!slist_length(&(x->tasks_))) {
+    int i;
+    for(i = 0; i < ret; ++i)
+      pfds[i].events = 0;
+  }
+  return ret;
+}
+
+int mixer_handle_revents(mixer_t* x, struct pollfd *pfds, int npfds)
+{
+	assert(x && pfds && npfds);
+
+  int err;
+  unsigned short revents;
+  if((err = snd_rawmidi_poll_descriptors_revents(x->output_, pfds, npfds, &revents)) < 0) {
+    error(0, 0, "MIXER: cannot get poll events: %s", snd_strerror(errno));
+    return -1;
+  }
+  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
+    error(0, 0, "MIXER: got POLLERR, POLLHUP or POLLNVAL");
+    return -1;
+  }
+  if(!(revents & POLLOUT))
+    return 0;
+
+  assert(x->tasks_.first_);
+  task_t* task = (task_t*)(x->tasks_.first_->data_);
+  assert(task);
+  assert(task->buf_);
+
+  int ret = snd_rawmidi_write(x->output_, &(task->buf_[task->write_idx_]), task->len_ - task->write_idx_);
+  if(ret == -EAGAIN)
+    return 0;
+  if(ret < 0) {
+    error(0, 0, "MIXER: cannot write to midi port: %s", snd_strerror(ret));
+    return -1;
+  }
+  task->write_idx_ += ret;
+  if(task->write_idx_ >= task->len_) {
+    if((err = snd_rawmidi_drain(x->output_)) < 0) {
+      error(0, 0, "MIXER: cannot drain output: %s", snd_strerror(err));
+      return -1;
+    }
+    if(task->done_cb_)
+      task->done_cb_(task->done_data_);
+
+    slist_remove(&(x->tasks_), task);
+  }
+
+  return 0;
+}
diff --git a/app/mixer.h b/app/mixer.h
new file mode 100644
index 0000000..5d9c666
--- /dev/null
+++ b/app/mixer.h
@@ -0,0 +1,61 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DOLMETSCHCTL_mixer_h_INCLUDED
+#define DOLMETSCHCTL_mixer_h_INCLUDED
+
+#include <alsa/asoundlib.h>
+#include <poll.h>
+
+#include "slist.h"
+
+typedef u_int8_t midi_cmd_t[3];
+
+typedef struct {
+  char* name_;
+  slist_t cmds_;
+} lang_t;
+
+typedef struct {
+  u_int8_t* buf_;
+  int len_;
+  int write_idx_;
+  void (*done_cb_)(void*);
+  void* done_data_;
+} task_t;
+
+typedef struct {
+  const char* name_;
+  snd_rawmidi_t* output_;
+  slist_t langs_;
+  slist_t tasks_;
+} mixer_t;
+
+int mixer_init(mixer_t* x, const char* name, const char* device);
+void mixer_print_langs(mixer_t* x);
+int mixer_switch_lang(mixer_t* x, const char* lang, void (*done_cb)(void*), void* done_data);
+void mixer_print_tasks(mixer_t* x);
+int mixer_get_poll_fd_count(mixer_t* x);
+int mixer_get_poll_fds(mixer_t* x, struct pollfd *pfds, int npfds);
+int mixer_handle_revents(mixer_t* x, struct pollfd *pfds, int npfds);
+
+#endif
diff --git a/app/osc_client.c b/app/osc_client.c
new file mode 100644
index 0000000..a70eb67
--- /dev/null
+++ b/app/osc_client.c
@@ -0,0 +1,123 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <error.h>
+#include <assert.h>
+
+#include "osc_client.h"
+#include "midi_client.h"
+
+
+static void print_error(int num, const char *msg, const char *path)
+{
+  error(0, 0, "liblo server error %d in path %s: %s", num, path, msg);
+}
+
+static int lang_handler(const char *path, const char *types, lo_arg ** argv,
+                    int argc, lo_message msg, void *user_data)
+{
+  osc_t* o = (osc_t*)user_data;
+  assert(o);
+
+  if(argc != 1 || !lo_is_string_type((lo_type)types[0]))
+    return 1;
+
+//  printf("got ack for: lang '%s'\n", &(argv[0]->s));
+  midi_enqueue_cmd((midi_t*)o->m_, &(argv[0]->s));
+
+  return 0;
+}
+
+int osc_init(osc_t* o, void* m, const char* host, const char* port)
+{
+  assert(o != NULL);
+
+  o->server_ = NULL;
+  o->target_ = lo_address_new(host, port);
+  o->m_ = m;
+
+  if(!port)
+    return 0;
+
+  o->server_ = lo_server_new(NULL, print_error);
+  if(!o->server_)
+    return -1;
+
+  if(!lo_server_add_method(o->server_, "/lang/ack", "s", lang_handler, (void*)o))
+    return -1;
+
+  return 0;
+}
+
+int osc_switch_lang(osc_t* o, const char* lang)
+{
+  lo_send_from(o->target_, o->server_, LO_TT_IMMEDIATE, "/lang/switch", "s", lang);
+  return 0;
+}
+
+int osc_get_poll_fd_count(osc_t* o)
+{
+  assert(o);
+
+  if(!o->server_)
+    return 0;
+
+  return 1;
+}
+
+int osc_get_poll_fds(osc_t* o, struct pollfd *pfds, int npfds)
+{
+  assert(o);
+
+  if(!o->server_)
+    return 0;
+
+  pfds[0].fd = lo_server_get_socket_fd(o->server_);
+  pfds[0].events = POLLIN;
+  pfds[0].revents = 0;
+
+  return 0;
+}
+
+int osc_handle_revents(osc_t* o, struct pollfd *pfds, int npfds)
+{
+  assert(o);
+
+  if(!o->server_)
+    return 0;
+
+  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
+    error(0, 0, "OSC: got POLLERR, POLLHUP or POLLNVAL");
+    return -1;
+  }
+  if(!(pfds[0].revents & POLLIN))
+    return 0;
+
+  lo_server_recv_noblock(o->server_, 0);
+
+  return 0;
+}
diff --git a/app/osc_client.h b/app/osc_client.h
new file mode 100644
index 0000000..9d1ad94
--- /dev/null
+++ b/app/osc_client.h
@@ -0,0 +1,41 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DOLMETSCHCTL_osc_h_INCLUDED
+#define DOLMETSCHCTL_osc_h_INCLUDED
+
+#include "lo/lo.h"
+#include <poll.h>
+
+typedef struct {
+  lo_server server_;
+  lo_address target_;
+  void* m_; // forward declarations of typedes are not possible -- this is a HACK! FIXME!!!
+} osc_t;
+
+int osc_init(osc_t* o, void* m, const char* host, const char* port);
+int osc_switch_lang(osc_t* o, const char* lang);
+int osc_get_poll_fd_count(osc_t* o);
+int osc_get_poll_fds(osc_t* o, struct pollfd *pfds, int npfds);
+int osc_handle_revents(osc_t* o, struct pollfd *pfds, int npfds);
+
+#endif
diff --git a/app/osc_server.c b/app/osc_server.c
new file mode 100644
index 0000000..223a192
--- /dev/null
+++ b/app/osc_server.c
@@ -0,0 +1,164 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <error.h>
+#include <assert.h>
+
+#include "osc_server.h"
+
+
+static void print_error(int num, const char *msg, const char *path)
+{
+  error(0, 0, "liblo server error %d in path %s: %s", num, path, msg);
+}
+
+static int lang_handler(const char *path, const char *types, lo_arg ** argv,
+                    int argc, lo_message msg, void *user_data)
+{
+  if(argc != 1 || !lo_is_string_type((lo_type)types[0]))
+    return 1;
+
+  lo_address from = lo_message_get_source(msg);
+  const char* host = lo_address_get_hostname(from);
+  const char* port = lo_address_get_port(from);
+  assert(host && port);
+
+  osc_t* o = (osc_t*)user_data;
+  assert(o);
+  osc_done_data_t* done_data = malloc(sizeof(osc_done_data_t));
+  assert(done_data);
+
+  done_data->self_ = o;
+  done_data->state_ = 0;
+  assert((done_data->lang_ = strdup(&(argv[0]->s))));
+  done_data->addr_ = lo_address_new(host, port);
+  assert(done_data->addr_);
+  done_data->msg_ = lo_message_new();
+  assert(done_data->msg_);
+  assert(!lo_message_add(done_data->msg_, "s", done_data->lang_));
+
+  assert(slist_add(&(o->done_data_), done_data));
+
+  return 0;
+}
+
+void free_osc_done_data(void* ptr)
+{
+  osc_done_data_t* done_data = (osc_done_data_t*)ptr;
+
+  lo_message_free(done_data->msg_);
+  lo_address_free(done_data->addr_);
+  free(done_data->lang_);
+  free(done_data);
+}
+
+void osc_lang_switch_done(void* data)
+{
+  assert(data);
+  osc_done_data_t* d = data;
+
+  lo_send_message_from(d->addr_, d->self_->server_, "/lang/ack", d->msg_);
+  slist_remove(&(d->self_->done_data_), d);
+}
+
+int osc_init(osc_t* o, const char* port)
+{
+  assert(o != NULL);
+
+  o->server_ = NULL;
+  slist_init(&(o->done_data_), free_osc_done_data);
+
+  if(!port)
+    return 0;
+
+  o->server_ = lo_server_new(port, print_error);
+  if(!o->server_)
+    return -1;
+
+  if(!lo_server_add_method(o->server_, "/lang/switch", "s", lang_handler, (void*)o))
+    return -1;
+
+  return 0;
+}
+
+
+int osc_get_poll_fd_count(osc_t* o)
+{
+  assert(o);
+
+  if(!o->server_)
+    return 0;
+
+  return 1;
+}
+
+int osc_get_poll_fds(osc_t* o, struct pollfd *pfds, int npfds)
+{
+  assert(o);
+
+  if(!o->server_)
+    return 0;
+
+  pfds[0].fd = lo_server_get_socket_fd(o->server_);
+  pfds[0].events = POLLIN;
+  pfds[0].revents = 0;
+
+  return 0;
+}
+
+int osc_handle_revents(osc_t* o, struct pollfd *pfds, int npfds, mixer_t* x)
+{
+  assert(o);
+
+  if(!o->server_)
+    return 0;
+
+  if(pfds[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
+    error(0, 0, "OSC: got POLLERR, POLLHUP or POLLNVAL");
+    return -1;
+  }
+  if(!(pfds[0].revents & POLLIN))
+    return 0;
+
+  lo_server_recv_noblock(o->server_, 0);
+
+  int ret = 0;
+  slist_element_t* tmp;
+  for(tmp = o->done_data_.first_; tmp; tmp = tmp->next_) {
+    osc_done_data_t* d = (osc_done_data_t*)(tmp->data_);
+    if(d->state_ == 0) {
+      ret = mixer_switch_lang(x, d->lang_, &osc_lang_switch_done, d);
+      if(ret)
+        break;
+
+      d->state_ = 1;
+    }
+  }
+
+
+  return ret;
+}
diff --git a/app/osc_server.h b/app/osc_server.h
new file mode 100644
index 0000000..40210b3
--- /dev/null
+++ b/app/osc_server.h
@@ -0,0 +1,50 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DOLMETSCHCTL_osc_h_INCLUDED
+#define DOLMETSCHCTL_osc_h_INCLUDED
+
+#include "lo/lo.h"
+#include <poll.h>
+
+#include "slist.h"
+#include "mixer.h"
+
+typedef struct {
+  lo_server server_;
+  slist_t done_data_;
+} osc_t;
+
+typedef struct {
+  osc_t* self_;
+  int state_;
+  char* lang_;
+  lo_address addr_;
+  lo_message msg_;
+} osc_done_data_t;
+
+int osc_init(osc_t* o, const char* port);
+int osc_get_poll_fd_count(osc_t* o);
+int osc_get_poll_fds(osc_t* o, struct pollfd *pfds, int npfds);
+int osc_handle_revents(osc_t* o, struct pollfd *pfds, int npfds, mixer_t* x);
+
+#endif
diff --git a/app/slist.c b/app/slist.c
new file mode 100644
index 0000000..b10aca7
--- /dev/null
+++ b/app/slist.c
@@ -0,0 +1,123 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "slist.h"
+
+slist_element_t* slist_get_last(slist_element_t* first)
+{
+  if(!first)
+    return NULL;
+
+  while(first->next_)
+    first = first->next_;
+
+  return first;
+}
+
+void slist_init(slist_t* lst, void (*delete_element)(void*))
+{
+  assert(lst && delete_element);
+
+  lst->delete_element = delete_element;
+  lst->first_ = NULL;
+}
+
+slist_element_t* slist_add(slist_t* lst, void* data)
+{
+  if(!lst || !data)
+    return NULL;
+
+  slist_element_t* new_element = malloc(sizeof(slist_element_t));
+  if(!new_element)
+    return NULL;
+
+  new_element->data_ = data;
+  new_element->next_ = NULL;
+
+  if(!lst->first_)
+    lst->first_ = new_element;
+  else
+    slist_get_last(lst->first_)->next_ = new_element;
+
+  return new_element;
+}
+
+void slist_remove(slist_t* lst, void* data)
+{
+  if(!lst || !lst->first_ || !data)
+    return;
+
+  slist_element_t* tmp = lst->first_->next_;
+  slist_element_t* prev = lst->first_;
+  if(lst->first_->data_ == data) {
+    lst->first_ = tmp;
+    lst->delete_element(prev->data_);
+    free(prev);
+  }
+  else {
+    while(tmp) {
+      if(tmp->data_ == data) {
+        prev->next_ = tmp->next_;
+        lst->delete_element(tmp->data_);
+        free(tmp);
+        return;
+      }
+      prev = tmp;
+      tmp = tmp->next_;
+    }
+  }
+}
+
+void slist_clear(slist_t* lst)
+{
+  if(!lst || !lst->first_)
+    return;
+
+  do {
+    slist_element_t* deletee = lst->first_;
+    lst->first_ = lst->first_->next_;
+    lst->delete_element(deletee->data_);
+    free(deletee);
+  }
+  while(lst->first_);
+
+  lst->first_ = NULL;
+}
+
+int slist_length(slist_t* lst)
+{
+  if(!lst || !lst->first_)
+    return 0;
+
+  int len = 0;
+  slist_element_t* tmp;
+  for(tmp = lst->first_; tmp; tmp = tmp->next_)
+    len++;
+
+  return len;
+}
diff --git a/app/slist.h b/app/slist.h
new file mode 100644
index 0000000..70a81b5
--- /dev/null
+++ b/app/slist.h
@@ -0,0 +1,46 @@
+/*
+ *  dolmetschctl
+ *
+ *
+ *  Copyright (C) 2015 Christian Pointner <equinox@spreadspace.org>
+ *
+ *  This file is part of dolmetschctl.
+ *
+ *  dolmetschctl 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
+ *  any later version.
+ *
+ *  dolmetschctl 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 dolmetschctl. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DOLMETSCHCTL_slist_h_INCLUDED
+#define DOLMETSCHCTL_slist_h_INCLUDED
+
+struct slist_element_struct {
+  void* data_;
+  struct slist_element_struct* next_;
+};
+typedef struct slist_element_struct slist_element_t;
+
+slist_element_t* slist_get_last(slist_element_t* first);
+
+struct slist_struct {
+  void (*delete_element)(void* element);
+  slist_element_t* first_;
+};
+typedef struct slist_struct slist_t;
+
+void slist_init(slist_t* lst, void (*delete_element)(void*));
+slist_element_t* slist_add(slist_t* lst, void* data);
+void slist_remove(slist_t* lst, void* data);
+void slist_clear(slist_t* lst);
+int slist_length(slist_t* lst);
+
+#endif