Added simple Python 3 example of library usage

2 files changed, 113 insertions, 0 deletions

diff --git a/examples/python-alsa/ReadMe.txt b/examples/python-alsa/ReadMe.txt
new file mode 100644
index 0000000..6ca3eff
--- /dev/null
+++ b/examples/python-alsa/ReadMe.txt
@@ -0,0 +1,7 @@
+Before to run this library, you must compile libADLMIDI shared library
+and then install pyalsaaudio package by PIP:
+
+===============================
+  sudo pip3 install alsaaudio
+===============================
+
diff --git a/examples/python-alsa/playmidi.py b/examples/python-alsa/playmidi.py
new file mode 100755
index 0000000..294ab16
--- /dev/null
+++ b/examples/python-alsa/playmidi.py
@@ -0,0 +1,106 @@
+#!/usr/bin/python3
+
+import sys
+import signal
+import wave
+import getopt
+import alsaaudio
+
+from ctypes import *
+
+# adl = CDLL("./libADLMIDI.so")
+adl = CDLL("/usr/local/lib/libADLMIDI.so")
+
+#class ADLMIDI_AudioFormat(Structure):
+#     _fields_ = [("type", c_int),
+#                 ("containerSize", c_uint),
+#                 ("outasampleOffset", c_uint)]
+
+playing = True
+
+# Allows to quit by Ctrl+C
+def catch_signal(signum, frame):
+    global playing
+    playing = False
+    print("Caught Ctrl+C!")
+
+def play(device, MIDIPlay, sampleRate):
+    global playing
+
+    # Opening ALSA output device
+    device = alsaaudio.PCM(device=device)
+
+    # Set attributes
+    device.setchannels(2)
+    device.setrate(sampleRate)
+    device.setperiodsize(512)
+
+    # format = ADLMIDI_AudioFormat(0, 2, 4);
+    device.setformat(alsaaudio.PCM_FORMAT_S16_LE)
+
+    # Preparing the audio output buffer
+    data = create_string_buffer(4096 * 2);
+    dataLen = 4096
+
+    print("Streaming...")
+
+    # Streaming the audio data into ALSA output
+    while playing:
+        got = adl.adl_play(MIDIPlay, dataLen, cast(data, POINTER(c_short)));
+        if got <= 0:
+            break;
+        device.write(bytearray(data.raw))
+
+    # Closing the audio output device
+    device.close()
+
+    print("Quiting...")
+
+
+def usage():
+    print('usage: playmidi.py <file>', file=sys.stderr)
+    sys.exit(2)
+
+if __name__ == '__main__':
+    device = 'default'
+    sampleRate = 44100
+
+    opts, args = getopt.getopt(sys.argv[1:], 'd:')
+    for o, a in opts:
+        if o == '-d':
+            device = a
+
+    if not args:
+        usage()
+
+    midiFile = args[0]
+
+    # Initialize the library
+    MIDIPlay = adl.adl_init(sampleRate)
+
+    # ============= Optional setup ====================
+    # Turn on looping (optionally)
+    # adl.adl_setLoopEnabled(MIDIPlay, 1)
+
+    # Changing the bank number (optionally)
+    # if adl.adl_setBank(MIDIPlay, 68) < 0:
+    #    print(c_char_p(adl.adl_errorInfo(MIDIPlay)).value)
+    #    sys.exit(1)
+    # ============= Optional setup =End================
+
+    # Open music file...
+    if adl.adl_openFile(MIDIPlay, midiFile.encode()) < 0:
+        print(c_char_p(adl.adl_errorInfo(MIDIPlay)).value)
+        sys.exit(1)
+
+    print("Playing MIDI file %s..." % (midiFile))
+
+    # Allows to quit by Ctrl+C
+    signal.signal(signal.SIGINT, catch_signal)
+
+    # Start the audio streaming
+    play(device, MIDIPlay, sampleRate)
+
+    # Closing the library
+    adl.adl_close(MIDIPlay)
+