2 midi.c -- implement Python midi parser module
4 source file of the GNU LilyPond music typesetter
6 (c) 2001--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
7 Jan Nieuwenhuizen <janneke@gnu.org>
15 s = open ("s.midi").read ()
23 /* PyMIDINIT_FUNC isn't defined in Python < 2.3 */
24 #ifndef PyMODINIT_FUNC
25 # if defined(__cplusplus)
26 # define PyMODINIT_FUNC extern "C" void
27 # else /* __cplusplus */
28 # define PyMODINIT_FUNC void
29 # endif /* __cplusplus */
35 #define debug_print(f, args...) fprintf (stderr, "%s:%d: track: %p :" f, __FUNCTION__, __LINE__, *track, ##args)
37 #define debug_print(f, args...)
40 static PyObject *Midi_error;
41 static PyObject *Midi_warning;
44 midi_error (char const *func, char *s)
46 char *dest = (char*) malloc (sizeof (char) * (strlen (func) + strlen (s) + 1));
49 PyErr_SetString (Midi_error, dest);
56 midi_warning (char const *s)
58 PyErr_SetString (Midi_warning, s);
63 typedef struct message {
68 message_t channelVoiceMessages[] = {
71 0xA0, "POLYPHONIC_KEY_PRESSURE",
72 0xB0, "CONTROLLER_CHANGE",
73 0xC0, "PROGRAM_CHANGE",
74 0xD0, "CHANNEL_KEY_PRESSURE",
79 message_t channelModeMessages[] = {
80 0x78, "ALL_SOUND_OFF",
81 0x79, "RESET_ALL_CONTROLLERS",
82 0x7A, "LOCAL_CONTROL",
83 0x7B, "ALL_NOTES_OFF",
84 0x7C, "OMNI_MODE_OFF",
91 message_t metaEvents[] = {
92 0x00, "SEQUENCE_NUMBER",
94 0x02, "COPYRIGHT_NOTICE",
95 0x03, "SEQUENCE_TRACK_NAME",
96 0x04, "INSTRUMENT_NAME",
100 0x20, "MIDI_CHANNEL_PREFIX",
102 0x2F, "END_OF_TRACK",
104 0x54, "SMTPE_OFFSET",
105 0x58, "TIME_SIGNATURE",
106 0x59, "KEY_SIGNATURE",
107 0x7F, "SEQUENCER_SPECIFIC_META_EVENT",
113 add_constants (PyObject *dict)
115 message_t * p[] = {metaEvents, channelModeMessages, channelVoiceMessages ,0};
117 for ( j =0; p[j]; j++)
118 for ( i = 0; p[j][i].description; i++)
119 PyDict_SetItemString (dict, p[j][i].description, Py_BuildValue ("i", p[j][i].msg));
123 get_number (unsigned char ** str, unsigned char * end_str, int length)
125 /* # MIDI uses big-endian for everything */
129 for (; i < length; i++)
130 sum = (sum << 8) + (unsigned char) (*str)[i];
133 debug_print ("%d:\n", sum);
138 get_variable_length_number (unsigned char **str, unsigned char * end_str)
142 while (*str < end_str)
144 unsigned char x = **str;
146 sum = (sum << 7) + (x & 0x7F);
150 debug_print ("%d:\n", sum);
155 read_one_byte (unsigned char **track, unsigned char *end,
158 PyObject *pyev = Py_BuildValue ("(i)", x);
159 debug_print ("%x:%s", x, "event\n");
165 read_two_bytes (unsigned char **track, unsigned char *end,
168 PyObject *pyev = Py_BuildValue ("(ii)", x, (*track)[0]);
170 debug_print ("%x:%s", x, "event\n");
175 read_three_bytes (unsigned char **track, unsigned char *end,
178 PyObject *pyev = Py_BuildValue ("(iii)", x, (*track)[0],
182 debug_print ("%x:%s", x, "event\n");
187 read_string (unsigned char **track, unsigned char *end)
189 unsigned long length = get_variable_length_number (track, end);
190 if (length > end - *track)
191 length = end - *track;
194 return Py_BuildValue ("s#", ((*track) -length), length);
197 typedef PyObject* (*Read_midi_event)
198 (unsigned char **track, unsigned char *end,
203 read_f0_byte (unsigned char **track, unsigned char *end,
207 debug_print ("%x:%s", x, "event\n");
210 unsigned char z = (*track)[0 ];
212 debug_print ("%x:%s", z, "f0-event\n");
214 return Py_BuildValue ("(iiO)", x, z, read_string (track, end));
217 return Py_BuildValue ("(iO)", x, read_string (track, end));
220 Read_midi_event read_midi_event [16] =
228 read_one_byte, // 60 data entry.
229 read_two_bytes, // 70 all notes off
230 read_three_bytes, // 80 note off
231 read_three_bytes, // 90 note on
232 read_three_bytes, // a0 poly aftertouch
233 read_three_bytes, // b0 control
234 read_two_bytes, // c0 prog change
235 read_two_bytes, // d0 ch aftertouch
236 read_three_bytes, // e0 pitchwheel range
242 read_event (unsigned char **track, unsigned char *end, PyObject *time,
243 unsigned char *running_status)
245 int rsb_skip = ((**track & 0x80)) ? 1 :0;
247 unsigned char x = (rsb_skip) ? (*track)[0]: *running_status;
249 PyObject * bare_event = 0;
250 debug_print ("%x:%s", x, "event\n");
254 // printf ("%x %x %d next %x\n", x, (*track)[0], rsb_skip, (*track)[1]);
255 bare_event = (*read_midi_event[x >> 4]) (track, end, x);
257 return Py_BuildValue ("(OO)", time, bare_event);
263 midi_parse_track (unsigned char **track, unsigned char *track_end)
265 unsigned int time = 0;
266 unsigned char running_status;
267 unsigned long track_len, track_size;
268 PyObject *pytrack = 0;
270 debug_print ("%s", "\n");
272 track_size = track_end - *track;
274 debug_print ("%s", "\n");
275 if (strcmp (*track, "MTrk"))
276 return midi_error (__FUNCTION__, ": MTrk expected");
280 track_len = get_number (track, *track + 4, 4);
283 debug_print ("track_len: %u\n", track_len);
284 debug_print ("track_size: %u\n", track_size);
285 debug_print ("track begin: %p\n", track);
286 debug_print ("track end: %p\n", track + track_len);
288 if (track_len > track_size)
289 return midi_error (__FUNCTION__, ": track size corrupt");
291 pytrack = PyList_New (0);
293 track_end = *track + track_len;
296 PyObject *pytime = PyInt_FromLong (0L);
297 while (*track < track_end)
299 long dt = get_variable_length_number(track, track_end);
304 pytime = PyInt_FromLong (time);
306 pyev = read_event (track, track_end, pytime,
309 PyList_Append (pytrack, pyev);
319 pymidi_parse_track (PyObject *self, PyObject *args)
321 unsigned char *track, *track_end;
322 unsigned long track_size, track_len;
324 PyObject * sobj = PyTuple_GetItem (args, 0);
326 debug_print ("%s", "\n");
327 if (!PyArg_ParseTuple (args, "s#", &track, &track_size))
331 return midi_error (__FUNCTION__, ": negative track size");
333 track_end = track + track_size;
335 return midi_parse_track (&track, track_end);
339 midi_parse (unsigned char **midi,unsigned char *midi_end)
341 PyObject *pymidi = 0;
342 unsigned long header_len;
343 unsigned format, tracks;
347 debug_print ("%s", "\n");
350 header_len = get_number (midi, *midi + 4, 4);
354 return midi_error (__FUNCTION__, ": header too short");
356 format = get_number (midi, *midi + 2, 2);
357 tracks = get_number (midi, *midi + 2, 2);
360 return midi_error (__FUNCTION__, ": too many tracks");
362 division = get_number (midi, *midi + 2, 2) * 4;
366 /* return midi_error ("can't handle non-metrical time"); */
368 *midi += header_len - 6;
370 pymidi = PyList_New (0);
373 for (i = 0; i < tracks; i++)
374 PyList_Append (pymidi, midi_parse_track (midi, midi_end));
376 pymidi = Py_BuildValue ("(OO)", Py_BuildValue ("(ii)", format, division),
382 pymidi_parse (PyObject *self, PyObject *args)
384 unsigned char *midi, *midi_end;
385 unsigned long midi_size, midi_len;
387 PyObject *sobj = PyTuple_GetItem (args, 0);
389 debug_print ("%s", "\n");
390 if (!PyArg_ParseTuple (args, "s#", &midi, &midi_size))
393 if (strcmp (midi, "MThd"))
394 return midi_error (__FUNCTION__, ": MThd expected");
398 midi_end = midi + midi_size;
400 return midi_parse (&midi, midi_end);
404 static PyMethodDef MidiMethods[] =
406 {"parse", pymidi_parse, 1},
407 {"parse_track", pymidi_parse_track, 1},
408 {0, 0} /* Sentinel */
415 m = Py_InitModule ("midi", MidiMethods);
416 d = PyModule_GetDict (m);
418 Midi_error = PyString_FromString ("midi.error");
419 PyDict_SetItemString (d, "error", Midi_error);
421 Midi_warning = PyString_FromString ("midi.warning");
422 PyDict_SetItemString (d, "warning", Midi_warning);