2 midi.c -- implement Python midi parser module
4 source file of the GNU LilyPond music typesetter
6 (c) 2001 Han-Wen Nienhuys <hanwen@cs.uu.nl>
7 Jan Nieuwenhuizen <janneke@gnu.org>
15 s = open ("s.midi").read ()
24 #if HAVE_PYTHON2_PYTHON_H
25 #include <python2/Python.h>
26 #elif HAVE_PYTHON2_0_PYTHON_H
27 #include <python2.0/Python.h>
28 #elif HAVE_PYTHON1_5_PYTHON_H
29 #include <python1.5/Python.h>
30 #elif HAVE_PYTHON_PYTHON_H
32 #include <python/Python.h>
43 #define debug_print(f, args...) fprintf (stderr, "%s:%d: track: %p :" f, __FUNCTION__, __LINE__, *track, ##args)
45 #define debug_print(f, args...)
48 static PyObject *Midi_error;
49 static PyObject *Midi_warning;
54 PyErr_SetString (Midi_error, s);
59 midi_warning (char *s)
61 PyErr_SetString (Midi_warning, s);
66 typedef struct message {
71 message_t channelVoiceMessages[] = {
74 0xA0, "POLYPHONIC_KEY_PRESSURE",
75 0xB0, "CONTROLLER_CHANGE",
76 0xC0, "PROGRAM_CHANGE",
77 0xD0, "CHANNEL_KEY_PRESSURE",
82 message_t channelModeMessages[] = {
83 0x78, "ALL_SOUND_OFF",
84 0x79, "RESET_ALL_CONTROLLERS",
85 0x7A, "LOCAL_CONTROL",
86 0x7B, "ALL_NOTES_OFF",
87 0x7C, "OMNI_MODE_OFF",
94 message_t metaEvents[] = {
95 0x00, "SEQUENCE_NUMBER",
97 0x02, "COPYRIGHT_NOTICE",
98 0x03, "SEQUENCE_TRACK_NAME",
99 0x04, "INSTRUMENT_NAME",
103 0x20, "MIDI_CHANNEL_PREFIX",
105 0x2F, "END_OF_TRACK",
107 0x54, "SMTPE_OFFSET",
108 0x58, "TIME_SIGNATURE",
109 0x59, "KEY_SIGNATURE",
110 0x7F, "SEQUENCER_SPECIFIC_META_EVENT",
116 add_constants (PyObject *dict)
118 message_t * p[] = {metaEvents, channelModeMessages, channelVoiceMessages ,0};
120 for ( j =0; p[j]; j++)
121 for ( i = 0; p[j][i].description; i++)
122 PyDict_SetItemString (dict, p[j][i].description, Py_BuildValue ("i", p[j][i].msg));
126 get_number (unsigned char ** str, unsigned char * end_str, int length)
128 /* # MIDI uses big-endian for everything */
132 for (; i < length; i++)
133 sum = (sum << 8) + (unsigned char) (*str)[i];
136 debug_print ("%d:\n", sum);
141 get_variable_length_number (unsigned char **str, unsigned char * end_str)
145 while (*str < end_str)
147 unsigned char x = **str;
149 sum = (sum << 7) + (x & 0x7F);
153 debug_print ("%d:\n", sum);
158 read_one_byte (unsigned char **track, unsigned char *end,
161 PyObject *pyev = Py_BuildValue ("(i)", x);
162 debug_print ("%x:%s", x, "event\n");
168 read_two_bytes (unsigned char **track, unsigned char *end,
171 PyObject *pyev = Py_BuildValue ("(ii)", x, (*track)[0]);
173 debug_print ("%x:%s", x, "event\n");
178 read_three_bytes (unsigned char **track, unsigned char *end,
181 PyObject *pyev = Py_BuildValue ("(iii)", x, (*track)[0],
185 debug_print ("%x:%s", x, "event\n");
190 read_string (unsigned char **track, unsigned char *end)
192 unsigned long length = get_variable_length_number (track, end);
193 if (length > end - *track)
194 length = end - *track;
197 return Py_BuildValue ("s", ((*track) -length));
200 typedef PyObject* (*Read_midi_event)
201 (unsigned char **track, unsigned char *end,
206 read_f0_byte (unsigned char **track, unsigned char *end,
210 debug_print ("%x:%s", x, "event\n");
213 unsigned char z = (*track)[0 ];
215 debug_print ("%x:%s", z, "f0-event\n");
217 if (z == 0x2f && (*track)[0] == 0x00) /* end of track */
223 return Py_BuildValue ("(iiO)", x, z, read_string (track, end));
226 return Py_BuildValue ("(iO)", x, read_string (track, end));
229 Read_midi_event read_midi_event [16] =
237 read_one_byte, // 60 data entry.
238 read_two_bytes, // 70 all notes off
239 read_three_bytes, // 80 note off
240 read_three_bytes, // 90 note on
241 read_three_bytes, // a0 poly aftertouch
242 read_three_bytes, // b0 control
243 read_two_bytes, // c0 prog change
244 read_two_bytes, // d0 ch aftertouch
245 read_three_bytes, // e0 pitchwheel range
251 read_event (unsigned char **track, unsigned char *end, PyObject *time,
252 unsigned char *running_status)
254 int rsb_skip = ((**track & 0x80)) ? 1 :0;
256 unsigned char x = (rsb_skip) ? (*track)[0]: *running_status;
258 PyObject * bare_event = 0;
259 debug_print ("%x:%s", x, "event\n");
263 // printf ("%x %x %d next %x\n", x, (*track)[0], rsb_skip, (*track)[1]);
264 bare_event = (*read_midi_event[x >> 4]) (track, end, x);
266 return Py_BuildValue ("(OO)", time, bare_event);
272 midi_parse_track (unsigned char **track, unsigned char *track_end)
274 unsigned int time = 0;
275 unsigned char running_status;
276 unsigned long track_len, track_size;
277 PyObject *pytrack = 0;
279 debug_print ("%s", "\n");
281 track_size = track_end - *track;
283 debug_print ("%s", "\n");
284 if (strcmp (*track, "MTrk"))
285 return midi_error (__FUNCTION__ ": MTrk expected");
289 track_len = get_number (track, *track + 4, 4);
292 debug_print ("track_len: %u\n", track_len);
293 debug_print ("track_size: %u\n", track_size);
294 debug_print ("track begin: %p\n", track);
295 debug_print ("track end: %p\n", track + track_len);
297 if (track_len > track_size)
298 return midi_error (__FUNCTION__ ": track size corrupt");
300 pytrack = PyList_New (0);
302 track_end = *track + track_len;
305 PyObject *pytime = PyInt_FromLong (0L);
306 while (*track < track_end)
308 long dt = get_variable_length_number(track, track_end);
313 pytime = PyInt_FromLong (time);
315 pyev = read_event (track, track_end, pytime,
318 PyList_Append (pytrack, pyev);
328 pymidi_parse_track (PyObject *self, PyObject *args)
330 unsigned char *track, *track_end;
331 unsigned long track_size, track_len;
333 PyObject * sobj = PyTuple_GetItem (args, 0);
335 debug_print ("%s", "\n");
336 if (!PyArg_ParseTuple (args, "s#", &track, &track_size))
340 return midi_error (__FUNCTION__ ": negative track size");
342 track_end = track + track_size;
344 return midi_parse_track (&track, track_end);
348 midi_parse (unsigned char **midi,unsigned char *midi_end)
350 PyObject *pymidi = 0;
351 unsigned long header_len;
352 unsigned format, tracks;
356 debug_print ("%s", "\n");
359 header_len = get_number (midi, *midi + 4, 4);
363 return midi_error (__FUNCTION__ ": header too short");
365 format = get_number (midi, *midi + 2, 2);
366 tracks = get_number (midi, *midi + 2, 2);
369 return midi_error (__FUNCTION__ ": too many tracks");
371 division = get_number (midi, *midi + 2, 2) * 4;
375 /* return midi_error ("can't handle non-metrical time"); */
377 *midi += header_len - 6;
379 pymidi = PyList_New (0);
382 for (i = 0; i < tracks; i++)
383 PyList_Append (pymidi, midi_parse_track (midi, midi_end));
385 pymidi = Py_BuildValue ("(OO)", Py_BuildValue ("(ii)", format, division),
391 pymidi_parse (PyObject *self, PyObject *args)
393 unsigned char *midi, *midi_end;
394 unsigned long midi_size, midi_len;
396 PyObject *sobj = PyTuple_GetItem (args, 0);
398 debug_print ("%s", "\n");
399 if (!PyArg_ParseTuple (args, "s#", &midi, &midi_size))
402 if (strcmp (midi, "MThd"))
403 return midi_error (__FUNCTION__ ": MThd expected");
407 midi_end = midi + midi_size;
409 return midi_parse (&midi, midi_end);
413 static PyMethodDef MidiMethods[] =
415 {"parse", pymidi_parse, 1},
416 {"parse_track", pymidi_parse_track, 1},
417 {0, 0} /* Sentinel */
423 m = Py_InitModule ("midi", MidiMethods);
424 d = PyModule_GetDict (m);
426 Midi_error = PyString_FromString ("midi.error");
427 PyDict_SetItemString (d, "error", Midi_error);
429 Midi_warning = PyString_FromString ("midi.warning");
430 PyDict_SetItemString (d, "warning", Midi_warning);