python/midi.c

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2001--2010 Han-Wen Nienhuys <hanwen@xs4all.nl>
   5             Jan Nieuwenhuizen <janneke@gnu.org>
   6
   7
   8   LilyPond is free software: you can redistribute it and/or modify
   9   it under the terms of the GNU General Public License as published by
  10   the Free Software Foundation, either version 3 of the License, or
  11   (at your option) any later version.
  12
  13   LilyPond is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 /*
  23
  24 python
  25 import midi
  26 s = open ("s.midi").read ()
  27 midi.parse_track (s)
  28 midi.parse (s)
  29
  30
  31 returns a MIDI file as the tuple
  32
  33  ((format, division), TRACKLIST)
  34
  35 each track is an EVENTLIST, where EVENT is
  36
  37   (time, (type, ARG1, [ARG2]))
  38
  39 */
  40
  41 #include <Python.h>
  42
  43 char *
  44 compat_itoa (int i)
  45 {
  46   static char buffer[9];
  47   snprintf (buffer, 8, "%d", i);
  48   return buffer;
  49 }
  50
  51 /* PyMIDINIT_FUNC isn't defined in Python < 2.3 */
  52 #ifndef PyMODINIT_FUNC
  53 #       if defined(__cplusplus)
  54 #               define PyMODINIT_FUNC extern "C" void
  55 #       else /* __cplusplus */
  56 #               define PyMODINIT_FUNC void
  57 #       endif /* __cplusplus */
  58 #endif
  59
  60 #if 0
  61 int x = 0;
  62 int *track = &x;
  63 #define debug_print(f, args...) fprintf (stderr, "%s:%d: track: %p :" f, __FUNCTION__, __LINE__, *track, ##args)
  64 #else
  65 #define debug_print(f, args...)
  66 #endif
  67
  68 static PyObject *Midi_error;
  69 static PyObject *Midi_warning;
  70
  71 static PyObject *
  72 midi_error (char const *func, char *s, char *t)
  73 {
  74   char *dest = (char*) malloc (sizeof (char)
  75                                * (strlen (func) + strlen (s) + strlen (t) + 1));
  76   strcpy (dest, func);
  77   strcat (dest, s);
  78   strcat (dest, t);
  79   PyErr_SetString (Midi_error, dest);
  80   free (dest);
  81
  82   return 0;
  83 }
  84
  85 static PyObject *
  86 midi_warning (char const *s)
  87 {
  88   PyErr_SetString (Midi_warning, s);
  89   return 0;
  90 }
  91
  92
  93 typedef struct message {
  94   unsigned char msg;
  95   char * description;
  96 } message_t;
  97
  98 message_t channelVoiceMessages[] = {
  99   {0x80, "NOTE_OFF"},
 100   {0x90, "NOTE_ON"},
 101   {0xA0, "POLYPHONIC_KEY_PRESSURE"},
 102   {0xB0, "CONTROLLER_CHANGE"},
 103   {0xC0, "PROGRAM_CHANGE"},
 104   {0xD0, "CHANNEL_KEY_PRESSURE"},
 105   {0xE0, "PITCH_BEND"},
 106   {0,0}
 107 };
 108
 109 message_t channelModeMessages[] = {
 110   {0x78, "ALL_SOUND_OFF"},
 111   {0x79, "RESET_ALL_CONTROLLERS"},
 112   {0x7A, "LOCAL_CONTROL"},
 113   {0x7B, "ALL_NOTES_OFF"},
 114   {0x7C, "OMNI_MODE_OFF"},
 115   {0x7D, "OMNI_MODE_ON"},
 116   {0x7E, "MONO_MODE_ON"},
 117   {0x7F, "POLY_MODE_ON"},
 118   {0,0}
 119 };
 120
 121 message_t metaEvents[] = {
 122   {0x00, "SEQUENCE_NUMBER"},
 123   {0x01, "TEXT_EVENT"},
 124   {0x02, "COPYRIGHT_NOTICE"},
 125   {0x03, "SEQUENCE_TRACK_NAME"},
 126   {0x04, "INSTRUMENT_NAME"},
 127   {0x05, "LYRIC"},
 128   {0x06, "MARKER"},
 129   {0x07, "CUE_POINT"},
 130   {0x20, "MIDI_CHANNEL_PREFIX"},
 131   {0x21, "MIDI_PORT"},
 132   {0x2F, "END_OF_TRACK"},
 133   {0x51, "SET_TEMPO"},
 134   {0x54, "SMTPE_OFFSET"},
 135   {0x58, "TIME_SIGNATURE"},
 136   {0x59, "KEY_SIGNATURE"},
 137   {0x7F, "SEQUENCER_SPECIFIC_META_EVENT"},
 138   {0xFF, "META_EVENT"},
 139   {0,0}
 140 };
 141
 142 void
 143 add_constants (PyObject *dict)
 144 {
 145   message_t * p[] = {metaEvents, channelModeMessages, channelVoiceMessages ,0};
 146   int i,j;
 147   for ( j =0; p[j]; j++)
 148     for ( i = 0; p[j][i].description; i++)
 149       PyDict_SetItemString (dict, p[j][i].description, Py_BuildValue ("i", p[j][i].msg));
 150 }
 151
 152 unsigned long int
 153 get_number (unsigned char ** str, unsigned char * end_str, int length)
 154 {
 155   /* # MIDI uses big-endian for everything */
 156   long sum = 0;
 157   int i = 0;
 158
 159   for (; i < length &&
 160          ((*str) + i < end_str); i++)
 161     sum = (sum << 8) + (unsigned char) (*str)[i];
 162
 163   *str += length;
 164   debug_print ("%d:\n", sum);
 165   return sum;
 166 }
 167
 168 unsigned long int
 169 get_variable_length_number (unsigned char **str, unsigned char * end_str)
 170 {
 171   long sum = 0;
 172
 173   while (*str < end_str)
 174     {
 175       unsigned char x = **str;
 176       (*str) ++;
 177       sum = (sum << 7) + (x & 0x7F);
 178       if (!(x & 0x80))
 179         break;
 180     }
 181   debug_print ("%d:\n", sum);
 182   return sum;
 183 }
 184
 185 PyObject *
 186 read_one_byte (unsigned char **track, unsigned char *end,
 187                unsigned char x)
 188 {
 189   PyObject *pyev = Py_BuildValue ("(i)", x);
 190   debug_print ("%x:%s", x, "event\n");
 191
 192   return pyev;
 193 }
 194
 195 PyObject *
 196 read_two_bytes (unsigned char **track, unsigned char *end,
 197                 unsigned char x)
 198 {
 199   PyObject *pyev = Py_BuildValue ("(ii)", x, (*track)[0]);
 200   *track += 1;
 201   debug_print ("%x:%s", x, "event\n");
 202   return pyev;
 203 }
 204
 205 PyObject *
 206 read_three_bytes (unsigned char **track, unsigned char *end,
 207                   unsigned char x)
 208 {
 209   PyObject *pyev = Py_BuildValue ("(iii)", x, (*track)[0],
 210                                   (*track)[1]);
 211
 212   *track += 2;
 213   debug_print ("%x:%s", x, "event\n");
 214   return pyev;
 215 }
 216
 217 PyObject *
 218 read_string (unsigned char **track, unsigned char *end)
 219 {
 220   unsigned long length = get_variable_length_number (track, end);
 221   if (length > end - *track)
 222     length = end - *track;
 223
 224   *track += length;
 225   return Py_BuildValue ("s#", ((*track) -length), length);
 226 }
 227
 228 typedef PyObject* (*Read_midi_event)
 229   (unsigned char **track, unsigned char *end,
 230    unsigned char x);
 231
 232
 233 static PyObject *
 234 read_f0_byte (unsigned char **track, unsigned char *end,
 235               unsigned char x)
 236
 237 {
 238   debug_print ("%x:%s", x, "event\n");
 239   if (x == 0xff)
 240     {
 241       unsigned char z = (*track)[0 ];
 242       *track += 1;
 243       debug_print ("%x:%s", z, "f0-event\n");
 244
 245       return Py_BuildValue ("(iiO)", x, z, read_string (track, end));
 246     }
 247
 248   return Py_BuildValue ("(iO)", x, read_string (track, end));
 249 }
 250
 251 Read_midi_event read_midi_event [16] =
 252 {
 253   read_one_byte,  //  0
 254   read_one_byte,  // 10
 255   read_one_byte,  // 20
 256   read_one_byte,  // 30
 257   read_one_byte,  // 40
 258   read_one_byte,  // 50
 259   read_one_byte,  // 60 data entry.
 260   read_two_bytes, // 70 all notes off
 261   read_three_bytes, // 80 note off
 262   read_three_bytes, // 90 note on
 263   read_three_bytes, // a0 poly aftertouch
 264   read_three_bytes, // b0 control
 265   read_two_bytes,  // c0 prog change
 266   read_two_bytes, // d0 ch aftertouch
 267   read_three_bytes, // e0 pitchwheel range
 268   read_f0_byte,   // f0
 269 };
 270
 271
 272 static PyObject *
 273 read_event (unsigned char **track, unsigned char *end, PyObject *time,
 274             unsigned char *running_status)
 275 {
 276   int rsb_skip = ((**track & 0x80)) ? 1 :0;
 277
 278   unsigned char x = (rsb_skip) ? (*track)[0]: *running_status;
 279
 280   PyObject * bare_event = 0;
 281   debug_print ("%x:%s", x, "event\n");
 282   *running_status = x;
 283   *track += rsb_skip;
 284
 285   //  printf ("%x %x %d next %x\n", x, (*track)[0], rsb_skip, (*track)[1]);
 286   bare_event = (*read_midi_event[x >> 4]) (track, end, x);
 287   if (bare_event)
 288     return Py_BuildValue ("(OO)", time, bare_event);
 289   else
 290     return NULL;
 291 }
 292
 293 static PyObject *
 294 midi_parse_track (unsigned char **track, unsigned char *track_end)
 295 {
 296   unsigned int time = 0;
 297   unsigned long track_len, track_size;
 298   PyObject *pytrack = 0;
 299
 300   debug_print ("%s", "\n");
 301
 302   track_size = track_end - *track;
 303
 304   debug_print ("%s", "\n");
 305   if (memcmp (*track, "MTrk", 4))
 306     {
 307       *track[4] = 0;
 308       return midi_error (__FUNCTION__,  ": MTrk expected, got: ", *(char**)track);
 309     }
 310
 311   *track += 4;
 312
 313   track_len = get_number (track, *track + 4, 4);
 314
 315   debug_print ("track_len: %u\n", track_len);
 316   debug_print ("track_size: %u\n", track_size);
 317   debug_print ("track begin: %p\n", track);
 318   debug_print ("track end: %p\n", track + track_len);
 319
 320   if (track_len > track_size)
 321     return midi_error (__FUNCTION__,  ": track length corrupt: ", compat_itoa (track_len));
 322
 323   pytrack = PyList_New (0);
 324
 325   if (*track + track_len < track_end)
 326     track_end = *track + track_len;
 327
 328   {
 329     PyObject *pytime = PyInt_FromLong (0L);
 330     unsigned char running_status = 0;
 331
 332     while (*track < track_end)
 333       {
 334         long dt = get_variable_length_number(track, track_end);
 335         PyObject *pyev = 0;
 336
 337         time += dt;
 338         if (dt)
 339           pytime = PyInt_FromLong (time);
 340
 341         pyev = read_event (track, track_end, pytime,
 342                            &running_status);
 343         if (pyev)
 344           PyList_Append (pytrack, pyev);
 345       }
 346   }
 347
 348   *track = track_end;
 349   return pytrack;
 350 }
 351
 352
 353 static PyObject *
 354 pymidi_parse_track (PyObject *self, PyObject *args)
 355 {
 356   unsigned char *track, *track_end;
 357   unsigned long track_size;
 358
 359   debug_print ("%s", "\n");
 360   if (!PyArg_ParseTuple (args, "s#", &track, &track_size))
 361     return 0;
 362
 363   if (track_size < 0)
 364     return midi_error (__FUNCTION__,   ": negative track size: ", compat_itoa (track_size));
 365
 366   track_end = track + track_size;
 367
 368   return midi_parse_track (&track, track_end);
 369 }
 370
 371 static PyObject *
 372 midi_parse (unsigned char **midi,unsigned  char *midi_end)
 373 {
 374   PyObject *pymidi = 0;
 375   unsigned long header_len;
 376   unsigned format, tracks;
 377   int division;
 378   int i;
 379
 380   debug_print ("%s", "\n");
 381
 382   /* Header */
 383   header_len = get_number (midi, *midi + 4, 4);
 384
 385   if (header_len < 6)
 386     return midi_error (__FUNCTION__,  ": header too short: ", compat_itoa (header_len));
 387
 388   format = get_number (midi, *midi + 2, 2);
 389   tracks = get_number (midi, *midi + 2, 2);
 390
 391   if (tracks > 32)
 392     return midi_error (__FUNCTION__,  ": too many tracks: ", compat_itoa (tracks));
 393
 394   division = get_number (midi, *midi + 2, 2) * 4;
 395
 396
 397   if (division < 0)
 398     /* return midi_error (cannot handle non-metrical time"); */
 399     ;
 400   *midi += header_len - 6;
 401
 402   pymidi = PyList_New (0);
 403
 404   /* Tracks */
 405   for (i = 0; i < tracks; i++)
 406     PyList_Append (pymidi, midi_parse_track (midi, midi_end));
 407
 408   pymidi = Py_BuildValue ("(OO)", Py_BuildValue ("(ii)", format, division),
 409                           pymidi);
 410   return pymidi;
 411 }
 412
 413 static PyObject *
 414 pymidi_parse (PyObject *self, PyObject *args)
 415 {
 416   unsigned char *midi, *midi_end;
 417   unsigned long midi_size;
 418
 419   debug_print ("%s", "\n");
 420   if (!PyArg_ParseTuple (args, "s#", &midi, &midi_size))
 421     return 0;
 422
 423   if (memcmp (midi, "MThd", 4))
 424     {
 425       midi[4] = 0;
 426       return midi_error (__FUNCTION__,  ": MThd expected, got: ", (char*)midi);
 427     }
 428
 429   midi += 4;
 430
 431   midi_end = midi + midi_size;
 432
 433   return midi_parse (&midi, midi_end);
 434 }
 435
 436
 437 static PyMethodDef MidiMethods[] =
 438 {
 439   {"parse",  pymidi_parse, 1},
 440   {"parse_track",  pymidi_parse_track, 1},
 441   {0, 0}        /* Sentinel */
 442 };
 443
 444 PyMODINIT_FUNC
 445 initmidi (void)
 446 {
 447   PyObject *m, *d;
 448   m = Py_InitModule ("midi", MidiMethods);
 449   d = PyModule_GetDict (m);
 450
 451   Midi_error = PyString_FromString ("midi.error");
 452   PyDict_SetItemString (d, "error", Midi_error);
 453   add_constants (d);
 454   Midi_warning = PyString_FromString ("midi.warning");
 455   PyDict_SetItemString (d, "warning", Midi_warning);
 456
 457   /*
 458     FIXME.
 459    */
 460   (void) midi_warning;
 461 }
 462