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