python/midi.c

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2001--2011 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 urg_debug_print(f, args...) fprintf (stderr, "%s:%d: track: %p: " f, __FUNCTION__, __LINE__, *track, ##args)
  64 #define debug_print(f, args...) fprintf (stderr, f, ##args)
  65 #else
  66 #define debug_print(f, args...)
  67 #endif
  68
  69 static PyObject *Midi_error;
  70 static PyObject *Midi_warning;
  71
  72 static PyObject *
  73 midi_error (char const *func, char *s, char *t)
  74 {
  75   char *dest = (char*) malloc (sizeof (char)
  76                                * (strlen (func) + strlen (s) + strlen (t) + 1));
  77   strcpy (dest, func);
  78   strcat (dest, s);
  79   strcat (dest, t);
  80   PyErr_SetString (Midi_error, dest);
  81   free (dest);
  82
  83   return 0;
  84 }
  85
  86 static PyObject *
  87 midi_warning (char const *s)
  88 {
  89   PyErr_SetString (Midi_warning, s);
  90   return 0;
  91 }
  92
  93
  94 typedef struct message {
  95   unsigned char msg;
  96   char * description;
  97 } message_t;
  98
  99 message_t channelVoiceMessages[] = {
 100   {0x80, "NOTE_OFF"},
 101   {0x90, "NOTE_ON"},
 102   {0xA0, "POLYPHONIC_KEY_PRESSURE"},
 103   {0xB0, "CONTROLLER_CHANGE"},
 104   {0xC0, "PROGRAM_CHANGE"},
 105   {0xD0, "CHANNEL_KEY_PRESSURE"},
 106   {0xE0, "PITCH_BEND"},
 107   {0,0}
 108 };
 109
 110 message_t channelModeMessages[] = {
 111   {0x78, "ALL_SOUND_OFF"},
 112   {0x79, "RESET_ALL_CONTROLLERS"},
 113   {0x7A, "LOCAL_CONTROL"},
 114   {0x7B, "ALL_NOTES_OFF"},
 115   {0x7C, "OMNI_MODE_OFF"},
 116   {0x7D, "OMNI_MODE_ON"},
 117   {0x7E, "MONO_MODE_ON"},
 118   {0x7F, "POLY_MODE_ON"},
 119   {0,0}
 120 };
 121
 122 message_t metaEvents[] = {
 123   {0x00, "SEQUENCE_NUMBER"},
 124   {0x01, "TEXT_EVENT"},
 125   {0x02, "COPYRIGHT_NOTICE"},
 126   {0x03, "SEQUENCE_TRACK_NAME"},
 127   {0x04, "INSTRUMENT_NAME"},
 128   {0x05, "LYRIC"},
 129   {0x06, "MARKER"},
 130   {0x07, "CUE_POINT"},
 131   {0x20, "MIDI_CHANNEL_PREFIX"},
 132   {0x21, "MIDI_PORT"},
 133   {0x2F, "END_OF_TRACK"},
 134   {0x51, "SET_TEMPO"},
 135   {0x54, "SMTPE_OFFSET"},
 136   {0x58, "TIME_SIGNATURE"},
 137   {0x59, "KEY_SIGNATURE"},
 138   {0x7F, "SEQUENCER_SPECIFIC_META_EVENT"},
 139   {0xFF, "META_EVENT"},
 140   {0,0}
 141 };
 142
 143 void
 144 add_constants (PyObject *dict)
 145 {
 146   message_t * p[] = {metaEvents, channelModeMessages, channelVoiceMessages ,0};
 147   int i,j;
 148   for ( j =0; p[j]; j++)
 149     for ( i = 0; p[j][i].description; i++)
 150       PyDict_SetItemString (dict, p[j][i].description, Py_BuildValue ("i", p[j][i].msg));
 151 }
 152
 153 unsigned long int
 154 get_number (unsigned char ** str, unsigned char * end_str, int length)
 155 {
 156   /* # MIDI uses big-endian for everything */
 157   long sum = 0;
 158   int i = 0;
 159
 160   for (; i < length &&
 161          ((*str) + i < end_str); i++)
 162     sum = (sum << 8) + (unsigned char) (*str)[i];
 163
 164   *str += length;
 165   debug_print ("%ld:\n", sum);
 166   return sum;
 167 }
 168
 169 unsigned long int
 170 get_variable_length_number (unsigned char **str, unsigned char * end_str)
 171 {
 172   long sum = 0;
 173
 174   while (*str < end_str)
 175     {
 176       unsigned char x = **str;
 177       (*str) ++;
 178       sum = (sum << 7) + (x & 0x7F);
 179       if (!(x & 0x80))
 180         break;
 181     }
 182   debug_print ("%ld:\n", sum);
 183   return sum;
 184 }
 185
 186 PyObject *
 187 read_one_byte (unsigned char **track, unsigned char *end,
 188                unsigned char x)
 189 {
 190   PyObject *pyev = Py_BuildValue ("(i)", x);
 191   debug_print ("%x:%s", x, "event\n");
 192
 193   return pyev;
 194 }
 195
 196 PyObject *
 197 read_two_bytes (unsigned char **track, unsigned char *end,
 198                 unsigned char x)
 199 {
 200   PyObject *pyev = Py_BuildValue ("(ii)", x, (*track)[0]);
 201   *track += 1;
 202   debug_print ("%x:%s", x, "event\n");
 203   return pyev;
 204 }
 205
 206 PyObject *
 207 read_three_bytes (unsigned char **track, unsigned char *end,
 208                   unsigned char x)
 209 {
 210   PyObject *pyev = Py_BuildValue ("(iii)", x, (*track)[0],
 211                                   (*track)[1]);
 212
 213   *track += 2;
 214   debug_print ("%x:%s", x, "event\n");
 215   return pyev;
 216 }
 217
 218 PyObject *
 219 read_string (unsigned char **track, unsigned char *end)
 220 {
 221   unsigned long length = get_variable_length_number (track, end);
 222   if (length > end - *track)
 223     length = end - *track;
 224
 225   *track += length;
 226   return Py_BuildValue ("s#", ((*track) -length), length);
 227 }
 228
 229 typedef PyObject* (*Read_midi_event)
 230   (unsigned char **track, unsigned char *end,
 231    unsigned char x);
 232
 233
 234 static PyObject *
 235 read_f0_byte (unsigned char **track, unsigned char *end,
 236               unsigned char x)
 237
 238 {
 239   debug_print ("%x:%s", x, "event\n");
 240   if (x == 0xff)
 241     {
 242       unsigned char z = (*track)[0 ];
 243       *track += 1;
 244       debug_print ("%x:%s", z, "f0-event\n");
 245
 246       return Py_BuildValue ("(iiO)", x, z, read_string (track, end));
 247     }
 248
 249   return Py_BuildValue ("(iO)", x, read_string (track, end));
 250 }
 251
 252 Read_midi_event read_midi_event [16] =
 253 {
 254   read_one_byte,  //  0
 255   read_one_byte,  // 10
 256   read_one_byte,  // 20
 257   read_one_byte,  // 30
 258   read_one_byte,  // 40
 259   read_one_byte,  // 50
 260   read_one_byte,  // 60 data entry.
 261   read_two_bytes, // 70 all notes off
 262   read_three_bytes, // 80 note off
 263   read_three_bytes, // 90 note on
 264   read_three_bytes, // a0 poly aftertouch
 265   read_three_bytes, // b0 control
 266   read_two_bytes,  // c0 prog change
 267   read_two_bytes, // d0 ch aftertouch
 268   read_three_bytes, // e0 pitchwheel range
 269   read_f0_byte,   // f0
 270 };
 271
 272
 273 static PyObject *
 274 read_event (unsigned char **track, unsigned char *end, PyObject *time,
 275             unsigned char *running_status)
 276 {
 277   int rsb_skip = ((**track & 0x80)) ? 1 :0;
 278
 279   unsigned char x = (rsb_skip) ? (*track)[0]: *running_status;
 280
 281   PyObject * bare_event = 0;
 282   debug_print ("%x:%s", x, "event\n");
 283   *running_status = x;
 284   *track += rsb_skip;
 285
 286   //  printf ("%x %x %d next %x\n", x, (*track)[0], rsb_skip, (*track)[1]);
 287   bare_event = (*read_midi_event[x >> 4]) (track, end, x);
 288   if (bare_event)
 289     return Py_BuildValue ("(OO)", time, bare_event);
 290   else
 291     return NULL;
 292 }
 293
 294 static PyObject *
 295 midi_parse_track (unsigned char **track, unsigned char *track_end, int clocks_max)
 296 {
 297   unsigned int time = 0;
 298   unsigned long track_len, track_size;
 299   PyObject *pytrack = 0;
 300
 301   debug_print ("%s", "\n");
 302
 303   track_size = track_end - *track;
 304
 305   debug_print ("%s", "\n");
 306   if (memcmp (*track, "MTrk", 4))
 307     {
 308       *track[4] = 0;
 309       return midi_error (__FUNCTION__,  ": MTrk expected, got: ", *(char**)track);
 310     }
 311
 312   *track += 4;
 313
 314   track_len = get_number (track, *track + 4, 4);
 315
 316   debug_print ("track_len: %lu\n", track_len);
 317   debug_print ("track_size: %lu\n", track_size);
 318   debug_print ("track begin: %p\n", track);
 319   debug_print ("track end: %p\n", track + track_len);
 320
 321   if (track_len > track_size)
 322     return midi_error (__FUNCTION__,  ": track length corrupt: ", compat_itoa (track_len));
 323
 324   pytrack = PyList_New (0);
 325
 326   if (*track + track_len < track_end)
 327     track_end = *track + track_len;
 328
 329   {
 330     PyObject *pytime = PyInt_FromLong (0L);
 331     unsigned char running_status = 0;
 332
 333     while (*track < track_end)
 334       {
 335         long dt = get_variable_length_number(track, track_end);
 336         PyObject *pyev = 0;
 337
 338         time += dt;
 339         if (dt)
 340           pytime = PyInt_FromLong (time);
 341         if (clocks_max && time > clocks_max)
 342           break;
 343         pyev = read_event (track, track_end, pytime,
 344                            &running_status);
 345         if (pyev)
 346           PyList_Append (pytrack, pyev);
 347       }
 348   }
 349
 350   *track = track_end;
 351   return pytrack;
 352 }
 353
 354
 355 static PyObject *
 356 pymidi_parse_track (PyObject *self, PyObject *args)
 357 {
 358   unsigned char *track, *track_end;
 359   unsigned long track_size;
 360   int clocks_max;
 361
 362   debug_print ("%s", "\n");
 363   if (!PyArg_ParseTuple (args, "s#|i", &track, &track_size, &clocks_max))
 364     return 0;
 365   debug_print ("clocks_max: %d\n", clocks_max);
 366
 367   if (track_size < 0)
 368     return midi_error (__FUNCTION__,   ": negative track size: ", compat_itoa (track_size));
 369
 370   track_end = track + track_size;
 371
 372   return midi_parse_track (&track, track_end, clocks_max);
 373 }
 374
 375 static PyObject *
 376 midi_parse (unsigned char **midi,unsigned  char *midi_end, int clocks_max)
 377 {
 378   PyObject *pymidi = 0;
 379   unsigned long header_len;
 380   unsigned format, tracks;
 381   int division;
 382   int i;
 383
 384   debug_print ("%s", "\n");
 385
 386   /* Header */
 387   header_len = get_number (midi, *midi + 4, 4);
 388
 389   if (header_len < 6)
 390     return midi_error (__FUNCTION__,  ": header too short: ", compat_itoa (header_len));
 391
 392   format = get_number (midi, *midi + 2, 2);
 393   tracks = get_number (midi, *midi + 2, 2);
 394
 395   if (tracks > 256)
 396     return midi_error (__FUNCTION__,  ": too many tracks: ", compat_itoa (tracks));
 397
 398   division = get_number (midi, *midi + 2, 2) * 4;
 399
 400
 401   if (division < 0)
 402     /* return midi_error (cannot handle non-metrical time"); */
 403     ;
 404   *midi += header_len - 6;
 405
 406   pymidi = PyList_New (0);
 407
 408   /* Tracks */
 409   for (i = 0; i < tracks; i++)
 410     PyList_Append (pymidi, midi_parse_track (midi, midi_end, clocks_max));
 411
 412   pymidi = Py_BuildValue ("(OO)", Py_BuildValue ("(ii)", format, division),
 413                           pymidi);
 414   return pymidi;
 415 }
 416
 417 static PyObject *
 418 pymidi_parse (PyObject *self, PyObject *args)
 419 {
 420   unsigned char *midi, *midi_end;
 421   unsigned long midi_size;
 422   int clocks_max;
 423
 424   debug_print ("%s", "\n");
 425   if (!PyArg_ParseTuple (args, "s#|i", &midi, &midi_size, &clocks_max))
 426     return 0;
 427   debug_print ("clocks_max: %d\n", clocks_max);
 428
 429   if (memcmp (midi, "MThd", 4))
 430     {
 431       midi[4] = 0;
 432       return midi_error (__FUNCTION__,  ": MThd expected, got: ", (char*)midi);
 433     }
 434
 435   midi += 4;
 436
 437   midi_end = midi + midi_size;
 438
 439   return midi_parse (&midi, midi_end, clocks_max);
 440 }
 441
 442 static PyMethodDef MidiMethods[] =
 443 {
 444   {"parse",  pymidi_parse, METH_VARARGS},
 445   {"parse_track",  pymidi_parse_track, METH_VARARGS},
 446   {0, 0}        /* Sentinel */
 447 };
 448
 449 PyMODINIT_FUNC
 450 initmidi (void)
 451 {
 452   PyObject *m, *d;
 453   m = Py_InitModule ("midi", MidiMethods);
 454   d = PyModule_GetDict (m);
 455
 456   Midi_error = PyString_FromString ("midi.error");
 457   PyDict_SetItemString (d, "error", Midi_error);
 458   add_constants (d);
 459   Midi_warning = PyString_FromString ("midi.warning");
 460   PyDict_SetItemString (d, "warning", Midi_warning);
 461
 462   /*
 463     FIXME.
 464    */
 465   (void) midi_warning;
 466 }
 467