apps/plugins/midi/midifile.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2005 Stepan Moskovchenko
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #include "plugin.h"
  22 #include "midiutil.h"
  23
  24 struct Track * readTrack(int file);
  25 int readID(int file);
  26
  27 struct MIDIfile midi_file IBSS_ATTR;
  28
  29 struct MIDIfile * loadFile(const char * filename)
  30 {
  31     struct MIDIfile * mfload;
  32     int file = rb->open (filename, O_RDONLY);
  33
  34     if(file==-1)
  35     {
  36         printf("Could not open file");
  37         return NULL;
  38     }
  39
  40     mfload = &midi_file;
  41
  42     rb->memset(mfload, 0, sizeof(struct MIDIfile));
  43
  44     int fileID = readID(file);
  45     if(fileID != ID_MTHD)
  46     {
  47         if(fileID == ID_RIFF)
  48         {
  49             printf("Detected RMID file");
  50             printf("Looking for MThd header");
  51             char dummy[17];
  52             rb->read(file, &dummy, 16);
  53             if(readID(file) != ID_MTHD)
  54             {
  55                 rb->close(file);
  56                 printf("Invalid MIDI header within RIFF.");
  57                 return NULL;
  58             }
  59
  60         } else
  61         {
  62             rb->close(file);
  63             printf("Invalid file header chunk.");
  64             return NULL;
  65         }
  66     }
  67
  68     if(readFourBytes(file)!=6)
  69     {
  70         rb->close(file);
  71         printf("Header chunk size invalid.");
  72         return NULL;
  73     }
  74
  75     if(readTwoBytes(file)==2)
  76     {
  77         rb->close(file);
  78         printf("MIDI file type 2 not supported");
  79         return NULL;
  80     }
  81
  82     mfload->numTracks = readTwoBytes(file);
  83     mfload->div = readTwoBytes(file);
  84
  85     int track=0;
  86
  87     printf("File has %d tracks.", mfload->numTracks);
  88
  89     while(! eof(file) && track < mfload->numTracks)
  90     {
  91         unsigned char id = readID(file);
  92
  93
  94         if(id == ID_EOF)
  95         {
  96             if(mfload->numTracks != track)
  97             {
  98                 printf("Warning: file claims to have %d tracks. I only see %d here.", mfload->numTracks, track);
  99                 mfload->numTracks = track;
 100             }
 101             rb->close(file);
 102             return mfload;
 103         }
 104
 105         if(id == ID_MTRK)
 106         {
 107             mfload->tracks[track] = readTrack(file);
 108             track++;
 109         } else
 110         {
 111             printf("SKIPPING TRACK");
 112             int len = readFourBytes(file);
 113             while(--len)
 114                 readChar(file);
 115         }
 116     }
 117
 118     rb->close(file);
 119     return mfload;
 120
 121 }
 122
 123 /* Global again. Not static. What if track 1 ends on a running status event
 124  * and then track 2 starts loading */
 125
 126 int rStatus = 0;
 127 /* Returns 0 if done, 1 if keep going */
 128 int readEvent(int file, void * dest)
 129 {
 130     struct Event dummy;
 131     struct Event * ev = (struct Event *) dest;
 132
 133     if(ev == NULL)
 134         ev = &dummy; /* If we are just counting events instead of loading them */
 135
 136     ev->delta = readVarData(file);
 137
 138
 139     int t=readChar(file);
 140
 141     if((t&0x80) == 0x80) /* if not a running status event */
 142     {
 143         ev->status = t;
 144         if(t == 0xFF)
 145         {
 146             ev->d1 = readChar(file);
 147             ev->len = readVarData(file);
 148
 149             /* Allocate and read in the data block */
 150             if(dest != NULL)
 151             {
 152                 /* Null-terminate for text events */
 153                 ev->evData = malloc(ev->len+1); /* Extra byte for the null termination */
 154
 155                 rb->read(file, ev->evData, ev->len);
 156                 ev->evData[ev->len] = 0;
 157
 158                 switch(ev->d1)
 159                 {
 160                     case 0x01:  /* Generic text */
 161                     {
 162                         printf("Text: %s", ev->evData);
 163                         break;
 164                     }
 165
 166                     case 0x02:  /* A copyright string within the file */
 167                     {
 168                         printf("Copyright: %s", ev->evData);
 169                         break;
 170                     }
 171
 172                     case 0x03:  /* Sequence of track name */
 173                     {
 174                         printf("Name: %s", ev->evData);
 175                         break;
 176                     }
 177
 178                     case 0x04:  /* Instrument (synth) name */
 179                     {
 180                         printf("Instrument: %s", ev->evData);
 181                         break;
 182                     }
 183
 184                     case 0x05:  /* Lyrics. These appear on the tracks at the right times */
 185                     {           /* Usually only a small 'piece' of the lyrics.           */
 186                                 /* Maybe the sequencer should print these at play time?  */
 187                         printf("Lyric: %s", ev->evData);
 188                         break;
 189                     }
 190
 191                     case 0x06:  /* Text marker */
 192                     {
 193                         printf("Marker: %s", ev->evData);
 194                         break;
 195                     }
 196
 197
 198                     case 0x07:  /* Cue point */
 199                     {
 200                         printf("Cue point: %s", ev->evData);
 201                         break;
 202                     }
 203
 204                     case 0x08:  /* Program name */
 205                     {
 206                         printf("Patch: %s", ev->evData);
 207                         break;
 208                     }
 209
 210
 211                     case 0x09:  /* Device name. Very much irrelevant here, though. */
 212                     {
 213                         printf("Port: %s", ev->evData);
 214                         break;
 215                     }
 216                 }
 217             }
 218             else
 219             {
 220                 /*
 221                  * Don't allocate anything, just see how much it would take
 222                  * To make memory usage efficient
 223                  */
 224                 unsigned int a=0;
 225                 for(a=0; a<ev->len; a++)
 226                     readChar(file); //Skip skip
 227             }
 228
 229             if(ev->d1 == 0x2F)
 230             {
 231                 return 0;   /* Termination meta-event */
 232             }
 233         } else              /* If part of a running status event */
 234         {
 235             rStatus = t;
 236             ev->status = t;
 237             ev->d1 = readChar(file);
 238
 239             if (  ((t & 0xF0) != 0xD0) && ((t & 0xF0) != 0xC0) && ((t & 0xF0) > 0x40) )
 240             {
 241                 ev->d2 = readChar(file);
 242             } else
 243                 ev->d2 = 127;
 244         }
 245     } else  /* Running Status */
 246     {
 247         ev->status = rStatus;
 248         ev->d1 = t;
 249         if (  ((rStatus & 0xF0) != 0xD0) && ((rStatus & 0xF0) != 0xC0) && ((rStatus & 0xF0) > 0x40) )
 250         {
 251             ev->d2 = readChar(file);
 252         } else
 253             ev->d2 = 127;
 254     }
 255     return 1;
 256 }
 257
 258 int curr_track = 0;
 259 struct Track tracks[48] IBSS_ATTR;
 260
 261 struct Track * readTrack(int file)
 262 {
 263     struct Track * trk = &tracks[curr_track++];
 264     rb->memset(trk, 0, sizeof(struct Track));
 265
 266     trk->size = readFourBytes(file);
 267     trk->pos = 0;
 268     trk->delta = 0;
 269
 270     int numEvents=0;
 271
 272     int pos = rb->lseek(file, 0, SEEK_CUR);
 273
 274     while(readEvent(file, NULL))    /* Memory saving technique                   */
 275         numEvents++;                /* Attempt to read in events, count how many */
 276                                     /* THEN allocate memory and read them in     */
 277     rb->lseek(file, pos, SEEK_SET);
 278
 279     int trackSize = (numEvents+1) * sizeof(struct Event);
 280     void * dataPtr = malloc(trackSize);
 281     trk->dataBlock = dataPtr;
 282
 283     numEvents=0;
 284
 285     while(readEvent(file, dataPtr))
 286     {
 287         if(trackSize < dataPtr-trk->dataBlock)
 288         {
 289             printf("Track parser memory out of bounds");
 290             exit(1);
 291         }
 292         dataPtr+=sizeof(struct Event);
 293         numEvents++;
 294     }
 295     trk->numEvents = numEvents;
 296
 297     return trk;
 298 }
 299
 300 int readID(int file)
 301 {
 302     char id[5];
 303     id[4]=0;
 304     BYTE a;
 305
 306     for(a=0; a<4; a++)
 307         id[a]=readChar(file);
 308     if(eof(file))
 309     {
 310         printf("End of file reached.");
 311         return ID_EOF;
 312     }
 313     if(rb->strcmp(id, "MThd")==0)
 314         return ID_MTHD;
 315     if(rb->strcmp(id, "MTrk")==0)
 316         return ID_MTRK;
 317     if(rb->strcmp(id, "RIFF")==0)
 318         return ID_RIFF;
 319     return ID_UNKNOWN;
 320 }
 321
 322
 323 int readFourBytes(int file)
 324 {
 325     int data=0;
 326     BYTE a=0;
 327     for(a=0; a<4; a++)
 328         data=(data<<8)+readChar(file);
 329     return data;
 330 }
 331
 332 int readTwoBytes(int file)
 333 {
 334     int data=(readChar(file)<<8)+readChar(file);
 335     return data;
 336 }
 337
 338 /* This came from the MIDI file format guide */
 339 int readVarData(int file)
 340 {
 341     unsigned int value;
 342     char c;
 343     if ( (value = readChar(file)) & 0x80 )
 344     {
 345        value &= 0x7F;
 346        do
 347        {
 348          value = (value << 7) + ((c = readChar(file)) & 0x7F);
 349        } while (c & 0x80);
 350     }
 351     return(value);
 352 }
 353
 354
 355 /*
 356 void unloadFile(struct MIDIfile * mf)
 357 {
 358     if(mf == NULL)
 359         return;
 360     int a=0;
 361     //Unload each track
 362     for(a=0; a<mf->numTracks; a++)
 363     {
 364         int b=0;
 365
 366         if(mf->tracks[a] != NULL)
 367             for(b=0; b<mf->tracks[a]->numEvents; b++)
 368             {
 369                 if(((struct Event*)((mf->tracks[a]->dataBlock)+b*sizeof(struct Event)))->evData!=NULL)
 370                     free(((struct Event*)((mf->tracks[a]->dataBlock)+b*sizeof(struct Event)))->evData);
 371             }
 372
 373         if(mf->tracks[a]!=NULL && mf->tracks[a]->dataBlock != NULL)
 374             free(mf->tracks[a]->dataBlock); //Unload the event block
 375
 376         if(mf->tracks[a]!=NULL)
 377             free(mf->tracks[a]);    //Unload the track structure itself
 378     }
 379     free(mf);   //Unload the main struct
 380 }
 381 */
 382