rockbox/apps/plugins/midi/midifile.c
Stepan Moskovchenko b9b2bcd9b9 Fixed freezing after loader error messages.
Added RMID (Windows MIDI) header support. Added .RMI extension to
viewers.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@9888 a1c6a512-1295-4272-9138-f99709370657
2006-05-08 02:43:29 +00:00

321 lines
7.8 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
*
* Copyright (C) 2005 Stepan Moskovchenko
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
extern struct plugin_api * rb;
struct Track * readTrack(int file);
int readID(int file);
struct MIDIfile * loadFile(char * filename)
{
struct MIDIfile * mfload;
int file = rb->open (filename, O_RDONLY);
if(file==-1)
{
printf("Could not open file\n");
return NULL;
}
mfload = (struct MIDIfile*)malloc(sizeof(struct MIDIfile));
if(mfload==NULL)
{
rb->close(file);
printf("Could not allocate memory for MIDIfile struct\n");
return NULL;
}
rb->memset(mfload, 0, sizeof(struct MIDIfile));
int fileID = readID(file);
if(fileID != ID_MTHD)
{
if(fileID == ID_RIFF)
{
printf("\nDetected RMID file");
printf("\nLooking for MThd header");
char dummy[17];
rb->read(file, &dummy, 16);
if(readID(file) != ID_MTHD)
{
rb->close(file);
printf("Invalid MIDI header within RIFF.");
return NULL;
}
} else
{
rb->close(file);
printf("Invalid file header chunk.");
return NULL;
}
}
if(readFourBytes(file)!=6)
{
rb->close(file);
printf("Header chunk size invalid.");
return NULL;
}
if(readTwoBytes(file)==2)
{
rb->close(file);
printf("MIDI file type 2 not supported");
return NULL;
}
mfload->numTracks = readTwoBytes(file);
mfload->div = readTwoBytes(file);
int track=0;
printf("\nFile has %d tracks.", mfload->numTracks);
while(! eof(file) && track < mfload->numTracks)
{
unsigned char id = readID(file);
if(id == ID_EOF)
{
if(mfload->numTracks != track)
{
printf("\nError: file claims to have %d tracks.\n I only see %d here.\n", mfload->numTracks, track);
mfload->numTracks = track;
}
return mfload;
}
if(id == ID_MTRK)
{
mfload->tracks[track] = readTrack(file);
track++;
} else
{
printf("\n SKIPPING TRACK");
int len = readFourBytes(file);
while(--len)
readChar(file);
}
}
rb->close(file);
return mfload;
}
/* Global again. Not static. What if track 1 ends on a running status event
* and then track 2 starts loading */
int rStatus = 0;
/* Returns 0 if done, 1 if keep going */
int readEvent(int file, void * dest)
{
struct Event dummy;
struct Event * ev = (struct Event *) dest;
if(ev == NULL)
ev = &dummy; /* If we are just counting events instead of loading them */
ev->delta = readVarData(file);
int t=readChar(file);
if((t&0x80) == 0x80) /* if not a running status event */
{
ev->status = t;
if(t == 0xFF)
{
ev->d1 = readChar(file);
ev->len = readVarData(file);
/* Allocate and read in the data block */
if(dest != NULL)
{
ev->evData = readData(file, ev->len);
/* printf("\nDATA: <%s>", ev->evData); */
}
else
{
/*
* Don't allocate anything, just see how much it would take
* To make memory usage efficient
*/
unsigned int a=0;
for(a=0; a<ev->len; a++)
readChar(file); //Skip skip
}
if(ev->d1 == 0x2F)
{
return 0; /* Termination meta-event */
}
} else /* If part of a running status event */
{
rStatus = t;
ev->status = t;
ev->d1 = readChar(file);
if ( ((t & 0xF0) != 0xD0) && ((t & 0xF0) != 0xC0) && ((t & 0xF0) > 0x40) )
{
ev->d2 = readChar(file);
} else
ev->d2 = 127;
}
} else /* Running Status */
{
ev->status = rStatus;
ev->d1 = t;
if ( ((rStatus & 0xF0) != 0xD0) && ((rStatus & 0xF0) != 0xC0) && ((rStatus & 0xF0) > 0x40) )
{
ev->d2 = readChar(file);
} else
ev->d2 = 127;
}
return 1;
}
struct Track * readTrack(int file)
{
struct Track * trk = (struct Track *)malloc(sizeof(struct Track));
rb->memset(trk, 0, sizeof(struct Track));
trk->size = readFourBytes(file);
trk->pos = 0;
trk->delta = 0;
int numEvents=0;
int pos = rb->lseek(file, 0, SEEK_CUR);
while(readEvent(file, NULL)) /* Memory saving technique */
numEvents++; /* Attempt to read in events, count how many */
/* THEN allocate memory and read them in */
rb->lseek(file, pos, SEEK_SET);
int trackSize = (numEvents+1) * sizeof(struct Event);
void * dataPtr = malloc(trackSize);
trk->dataBlock = dataPtr;
numEvents=0;
while(readEvent(file, dataPtr))
{
if(trackSize < dataPtr-trk->dataBlock)
{
printf("\nTrack parser memory out of bounds");
exit(1);
}
dataPtr+=sizeof(struct Event);
numEvents++;
}
trk->numEvents = numEvents;
return trk;
}
int readID(int file)
{
char id[5];
id[4]=0;
BYTE a;
for(a=0; a<4; a++)
id[a]=readChar(file);
if(eof(file))
{
printf("\End of file reached.");
return ID_EOF;
}
if(rb->strcmp(id, "MThd")==0)
return ID_MTHD;
if(rb->strcmp(id, "MTrk")==0)
return ID_MTRK;
if(rb->strcmp(id, "RIFF")==0)
return ID_RIFF;
return ID_UNKNOWN;
}
int readFourBytes(int file)
{
int data=0;
BYTE a=0;
for(a=0; a<4; a++)
data=(data<<8)+readChar(file);
return data;
}
int readTwoBytes(int file)
{
int data=(readChar(file)<<8)+readChar(file);
return data;
}
/* This came from the MIDI file format guide */
int readVarData(int file)
{
unsigned int value;
char c;
if ( (value = readChar(file)) & 0x80 )
{
value &= 0x7F;
do
{
value = (value << 7) + ((c = readChar(file)) & 0x7F);
} while (c & 0x80);
}
return(value);
}
/*
void unloadFile(struct MIDIfile * mf)
{
if(mf == NULL)
return;
int a=0;
//Unload each track
for(a=0; a<mf->numTracks; a++)
{
int b=0;
if(mf->tracks[a] != NULL)
for(b=0; b<mf->tracks[a]->numEvents; b++)
{
if(((struct Event*)((mf->tracks[a]->dataBlock)+b*sizeof(struct Event)))->evData!=NULL)
free(((struct Event*)((mf->tracks[a]->dataBlock)+b*sizeof(struct Event)))->evData);
}
if(mf->tracks[a]!=NULL && mf->tracks[a]->dataBlock != NULL)
free(mf->tracks[a]->dataBlock); //Unload the event block
if(mf->tracks[a]!=NULL)
free(mf->tracks[a]); //Unload the track structure itself
}
free(mf); //Unload the main struct
}
*/