//
// GetTrackVDWord
//
// Attempts to parse a variable length DWORD from the given track. A VDWord
// in a MIDI file
// (a) is in lo-hi format
// (b) has the high bit set on every byte except the last
//
// Returns the DWORD in *lpdw and TRUE on success; else
// FALSE if we hit end of track first. Sets ITS_F_ENDOFTRK
// if we hit end of track.
//
static BOOL GetTrackVDWord( PINTRACKSTATE ptsTrack, LPDWORD lpdw )
{
BYTE byByte;
DWORD dw = 0;
if( ptsTrack->fdwTrack & ITS_F_ENDOFTRK )
return( TRUE );
do
{
if( !ptsTrack->dwLeftInBuffer && !ptsTrack->dwLeftOnDisk )
{
ptsTrack->fdwTrack |= ITS_F_ENDOFTRK;
return( TRUE );
}
if( GetTrackByte( ptsTrack, &byByte ))
return( TRUE );
dw = ( dw << 7 ) | ( byByte & 0x7F );
} while( byByte & 0x80 );
*lpdw = dw;
return( FALSE );
}
/* GetTrackVDWord
*
* Parse a variable length DWORD from the given track. A VDWord in
* a MIDI file is in lo-hi format and has the high bit set on every
* byte except the last.
*
* Returns the DWORD in *v and zero on success; else non-zero if we
* hit end of track. Sets ITS_F_ENDOFTRK if we hit end of track.
*/
static int GetTrackVDWord (track_state_t *ts, DWORD *v)
{
BYTE b;
DWORD val = 0;
if (ts->status & ITS_F_ENDOFTRK)
return 1;
do
{
if (!ts->left_in_buffer && !ts->left_on_disk)
{
ts->status |= ITS_F_ENDOFTRK;
return 1;
}
if (GetTrackByte(ts, &b))
return 1;
val = (val << 7) | (b & 0x7F);
} while (b & 0x80);
*v = val;
return 0;
}
//
// GetTrackEvent
//
// Fills in the event struct with the next event from the track
//
// pteTemp->tkEvent will contain the absolute tick time of the event
// pteTemp->byShortData[0] will contain
// MIDI_META if the event is a meta event;
// in this case pteTemp->byShortData[1] will contain the meta class
// MIDI_SYSEX or MIDI_SYSEXEND if the event is a SysEx event
// Otherwise, the event is a channel message and pteTemp->byShortData[1]
// and pteTemp->byShortData[2] will contain the rest of the event.
//
// pteTemp->dwEventLength will contain
// The total length of the channel message in pteTemp->byShortData if
// the event is a channel message
// The total length of the paramter data pointed to by
// pteTemp->pLongData otherwise
//
// pteTemp->pLongData will point at any additional paramters if the
// event is a SysEx or meta event with non-zero length; else
// it will contain NULL
//
// Returns FALSE on success or TRUE on any kind of parse error
// Prints its own error message ONLY in the debug version
//
// Maintains the state of the input track (i.e. ptsTrack->dwLeftInBuffer,
// ptsTrack->pTrackPointers, and ptsTrack->byRunningStatus).
//
static BOOL GetTrackEvent( INTRACKSTATE *ptsTrack, PTEMPEVENT pteTemp )
{
DWORD idx;
BYTE byByte;
UINT dwEventLength;
// Clear out the temporary event structure to get rid of old data...
memset( pteTemp, 0, sizeof(TEMPEVENT));
// Already at end of track? There's nothing to read.
//
if(( ptsTrack->fdwTrack & ITS_F_ENDOFTRK )
|| ( !ptsTrack->dwLeftInBuffer && !ptsTrack->dwLeftOnDisk ))
return( TRUE );
// Get the first byte, which determines the type of event.
//
if( GetTrackByte( ptsTrack, &byByte ))
return( TRUE );
// If the high bit is not set, then this is a channel message
// which uses the status byte from the last channel message
// we saw. NOTE: We do not clear running status across SysEx or
// meta events even though the spec says to because there are
// actually files out there which contain that sequence of data.
//
if( !( byByte & 0x80 ))
{
// No previous status byte? We're hosed.
if( !ptsTrack->byRunningStatus )
{
TRACKERR(ptsTrack, gteBadRunStat);
return( TRUE );
}
pteTemp->byShortData[0] = ptsTrack->byRunningStatus;
pteTemp->byShortData[1] = byByte;
byByte = pteTemp->byShortData[0] & 0xF0;
pteTemp->dwEventLength = 2;
// Only program change and channel pressure events are 2 bytes long;
// the rest are 3 and need another byte
//
if(( byByte != MIDI_PRGMCHANGE ) && ( byByte != MIDI_CHANPRESS ))
{
if( !ptsTrack->dwLeftInBuffer && !ptsTrack->dwLeftOnDisk )
{
TRACKERR( ptsTrack, gteRunStatMsgTrunc );
ptsTrack->fdwTrack |= ITS_F_ENDOFTRK;
return( TRUE );
}
if( GetTrackByte( ptsTrack, &pteTemp->byShortData[2] ))
return( TRUE );
++pteTemp->dwEventLength;
}
}
else if(( byByte & 0xF0 ) != MIDI_SYSEX )
{
// Not running status, not in SysEx range - must be
// normal channel message (0x80-0xEF)
//
pteTemp->byShortData[0] = byByte;
ptsTrack->byRunningStatus = byByte;
// Strip off channel and just keep message type
//
byByte &= 0xF0;
dwEventLength = ( byByte == MIDI_PRGMCHANGE || byByte == MIDI_CHANPRESS ) ? 1 : 2;
pteTemp->dwEventLength = dwEventLength + 1;
if(( ptsTrack->dwLeftInBuffer + ptsTrack->dwLeftOnDisk ) < dwEventLength )
{
TRACKERR( ptsTrack, gteChanMsgTrunc );
ptsTrack->fdwTrack |= ITS_F_ENDOFTRK;
return( TRUE );
}
if( GetTrackByte( ptsTrack, &pteTemp->byShortData[1] ))
return( TRUE );
if( dwEventLength == 2 )
if( GetTrackByte( ptsTrack, &pteTemp->byShortData[2] ))
return( TRUE );
}
else if(( byByte == MIDI_SYSEX ) || ( byByte == MIDI_SYSEXEND ))
{
// One of the SysEx types. (They are the same as far as we're concerned;
// there is only a semantic difference in how the data would actually
// get sent when the file is played. We must take care to put the proper
// event type back on the output track, however.)
//
// Parse the general format of:
// BYTE bEvent (MIDI_SYSEX or MIDI_SYSEXEND)
// VDWORD cbParms
// BYTE abParms[cbParms]
//
pteTemp->byShortData[0] = byByte;
if( GetTrackVDWord( ptsTrack, &pteTemp->dwEventLength ))
{
TRACKERR( ptsTrack, gteSysExLenTrunc );
return( TRUE );
}
if(( ptsTrack->dwLeftInBuffer + ptsTrack->dwLeftOnDisk )
< pteTemp->dwEventLength )
{
TRACKERR( ptsTrack, gteSysExTrunc );
ptsTrack->fdwTrack |= ITS_F_ENDOFTRK;
return( TRUE );
}
// Malloc a temporary memory block to hold the parameter data
if(( pteTemp->pLongData = malloc( pteTemp->dwEventLength )) == NULL )
{
TRACKERR( ptsTrack, gteNoMem );
return( TRUE );
}
// Copy from the input buffer to the parameter data buffer
for( idx = 0; idx < pteTemp->dwEventLength; idx++ )
if( GetTrackByte( ptsTrack, pteTemp->pLongData + idx ))
{
TRACKERR( ptsTrack, gteSysExTrunc );
return( TRUE );
}
// Increment our counter, which tells the program to look around for
// a malloc block to free, should it need to exit or reset before the
// block would normally be freed
dwMallocBlocks++;
}
else if( byByte == MIDI_META )
{
// It's a meta event. Parse the general form:
// BYTE bEvent (MIDI_META)
// BYTE bClass
// VDWORD cbParms
// BYTE abParms[cbParms]
//
pteTemp->byShortData[0] = byByte;
if( !ptsTrack->dwLeftInBuffer && !ptsTrack->dwLeftOnDisk )
{
TRACKERR(ptsTrack, gteMetaNoClass );
ptsTrack->fdwTrack |= ITS_F_ENDOFTRK;
return( TRUE );
}
if( GetTrackByte( ptsTrack, &pteTemp->byShortData[1] ))
return( TRUE );
if( GetTrackVDWord( ptsTrack, &pteTemp->dwEventLength ))
{
TRACKERR( ptsTrack, gteMetaLenTrunc );
return( TRUE );
}
// NOTE: It's perfectly valid to have a meta with no data
// In this case, dwEventLength == 0 and pLongData == NULL
//
if( pteTemp->dwEventLength )
{
if(( ptsTrack->dwLeftInBuffer + ptsTrack->dwLeftOnDisk )
< pteTemp->dwEventLength )
{
TRACKERR( ptsTrack, gteMetaTrunc );
ptsTrack->fdwTrack |= ITS_F_ENDOFTRK;
return( TRUE );
}
// Malloc a temporary memory block to hold the parameter data
if(( pteTemp->pLongData = malloc( pteTemp->dwEventLength ))
== NULL )
{
TRACKERR( ptsTrack, gteNoMem );
return( TRUE );
}
// Copy from the input buffer to the parameter data buffer
for( idx = 0; idx < pteTemp->dwEventLength; idx++ )
if( GetTrackByte( ptsTrack, pteTemp->pLongData + idx ))
{
TRACKERR( ptsTrack, gteMetaTrunc );
return( TRUE );
}
// Increment our counter, which tells the program to look around for
// a malloc block to free, should it need to exit or reset before the
// block would normally be freed
dwMallocBlocks++;
}
if( pteTemp->byShortData[1] == MIDI_META_EOT )
ptsTrack->fdwTrack |= ITS_F_ENDOFTRK;
}
else
{
// Messages in this range are system messages and aren't supposed to
// be in a normal MIDI file. If they are, we've either misparsed or the
// authoring software is stupid.
//
return( TRUE );
}
// Event time was already stored as the current track time
//
pteTemp->tkEvent = ptsTrack->tkNextEventDue;
// Now update to the next event time. The code above MUST properly
// maintain the end of track flag in case the end of track meta is
// missing. NOTE: This code is a continuation of the track event
// time pre-read which is done at the end of track initialization.
//
if( !( ptsTrack->fdwTrack & ITS_F_ENDOFTRK ))
{
DWORD tkDelta;
if( GetTrackVDWord( ptsTrack, &tkDelta ))
return( TRUE );
ptsTrack->tkNextEventDue += tkDelta;
}
return( FALSE );
}
/* GetTrackEvent
*
* Fills in the event struct with the next event from the track
*
* te->event_time will contain the absolute tick time of the event.
*
* te->shortdata[0] will contain:
* - MIDI_META_EVENT if the event is a meta event; in this case
* te->shortdata[1] will contain the meta class.
* - MIDICMD_SYSEX or MIDICMD_SYSEX_END if the event is a SysEx event
* - Otherwise, event is a channel message and te->shortdata[1] and
* te->shortdata[2] will contain the rest of the event.
*
* te->event_len will contain:
* - The total length of the channel message in te->shortdata if the
* event is a channel message,
* - The total length of the paramter data pointed to by te->longdata,
* otherwise.
*
* te->longdata will point at any additional paramters if the event is
* a SysEx or meta event with non-zero length; else it will be NULL.
*
* Returns zero on success or non-zero on any kind of parse error
* Maintains the state of the input track (i.e. ts->left_in_buffer,
* ts->pTrackPointers, and ts->running_status).
*/
static int GetTrackEvent (track_state_t *ts, temp_event_t *te)
{
DWORD idx;
BYTE b;
UINT event_len;
/* Clear out the temporary event structure to get rid of old data */
memset(te, 0, sizeof(struct _temp_event_s));
/* Already at end of track? There's nothing to read. */
if (ts->status & ITS_F_ENDOFTRK)
return 1;
if (!ts->left_in_buffer && !ts->left_on_disk)
return 1;
/* Get the first byte, which determines the type of event. */
if (GetTrackByte(ts, &b))
return 1;
/* If the high bit is not set, then this is a channel message
* which uses the status byte from the last channel message
* we saw. NOTE: We do not clear running status across SysEx or
* meta events even though the spec says to because there are
* actually files out there which contain that sequence of data.
*/
if ( !(b & 0x80))
{
/* No previous status byte? We're hosed. */
if (!ts->running_status)
{
TRACKERR(ts, err_bad_runstat);
return 1;
}
te->shortdata[0] = ts->running_status;
te->shortdata[1] = b;
b = te->shortdata[0] & 0xF0;
te->event_len = 2;
/* Only program change and channel pressure events are
* 2 bytes long. the rest are 3 and need another byte. */
if (b != MIDICMD_PGM_CHANGE && b != MIDICMD_CHANNEL_PRESSURE)
{
if (!ts->left_in_buffer && !ts->left_on_disk)
{
TRACKERR(ts, err_trunc_runstat);
ts->status |= ITS_F_ENDOFTRK;
return 1;
}
if (GetTrackByte(ts, &te->shortdata[2]))
return 1;
++te->event_len;
}
}
else if ((b & 0xF0) != MIDICMD_SYSEX)
{
/* Not running status, not in SysEx range - must be
* normal channel message (0x80-0xEF) */
te->shortdata[0] = b;
ts->running_status = b;
/* Strip off channel and just keep message type */
b &= 0xF0;
event_len = (b == MIDICMD_PGM_CHANGE || b == MIDICMD_CHANNEL_PRESSURE) ? 1 : 2;
te->event_len = event_len + 1;
if ((ts->left_in_buffer + ts->left_on_disk) < event_len)
{
TRACKERR(ts, err_trunc_chan_msg);
ts->status |= ITS_F_ENDOFTRK;
return 1;
}
if (GetTrackByte(ts, &te->shortdata[1]))
return 1;
if (event_len == 2)
{
if (GetTrackByte(ts, &te->shortdata[2]))
return 1;
}
}
else if (b == MIDICMD_SYSEX || b == MIDICMD_SYSEX_END)
{
/* One of the SysEx types. (They are the same as far as we're
* concerned; there is only a semantic difference in how the
* data would actually get sent when the file is played.
* We must take care to put the proper event type back on the
* output track, however.)
*
* Parse the general format of:
* BYTE event (MIDICMD_SYSEX or MIDICMD_SYSEX_END)
* VDWORD num_parms
* BYTE ab_parms[num_parms]
*/
te->shortdata[0] = b;
if (GetTrackVDWord(ts, &te->event_len))
{
TRACKERR(ts, err_trunc_sysex_len);
return 1;
}
if ((ts->left_in_buffer + ts->left_on_disk) < te->event_len)
{
TRACKERR(ts, err_trunc_sysex);
ts->status |= ITS_F_ENDOFTRK;
return 1;
}
te->longdata = (BYTE *) Z_Malloc(te->event_len, Z_MAINZONE);
for (idx = 0; idx < te->event_len; idx++)
{
if (GetTrackByte(ts, te->longdata + idx))
{
Z_Free(te->longdata);
te->longdata = NULL;
TRACKERR(ts, err_trunc_sysex);
return 1;
}
}
}
else if (b == MIDI_META_EVENT)
{
/* It's a meta event. Parse the general form:
* BYTE event (MIDI_META_EVENT)
* BYTE class
* VDWORD num_parms
* BYTE ab_parms[num_parms]
*/
te->shortdata[0] = b;
if (!ts->left_in_buffer && !ts->left_on_disk)
{
TRACKERR(ts, err_meta_noclass);
ts->status |= ITS_F_ENDOFTRK;
return 1;
}
if (GetTrackByte(ts, &te->shortdata[1]))
return 1;
if (GetTrackVDWord(ts, &te->event_len))
{
TRACKERR(ts, err_trunc_meta_len);
return 1;
}
/* NOTE: It's perfectly valid to have a meta with no data
* In this case, event_len == 0 and longdata == NULL */
if (te->event_len)
{
if ((ts->left_in_buffer + ts->left_on_disk) < te->event_len)
{
TRACKERR(ts, err_trunc_meta);
ts->status |= ITS_F_ENDOFTRK;
return 1;
}
te->longdata = (BYTE *) Z_Malloc(te->event_len, Z_MAINZONE);
for (idx = 0; idx < te->event_len; idx++)
{
if (GetTrackByte(ts, te->longdata + idx))
{
Z_Free(te->longdata);
te->longdata = NULL;
TRACKERR(ts, err_trunc_meta);
return 1;
}
}
}
if (te->shortdata[1] == MIDI_META_EOT)
ts->status |= ITS_F_ENDOFTRK;
}
else
{
/* Messages in this range are system messages and aren't
* supposed to be in a normal MIDI file. If they are, we
* have either misparsed or the authoring software is stupid.
*/
return 1;
}
/* Event time was already stored as the current track time */
te->event_time = ts->next_event_time;
/* Now update to the next event time. The code above MUST properly
* maintain the end of track flag in case the end of track meta is
* missing. NOTE: This code is a continuation of the track event
* time pre-read which is done at the end of track initialization.
*/
if ( !(ts->status & ITS_F_ENDOFTRK))
{
DWORD delta_time;
if (GetTrackVDWord(ts, &delta_time))
return 1;
ts->next_event_time += delta_time;
}
return 0;
}
