mfi.c

MIDI解码程序(用VC编写)

		if (length > infoLength)
			break;
		infoLength -= length;
		if (type == BE_FCC(0x7469746C /*titl*/))
		{
			char				*title;
			
			if (length == 0)
				return NULL;
			if ((title = malloc(length + 1)) == NULL)
				break;
			if (tf_read(title, length, 1, tf) != 1)
			{
				free(title);
				break;
			}
			title[length] = '\0';
			return title;
		}
		else if (length != 0 && tf_seek(tf, length, SEEK_CUR) == -1)
			break;
	}
	return NULL;
}

typedef struct LastNoteInfo {
	int				on, off, note, velocity;
} LastNoteInfo;

#define NO_LAST_NOTE_INFO	-1
#define LASTNOTEINFO_HAS_DATA(lni)	((lni).on != NO_LAST_NOTE_INFO)
#define SEND_LASTNOTEINFO(lni, ch)				if (LASTNOTEINFO_HAS_DATA((lni)[ch])) SendLastNoteInfo(lni, ch);
#define SEND_AND_CLEAR_LASTNOTEINFO(lni, ch)	if (LASTNOTEINFO_HAS_DATA((lni)[ch])) { SendLastNoteInfo(lni, ch); (lni)[ch].on = NO_LAST_NOTE_INFO; }

inline void StoreLastNoteInfo(LastNoteInfo *info, int channel, int time, int duration, int note, int velocity)
{
	info[channel].on = time;
	info[channel].off = time + duration;
	info[channel].note = note;
	info[channel].velocity = velocity;
}

inline void SendLastNoteInfo(const LastNoteInfo *info, int channel)
{
	NOTE_BUF_EV_DEBUGSTR(channel, info[channel].on, note_name[info[channel].note % 12], info[channel].note / 12, info[channel].velocity, info[channel].off);
	MIDIEVENT(info[channel].on, ME_NOTEON, channel, info[channel].note, info[channel].velocity);
	MIDIEVENT(info[channel].off, ME_NOTEOFF, channel, info[channel].note, 0);
}

#define CHECK_AND_READ_FROM_FILE(ptr, readLen)		do {	\
						if ((length) < (readLen) || tf_read(ptr, readLen, 1, tf) != 1) {	\
							ctl->cmsg(CMSG_WARNING, VERB_NORMAL, "Odd track length.");	\
							return 1;	\
						}	\
						length -= readLen;	\
					} while(0)
static int read_mfi_track(int trackNo, int length, int mfiVersion, int noteType, int extStDLength, timidity_file *tf)
{
	uint8				data[5];
	int					i, pos, note, velocity, dataLength;
	uint8				instruments[MAX_CHANNELS];
	int					channelMap[4];
	LastNoteInfo		lastNotes[MAX_CHANNELS];
	
	readmidi_set_track(trackNo, 1);
	pos = 0;
	velocity = 0x7F;
	for(i = 0; i < 4; i++)
		channelMap[i] = (trackNo * 4) + i;
	dataLength = (noteType == 1) ? 4 : 3;
	data[3] = 0;	/* initialize for debugging purpose */
	for(i = 0; i < MAX_CHANNELS; i++)
		lastNotes[i].on = NO_LAST_NOTE_INFO;
	while (length > 0)
	{
		CHECK_AND_READ_FROM_FILE(data, dataLength);
		pos += data[0];
		if (data[1] != 0xFF)	/* note */
		{
			int					channel;
			
			channel = channelMap[data[1] >> 6];
			note = 0x48 - 0x1B + (data[1] & 0x3F);
			if (dataLength >= 4)
			{
				velocity = ((data[3] & 0xFC) >> 1) | (data[3] >> 7);	/* abcdefgh -> 0abcdefa */
				if (data[3] & 0x2)		/* sign */
					data[3] |= ~0x01;
				else
					data[3] &= 0x01;
				note += ((int8)data[3]) * 12;	/* octave shift */
			}
			if (LASTNOTEINFO_HAS_DATA(lastNotes[channel]))
			{
				if (lastNotes[channel].off <= pos
						|| note != lastNotes[channel].note)
				{
					SendLastNoteInfo(lastNotes, channel);
					StoreLastNoteInfo(lastNotes, channel, pos, data[2], note, velocity);
				}
				#if 0
				else if (note != lastNotes[channel].note)	/* possible slur */
				{
					if (lastNotes[channel].on == pos)	/* may be a chord */
					{
						SendLastNoteInfo(lastNotes, channel);
						StoreLastNoteInfo(lastNotes, channel, pos, data[2], note, velocity);
					}
					else	/* slur */
					{
						/* not implemented */
					}
				}
				#endif
				else	/* tie, what if the velocity isn't the same? :-) */
					lastNotes[channel].off = pos + data[2];
			}
			else
				StoreLastNoteInfo(lastNotes, channel, pos, data[2], note, velocity);
			NOTE_EVENT_DEBUGSTR(channel, note_name[note % 12], note / 12, velocity, data[2]);
		}
		else	/* controls */
		{
			if (dataLength == 3)
				CHECK_AND_READ_FROM_FILE(&data[3], 1);
			if ((data[2] & 0xF0) == 0xC0)	/* tempo */
			{
				int				timebase, tempo;
				
				timebase = data[2] & 0xF;
				if ((timebase & 0x7) == 0x7)
					ctl->cmsg(CMSG_INFO, VERB_DEBUG, "Undefined tempo timebase.");
				else
				{
					if (timebase & 0x8)
						timebase = 15 << (timebase & 0x7);
					else
						timebase = 6 << (timebase & 0x7);
					tempo = 48 * (1000000 * 60 / data[3] / timebase);
					MIDIEVENT(pos, ME_TEMPO, tempo & 0xFF, (tempo >> 16) & 0xFF, (tempo >> 8) & 0xFF);
				}
			}
			else if ((data[2] & 0xF0) == 0xF0)	/* extended controls */
			{
				int				extLength, channel;
				uint8			extData[512];
				
				CHECK_AND_READ_FROM_FILE(&data[4], 1);
				extLength = (data[3] << 8) | data[4];
				if (extLength <= sizeof extData)
				{
					CHECK_AND_READ_FROM_FILE(extData, extLength);
					switch(data[2] & 0xF)
					{
						/* case 0x0:	/-* modify envelope (MFi1) */
						case 0x1:	/* vibrato (MFi1) */
							if (mfiVersion == 1 && extData[0] == 0x01 && extData[1] & 0x01)
							{
								channel = channelMap[extData[1] >> 5];
								MIDIEVENT(pos, ME_MODULATION_WHEEL, channel, (extData[2] & 0xC0) ? 64 : 0, 0)
							}
							break;
						/*case 0xF:	/-* system exclusive (MFi2 or MFi3) */
						default:
							EX_UNKNOWN_EXT_DATA_DEBUGSTR(extLength);
					}
				}
				else
				{
					if (tf_seek(tf, extLength, SEEK_CUR) == -1)
						return 1;
					EX_UNKNOWN_EXT_DATA_DEBUGSTR(extLength);
					length -= extLength;
				}
			}
			else
			{
				int				part, channel, value;
				#define GET_PART_AND_CHANNEL(p, c)		(p) = data[3] >> 6; (c) = channelMap[p]
				
				switch(data[2])
				{
					case 0xB0:	/* master volume */
						value = MAPBITS2(data[3] & 0x7F, 7, 16);
						MIDIEVENT(pos, ME_MASTER_VOLUME, 0, value & 0xFF, value >> 8);
						EX_NCDATA_DEBUGSTR1("Master Volume", "%d", value);
						break;
					case 0xBA:	/* set drum channel flag */
						channel = (data[3] >> 3) & 0xF;
						value = data[3] & 0x1;
						MIDIEVENT(pos, ME_DRUMPART, channel, value, 0);
						EX_DATA_DEBUGSTR1("Drum Flag", channel, "%d", value);
						break;
					case 0xD0:	/* music begin/end */
						/* ignored */
						break;
					/* case 0xDD:	/-* loop begin/end */
					case 0xDE:	/* nop */
						break;
					case 0xDF:	/* end-of-track */
						if (length != 0)
						{
							ctl->cmsg(CMSG_WARNING, VERB_NORMAL, "Premature end-of-track (%d)", length);
							length = 0;
						}
						break;
					case 0xE0:	/* program change */
						GET_PART_AND_CHANNEL(part, channel);
						SEND_AND_CLEAR_LASTNOTEINFO(lastNotes, channel);
						/*MIDIEVENT(pos, ME_DRUMPART, channel, 0, 0);*/
						instruments[channel] = (instruments[channel] & 0x40) | (data[3] & 0x3F);
						MIDIEVENT(pos, ME_PROGRAM, channel, instruments[channel], 0);
						EX_DATA_DEBUGSTR1("Program Change", channel, "%d", instruments[channel]);
						break;
					case 0xE1:	/* pre program change */
						GET_PART_AND_CHANNEL(part, channel);
						instruments[channel] = (data[3] & 0x1) << 6;
						EX_DATA_DEBUGSTR1("Pre Program Change", channel, "%d", instruments[channel]);
						break;
					case 0xE2:	/* volume */
						GET_PART_AND_CHANNEL(part, channel);
						value = MAPBITS(data[3] & 0x3F, 6, 7);
						MIDIEVENT(pos, ME_MAINVOLUME, channel, value, 0);
						EX_DATA_DEBUGSTR1("Volume", channel, "%d", value);
						break;
					case 0xE3:	/* pan */
						GET_PART_AND_CHANNEL(part, channel);
						value = MAPBITS(data[3] & 0x3F, 6, 7);
						MIDIEVENT(pos, ME_PAN, channel, value, 0);
						EX_DATA_DEBUGSTR1("Pan", channel, "%d", value);
						break;
					case 0xE4:	/* pitch bend (MFi3) */
						if (mfiVersion >= 3)
						{
							GET_PART_AND_CHANNEL(part, channel);
							value = MAPBITS2(data[3] & 0x3F, 6, 14);
							MIDIEVENT(pos, ME_PITCHWHEEL, channel, value & 0x7F, value >> 7);
							EX_DATA_DEBUGSTR1("Pitch Bend", channel, "%d", value);
						}
						break;
					case 0xE5:	/* map part to channel */
						part = data[3] >> 6;
						SEND_AND_CLEAR_LASTNOTEINFO(lastNotes, channelMap[part]);
						channelMap[part] = data[3] & 0xF;
						SEND_AND_CLEAR_LASTNOTEINFO(lastNotes, channelMap[part]);
						EX_DATA_DEBUGSTR1("Map Channel", part, "%d", channelMap[part]);
						break;
					case 0xE6:	/* expression */
						GET_PART_AND_CHANNEL(part, channel);
						value = data[3] & 0x3F;
						if (value & 0x20)
							value = 64 - (((value ^ 0x3F) + 1) << 1);
						else if (value & 0x10)
							value = 64 + 1 + (value << 1);
						else
							value = 64 + (value << 1);
						MIDIEVENT(pos, ME_EXPRESSION, channel, value, 0);
						EX_DATA_DEBUGSTR1("Expression", channel, "%d", value);
						break;
					case 0xE7:	/* pitch bend range (MFi3) */
						if (mfiVersion >= 3)
						{
							GET_PART_AND_CHANNEL(part, channel);
							value = data[3] & 0x3F;
							MIDIEVENT(pos, ME_RPN_MSB, channel, 0, 0);
							MIDIEVENT(pos, ME_RPN_LSB, channel, 0, 0);
							MIDIEVENT(pos, ME_DATA_ENTRY_MSB, channel, value, 0);
							EX_DATA_DEBUGSTR1("Pitch Bend Range", channel, "%d", value);
						}
						break;
					case 0xEA:	/* vibrato (MFi3) */
						if (mfiVersion >= 3)
						{
							GET_PART_AND_CHANNEL(part, channel);
							value = MAPBITS(data[3] & 0x3F, 6, 7);
							MIDIEVENT(pos, ME_MODULATION_WHEEL, channel, value, 0);
							EX_DATA_DEBUGSTR1("Vibrato", channel, "%d", value);
						}
						break;
					default:
						EX_UNKNOWN_DATA_DEBUGSTR();
				}
			}
		}
	}
	for(i = 0; i < MAX_CHANNELS; i++)
	{
		SEND_LASTNOTEINFO(lastNotes, i);
	}
	return 0;
}

static int tf_read_beint16(int *value, timidity_file *tf)
{
	uint16				value_;
	
	if (tf_read(&value_, 2, 1, tf) != 1)
		return 0;
	*value = BE_SHORT(value_);
	return 1;
}

static int tf_read_beint32(int *value, timidity_file *tf)
{
	uint32				value_;
	
	if (tf_read(&value_, 4, 1, tf) != 1)
		return 0;
	*value = BE_LONG(value_);
	return 1;
}