/*
* SYTCID3V2Frame.java
*
* Created on September 6, 2004, 12:11 AM
*
* Copyright (C)2004,2005 Paul Grebenc
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* $Id: SYTCID3V2Frame.java,v 1.7 2005/02/06 18:11:16 paul Exp $
*/
package org.blinkenlights.jid3.v2;
import java.io.*;
import java.util.*;
import org.blinkenlights.jid3.*;
import org.blinkenlights.jid3.io.*;
import org.blinkenlights.jid3.util.*;
/** Frame containing synchronized tempo codes.
*
* @author paul
*/
public class SYTCID3V2Frame extends ID3V2Frame
{
private TimestampFormat m_oTimestampFormat = null;
private SortedMap m_oTempoChangeMap = null;
/** Creates a new instance of SYTCID3V2Frame.
*
* @param oTimestampFormat the timestamp format used in this frame
* @throws ID3Exception if oTimestampFormat is null
*/
public SYTCID3V2Frame(TimestampFormat oTimestampFormat)
throws ID3Exception
{
if (oTimestampFormat == null)
{
throw new ID3Exception("Timestamp cannot be null in SYTC frame.");
}
m_oTimestampFormat = oTimestampFormat;
m_oTempoChangeMap = new TreeMap();
}
public SYTCID3V2Frame(InputStream oIS)
throws ID3Exception
{
try
{
ID3DataInputStream oFrameDataID3DIS = new ID3DataInputStream(oIS);
// timestamp format
m_oTimestampFormat = new TimestampFormat((byte)oFrameDataID3DIS.readUnsignedByte());
// tempo changes
m_oTempoChangeMap = new TreeMap();
while (oFrameDataID3DIS.available() > 0)
{
// one byte if < 255, or sum of two bytes if >= 255
int iBeatsPerMinute = oFrameDataID3DIS.readUnsignedByte();
if (iBeatsPerMinute == 255)
{
iBeatsPerMinute += oFrameDataID3DIS.readUnsignedByte();
}
int iTimestamp = oFrameDataID3DIS.readBE32();
m_oTempoChangeMap.put(new Integer(iTimestamp), new Integer(iBeatsPerMinute));
}
}
catch (Exception e)
{
throw new InvalidFrameID3Exception(e);
}
}
public void accept(ID3Visitor oID3Visitor)
{
oID3Visitor.visitSYTCID3V2Frame(this);
}
/** Add a tempo change to the frame.
*
* @param oTempoChange the tempo change to be added to this frame
* @throws ID3Exception if oTempoChange is null, or if a sync entry for this timestamp already exists in this frame
*/
public void addTempoChange(TempoChange oTempoChange)
throws ID3Exception
{
if (oTempoChange == null)
{
throw new ID3Exception("TempoChange cannot be null.");
}
if (m_oTempoChangeMap.keySet().contains(new Integer(oTempoChange.getTimestamp())))
{
throw new ID3Exception("SYTC frame already contains a tempo change for timestamp " + oTempoChange.getTimestamp() + ".");
}
m_oTempoChangeMap.put(new Integer(oTempoChange.getTimestamp()), new Integer(oTempoChange.getBeatsPerMinute()));
}
/** Get a tempo change from this frame.
*
* @param iTimestamp the timestamp for which the sync entry should be returned
* @return the tempo change object matching the specified timestamp, or null if no matching tiemstamp exists
*/
public TempoChange getTempoChange(int iTimestamp)
{
if (m_oTempoChangeMap.keySet().contains(new Integer(iTimestamp)))
{
try
{
return new TempoChange(((Integer)m_oTempoChangeMap.get(new Integer(iTimestamp))).intValue(), iTimestamp);
}
catch (Exception e) { return null; } // we've already created this object, so this can't happen
}
else
{
return null;
}
}
/** Remove a tempo change from this frame.
*
* @param iTimestamp the timestamp for which the tempo change is to be removed
* @return the previously set sync entry for this timestamp, or null if no tempo change was set for this timestamp
*/
public TempoChange removeTempoChange(int iTimestamp)
{
if (m_oTempoChangeMap.keySet().contains(new Integer(iTimestamp)))
{
try
{
return new TempoChange(((Integer)m_oTempoChangeMap.remove(new Integer(iTimestamp))).intValue(), iTimestamp);
}
catch (Exception e) { return null; } // we've already created this object, so this can't happen
}
else
{
return null;
}
}
protected byte[] getFrameId()
{
return "SYTC".getBytes();
}
public String toString()
{
StringBuffer sbText = new StringBuffer();
sbText.append("Synchronized tempo codes: Timestamp format=[" + m_oTimestampFormat.getValue() + "]");
Iterator oIter = m_oTempoChangeMap.keySet().iterator();
while (oIter.hasNext())
{
Integer oTimestamp = (Integer)oIter.next();
Integer oBeatsPerMinute = (Integer)m_oTempoChangeMap.get(oTimestamp);
sbText.append(" TempoChange(" + oTimestamp.intValue() + ", BPM=" + oBeatsPerMinute.intValue() + ")");
}
return sbText.toString();
}
protected void writeBody(ID3DataOutputStream oIDOS)
throws IOException
{
oIDOS.write(m_oTimestampFormat.getValue());
// tempo changes
Iterator oIter = m_oTempoChangeMap.keySet().iterator();
while (oIter.hasNext())
{
Integer oTimestamp = (Integer)oIter.next();
// beats per minute (one byte if < 255, sum of two bytes if >= 255)
Integer oBeatsPerMinute = (Integer)m_oTempoChangeMap.get(oTimestamp);
int iBeatsPerMinute = oBeatsPerMinute.intValue();
if (iBeatsPerMinute >= 255)
{
oIDOS.write(255);
oIDOS.write(iBeatsPerMinute - 255);
}
else
{
oIDOS.write(iBeatsPerMinute);
}
oIDOS.writeBE32(oTimestamp.intValue()); // timestamp
}
}
/** Timestamp format. The timestamp format is used to specify how offsets from the start of the
* the file are measured for events.
*/
public static class TimestampFormat
{
private byte m_byTimestampFormat;
private TimestampFormat(byte byTimestampFormat)
{
m_byTimestampFormat = byTimestampFormat;
}
private byte getValue()
{
return m_byTimestampFormat;
}
/** Timestamp format indicating that timestamps are measured in MPEG frames from the start of the file. */
public static final TimestampFormat ABSOLUTE_MPEG_FRAMES = new TimestampFormat((byte)0x01);
/** Timestamp format indicating that timestamps are measured in milliseconds from the start of the file. */
public static final TimestampFormat ABSOLUTE_MILLISECONDS = new TimestampFormat((byte)0x02);
public boolean equals(Object oOther)
{
try
{
TimestampFormat oOtherTF = (TimestampFormat)oOther;
return (m_byTimestampFormat == oOtherTF.m_byTimestampFormat);
}
catch (Exception e)
{
return false;
}
}
}
/** TempoChange class. This container class is used to hold a timestamp and bpm value pair.
*/
public static class TempoChange
{
private int m_iBeatsPerMinute;
private int m_iTimestamp;
/** Constructor.
*
* @param iBeatsPerMinute the number of beats per minute (0 = beat free, 1 = single beat stroke followed by beat free period)
* @throws ID3Exception if beats per minute is outside range from 0-510, or if timestamp is negative
*/
public TempoChange(int iBeatsPerMinute, int iTimestamp)
throws ID3Exception
{
if ((iBeatsPerMinute < 0) || (iBeatsPerMinute > 510))
{
throw new ID3Exception("Beats per minute value must be between 0 and 510 in SYTC frame.");
}
m_iBeatsPerMinute = iBeatsPerMinute;
if (iTimestamp < 0)
{
throw new ID3Exception("Timestamp cannot be negative in sync entry in SYLT frame.");
}
m_iTimestamp = iTimestamp;
}
/** Get the number of beats per minute.
*
* @return the number of beats per minute (0 = beat free, 1 = single beat stroke followed by beat free period)
*/
public int getBeatsPerMinute()
{
return m_iBeatsPerMinute;
}
/** Get the timestamp.
*
* @return the timestamp value
*/
public int getTimestamp()
{
return m_iTimestamp;
}
}
public boolean equals(Object oOther)
{
if ((oOther == null) || (!(oOther instanceof SYTCID3V2Frame)))
{
return false;
}
SYTCID3V2Frame oOtherSYTC = (SYTCID3V2Frame)oOther;
return (m_oTimestampFormat.equals(oOtherSYTC.m_oTimestampFormat) &&
m_oTempoChangeMap.equals(oOtherSYTC.m_oTempoChangeMap));
}
}