package org.jaudiotagger.tag.mp4.field;
import org.jaudiotagger.audio.generic.Utils;
import org.jaudiotagger.audio.mp4.atom.Mp4BoxHeader;
import org.jaudiotagger.tag.FieldDataInvalidException;
import org.jaudiotagger.tag.mp4.Mp4FieldKey;
import org.jaudiotagger.tag.mp4.atom.Mp4DataBox;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
/**
* Represents a single byte as a number
* <p/>
* <p>Usually single byte fields are used as a boolean field, but not always so we dont do this conversion
*/
public class Mp4TagByteField extends Mp4TagTextField {
public static String TRUE_VALUE = "1"; //when using this field to hold a boolean
//Holds the actual size of the data content as held in the databoxitem, this is required when creating new
//items because we cant accurately work out the size by looking at the content because sometimes field must be longer
//than is actually required to hold the value
//e.g byte data length seems to be 1 for pgap and cpil but 2 for tmpo, so we stored the dataSize
//when we loaded the value so if greater than 1 we pad the value.
private int realDataLength;
//Preserved from data from file
private byte[] bytedata;
/**
* Create new field
* <p/>
* Assume length of 1 which is correct for most but not all byte fields
*
* @param id
* @param value is a String representation of a number
* @throws org.jaudiotagger.tag.FieldDataInvalidException
*
*/
public Mp4TagByteField(Mp4FieldKey id, String value) throws FieldDataInvalidException {
this(id, value, 1);
}
/**
* Create new field with known length
*
* @param id
* @param value is a String representation of a number
* @param realDataLength
* @throws org.jaudiotagger.tag.FieldDataInvalidException
*
*/
public Mp4TagByteField(Mp4FieldKey id, String value, int realDataLength) throws FieldDataInvalidException {
super(id.getFieldName(), value);
this.realDataLength = realDataLength;
//Check that can actually be stored numercially, otherwise will have big problems
//when try and save the field
try {
Long.parseLong(value);
} catch (NumberFormatException nfe) {
throw new FieldDataInvalidException("Value of:" + value + " is invalid for field:" + id);
}
}
/**
* Construct from rawdata from audio file
*
* @param id
* @param raw
* @throws UnsupportedEncodingException
*/
public Mp4TagByteField(String id, ByteBuffer raw) throws UnsupportedEncodingException {
super(id, raw);
}
public Mp4FieldType getFieldType() {
return Mp4FieldType.INTEGER;
}
/**
* Return raw data bytes
* <p/>
* TODO this code should be done better so generalised to any length
*
* @return
* @throws UnsupportedEncodingException
*/
protected byte[] getDataBytes() throws UnsupportedEncodingException {
//Write original data
if (bytedata != null) {
return bytedata;
}
//new field, lets hope the realDataLength is correct
switch (realDataLength) {
case 2: {
//Save as two bytes
Short shortValue = new Short(content);
byte rawData[] = Utils.getSizeBEInt16(shortValue);
return rawData;
}
case 1: {
//Save as 1 bytes
Short shortValue = new Short(content);
byte rawData[] = new byte[1];
rawData[0] = shortValue.byteValue();
return rawData;
}
case 4: {
//Assume could be int
Integer intValue = new Integer(content);
byte rawData[] = Utils.getSizeBEInt32(intValue);
return rawData;
}
default: {
//TODO
throw new RuntimeException(id + ":" + realDataLength + ":" + "Dont know how to write byte fields of this length");
}
}
}
protected void build(ByteBuffer data) throws UnsupportedEncodingException {
//Data actually contains a 'Data' Box so process data using this
Mp4BoxHeader header = new Mp4BoxHeader(data);
Mp4DataBox databox = new Mp4DataBox(header, data);
dataSize = header.getDataLength();
//Needed for subsequent write
realDataLength = dataSize - Mp4DataBox.PRE_DATA_LENGTH;
bytedata = databox.getByteData();
content = databox.getContent();
}
}