/**
* @author : Paul Taylor
* @author : Eric Farng
*
* Version @version:$Id: NumberFixedLength.java 836 2009-11-12 15:44:07Z paultaylor $
*
* MusicTag Copyright (C)2003,2004
*
* 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,
* you can get a copy from http://www.opensource.org/licenses/lgpl-license.php or write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Description:
* Represents a Number of a fixed number of decimal places.
*/
package org.jaudiotagger.tag.datatype;
import org.jaudiotagger.tag.InvalidDataTypeException;
import org.jaudiotagger.tag.id3.AbstractTagFrameBody;
import org.jaudiotagger.tag.id3.ID3Tags;
/**
* Represents a number held as a fixed number of digits.
* <p/>
* The bitorder in ID3v2 is most significant bit first (MSB). The byteorder in multibyte numbers is most significant
* byte first (e.g. $12345678 would be encoded $12 34 56 78), also known as big endian and network byte order.
* <p/>
* In ID3Specification would be denoted as $xx xx this denotes exactly two bytes required
*/
public class NumberFixedLength extends AbstractDataType {
/**
* Creates a new ObjectNumberFixedLength datatype.
*
* @param identifier
* @param frameBody
* @param size the number of significant places that the number is held to
* @throws IllegalArgumentException
*/
public NumberFixedLength(String identifier, AbstractTagFrameBody frameBody, int size) {
super(identifier, frameBody);
if (size < 0) {
throw new IllegalArgumentException("Length is less than zero: " + size);
}
this.size = size;
}
public NumberFixedLength(NumberFixedLength copy) {
super(copy);
this.size = copy.size;
}
/**
* Set Size in Bytes of this Object
*
* @param size in bytes that this number will be held as
*/
public void setSize(int size) {
if (size > 0) {
this.size = size;
}
}
/**
* Return size
*
* @return the size of this number
*/
public int getSize() {
return size;
}
public void setValue(Object value) {
if (!(value instanceof Number)) {
throw new IllegalArgumentException("Invalid value type for NumberFixedLength:" + value.getClass());
}
super.setValue(value);
}
/**
* @param obj
* @return true if obj equivalent to this
*/
public boolean equals(Object obj) {
if (!(obj instanceof NumberFixedLength)) {
return false;
}
NumberFixedLength object = (NumberFixedLength) obj;
return this.size == object.size && super.equals(obj);
}
/**
* Read the number from the byte array
*
* @param arr
* @param offset
* @throws NullPointerException
* @throws IndexOutOfBoundsException
*/
public void readByteArray(byte[] arr, int offset) throws InvalidDataTypeException {
if (arr == null) {
throw new NullPointerException("Byte array is null");
}
if ((offset < 0) || (offset >= arr.length)) {
throw new InvalidDataTypeException("Offset to byte array is out of bounds: offset = " + offset + ", array.length = " + arr.length);
}
if (offset + size > arr.length) {
throw new InvalidDataTypeException("Offset plus size to byte array is out of bounds: offset = "
+ offset + ", size = " + size + " + arr.length " + arr.length);
}
long lvalue = 0;
for (int i = offset; i < (offset + size); i++) {
lvalue <<= 8;
lvalue += (arr[i] & 0xff);
}
value = lvalue;
//logger.info("Read NumberFixedlength:" + value);
}
/**
* @return String representation of this datatype
*/
public String toString() {
if (value == null) {
return "";
} else {
return value.toString();
}
}
/**
* Write data to byte array
*
* @return the datatype converted to a byte array
*/
public byte[] writeByteArray() {
byte[] arr;
arr = new byte[size];
if (value != null) {
//Convert value to long
long temp = ID3Tags.getWholeNumber(value);
for (int i = size - 1; i >= 0; i--) {
arr[i] = (byte) (temp & 0xFF);
temp >>= 8;
}
}
return arr;
}
}