File	Doc	Category	Size	Date	Package
NumberVariableLength.java	API Doc	Jaudiotagger 2.0.4	7323	Wed Mar 30 16:12:12 BST 2011	org.jaudiotagger.tag.datatype

NumberVariableLength

• java.lang.Object
  • AbstractDataType

Fields Summary
private static final int	MINIMUM_NO_OF_DIGITS
private static final int	MAXIMUM_NO_OF_DIGITS
int	minLength

Constructors Summary
public NumberVariableLength(String identifier, org.jaudiotagger.tag.id3.AbstractTagFrameBody frameBody, int minimumSize) Creates a new ObjectNumberVariableLength datatype, set minimum length to zero if this datatype is optional. param identifier param frameBody param minimumSize super(identifier, frameBody); //Set minimum length, which can be zero if optional this.minLength = minimumSize;
public NumberVariableLength(NumberVariableLength copy) super(copy); this.minLength = copy.minLength;

Methods Summary
public boolean	equals(java.lang.Object obj) param obj return if (!(obj instanceof NumberVariableLength)) { return false; } NumberVariableLength object = (NumberVariableLength) obj; return this.minLength == object.minLength && super.equals(obj);
public int	getMaximumLenth() Return the maximum number of digits that can be used to express the number return the maximum number of digits that can be used to express the number return MAXIMUM_NO_OF_DIGITS;
public int	getMinimumLength() Return the minimum number of digits that can be used to express the number return the minimum number of digits that can be used to express the number return minLength;
public int	getSize() return the number of bytes required to write this to a file if (value == null) { return 0; } else { int current; long temp = ID3Tags.getWholeNumber(value); int size = 0; for (int i = MINIMUM_NO_OF_DIGITS; i <= MAXIMUM_NO_OF_DIGITS; i++) { current = (byte) temp & 0xFF; if (current != 0) { size = i; } temp >>= MAXIMUM_NO_OF_DIGITS; } return (minLength > size) ? minLength : size; }
public void	readByteArray(byte[] arr, int offset) Read from Byte Array param arr param offset throws NullPointerException throws IndexOutOfBoundsException //Coding error, should never happen if (arr == null) { throw new NullPointerException("Byte array is null"); } //Coding error, should never happen as far as I can see if (offset < 0) { throw new IllegalArgumentException("negativer offset into an array offset:" + offset); } //If optional then set value to zero, this will mean that if this frame is written back to file it will be created //with this additional datatype wheras it didnt exist but I think this is probably an advantage the frame is //more likely to be parsed by other applications if it contains optional fields. //if not optional problem with this frame if (offset >= arr.length) { if (minLength == 0) { value = (long) 0; return; } else { throw new InvalidDataTypeException("Offset to byte array is out of bounds: offset = " + offset + ", array.length = " + arr.length); } } long lvalue = 0; //Read the bytes (starting from offset), the most significant byte of the number being constructed is read first, //we then shift the resulting long one byte over to make room for the next byte for (int i = offset; i < arr.length; i++) { lvalue <<= 8; lvalue += (arr[i] & 0xff); } value = lvalue;
public void	setMinimumSize(int minimumSize) param minimumSize if (minimumSize > 0) { this.minLength = minimumSize; }
public java.lang.String	toString() return String representation of the number if (value == null) { return ""; } else { return value.toString(); }
public byte[]	writeByteArray() Write to Byte Array return the datatype converted to a byte array int size = getSize(); byte[] arr; if (size == 0) { arr = new byte[0]; } else { long temp = ID3Tags.getWholeNumber(value); arr = new byte[size]; //keeps shifting the number downwards and masking the last 8 bist to get the value for the next byte //to be written for (int i = size - 1; i >= 0; i--) { arr[i] = (byte) (temp & 0xFF); temp >>= 8; } } return arr;