BitStuff.java

public class BitStuff {
	/**
	 * Rotates a long.
	 *
	 * @param data       The long to be rotated.
	 * @param amount     The amount to rotate the byte by, if greater than 0, rotate right, if less than 0, rotate left.
	 * @param dataLength The length of the data. If 0, assumes long length (65 bits).
	 * @return The rotated byte.
	 */
	// TODO: optimise?
	public static long rotate(long data, int dataLength, int amount) {
		if (dataLength == 0) dataLength = Long.SIZE;
		if (amount > 0) {
			// Rotate Right
			// Shift the whole thing right.
			long rotated = data >>> amount;
			// Get the chopped off bits and move them.
			long removed = data << dataLength - amount;
			// stick the chopped off bits back on.
			rotated = rotated | removed;
			return rotated;
		} else if (amount < 0) {
			amount = Math.abs(amount);
			// Rotate Left
			// Shift the whole thing left.
			long rotated = data << amount;
			// Get the chopped off bits and move them.
			long removed = data >>> dataLength - amount;
			// stick the chopped off bits back on.
			rotated = rotated | removed;
			return rotated;
		} else {
			// No Rotation
			return data;
		}
	}
	
	/**
	 * Rotates an integer.
	 *
	 * @param data       The integer to be rotated.
	 * @param amount     The amount to rotate the byte by, if greater than 0, rotate right, if less than 0, rotate left.
	 * @param dataLength The length of the data. If 0, assumes integer length (32 bits).
	 * @return The rotated byte.
	 */
	public static int rotate(int data, int dataLength, int amount) {
		if (dataLength == 0) dataLength = Integer.SIZE;
		if (amount > 0) {
			return (data >>> amount) | (data << dataLength - amount);
		} else if (amount < 0) {
			amount = Math.abs(amount);
			return (data << amount) | (data >>> dataLength - amount);
		} else {
			// No Rotation
			return data;
		}
	}
	
	/**
	 * Rotates a short.
	 *
	 * @param data       The integer to be rotated.
	 * @param amount     The amount to rotate the byte by, if greater than 0, rotate right, if less than 0, rotate left.
	 * @param dataLength The length of the data. If 0, assumes short length (16 bits).
	 * @return The rotated byte.
	 */
	public static short rotate(short data, int dataLength, int amount) {
		if (dataLength == 0) dataLength = Short.SIZE;
		if (amount > 0) {
			return (short) ((data >>> amount) | (data << dataLength - amount));
		} else if (amount < 0) {
			amount = Math.abs(amount);
			return (short) ((data << amount) | (data >>> dataLength - amount));
		} else {
			// No Rotation
			return data;
		}
	}

	/**
	 * Rotates a byte.
	 *
	 * @param data       The integer to be rotated.
	 * @param amount     The amount to rotate the byte by, if greater than 0, rotate right, if less than 0, rotate left.
	 * @param dataLength The length of the data. If 0, assumes byte length (8 bits).
	 * @return The rotated byte.
	 */
	public static byte rotate(byte data, int dataLength, int amount) {
		if (dataLength == 0) dataLength = Byte.SIZE;
		if (amount > 0) {
			return (byte) ((data >>> amount) | (data << dataLength - amount));
		} else if (amount < 0) {
			amount = Math.abs(amount);
			return (byte) ((data << amount) | (data >>> dataLength - amount));
		} else {
			// No Rotation
			return data;
		}
	}
}