Minecraft get ID values from blockStates-Array

public static short[] getBlockArray(/*unsigned*/ long[] blockStates)
{
	short[] retVal = new short[4096];
	//The size in bits of every block ID in the blockStates Array. Theoretical maximum is 13.
	final byte bitPerIndex = (byte) (blockStates.length * 64 / 4096);
	int curRefIndex = 0;

	for (int i = 0; i < blockStates.length; ++i)
	{
		/*unsigend*/ long cur = blockStates[i];

		//If the beginning of cur has bits from last iteration, add it to already read bits from last filled index
		int overhang = (bitPerIndex - (i * Long.SIZE /*64*/) % bitPerIndex) % bitPerIndex;
		if(overhang > 0)
		{
			retVal[curRefIndex - 1] |= Long.remainderUnsigned(cur, (1 << (overhang - 1)));
			System.out.print("(" + retVal[curRefIndex - 1] + "), ");
		}
		cur >>>= overhang;

		//Read all reamaining bits, that is ("size of Long" - "already read bits due to overhang") / bitPerIndex ceiled.
		final int remainingBitsToBeRead = Long.SIZE - overhang;
		for(int j = 0; j < (remainingBitsToBeRead + (bitPerIndex - remainingBitsToBeRead % bitPerIndex) % bitPerIndex) / bitPerIndex; ++j)
		{
			retVal[curRefIndex++] = (short) (Long.remainderUnsigned(cur, (1 << (bitPerIndex - 1))));
			cur >>>= bitPerIndex;
		}
	}

	return retVal;
}