misc/libphysfs/lzma/Java/SevenZip/CRC.java
author nemo
Mon, 10 Apr 2017 12:06:43 -0400
changeset 12218 bb5522e88ab2
permissions -rw-r--r--
bulk copy of latest physfs to our misc/libphysfs since this seems to fix an off-by-1 error reliably hit in readln read of 1 byte probably introduced in the addition of the buffered read. Whether this is excessive or whether libphysfs should even be maintained by us is another matter. But at least we shouldn't crash

// SevenZip/CRC.java

package SevenZip;

public class CRC
{
	static public int[] Table = new int[256];
	
	static
	{
		for (int i = 0; i < 256; i++)
		{
			int r = i;
			for (int j = 0; j < 8; j++)
				if ((r & 1) != 0)
					r = (r >>> 1) ^ 0xEDB88320;
				else
					r >>>= 1;
			Table[i] = r;
		}
	}
	
	int _value = -1;
	
	public void Init()
	{
		_value = -1;
	}
	
	public void Update(byte[] data, int offset, int size)
	{
		for (int i = 0; i < size; i++)
			_value = Table[(_value ^ data[offset + i]) & 0xFF] ^ (_value >>> 8);
	}
	
	public void Update(byte[] data)
	{
		int size = data.length;
		for (int i = 0; i < size; i++)
			_value = Table[(_value ^ data[i]) & 0xFF] ^ (_value >>> 8);
	}
	
	public void UpdateByte(int b)
	{
		_value = Table[(_value ^ b) & 0xFF] ^ (_value >>> 8);
	}
	
	public int GetDigest()
	{
		return _value ^ (-1);
	}
}