AxibugEmuOnline/OtherCore/MyNes.Standard2/MyNes.Core/ComponentAce.Compression.Libs.zlib/Adler32.cs

namespace ComponentAce.Compression.Libs.zlib
{
    internal sealed class Adler32
    {
    	private const int BASE = 65521;

    	private const int NMAX = 5552;

    	internal long adler32(long adler, byte[] buf, int index, int len)
    	{
    		if (buf == null)
    		{
    			return 1L;
    		}
    		long num = adler & 0xFFFF;
    		long num2 = (adler >> 16) & 0xFFFF;
    		while (len > 0)
    		{
    			int num3 = ((len < 5552) ? len : 5552);
    			len -= num3;
    			while (num3 >= 16)
    			{
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num += buf[index++] & 0xFF;
    				num2 += num;
    				num3 -= 16;
    			}
    			if (num3 != 0)
    			{
    				do
    				{
    					num += buf[index++] & 0xFF;
    					num2 += num;
    				}
    				while (--num3 != 0);
    			}
    			num %= 65521;
    			num2 %= 65521;
    		}
    		return (num2 << 16) | num;
    	}
    }
}