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

73 lines
1.7 KiB
C#

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;
}
}
}