Files
2011-10-24 00:13:35 +00:00

44 lines
1.0 KiB
C#

namespace CUETools.Codecs
{
public class Crc8
{
private const ushort poly8 = 0x07;
private ushort[] table = new ushort[256];
public Crc8()
{
int bits = 8;
ushort poly = (ushort) (poly8 + (1U << bits));
for (ushort i = 0; i < table.Length; i++)
{
ushort crc = i;
for (int j = 0; j < bits; j++)
{
if ((crc & (1U << (bits - 1))) != 0)
crc = (ushort)((crc << 1) ^ poly);
else
crc <<= 1;
}
table[i] = (ushort)(crc & 0x00ff);
}
}
public byte ComputeChecksum(byte[] bytes, int pos, int count)
{
ushort crc = 0;
for (int i = pos; i < pos + count; i++)
crc = table[crc ^ bytes[i]];
return (byte)crc;
}
public unsafe byte ComputeChecksum(byte* bytes, int pos, int count)
{
ushort crc = 0;
for (int i = pos; i < pos + count; i++)
crc = table[crc ^ bytes[i]];
return (byte)crc;
}
}
}