On Wed, Mar 14, 2007 at 12:37:15PM +0100, Paolo Pasquali wrote:
> Hi to all,
> I'm doing an application to off-line analyze and edit a generic DVB TS. I
> have a lot og problems with CRC32 calculation on PSI/SI tables.
> I'm using a fast calculation CRC32:
>
> poly: 0x04c11db7
>
> table: 0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc,
> 0x17c56b6b, etc.............
>
> algorithm:
>
> public long CRC(byte[] by)
> {
> ulong ulCRC = 0xFFFFFFFF;
> long len;
> len = by.Length;
> for(long i = 0; i < len; i++)
> {
>
>
> ulCRC = (ulCRC >> 8) ^ crcLookup[by[i] ^ (ulCRC & 0xFF) ];
> }
> return Convert.ToInt64( ulCRC ^ 0xFFFFFFFF);
> }
>
Try this:
for (i = 0; i < len; ++i)
CRC = (CRC<<8) ^ crc_tab[((CRC>>24)^*p++) &0xff];
Wolfgang
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