Re: crc32 routines

 BBS: Inland Empire Archive
Date: 10-07-92 (16:19)             Number: 389
From: JIM BREWER                   Refer#: NONE
  To: RICH GELDREICH                Recvd: NO  
Subj: Re: crc32 routines             Conf: (2) Quik_Bas
->   That'll make it work in the environment- but it'll slow the entire
-> CRC calculation down when compiled. When you compile it, put back the
-> CINT(), it does make a difference(a small but noticable one).

        Rich, I found with the CINT in the calculation that
it gives erroneous results.

Program               File      CRC32       Execution time -------
  ------ -------------- --------------- CRC32 (w/o CINT)
 QB.EXE CRC32=B08BC0FE 14.8 seconds CRC32 (w/ CINT)
QB.EXE CRC32=ABA9EE21 13.3 seconds QBCRC32 (my routine)
QB.EXE CRC32=B08BC0FE 2.6 seconds PKZip
QB.EXE CRC32=B08BC0FE N/A

        It is faster with CINT (1.5 seconds on QB.EXE), but
the resulting CRC is wrong.

        The routine I use for CRC32 calculations is
available for F'req/download as QBCRC32.ZIP (12.5K) from
below if you would like to use it for comparison.


                                                Jim Brewer

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