Short:    V1.17 calculates different checksums
Author:   stoecker@epost.de (Dirk Stoecker)
Uploader: stoecker@epost.de (Dirk Stoecker)
Version:  1.17
Type:     dev/c

This program has 2 aims. First it allows to calculate different types
of checksums including CRC and much other types and thus allows to
identify a given checksum. Second its source code shows how to create
these checksums, so they can be used in own projects.

It is plain and portable ANSI-C code. The program is called like
"GetCRC <filename>" and prints the resulting checksums of this file.

Text modes aren't supported, but it always uses binary mode. The file
must fit completely in memory. These are no restrictions to the
algorithms, but are restrictions of using all of them in one program.

When choosing own algorithms, I suggest usage of "CRC-32 2", which
is one of the reliable standard algorithms.

In the output the lines with (M/I) always have two numbers, where
the first is Motorola byte ordering and the second Intel byte
ordering. The Word and Longword checksums can't be calculated, if the
file size isn't a multiple of 2 or 4. GetCRC calculates the checksum
of the largest part, which is such an multiple and prints the
additional bytes after the checksum. Depending on the checksum generator
such bytes are either ignored, added to the higher bytes or added to
the lower bytes of the result.

Here is the list of currently supported checksums. It also includes
a list, where these are used. Tell me other places, so I may update
this list. Send me new algorithms, source comments, better or different
calculation methods, ...

CRC-16 1          : PCompress2, Arc, DMS, ProPack, LhA, Zoo, Shrink
CRC-16 2          : CCITT, XModem, LU
CRC-16 3          : Donald Kindred's CRC
CRC-16 4          : old Zoom, CompDisk
CRC-32 1          : Olaf Barthel's CRC, PCompress, Zoom 5, LhPak
CRC-32 2          : Zip, GZip, LZX, RAR, Arj
CRC-32 3          : Brik (Binary mode), Ace
CRC-32 4          : GPatch
CRC-32 5          : BZip2
CRC-32 6          : BZip2 inverted
CHS-16 1          : PowerPacker Passwords
CHS-32 1M (WRAP)  : Olaf Barthel's CRC, Bootblock of OFS/FFS
CHS-32 1I         : 
CHS-32 2          : LightFileSystem
EOR Byte          : 
EOR Word (M/I)    : 
EOR Long (M/I)    : ByteKiller, RSI-Packer
Sum Byte Signed   : 
Sum Byte Unsigned : SQ
Sum Word Si (M/I) : 
Sum Word Un (M/I) : 
Sum Long M	  : Root-, Bitmap-, File-, Datablock of OFS/FFS
Sum Long I        : 
md4sum            : EDonkey, Samba
md5sum            : 

GetCRC maybe used to calculate only one CRC and only print this one.
This is done by passing a number as 3rd argument. Currently only the
CRC's and checksums are supported:

  CRC-16 x: 161, 162, 163, 164
  CRC-32 x: 321, 322, 323, 324, 325, 326
  CHS-16 x: 401
  CHS-32 x: 5010, 5011, 502

The result is the checksum printed to output without carriage return
or anything else. This maybe used in scripts, with pipes and ...

Use this tool as you want, but WITHOUT ANY WARRANTY!

Contact me at:

*********************************************************************
* snail-mail:                  * e-mail:                            *
*   Dirk Stoecker              *   stoecker@epost.de                *
*   Geschwister-Scholl-Str. 10 *   dirk@dstoecker.de                *
*   01877 Bischofswerda        * world wide web:                    *
*   GERMANY                    *   http://www.dstoecker.de/         *
* phone:                       * pgp key:                           *
*   GERMANY +49 (0)3594/706666 *   get from WWW pages or keyservers *
*********************************************************************