sum - Calculate a sum(1) compatible checksum
package require Tcl 8.2
package require sum ?1.1.0?
::crc::sum ?-bsd | -sysv? ?-format
fmt? ?-chunksize size? [ -filename file | -channel
chan | string ]
This package provides a Tcl-only implementation of the sum(1)
command which calculates a 16 bit checksum value from the input data. The
BSD sum algorithm is used by default but the SysV algorithm is also
available.
- ::crc::sum ?-bsd | -sysv? ?-format fmt?
?-chunksize size? [ -filename file | -channel chan |
string ]
- The command takes string data or a file name or a channel and returns a
checksum value calculated using the sum(1) algorithm. The result is
formatted using the format(n) specifier provided or as an unsigned
integer (%u) by default.
- -sysv
- The SysV algorithm is fairly naive. The byte values are summed and any
overflow is discarded. The lowest 16 bits are returned as the checksum.
Input with the same content but different ordering will give the same
result.
- -bsd
- This algorithm is similar to the SysV version but includes a bit rotation
step which provides a dependency on the order of the data values.
- -filename
name
- Return a checksum for the file contents instead of for parameter
data.
- -channel
chan
- Return a checksum for the contents of the specified channel. The channel
must be open for reading and should be configured for binary translation.
The channel will no be closed on completion.
- -chunksize
size
- Set the block size used when reading data from either files or channels.
This value defaults to 4096.
- -format
string
- Return the checksum using an alternative format template.
% crc::sum "Hello, World!"
37287
% crc::sum -format 0x%X "Hello, World!"
0x91A7
% crc::sum -file sum.tcl
13392
This document, and the package it describes, will undoubtedly
contain bugs and other problems. Please report such in the category
crc of the Tcllib SF Trackers
[http://sourceforge.net/tracker/?group_id=12883]. Please also report any
ideas for enhancements you may have for either package and/or
documentation.
cksum(n), crc32(n), sum(1)
checksum, cksum, crc, crc32, cyclic redundancy check, data
integrity, security, sum
Hashes, checksums, and encryption
Copyright (c) 2002, Pat Thoyts <patthoyts@users.sourceforge.net>