tcl::transform::crc32(3Reflected/virtual channel sutcl::transform::crc32(3tcl)
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NAME
tcl::transform::crc32 - Crc32 transformation
SYNOPSIS
package require Tcl 8.6
package require tcl::transform::core ?1?
package require tcl::transform::crc32 ?1?
::tcl::transform::crc32 chan -option value...
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DESCRIPTION
The tcl::transform::crc32 package provides a command creating a channel
transformation which passes the read and written bytes through un-
changed (like tcl::transform::identity), but additionally continuously
computes the crc32 checksums of the data it has seen for each direction
and stores them in Tcl variables specified at construction time. The
checksum in question is zlib's crc32.
Related transformations in this module are tcl::transform::adler32,
tcl::transform::counter, tcl::transform::identity, and tcl::trans-
form::observe.
The internal TclOO class implementing the transform handler is a sub-
class of the tcl::transform::core framework.
API
::tcl::transform::crc32 chan -option value...
This command creates a crc32 checksumming transformation on top
of the channel chan and returns its handle. The accepted options
are
-read-variable varname
The value of the option is the name of a global or names-
paced variable, the location where the transformation has
to store the crc32 checksum of the data read from the
channel.
If not specified, or the empty string, the checksum of
the read direction is not saved.
-write-variable varname
The value of the option is the name of a global or names-
paced variable, the location where the transformation has
to store the crc32 checksum of the data written to the
channel.
If not specified, or the empty string, the checksum of
the write direction is not saved.
BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain
bugs and other problems. Please report such in the category virtchan-
nel of the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist].
Please also report any ideas for enhancements you may have for either
package and/or documentation.
When proposing code changes, please provide unified diffs, i.e the out-
put of diff -u.
Note further that attachments are strongly preferred over inlined
patches. Attachments can be made by going to the Edit form of the
ticket immediately after its creation, and then using the left-most
button in the secondary navigation bar.
KEYWORDS
channel transformation, checksum, crc32, reflected channel, tip 230,
transformation, virtual channel
CATEGORY
Channels
COPYRIGHT
Copyright (c) 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>
tcllib 1 tcl::transform::crc32(3tcl)