'\"
'\" Generated from file 'vt_crc32\&.man' by tcllib/doctools with format 'nroff'
'\" Copyright (c) 2009 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>
'\"
.TH "tcl::transform::crc32" n 1\&.1 tcllib "Reflected/virtual channel support"
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.SH NAME
tcl::transform::crc32 \- Crc32 transformation
.SH SYNOPSIS
package require \fBTcl 8\&.6 9\fR
.sp
package require \fBtcl::transform::core ?1\&.1?\fR
.sp
package require \fBtcl::transform::crc32 ?1\&.1?\fR
.sp
\fB::tcl::transform::crc32\fR \fIchan\fR \fB-option\fR \fIvalue\fR\&.\&.\&.
.sp
.BE
.SH DESCRIPTION
.PP
The \fBtcl::transform::crc32\fR package provides a command
creating a channel transformation which passes the read and written
bytes through unchanged (like \fBtcl::transform::identity\fR), 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\&.
.PP
Related transformations in this module are
\fBtcl::transform::adler32\fR,
\fBtcl::transform::counter\fR,
\fBtcl::transform::identity\fR, and
\fBtcl::transform::observe\fR\&.
.PP
The internal \fBTclOO\fR class implementing the transform
handler is a sub-class of the \fBtcl::transform::core\fR
framework\&.
.SH API
.TP
\fB::tcl::transform::crc32\fR \fIchan\fR \fB-option\fR \fIvalue\fR\&.\&.\&.
This command creates a crc32 checksumming transformation on top of
the channel \fIchan\fR and returns its handle\&. The accepted options are
.RS
.TP
\fB-read-variable\fR varname
The value of the option is the name of a global or namespaced
variable, the location where the transformation has to store the
crc32 checksum of the data read from the channel\&.
.sp
If not specified, or the empty string, the checksum of the read
direction is not saved\&.
.TP
\fB-write-variable\fR varname
The value of the option is the name of a global or namespaced
variable, the location where the transformation has to store the
crc32 checksum of the data written to the channel\&.
.sp
If not specified, or the empty string, the checksum of the
write direction is not saved\&.
.RE
.PP
.SH "BUGS, IDEAS, FEEDBACK"
This document, and the package it describes, will undoubtedly contain
bugs and other problems\&.
Please report such in the category \fIvirtchannel\fR of the
\fITcllib Trackers\fR [http://core\&.tcl\&.tk/tcllib/reportlist]\&.
Please also report any ideas for enhancements you may have for either
package and/or documentation\&.
.PP
When proposing code changes, please provide \fIunified diffs\fR,
i\&.e the output of \fBdiff -u\fR\&.
.PP
Note further that \fIattachments\fR are strongly preferred over
inlined patches\&. Attachments can be made by going to the \fBEdit\fR
form of the ticket immediately after its creation, and then using the
left-most button in the secondary navigation bar\&.
.SH KEYWORDS
channel transformation, checksum, crc32, reflected channel, tip 230, transformation, virtual channel
.SH CATEGORY
Channels
.SH COPYRIGHT
.nf
Copyright (c) 2009 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>

.fi
