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<h1 class="title">tcl::transform::crc32(n) 1 tcllib &quot;Reflected/virtual channel support&quot;</h1>
<div id="name" class="section"><h2><a name="name">Name</a></h2>
<p>tcl::transform::crc32 - Crc32 transformation</p>
</div>
<div id="toc" class="section"><h2><a name="toc">Table Of Contents</a></h2>
<ul class="toc">
<li class="section"><a href="#toc">Table Of Contents</a></li>
<li class="section"><a href="#synopsis">Synopsis</a></li>
<li class="section"><a href="#section1">Description</a></li>
<li class="section"><a href="#section2">API</a></li>
<li class="section"><a href="#section3">Bugs, Ideas, Feedback</a></li>
<li class="section"><a href="#keywords">Keywords</a></li>
<li class="section"><a href="#category">Category</a></li>
<li class="section"><a href="#copyright">Copyright</a></li>
</ul>
</div>
<div id="synopsis" class="section"><h2><a name="synopsis">Synopsis</a></h2>
<div class="synopsis">
<ul class="requirements">
<li>package require <b class="pkgname">Tcl 8.6</b></li>
<li>package require <b class="pkgname">tcl::transform::core <span class="opt">?1?</span></b></li>
<li>package require <b class="pkgname">tcl::transform::crc32 <span class="opt">?1?</span></b></li>
</ul>
<ul class="syntax">
<li><a href="#1"><b class="cmd">::tcl::transform::crc32</b> <i class="arg">chan</i> <b class="option">-option</b> <i class="arg">value</i>...</a></li>
</ul>
</div>
</div>
<div id="section1" class="section"><h2><a name="section1">Description</a></h2>
<p>The <b class="package">tcl::transform::crc32</b> package provides a command
creating a channel transformation which passes the read and written
bytes through unchanged (like <b class="package"><a href="identity.html">tcl::transform::identity</a></b>), 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.</p>
<p>Related transformations in this module are
<b class="package"><a href="adler32.html">tcl::transform::adler32</a></b>,
<b class="package"><a href="vt_counter.html">tcl::transform::counter</a></b>,
<b class="package"><a href="identity.html">tcl::transform::identity</a></b>, and
<b class="package"><a href="observe.html">tcl::transform::observe</a></b>.</p>
<p>The internal <b class="package"><a href="../../../../index.html#key765">TclOO</a></b> class implementing the transform
handler is a sub-class of the <b class="package"><a href="../virtchannel_core/transformcore.html">tcl::transform::core</a></b>
framework.</p>
</div>
<div id="section2" class="section"><h2><a name="section2">API</a></h2>
<dl class="definitions">
<dt><a name="1"><b class="cmd">::tcl::transform::crc32</b> <i class="arg">chan</i> <b class="option">-option</b> <i class="arg">value</i>...</a></dt>
<dd><p>This command creates a crc32 checksumming transformation on top of
the channel <i class="arg">chan</i> and returns its handle. The accepted options are</p>
<dl class="options">
<dt><b class="option">-read-variable</b> varname</dt>
<dd><p>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.</p>
<p>If not specified, or the empty string, the checksum of the read
direction is not saved.</p></dd>
<dt><b class="option">-write-variable</b> varname</dt>
<dd><p>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.</p>
<p>If not specified, or the empty string, the checksum of the
write direction is not saved.</p></dd>
</dl></dd>
</dl>
</div>
<div id="section3" class="section"><h2><a name="section3">Bugs, Ideas, Feedback</a></h2>
<p>This document, and the package it describes, will undoubtedly contain
bugs and other problems.
Please report such in the category <em>virtchannel</em> of the
<a href="http://core.tcl.tk/tcllib/reportlist">Tcllib Trackers</a>.
Please also report any ideas for enhancements you may have for either
package and/or documentation.</p>
</div>
<div id="keywords" class="section"><h2><a name="keywords">Keywords</a></h2>
<p><a href="../../../../index.html#key275">channel transformation</a>, <a href="../../../../index.html#key150">checksum</a>, <a href="../../../../index.html#key147">crc32</a>, <a href="../../../../index.html#key47">reflected channel</a>, <a href="../../../../index.html#key276">tip 230</a>, <a href="../../../../index.html#key277">transformation</a>, <a href="../../../../index.html#key44">virtual channel</a></p>
</div>
<div id="category" class="section"><h2><a name="category">Category</a></h2>
<p>Channels</p>
</div>
<div id="copyright" class="section"><h2><a name="copyright">Copyright</a></h2>
<p>Copyright &copy; 2009 Andreas Kupries &lt;andreas_kupries@users.sourceforge.net&gt;</p>
</div>
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