1tcl::transform::crc32(n)Reflected/virtual channel supporttcl::transform::crc32(n)
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NAME

8       tcl::transform::crc32 - Crc32 transformation
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SYNOPSIS

11       package require Tcl  8.6
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13       package require tcl::transform::core  ?1?
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15       package require tcl::transform::crc32  ?1?
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17       ::tcl::transform::crc32 chan -option value...
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DESCRIPTION

22       The tcl::transform::crc32 package provides a command creating a channel
23       transformation which passes the read  and  written  bytes  through  un‐
24       changed  (like tcl::transform::identity), but additionally continuously
25       computes the crc32 checksums of the data it has seen for each direction
26       and  stores  them  in Tcl variables specified at construction time. The
27       checksum in question is zlib's crc32.
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29       Related transformations in  this  module  are  tcl::transform::adler32,
30       tcl::transform::counter,   tcl::transform::identity,   and  tcl::trans‐
31       form::observe.
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33       The internal TclOO class implementing the transform handler is  a  sub-
34       class of the tcl::transform::core framework.
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API

37       ::tcl::transform::crc32 chan -option value...
38              This  command creates a crc32 checksumming transformation on top
39              of the channel chan and returns its handle. The accepted options
40              are
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42              -read-variable varname
43                     The value of the option is the name of a global or names‐
44                     paced variable, the location where the transformation has
45                     to  store  the  crc32  checksum of the data read from the
46                     channel.
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48                     If not specified, or the empty string,  the  checksum  of
49                     the read direction is not saved.
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51              -write-variable varname
52                     The value of the option is the name of a global or names‐
53                     paced variable, the location where the transformation has
54                     to  store  the  crc32 checksum of the data written to the
55                     channel.
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57                     If not specified, or the empty string,  the  checksum  of
58                     the write direction is not saved.
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BUGS, IDEAS, FEEDBACK

61       This  document,  and the package it describes, will undoubtedly contain
62       bugs and other problems.  Please report such in the category  virtchan‐
63       nel  of  the  Tcllib  Trackers  [http://core.tcl.tk/tcllib/reportlist].
64       Please also report any ideas for enhancements you may have  for  either
65       package and/or documentation.
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67       When proposing code changes, please provide unified diffs, i.e the out‐
68       put of diff -u.
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70       Note further that  attachments  are  strongly  preferred  over  inlined
71       patches.  Attachments  can  be  made  by  going to the Edit form of the
72       ticket immediately after its creation, and  then  using  the  left-most
73       button in the secondary navigation bar.
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KEYWORDS

76       channel  transformation,  checksum,  crc32, reflected channel, tip 230,
77       transformation, virtual channel
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CATEGORY

80       Channels
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83       Copyright (c) 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>
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88tcllib                                 1              tcl::transform::crc32(n)
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