NAME

       tcl::transform::counter - Counter transformation

SYNOPSIS

       package require Tcl  8.6

       package require tcl::transform::core  ?1?

       package require tcl::transform::counter  ?1?

       ::tcl::transform::counter chan -option value...

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DESCRIPTION

       The  tcl::transform::counterr package provides a command creating a channel transformation
       which passes the read and written bytes through unchanged (like tcl::transform::identity),
       but  additionally  counts the bytes it has seen for each direction and stores these counts
       in Tcl variables specified at construction time.

       Related transformations in this module are tcl::transform::adler32, tcl::transform::crc32,
       tcl::transform::identity, and tcl::transform::observe.

       The  internal  TclOO  class  implementing  the  transform  handler  is  a sub-class of the
       tcl::transform::core framework.

API

       ::tcl::transform::counter chan -option value...
              This command creates a counter 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 namespaced variable, the
                     location where the transformation has to store the byte count  of  the  data
                     read from the channel.

                     If  not specified, or the empty string, the counter of the read direction is
                     not saved.

              -write-variable varname
                     The value of the option is the name of a global or namespaced variable,  the
                     location  where  the  transformation has to store the byte count of the data
                     written to the channel.

                     If not specified, or the empty string, the counter 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  virtchannel  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 output 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, counter,  reflected  channel,  tip  230,  transformation,  virtual
       channel

CATEGORY

       Channels

COPYRIGHT

       Copyright (c) 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>